Abstract
Objective
The objective of the study was to clarify the associations of HLA class I and II alleles with ankylosing spondylitis (AS) among Chinese Han.
Methods
We performed HLA genotyping and Sanger sequencing for 68 HLA‐B*27(−), 62 HLA‐B*27(+) AS patients, and 70 controls. Case–control analyses and separate analyses of HLA‐B*27(−) patients were performed. One‐way ANOVA and Kruskal–Wallis multiple comparisons test were used to analyze the effects of HLA‐A\B\C\DRB1\DQB1 alleles on clinical characteristics of HLA‐B*27(−) and HLA‐B*27(+) patients.
Results
In the HLA‐B*27(+) group, positive associations were seen with A*11:02, B*27:04, B*27:05, C*02:02, C*12:02, and DRB1*04:01 and negative associations were seen with A*33:03, B*07:02, B*57:01, and C*07:02. The age at onset was greater in HLA‐B*27(−) patients than in HLA‐B*27(+) patients (30.03 ± 15.15 vs. 23.08 ± 7.79 years). In the HLA‐B*27(−) group, those with A*01:01, B*13:01, B*13:02, C*01:02, C*04:01, DQB1*02:01, DQB1*06:01, and DRB1*03:01 had an earlier onset than those without these alleles, while patients carrying B*40:02, C*07:02, C*12:02, C*15:02, DQB1*05:02, and DQB1*05:03 had a delayed onset. In the HLA‐B*27(−) group, A*32:01(+), C*08:01(+), and DRB1*04:05(−) women were likely to develop AS. In the HLA‐B*27(+) group, DQB1*03:02(+) women may be more likely to develop AS. DRB1*12:02 and HLA‐B*27 interacted with the distribution of AS‐affected sites. In the HLA‐B*27(+) group, DRB1*12:02(+) patients were likely to have peripheral joint involvement.
Conclusion
HLA class I and II alleles other than HLA‐B*27 contribute to AS predisposition and characteristics among Chinese Han patients.
Keywords: ankylosing spondylitis, Chinese Han, HLA allele typing, Sanger sequencing, susceptibility
Some alleles of HLA‐I and HLA‐II other than HLA‐B*27 are associated with the onset of AS. HLA‐B*27‐positive patients show ankylosing spondylitis symptoms earlier. Some alleles of HLA‐I and HLA‐II affect the onset age of ankylosing spondylitis in HLA‐B*27(−) group. DRB1*12:02 and HLA‐B*27 interacted with the distribution of AS‐affected sites.
1. INTRODUCTION
Ankylosing spondylitis (AS) is a common chronic arthritic disease caused by immune abnormalities. AS mainly involves the sacroiliac, spinal, and other axial joints, but can also affect the peripheral joints, ends of tendons, and other joints. 1 Low back pain and morning stiffness are the early symptoms of AS; spinal stiffness and deformity may occur in advanced stages, seriously impairing patients' ability to work, their quality of life, and financial situation. 2 The clinical diagnosis of AS is mainly based on its symptoms, signs, and imaging findings. However, due to its slow and insidious onset, obvious sacroiliac joint destruction is rarely observed on imaging in the early stage, which can seriously delay diagnosis and treatment, and impact patients' prognosis.
Based on long‐term research findings, AS is a hereditary disease caused by multiple genes, which have a heritability of >90%. 3 Therefore, understanding the susceptibility genes of AS is crucial for studying its pathogenesis and exploring new treatments. Susceptibility to AS is mainly attributed to genetic factors, among which the human leukocyte antigen (HLA) system, plays an important role in immune regulation, and is most closely related to AS. The British scientists Brewerton et al. first reported a correlation between HLA‐B*27 and AS in 1973. 4 Since then, studies have confirmed that the occurrence of AS is closely related to HLA‐B*27, and the rate of HLA‐B*27 positivity among AS patients can reach 95%. 5 However, the incidence of AS among people who are HLA‐B*27‐positive is only 2%–5%, 6 suggesting HLA‐B*27 is not the only factor that determines the occurrence of AS, and other HLA alleles may also play an important role in AS. 7
Until now, 209 individual major histocompatibility complex (MHC) genes have been referenced in the Immuno Polymorphism Database–international ImMunoGeneTics project/HLA database (IPD–IMGT/HLA; version 3.9.0.1). Numerous studies have confirmed the correlation between HLA‐B*27 and AS in Chinese population. 8 , 9 , 10 In the present study, we constructed a genoset for 5 MHC genes, namely HLA‐A, HLA‐B, HLA‐C, HLA‐DQB1, and HLA‐DRB1, in the Chinese Han population, by analyzing samples from AS patients (both HLA‐B*27‐negative and HLA‐B*27‐positive cases) and control subjects. We aimed to identify novel alleles associated with AS in Chinese Han population and find the effects of these alleles on occurrence of AS, age at onset, gender distribution, and disease site involvement in AS independent of the HLA‐B*27. Our findings may enable clinicians to learn about HLA alleles other than HLA‐B*27 that predispose to AS and about other effects that these alleles may have on AS.
2. MATERIALS AND METHODS
2.1. Research subjects
We collected 68 cases of HLA‐B*27‐negative AS (HLA‐B*27(−) group), 62 cases of HLA‐B*27‐positive AS (HLA‐B*27(+) group), and 70 matched healthy controls. A total of 130 AS patients were named mixed samples when conducting statistical analysis. The patients were recruited from the inpatients of China‐Japan Friendship Hospital between 2018.2 and 2021.2, and all subjects (cases and controls) were of Chinese Han ethnicity. All the involved researchers signed the relevant informed consent forms.
All patients were diagnosed with AS according to the strict diagnostic criteria issued by the American Rheumatology Association in 1987. The diagnoses were made by senior physicians, after excluding other autoimmune diseases. Inclusion criteria for AS group: All patients met the AS diagnostic criteria of the New York diagnostic criteria revised by the American Society of Rheumatology in 1984. Exclusion criteria for AS group: other types of spinal arthritis and other rheumatic immune diseases. Inclusion criteria for the healthy controls: matched with geographic region, age, and gender of AS. Exclusion criteria for the healthy controls: chronic arthritis, chronic back inflammatory disease, family history of spinal arthritis, and history of rheumatic immune disease.
Blood samples and clinical data were collected from the patients. The study protocol was reviewed and approved by the Human Experiment Ethics Committee of China‐Japan Friendship Hospital (ethics number: 2021‐106‐K67). In addition, the study was conducted in accordance with the principles of the Declaration of Helsinki.
2.2. Nucleic acid extraction
DNA was extracted from the collected blood samples by using the magnetic bead method. DNA binding and purification were performed using superparamagnetic magnetic beads precoated with silica (Xi'an Tianlong Nucleic Acid Extraction Reagent; lot: 21072810 T148). According to the manufacturer's instructions, 200 μL of whole blood, 15 μL of proteinase K solution, and 60 μL of nucleic acid release agents were mixed and placed in a nucleic acid extractor (Xi'an Tianlong Automatic Nucleic Acid Extraction instrument; model: NP968‐C). The extracted DNA was assessed using a K5500plus DNA concentration analyzer, and samples with concentrations above 30 ng/μl and OD260/OD280 between 1.7 and 1.9 were selected for further analysis.
2.3. Sanger sequencing
HLA gene sequence information obtained from the European Bioinformatics Institute (EBI) database and the IPD–IMGT/HLA database, we designed amplification primers and sequencing primers to detect different sites on 5 HLA genes: the 2nd, 3rd, and 4th exons of HLA‐A, HLA‐B, and HLA‐C; the 2nd and 3rd exons of HLA‐DQB1; and the 2nd exon of HLA‐DRB1. According to the following reaction system, the exons involved in the above five loci were amplified separately, with one exon amplified for each reaction.
Reaction system:
| Components | Dosage (μL) |
|---|---|
| GC Buffer (lot:210314001, Tianjin SUPER BIOTECHNOLOGY Developing Co., Ltd.) | 43.5 |
| LA Taq (lot:AL12591A, Takara Biotechnology (Dalian) Co., Ltd.) | 0.5 |
| Specific primer | 1 |
| DNA | 5 |
Reaction procedure:
| Step | Temperature and Time | Number of cycles |
|---|---|---|
| 1 | 96°C/2 min | 1 |
| 2 | 96°C/20 s, 68°C/60 s | 5 |
| 3 | 96°C/20 s, 64°C/50 s, 72°C/90 s | 10 |
| 4 | 96°C/20 s, 61°C/50 s, 72°C/90 s | 25 |
| 5 | 72°C/5 min | 1 |
| 6 | 4°C st |
After amplifying the target fragments (PCR instrument: Hangzhou Bori Life ECO), we used 2.5% agarose gels (electrophoresis instrument: Beijing Junyi Oriental JY300C) for identification. After confirming that the product bands were uniform and the brightness were sufficient, we identified the remaining products and sequencing primers via Sanger sequencing(GENERAL Biosystems (Anhui) Co., Ltd.). The sequencing maps were interpreted using uTYPE7.0 software.
2.4. Statistical analysis
The chi‐square test was used to analyze and compare patients' age, gender, age of AS onset, duration of disease, incidence of uveitis, and involved joints (axial joints only, peripheral joints only, and both axial and peripheral joints) between the HLA‐B*27(−) and HLA‐B*27(+) AS patients. Univariate regression analysis was used to show the correlations between different alleles of the five HLA genes tested in the 130 AS patients and the incidence of AS. Interaction effects between each allele and HLA‐B*27 in relation to AS were examined using stratified models where the effects of each allele on AS were estimated for HLA‐B*27(−) and HLA‐B*27(+) groups separately. One‐way analysis of variance (ANOVA) was used to analyze the effects of the HLA alleles on the age of AS onset in the HLA‐B*27(−) and HLA‐B*27(+) groups. The Kruskal–Wallis multiple comparisons test was used to compare the effects of the HLA alleles on sex distribution and the disease sites between the HLA‐B*27(−) and HLA‐B*27(+) groups. SPSS version 22.0 was used for all statistical analyses. p < 0.05 was considered statistically significant.
3. RESULTS
The age at enrollment in the study, disease duration, incidence of uveitis, and joint involvement did not significantly differ between the HLA‐B*27(−) and HLA‐B*27(+) groups. There were significantly more male AS patients (98/130, 75.38%) than female AS patients (32/130, 24.62%), which is consistent with the more common occurrence of AS in male patients. The proportion of female patients (23/68, 33.82%) was significantly higher in the HLA‐B*27(−) group than in the HLA‐B*27(+) group (9/62, 14.52%; p < 0.05). The average age at AS onset was significantly higher in the HLA‐B*27(−) group (30.03 ± 15.15 years) than in the HLA‐B*27(+) group (23.08 ± 7.79 years, p < 0.01), which suggests HLA‐B*27 may affect the age of AS onset, and patients carrying the HLA‐B*27 gene may develop AS at a younger age (Table 1).
TABLE 1.
Demographic, clinical, and laboratory characteristics of 130 AS patients.
| HLA‐B27 (−) | HLA‐B27 (+) | |
|---|---|---|
| Sex (Male/Female)* | 45/23 | 53/9 |
| Age (years) | 39.18 (17.84) a | 34.81 (12.42) a |
| Age at AS onset (years)* | 30.03 (15.15) a | 23.08 (7.79) a |
| Disease duration at study entry b (years) | 9.13 (9.32) a | 11.73 (10.82) a |
| With uveitis (%) | 4 (5.88%) | 7 (11.29%) |
| Axial joint (%)/Peripheral joint (%)/both (%) | 38/10/20 | 32/10/19 |
Mean ± SD in parentheses.
Duration of RA at time of entry to longitudinal study.
p < 0.05 was considered to be statistically significant.
Univariate analysis was used to reveal correlations between the different HLA alleles carried by the 130 AS patients. The results showed the following alleles were positively correlated with the incidence of AS: HLA‐A*02:01 (OR: 1.85, 95% CI: 1.01–3.38, p < 0.05; Table 2A), HLA‐B*27:04 (OR: 11.09, 95% CI: 2.63–46.79, p < 0.01), HLA‐B*27:05 (OR: 14.79, 95% CI: 1.98–110.33, p < 0.01; Table 2B), HLA‐C*02:02 (OR: 11.58, 95% CI: 1.54–87.25, p < 0.05), and HLA‐C*12:02 (OR: 4.94, 95% CI: 1.71–14.26, p < 0.01; Table 2C). This indicated that people who carry the above genes are more likely to develop AS. HLA‐A*33:03 (OR: 0.32, 95% CI: 0.12–0.86, p < 0.05; Table 2A) was negatively correlated with the incidence of AS, suggesting that this gene may play a protective role and reduce the incidence of AS.
TABLE 2.
HLA class I and II allele frequencies among AS patients and healthy controls.
| Allele | Univariable model | Stratified model | ||||
|---|---|---|---|---|---|---|
| B27(−) | B27(+) | |||||
| OR | p‐value | OR | p‐value | OR | p‐value | |
| (A) HLA‐A allele frequencies among AS patients and controls | ||||||
| A*01:01 | 0.62 | >0.05 | 0.97 (0.28–3.43) | >0.05 | 2.26 (0.43–11.86) | >0.05 |
| A*02:01 | 1.85 (1.01–3.38) | <0.05* | 2.48 (1.29–4.77) | <0.05* | 0.87 (0.42–1.82) | >0.05 |
| A*02:03 | 0.64 (0.19–2.13) | >0.05 | 1.22 (0.32–4.65) | >0.05 | 2.26 (0.43–11.86) | >0.05 |
| A*02:05 | 1.08 (0.10–11.99) | >0.05 | 0.95 (0.06–15.34) | >0.05 | 0.89 (0.06–14.30) | >0.05 |
| A*02:06 | 1.00 (0.39–2.57) | >0.05 | 0.84 (0.30–2.39) | >0.05 | 1.25 (0.39–4.05) | >0.05 |
| A*02:07 | 0.52 (0.23–1.18) | >0.05 | 1.73 (0.66–4.53) | >0.05 | 2.23 (0.76–6.52) | >0.05 |
| A*03:01 | 1.79 (0.57–5.60) | >0.05 | 0.77 (0.20–2.93) | >0.05 | 0.43 (0.13–1.45) | >0.05 |
| A*11:01 | 0.76 (0.45–1.28) | >0.05 | 1.61 (0.85–3.03) | >0.05 | 1.09 (0.60–1.99) | >0.05 |
| A*11:02 | 4.53 (1.03–19.97) | <0.05* | 0.64 (011–3.91) | >0.05 | 8.08 (1.79–36.56) | <0.05* |
| A*11:03 | — | >0.05 | — | — | — | — |
| A*24:02 | 0.92 (0.52–1.62) | >0.05 | 0.08 (0.02–0.35) | <0.05* | — | — |
| A*24:03 | 0.54 (0.03–8.65) | >0.05 | 0.05 (0.01–0.41) | <0.05* | 0.03 (0.00–0.25) | <0.05* |
| A*24:07 | 0.54 (0.03–8.65) | >0.05 | 0.24 (0.03–2.15) | >0.05 | 0.44 (0.04–4.90) | >0.05 |
| A*24:20 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| A*26:01 | 1.64 (0.44–6.15) | >0.05 | 2.96 (0.30–28.78) | >0.05 | 2.69 (0.28–26.23) | >0.05 |
| A*30:01 | 1.31 (0.55–3.05) | >0.05 | 8.18 (1.01–66.33) | 0.05 | — | — |
| A*31:01 | 0.52 (0.19–1.43) | >0.05 | 2.00 (0.59–6.80) | >0.05 | 7.46 (0.92–60.47) | >0.05 |
| A*32:01 | 2.73 (0.32–23.56) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| A*33:03 | 0.32 (0.12–0.86) | <0.05* | 2.23 (0.76–6.61) | >0.05 | 2.56 (0.79–8.25) | >0.05 |
| A*68:01 | — | — | 0.24 (0.03–2.15) | >0.05 | 19.13 (2.49–147.07) | <0.05* |
| A*68:02 | — | — | — | — | — | — |
| (B) HLA‐B allele frequencies among AS patients and controls | ||||||
| B*07:02 | 0.53 (0.11–2.68) | >0.05 | 1.47 (0.24–8.92) | >0.05 | 2.69 (0.28–26.23) | >0.05 |
| B*08:01 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| B*13:01 | 1.00 (0.39–2.57) | >0.05 | 0.74 (0.27–2.05) | >0.05 | 1.58 (0.45–5.53) | >0.05 |
| B*13:02 | 0.80 (0.35–1.82) | >0.05 | 1.67 (0.59–4.72) | >0.05 | 0.98 (0.39–2.50) | >0.05 |
| B*15:01 | 0.52 (0.19–1.42) | >0.05 | 1.12 (0.39–3.17) | >0.05 | 7.46 (0.92–60.47) | >0.05 |
| B*15:02 | 0.64 (0.19–2.13) | >0.05 | 0.97 (0.28–3.43) | >0.05 | 4.56 (0.53–39.54) | >0.05 |
| B*15:08 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| B*15:11 | 0.72 (0.16–3.23) | >0.05 | 0.97 (0.19–4.90) | >0.05 | 2.69 (0.28–26.23) | >0.05 |
| B*15:12 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| B*15:18 | 0.27 (0.02–2.96) | >0.05 | — | — | 1.78 (0.16–19.90) | >0.05 |
| B*15:25 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| B*15:27 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| B*27:04 | 11.09 (2.63–46.79) | <0.05* | — | — | 28.23 (6.63–120.19) | <0.05* |
| B*27:05 | 14.79 (1.98–110.33) | <0.05* | — | — | 35.10 (4.68–263.67) | <0.05* |
| B*27:07 | — | >0.05 | — | — | — | >0.05 |
| B*35:03 | 1.08 (0.10–11.99) | >0.05 | 0.97 (0.06–15.69) | >0.05 | 0.89 (0.06–14.30) | >0.05 |
| B*35:08 | — | >0.05 | — | — | — | >0.05 |
| B*37:01 | 0.27 (0.02–2.96) | >0.05 | 1.96 (0.18–21.83) | >0.05 | — | — |
| B*38:01 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| B*38:02 | 0.80 (0.22–2.90) | >0.05 | 0.77 (0.20–2.93) | >0.05 | 3.62 (0.40–32.81) | >0.05 |
| B*39:01 | 1.35 (0.26–7.07) | >0.05 | 0.38 (0.07–1.99) | >0.05 | — | — |
| B*39:09 | — | >0.05 | — | — | — | >0.05 |
| B*40:01 | 0.47 (0.22–1.01) | >0.05 | 1.18 (0.49–2.83) | >0.05 | 0.83 (0.88–8.96) | >0.05 |
| B*40:02 | 0.53 (0.13–2.16) | >0.05 | 1.97 (0.36–10.94) | >0.05 | 1.79 (0.32–9.97) | >0.05 |
| B*40:03 | — | >0.05 | — | >0.05 | — | >0.05 |
| B*40:06 | 1.08 (0.32–3.65) | >0.05 | 0.77 (0.20–2.93) | >0.05 | 1.19 (0.26–5.41) | >0.05 |
| B*41:01 | — | >0.05 | — | >0.05 | — | — |
| B*44:02 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| B*44:03 | 1.22 (0.37–4.03) | >0.05 | 0.47 (0.14–1.60) | >0.05 | 3.62 (0.40–32.81) | >0.05 |
| B*46:01 | 0.67 (0.32–1.39) | >0.05 | 1.15 (0.51–2.58) | >0.05 | 2.19 (0.81–5.87) | >0.05 |
| B*48:01 | 1.64 (0.44–6.15) | >0.05 | 0.40 (0.10–1.59) | >0.05 | 1.34 (0.22–8.13) | >0.05 |
| B*50:01 | 2.14 (0.24–19.12) | >0.05 | 0.97 (0.06–15.69) | >0.05 | 0.29 (0.03–2.83) | >0.05 |
| B*51:01 | 1.33 (0.54–3.29) | >0.05 | 0.46 (0.18–1.17) | >0.05 | 2.12 (0.54–8.39) | >0.05 |
| B*51:02 | 4.98 (0.63–39.75) | >0.05 | 8.69 (1.07–70.43) | <0.05* | 0.89 (0.06–14.30) | >0.05 |
| B*52:01 | 1.19 (0.41–3.50) | >0.05 | 0.59 (0.19–1.86) | 0.37 | 1.49 (0.35–6.38) | >0.05 |
| B*54:01 | 1.08 (0.36–3.22) | >0.05 | 0.59 (0.19–1.86) | 0.37 | 2.26 (0.43–11.86) | >0.05 |
| B*55:01 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| B*55:02 | 0.18 (0.02–1.71) | >0.05 | — | — | 2.69 (0.28–26.23) | >0.05 |
| B*56:01 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| B*56:04 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| B*57:01 | 0.93 | >0.05 | 1.96 (0.18–21.83) | >0.05 | 0.88 (0.12–6.37) | >0.05 |
| B*57:02 | 1.08 (0.10–11.99) | >0.05 | 0.48 (0.04–5.38) | >0.05 | — | — |
| B*67:01 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| (C) HLA‐C allele frequencies among AS patients and controls | ||||||
| C*01:02 | 0.95 (0.54–1.67) | >0.05 | 0.87 (0.46–1.64f) | >0.05 | 1.36 (0.67–2.75) | >0.05 |
| C*01:03 | 0.81 (0.13–4.88) | >0.05 | 0.97 (0.14–6.99) | >0.05 | 1.78 (0.16–19.90) | >0.05 |
| C*02:02 | 11.58 (1.54–87.25) | <0.05* | 0.97 (0.06–15.69) | >0.05 | 25.15 (3.31–190.90) | <0.05* |
| C*03:02 | 0.13 (0.03–0.61) | <0.05* | 4.06 (0.85–19.48) | >0.05 | — | — |
| C*03:03 | 0.68 (0.29–1.60) | >0.05 | 1.09 (0.43–2.76) | >0.05 | 3.10 (0.83–11.54) | >0.05 |
| C*03:04 | 0.69 (0.34–1.40) | >0.05 | 1.14 (0.52–2.49) | >0.05 | 1.74 (0.71–4.26) | >0.05 |
| C*04:01 | 0.66 (0.25–1.71) | >0.05 | 1.12 (0.39–3.17) | >0.05 | 2.44 (0.63–9.43) | >0.05 |
| C*04:03 | 0.81 (0.13–4.88) | >0.05 | 0.97 (0.14–6.99) | >0.05 | 1.78 (0.16–19.90) | >0.05 |
| C*05:01 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| C*06:02 | 0.99 (0.49–2.02) | >0.05 | 1.44 (0.60–3.50) | >0.05 | 0.74 (0.34–1.63) | >0.05 |
| C*07:01 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| C*07:02 | 0.55 (0.29–1.01) | >0.05 | 1.02 (0.53–1.96) | >0.05 | 0.32 (0.13–0.78) | <0.05* |
| C*07:04 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| C*08:01 | 1.14 (0.55–2.33) | >0.05 | 0.66 (0.30–1.43) | >0.05 | 1.36 (0.54–3.44) | >0.05 |
| C*08:03 | 2.17 (0.24–19.62) | >0.05 | 0.32 (0.03–3.11) | >0.05 | 0.89 (0.06–14.30) | >0.05 |
| C*08:10 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| C*12:02 | 4.94 (1.71–14.26) | <0.05* | 0.77 (0.20–2.93) | >0.05 | 9.92 (3.37–29.19) | <0.05* |
| C*12:03 | 0.53 (0.11–2.68) | >0.05 | 1.47 (0.24–8.92) | >0.05 | 2.69 (0.28–26.23) | >0.05 |
| C*14:02 | 1.08 (0.40–2.94) | >0.05 | 0.63 (0.22–1.83) | >0.05 | 1.81 (0.44–7.38) | >0.05 |
| C*14:03 | 1.08 (0.20–5.96) | >0.05 | 0.48 (0.09–2.66) | >0.05 | — | — |
| C*15:02 | 0.86 (0.28–2.67) | >0.05 | 2.48 (0.47–13.01) | >0.05 | 0.73 (0.22–2.45) | >0.05 |
| C*15:04 | 0.54 (0.03–8.65) | >0.05 | — | — | 0.89 (0.06–14.30) | >0.05 |
| C*15:13 | — | >0.05 | — | — | — | — |
| C*17:22 | — | — | — | — | — | — |
| (D) HLA‐DQB1 allele frequencies among AS patients and controls | ||||||
| DQB1*02:01 | 0.30 (0.09–1.03) | >0.05 | 1.74 (0.50–6.07) | >0.05 | — | — |
| DQB1*02:02 | 0.93 (0.43–2.00) | >0.05 | 1.34 (0.53–3.50) | >0.05 | 0.88 (0.37–2.10) | >0.05 |
| DQB1*03:01 | 0.98 (0.59–1.63) | >0.05 | 1.35 (0.73–2.50) | >0.05 | 0.78 (0.44–1.40) | >0.05 |
| DQB1*03:02 | 1.15 (0.49–2.75) | >0.05 | 1.12 (0.39–3.17) | >0.05 | 0.69 (0.26–1.81) | >0.05 |
| DQB1*03:03 | 1.03 (0.59–1.81) | >0.05 | 0.75 (0.41–1.40) | >0.05 | 1.36 (0.67–2.75) | >0.05 |
| DQB1*04:01 | 1.18 (0.44–3.16) | >0.05 | 1.48 (0.41–5.36) | >0.05 | 0.57 (0.20–1.66) | >0.05 |
| DQB1*04:02 | 1.91 (0.39–9.32) | >0.05 | 0.97 (0.14–6.99) | >0.05 | 0.35 (0.07–1.81) | >0.05 |
| DQB1*05:01 | 0.68 (0.25–1.87) | >0.05 | 1.14 (0.37–3.48) | >0.05 | 2.12 (0.54–8.39) | >0.05 |
| DQB1*05:02 | 0.74 (0.32–1.71) | >0.05 | 0.97 (0.39–2.41) | >0.05 | 2.31 (0.71–7.55) | >0.05 |
| DQB1*05:03 | 1.27 (0.48–3.38) | >0.05 | 0.63 (0.22–1.83) | >0.05 | 1.07 (0.32–3.58) | >0.05 |
| DQB1*05:10 | — | >0.05 | — | — | — | — |
| DQB1*06:01 | 1.31 (0.68–2.54) | >0.05 | 0.83 (0.39–1.78) | >0.05 | 0.70 (0.33–1.49) | >0.05 |
| DQB1*06:02 | 1.03 (0.48–2.20) | >0.05 | 1.36 (0.53–3.50) | >0.05 | 0.88 (0.37–2.10) | >0.05 |
| DQB1*06:03 | 1.08 (0.20–5.96) | >0.05 | 0.97 (0.14–6.99) | >0.05 | 0.88 (0.12–6.37) | >0.05 |
| DQB1*06:04 | 1.08 (0.20–5.96) | >0.05 | 0.48 (0.09–2.66) | >0.05 | — | — |
| DQB1*06:09 | 0.53 (0.11–2.68) | >0.05 | 1.47 (0.24–8.92) | >0.05 | 2.69 (0.28–26.23) | >0.05 |
| (E) HLA‐DRB1 allele frequencies among AS patients and controls | ||||||
| DRB1*01:01 | 1.45 (0.38–5.55) | >0.05 | 0.57 (0.13–2.45) | >0.05 | 0.88 (0.18–4.46) | >0.05 |
| DRB1*03:01 | 0.30 (0.09–1.03) | >0.05 | 1.74 (0.50–6.07) | >0.05 | — | >0.05 |
| DRB1*04:01 | 5.56 (0.70–43.89) | >0.05 | 0.24 (0.03–2.15) | >0.05 | 1.41 (0.02–1.19) | >0.05 |
| DRB1*04:02 | — | >0.05 | — | >0.05 | — | — |
| DRB1*04:03 | 0.54 (0.08–3.84) | >0.05 | 0.97 (0.14–6.99) | >0.05 | — | — |
| DRB1*04:04 | 3.85 (0.47–31.58) | >0.05 | 0.48 (0.04–5.38) | >0.05 | 0.17 (0.02–1.49) | >0.05 |
| DRB1*04:05 | 1.00 (0.39–2.57) | >0.05 | 2.33 (0.59–9.22) | >0.05 | 0.60 (0.22–1.63) | >0.05 |
| DRB1*04:06 | 0.53 (0.13–2.16) | >0.05 | 1.30 (0.29–5.94) | >0.05 | 3.62 (0.40–32.81) | >0.05 |
| DRB1*04:07 | — | >0.05 | — | — | — | >0.05 |
| DRB1*04:08 | — | >0.05 | — | — | — | >0.05 |
| DRB1*04:10 | — | >0.05 | — | >0.05 | — | — |
| DRB1*06:02 | — | >0.05 | — | — | — | — |
| DRB1*07:01 | 0.92 (0.46–1.83) | >0.05 | 1.57 (0.66–3.75) | >0.05 | 0.95 (0.43–2.11) | >0.05 |
| DRB1*08:01 | — | >0.05 | — | — | — | >0.05 |
| DRB1*08:02 | 1.62 (0.17–15.75) | >0.05 | 0.97 (0.06–15.69) | >0.05 | 0.44 (0.39–4.90) | >0.05 |
| DRB1*08:03 | 1.21 (0.54–2.74) | >0.05 | 0.78 (0.31–1.95) | >0.05 | 0.88 (0.34–2.29) | >0.05 |
| DRB1*09:01 | 0.97 (0.54–1.73) | >0.05 | 0.78 (0.42–1.48) | >0.05 | 1.51 (0.72–3.15) | >0.05 |
| DRB1*09:06 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| DRB1*10:01 | 0.27 (0.02–2.96) | >0.05 | 1.96 (0.18–21.83) | >0.05 | — | — |
| DRB1*11:01 | 0.73 (0.29–1.86) | >0.05 | 1.31 (0.44–3.89) | >0.05 | 1.44 (0.46–4.53) | >0.05 |
| DRB1*12:01 | 0.80 (0.22–2.90) | >0.05 | 1.97 (0.36–10.94) | >0.05 | 0.88 (0.22–3.61) | >0.05 |
| DRB1*12:02 | 1.19 (0.58–2.43) | >0.05 | 1.07 (0.45–2.50) | >0.05 | 0.68 (0.31–1.52) | >0.05 |
| DRB1*13:01 | 1.08 (0.20–5.96) | >0.05 | 0.97 (0.14–6.99) | >0.05 | 0.88 (0.12–6.37) | >0.05 |
| DRB1*13:02 | 0.75 (0.23–2.40) | >0.05 | 0.80 (0.24–2.69) | >0.05 | 4.56 (0.53–39.54) | >0.05 |
| DRB1*13:50 | — | >0.05 | — | — | — | — |
| DRB1*14:04 | 3.28 (0.39–27.55) | >0.05 | 0.24 (0.03–2.15) | >0.05 | 0.44 (0.04–4.90) | >0.05 |
| DRB1*14:05 | 1.26 (0.32–4.96) | >0.05 | 0.57 (0.13–2.45) | >0.05 | 1.34 (0.22–8.13) | >0.05 |
| DRB1*14:07 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| DRB1*14:10 | 0.54 (0.03–8.65) | >0.05 | 0.97 (0.06–15.69) | >0.05 | — | — |
| DRB1*14:12 | — | >0.05 | — | — | — | >0.05 |
| DRB1*14:54 | 0.53 (0.13–2.16) | >0.05 | 3.97 (0.44–35.99) | >0.05 | 1.19 (0.26–5.41) | >0.05 |
| DRB1*15:01 | 0.86 (0.45–1.67) | >0.05 | 1.47 (0.65–3.29) | >0.05 | 0.94 (0.44–1.99) | >0.05 |
| DRB1*15:02 | 1.08 (0.32–3.65) | >0.05 | 0.97 (0.24–3.96) | >0.05 | 0.88 (0.22–3.61) | >0.05 |
| DRB1*15:04 | — | >0.05 | — | — | — | >0.05 |
| DRB1*16:02 | 1.22 (0.37–4.03 | >0.05 | 0.54 (0.16–1.90) | >0.05 | 1.79 (0.32–9.97) | >0.05 |
Note: The univariate model were used to analyze the correlation of the HLA‐A\B\C\DQB1\DRB1 alleles between 130 AS patients and the control. The stratified model was used to analyze the HLA‐A\B\C\DQB1\DRB1 alleles carried by the HLA‐B*27(−) group and the HLA‐B*27(+) group to analysis the correlation of the alleles and AS and further hints their interaction with HLA‐B*27.
p < 0.05 was considered to be statistically significant.
The 130 AS patients were divided into two groups based on the absence or presence of HLA‐B*27. Then, the stratified model was used to compare the distributions of different HLA alleles between the HLA‐B*27(−) and HLA‐B*27(+) groups in order to evaluate the correlation between genetics and the pathogenesis of AS and determine whether HLA‐B*27 interacts with the effects of other HLA alleles on AS. Among the 68 HLA‐B*27(−) patients, HLA‐A*02:01 (OR: 2.48, 95% CI: 1.29–4.77, p = 0.01; Table 2A) was positively correlated with the occurrence of AS, while HLA‐A*24:03 (OR: 0.05, 95% CI: 0.01–0.41, p = 0.01; Table 2A), HLA‐B*51:02 (OR: 0.12, 95% CI: 0.01–0.93, p < 0.05; Table 2B), and HLA‐A*24:02 (OR: 0.08, 95% CI: 0.02–0.35, p < 0.01; Table 2A) were negatively correlated with the incidence of AS. Among the 62 HLA‐B*27(+) patients, the following alleles were positively correlated with the incidence of AS: HLA‐A*11:02 (OR: 8.08, 95% CI: 1.79–36.56, p = 0.01), HLA‐A*68:01 (OR: 19.13, 95% CI: 2.49–147.07, p = 0.01; Table 2A), HLA‐C*02:02 (OR: 25.15, 95% CI: 3.31–190.90, p < 0.01), and HLA‐C*12:02 (OR: 9.92; 95% CI: 3.37–29.19, p < 0.01; Table 2C). In contrast, HLA‐A*24:03 (OR: 0.03, 95% CI: 0.00–0.25, p < 0.01; Table 2A), HLA‐B*51:02 (OR: 0.12; 95% CI: 0.01–0.93, p < 0.05; Table 2B) and HLA‐C*07:02 (OR: 0.32, 95% CI: 0.13–0.78, p = 0.01; Table 2C) were negatively correlated with the incidence of AS among HLA‐B*27(+) patients. However, we have no finding in the HLA‐DQB1 (Table 2D) and HLA‐DRB1 (Table 2E) either in univariable model or in stratified model which may perhaps due to a relatively small sample size.
One‐way ANOVA was used to analyze the effects of the interaction between HLA‐B*27 and the other alleles on the age at AS onset. The age at AS onset was significantly lower in the HLA‐B*27(+) group than in the HLA‐B*27(−) group, which is consistent with the results of the chi‐square test in Table 1. Other HLA alleles also affected the age at AS onset. In the HLA‐B*27(−) group, the average ages at AS onset among those without the alleles A*01:01, B*13:01, B*13:02, C*01:02, C*04:01, DQB1*02:01, DQB1*06:01, and DRB1*03:01 were 31.48 ± 14.07, 32.54 ± 13.35, 31.53 ± 13.78, 36.39 ± 12.36, 31.57 ± 14.16, 30.87 ± 14.02, 32.04 ± 14.57, and 30.97 ± 13.91 years, respectively. In contrast, the corresponding average ages at AS onset among patients with the above alleles were 22.10 ± 15.45, 13.13 ± 1.36, 14.20 ± 2.59, 17.43 ± 6.78, 18.86 ± 4.98, 18.88 ± 11.82, 23.63 ± 10.31, and 18.88 ± 11.82 years, respectively. Thus, it can be seen that in the HLA‐B*27(−) group, the presence of the above alleles was associated with a significantly earlier onset of AS (p < 0.05, Table 3). In contrast, the following alleles were associated with a significantly delayed onset of AS (p < 0.05) in the HLA‐B*27(−) group: the mean age at AS onset among those without the alleles B*40:02, C* 07:02, C*12:02, C*15:02, DQB1*05:02, and DQB1*05:03 was 29.64 ± 13.30, 27.03 ± 12.59, 27.91 ± 11.24, 29.77 ± 13.94, 28.17 ± 12.79, and 28.67 ± 13.46 years, respectively, whereas the mean age at AS onset among those with the above alleles was 50.50 ± 29.00, 38.58 ± 14.43, 59.80 ± 12.74, 46.50 ± 3.54, 41.50 ± 16.54, and 41.13 ± 14.83 years, respectively.
TABLE 3.
HLA‐Class I and II associations with age at AS onset, gender and disease site in Chinese AS cases.
| Allele | B27(−) (Years) (Mean ± SD) | B27(+) (Years) (Mean ± SD) | p‐Value | Gender | Disease site | ||||
|---|---|---|---|---|---|---|---|---|---|
| Allele (−) | Allele (+) | Allele (−) | Allele (+) | H value | p‐Value | H value | p‐Value | ||
| A*01:01 | 31.48 ± 14.07 | 22.10 ± 15.45 | 23.22 ± 7.85 | 19.00 ± 5.66 | <0.05 a , b | 8.41 | <0.05 b | 1.99 | >0.05 |
| A*02:01 | 28.56 ± 14.25 | 33.96 ± 13.93 | 23.60 ± 8.21 | 21.29 ± 6.02 | <0.05 b , c , d , e | 7.23 | >0.05 | 3.61 | >0.05 |
| A*02:03 | 30.16 ± 14.10 | 40.75 ± 15.17 | 22.77 ± 7.68 | 32.50 ± 6.36 | <0.05 b , d | 9.30 | <0.05 b | 2.06 | >0.05 |
| A*02:05 | 31.08 ± 14.16 | — | 23.02 ± 7.84 | — | — | 8.96 | <0.05 b | 2.24 | >0.05 |
| A*02:06 | 30.73 ± 14.33 | 31.29 ± 14.76 | 23.09 ± 8.03 | 23.00 ± 4.69 | <0.05 b | 6.89 | >0.05 | 3.59 | >0.05 |
| A*02:07 | 31.30 ± 14.31 | 26.29 ± 14.12 | 23.00 ± 7.89 | 24.25 ± 6.95 | <0.05 b | 7.42 | >0.05 | 2.46 | >0.05 |
| A*03:01 | 31.44 ± 14.50 | 22.50 ± 7.58 | 23.19 ± 7.77 | 22.38 ± 8.40 | <0.05 b | 6.60 | >0.05 | 2.28 | >0.05 |
| A*11:01 | 31.50 ± 14.22 | 28.95 ± 14.59 | 23.38 ± 7.69 | 22.57 ± 12.22 | <0.05 b | 8.28 | <0.05 b | 1.86 | >0.05 |
| A*11:02 | 31.22 ± 14.24 | 21.33 ± 13.65 | 22.78 ± 7.10 | 24.33 ± 10.49 | <0.05 b | 6.52 | >0.05 | 3.57 | >0.05 |
| A*11:03 | 30.30 ± 13.95 | — | 23.08 ± 7.79 | — | <0.05 b | 11.29 | <0.05 d | 1.94 | >0.05 |
| A*24:02 | 31.41 ± 15.16 | 28.75 ± 11.02 | 22.76 ± 7.78 | 23.94 ± 8.00 | <0.05 b , c | 7.46 | >0.05 | 1.31 | >0.05 |
| A*24:03 | 30.98 ± 14.29 | — | 23.18 ± 7.84 | — | — | 7.32 | >0.05 | 0.96 | >0.05 |
| A*24:07 | 30.92 ± 14.33 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| A*24:20 | 30.90 ± 14.34 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| A*26:01 | 30.59 ± 14.54 | 34.00 ± 9.49 | 22.81 ± 7.57 | 21.00 ± 11.51 | <0.05 b | 7.50 | >0.05 | 2.12 | >0.05 |
| A*30:01 | 30.48 ± 13.93 | 35.75 ± 20.79 | 23.21 ± 7.95 | 22.40 ± 7.23 | <0.05 b , c , d | 6.72 | >0.05 | 0.57 | >0.05 |
| A*31:01 | 31.42 ± 14.71 | 25.29 ± 8.38 | 23.02 ± 8.08 | 23.80 ± 3.19 | <0.05 b | 6.93 | >0.05 | 3.37 | >0.05 |
| A*32:01 | 31.12 ± 14.43 | 25.50 ± 11.50 | 23.26 ± 7.72 | — | — | 16.53 | <0.05 a , d | 2.52 | >0.05 |
| A*33:03 | 30.31 ± 14.03 | 36.80 ± 17.58 | 23.17 ± 7.90 | 20.50 ± 0.71 | <0.05 b , d | 7.25 | >0.05 | 0.79 | >0.05 |
| A*68:01 | 30.35 ± 14.36 | 37.35 ± 12.04 | 23.17 ± 7.90 | 20.50 ± 0.71 | <0.05 b , d | 6.88 | >0.05 | 4.52 | >0.05 |
| A*68:02 | 30.79 ± 14.27 | — | 23.08 ± 7.85 | — | — | 6.58 | <0.05 b | 1.88 | >0.05 |
| B*07:02 | 30.51 ± 13.92 | — | 23.26 ± 7.72 | — | — | 6.87 | >0.05 | 2.12 | >0.05 |
| B*08:01 | 30.57 ± 13.90 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.39 | >0.05 |
| B*13:01 | 32.54 ± 13.35 | 13.13 ± 1.36 | 23.34 ± 7.91 | 19.25 ± 4.79 | <0.05 a , b , c , d | 8.22 | <0.05 b , d | 0.92 | >0.05 |
| B*13:02 | 31.53 ± 13.78 | 14.20 ± 2.59 | 23.47 ± 7.91 | 20.78 ± 6.96 | <0.05 a , b , c | 6.64 | >0.05 | 1.16 | >0.05 |
| B*15:01 | 30.14 ± 12.05 | 30.83 ± 21.75 | 22.79 ± 7.50 | — | — | 6.58 | >0.05 | 2.66 | >0.05 |
| B*15:02 | 29.09 ± 12.21 | 39.00 ± 22.00 | 23.18 ± 7.81 | — | — | 7.85 | <0.05 b | 0.95 | >0.05 |
| B*15:08 | 30.29 ± 14.13 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| B*15:11 | 29.80 ± 13.90 | 37.50 ± 16.34 | 22.97 ± 7.80 | — | — | 10.43 | <0.05 b , d | 3.84 | >0.05 |
| B*15:12 | 30.62 ± 14.31 | — | 23.08 ± 7.79 | — | — | 8.84 | <0.05 b | 2.06 | >0.05 |
| B*15:18 | 30.79 ± 14.27 | — | 22.89 ± 7.70 | — | — | 10.44 | <0.05 b | 1.01 | >0.05 |
| B*15:25 | 30.79 ± 14.27 | — | 23.08 ± 7.85 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| B*15:27 | 30.79 ± 14.27 | — | 23.03 ± 7.84 | — | — | 6.58 | <0.05 b | 0.33 | >0.05 |
| B*27:04 | 30.79 ± 14.27 | — | 23.08 ± 7.45 | 23.18 ± 8.13 | <0.05 b , c | 7.00 | <0.05 c | 0.44 | >0.05 |
| B*27:05 | 30.79 ± 14.27 | — | 22.92 ± 8.08 | 23.32 ± 7.49 | <0.05 b , c | 7.19 | <0.05 b | 0.92 | >0.05 |
| B*27:07 | 30.79 ± 14.27 | — | 23.00 ± 8.15 | — | — | 6.58 | <0.05 b | 1.88 | >0.05 |
| B*35:03 | 30.25 ± 13.14 | — | 23.18 ± 7.81 | — | — | 7.20 | >0.05 | 2.61 | >0.05 |
| B*35:08 | 30.32 ± 13.84 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| B*37:01 | 30.96 ± 14.30 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| B*38:01 | 30.95 ± 14.31 | — | 23.08 ± 7.79 | 7.09 | <0.05 b | 0.89 | >0.05 | ||
| B*38:02 | 30.74 ± 14.67 | 29.00 ± 6.48 | 23.31 ± 7.64 | — | — | 6.48 | >0.05 | 2.00 | >0.05 |
| B*39:01 | 30.73 ± 14.69 | 31.70 ± 3.10 | 23.08 ± 7.79 | — | <0.05 b | 7.06 | <0.05 b | 1.66 | >0.05 |
| B*39:09 | 30.78 ± 14.37 | — | 23.08 ± 7.79 | — | — | 8.84 | >0.05 b | 0.89 | >0.05 |
| B*40:01 | 31.00 ± 14.34 | 25.33 ± 11.25 | 23.19 ± 7.83 | 21.50 ± 8.06 | <0.05 b | 9.34 | >0.05 d | 0.57 | >0.05 |
| B*40:02 | 29.64 ± 13.30 | 50.50 ± 29.00 | 22.90 ± 7.81 | 28.50 ± 6.36 | <0.05 a , b | 8.15 | <0.05 b | 3.81 | >0.05 |
| B*40:03 | 30.26 ± 14.03 | — | 23.10 ± 7.85 | — | — | 10.44 | <0.05 b | 0.33 | >0.05 |
| B*40:06 | 30.25 ± 14.23 | 30.30 ± 12.59 | 22.51 ± 7.41 | 34.33 ± 7.57 | <0.05 b | 6.93 | >0.05 | 0.76 | >0.05 |
| B*41:01 | 30.26 ± 14.03 | — | 23.16 ± 7.83 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| B*44:02 | 30.26 ± 14.03 | — | 23.26 ± 7.76 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| B*44:03 | 28.61 ± 12.89 | 42.63 ± 12.91 | 23.08 ± 7.85 | — | — | 7.85 | <0.05 b | 2.93 | >0.05 |
| B*46:01 | 30.69 ± 14.21 | 28.25 ± 13.54 | 23.02 ± 8.05 | 23.67 ± 5.24 | <0.05 b | 7.69 | >0.05 | 6.07 | >0.05 |
| B*48:01 | 30.15 ± 14.29 | 31.33 ± 12.06 | 23.03 ± 7.91 | 24.50 ± 0.71 | <0.05 b | 7.73 | >0.05 | 0.31 | >0.05 |
| B*50:01 | 30.54 ± 13.93 | — | 23.27 ± 7.20 | 19.33 ± 8.02 | — | 9.20 | <0.05 b | 3.67 | >0.05 |
| B*51:01 | 30.82 ± 14.63 | 27.88 ± 11.35 | 23.22 ± 7.87 | 20.33 ± 6.51 | <0.05 b | 8.05 | <0.05 b | 3.04 | >0.05 |
| B*51:02 | 30.26 ± 14.03 | — | 23.03 ± 7.84 | — | — | 10.44 | <0.05 b | 1.01 | >0.05 |
| B*52:01 | 29.31 ± 12.07 | 37.38 ± 24.32 | 23.20 ± 7.95 | 20.67 ± 2.52 | <0.05 b , d | 7.20 | >0.05 | 3.02 | >0.05 |
| B*54:01 | 29.68 ± 14.72 | 34.63 ± 5.80 | 22.92 ± 7.43 | — | <0.05 b , d | 13.40 | <0.05 b | 5.16 | >0.05 |
| B*55:01 | 30.26 ± 14.03 | — | 23.00 ± 7.83 | — | — | 6.58 | <0.05 b | 1.88 | >0.05 |
| B*55:02 | 30.26 ± 14.03 | — | 23.18 ± 7.81 | — | — | 6.58 | <0.05 b | 1.88 | >0.05 |
| B*56:01 | 30.26 ± 14.03 | — | 23.15 ± 7.84 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| B*56:04 | 30.26 ± 14.03 | — | 22.92 ± 7.75 | — | 6.58 | <0.05 b | 1.88 | >0.05 | |
| B*57:01 | 30.26 ± 14.09 | 42.00 ± 2.83 | 22.85 ± 7.71 | 30.00 ± 9.90 | <0.05 b , d | 9.12 | <0.05 b | 0.42 | >0.05 |
| B*67:01 | 30.26 ± 14.03 | — | 23.05 ± 7.85 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| C*01:02 | 36.39 ± 12.36 | 17.43 ± 6.78 | 22.62 ± 7.74 | 24.53 ± 8.04 | <0.05 a , b , c , d , e | 6.85 | >0.05 | 1.50 | >0.05 |
| C*01:03 | 30.36 ± 14.23 | — | 23.03 ± 7.84 | — | — | 6.87 | >0.05 | 1.15 | >0.05 |
| C*02:02 | 30.29 ± 14.13 | — | 23.07 ± 7.81 | 23.11 ± 7.94 | — | 7.11 | >0.05 | 1.30 | >0.05 |
| C*03:02 | 30.54 ± 14.08 | — | 23.08 ± 7.79 | — | <0.05 b | 6.73 | <0.05 b | 1.94 | >0.05 |
| C*03:03 | 30.40 ± 15.00 | 29.33 ± 4.00 | 22.90 ± 7.92 | 26.67 ± 3.06 | <0.05 b | 7.45 | >0.05 | 1.01 | >0.05 |
| C*03:04 | 31.24 ± 14.90 | 26.46 ± 9.45 | 23.09 ± 8.02 | 23.00 ± 6.48 | <0.05 b | 9.47 | >0.05 | 2.09 | >0.05 |
| C*04:01 | 31.57 ± 14.16 | 18.86 ± 4.98 | 22.86 ± 7.87 | 27.33 ± 5 | <0.05 a , b | 7.18 | >0.05 | 2.09 | >0.05 |
| C*04:03 | 30.52 ± 14.16 | — | 23.08 ± 7.85 | — | — | 6.87 | >0.05 | 1.50 | >0.05 |
| C*05:01 | 30.26 ± 14.03 | — | 23.26 ± 7.72 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| C*06:02 | 30.39 ± 14.85 | 29.25 ± 4.77 | 23.64 ± 7.83 | 21.33 ± 7.65 | <0.05 b , c | 6.86 | >0.05 | 2.45 | >0.05 |
| C*07:01 | 30.25 ± 14.14 | — | 23.08 ± 7.79 | — | — | 8.84 | <0.05 b | 0.81 | >0.05 |
| C*07:02 | 27.03 ± 12.59 | 38.58 ± 14.43 | 23.56 ± 7.28 | 19.29 ± 10.97 | <0.05 a , d , e | 9.94 | <0.05 d | 6.11 | >0.05 |
| C*07:04 | 30.26 ± 14.03 | — | 22.89 ± 7.70 | — | — | 10.44 | <0.05 b | 1.01 | >0.05 |
| C*08:01 | 29.03 ± 15.37 | 35.00 ± 4.51 | 23.15 ± 7.53 | 22.63 ± 9.97 | <0.05 b , d , e | 15.23 | <0.05 a , d , e | 4.10 | >0.05 |
| C*08:03 | 29.60 ± 13.68 | — | 23.07 ± 13.85 | — | — | 7.84 | <0.05 b | 2.50 | >0.05 |
| C*08:10 | 30.26 ± 14.03 | — | 23.16 ± 7.83 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| C*12:02 | 27.91 ± 11.24 | 59.80 ± 12.74 | 23.06 ± 8.16 | 23.11 ± 7.46 | <0.05 a , b , c , d , e | 6.97 | >0.05 | 0.51 | >0.05 |
| C*12:03 | 30.69 ± 14.01 | — | 23.18 ± 7.81 | — | — | 7.84 | <0.05 b | 2.02 | >0.05 |
| C*14:02 | 30.35 ± 14.84 | 29.67 ± 7.21 | 23.22 ± 7.87 | 20.33 ± 6.51 | <0.05 b | 13.41 | <0.05 b | 0.29 | >0.05 |
| C*14:03 | 29.68 ± 14.27 | 39.50 ± 1.50 | 23.08 ± 7.79 | — | <0.05 b , d | 9.07 | <0.05 b | 0.52 | >0.05 |
| C*15:02 | 29.77 ± 13.94 | 46.50 ± 3.54 | 22.59 ± 7.61 | 27.67 ± 8.71 | <0.05 a , b , d , e | 7.74 | >0.05 | 1.66 | >0.05 |
| C*15:04 | 30.26 ± 14.03 | — | 23.03 ± 7.84 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| C*15:13 | 29.92 ± 13.85 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 2.06 | >0.05 |
| C*17:22 | 30.26 ± 14.03 | — | 23.16 ± 7.83 | — | 6.58 | <0.05 b | 1.01 | >0.05 | |
| DQB1*02:01 | 30.87 ± 14.02 | 18.88 ± 11.82 | 23.08 ± 7.79 | — | <0.05 a , b | 6.92 | <0.05 b | 0.27 | >0.05 |
| DQB1*02:02 | 30.16 ± 14.48 | 30.14 ± 11.35 | 23.69 ± 7.83 | 20.27 ± 7.28 | <0.05 b , c | 7.07 | >0.05 | 7.27 | >0.05 |
| DQB1*03:01 | 29.43 ± 14.08 | 31.64 ± 14.38 | 23.91 ± 6.94 | 22.00 ± 8.78 | <0.05 b , c , d , e | 7.59 | >0.05 | 2.91 | >0.05 |
| DQB1*03:02 | 30.13 ± 14.24 | 29.57 ± 14.92 | 22.51 ± 8.03 | 26.44 ± 5.39 | <0.05 b | 16.46 | <0.05 b , f | 3.27 | >0.05 |
| DQB1*03:03 | 31.25 ± 13.47 | 28.32 ± 15.23 | 22.52 ± 7.51 | 25.00 ± 8.71 | <0.05 b , d | 9.43 | <0.05 e | 1.57 | >0.05 |
| DQB1*04:01 | 30.37 ± 14.37 | 26.75 ± 9.88 | 22.58 ± 7.37 | 26.00 ± 9.00 | <0.05 b | 10.80 | <0.05 d | 1.40 | >0.05 |
| DQB1*04:02 | 30.45 ± 14.20 | 20.50 ± 6.36 | 23.60 ± 7.86 | 17.20 ± 3.70 | <0.05 b | 8.63 | <0.05 b | 0.31 | >0.05 |
| DQB1*05:01 | 30.70 ± 14.40 | 24.67 ± 9.93 | 23.31 ± 7.84 | 18.67 ± 6.11 | <0.05 b | 10.74 | <0.05 d | 3.61 | >0.05 |
| DQB1*05:02 | 28.17 ± 12.79 | 41.50 ± 16.54 | 23.10 ± 8.00 | 22.75 ± 4.03 | <0.05 a , b , e | 7.40 | >0.05 | 3.49 | >0.05 |
| DQB1*05:03 | 28.67 ± 13.46 | 41.13 ± 14.83 | 22.35 ± 7.42 | 31.40 ± 7.70 | <0.05 a , b , d | 7.23 | >0.05 | 0.37 | >0.05 |
| DQB1*05:10 | 30.11 ± 14.21 | — | 23.08 ± 7.79 | — | — | 7.36 | <0.05 b | 0.96 | >0.05 |
| DQB1*06:01 | 32.04 ± 14.57 | 23.63 ± 10.31 | 23.54 ± 8.41 | 21.75 ± 5.66 | <0.05 a , b , c | 7.10 | >0.05 | 2.72 | >0.05 |
| DQB1*06:02 | 30.24 ± 14.47 | 29.70 ± 12.53 | 22.92 ± 7.56 | 23.82 ± 9.15 | <0.05 b | 6.94 | >0.05 | 0.59 | >0.05 |
| DQB1*06:03 | 30.15 ± 14.33 | — | 23.00 ± 7.83 | — | — | 7.11 | >0.05 | 3.42 | >0.05 |
| DQB1*06:04 | 29.80 ± 14.28 | 35.75 ± 11.09 | 23.08 ± 7.79 | — | <0.05 b , d | 6.92 | <0.05 b | 0.58 | >0.05 |
| DQB1*06:09 | 29.53 ± 13.81 | — | 23.08 ± 7.85 | — | — | 8.13 | <0.05 b | 3.42 | >0.05 |
| DRB1*01:01 | 30.42 ± 14.51 | 28.20 ± 5.45 | 23.12 ± 7.91 | — | <0.05 b | 8.68 | <0.05 b | 3.67 | >0.05 |
| DRB1*03:01 | 30.97 ± 13.91 | 18.88 ± 11.82 | 23.08 ± 7.79 | — | <0.05 a , b | 6.64 | <0.05 b | 0.16 | >0.05 |
| DRB1*04:01 | 30.21 ± 14.16 | 31.00 ± 13.66 | 22.66 ± 7.53 | 27.00 ± 9.82 | <0.05 b | 7.90 | <0.05 b | 3.24 | >0.05 |
| DRB1*04:02 | 30.43 ± 14.06 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| DRB1*04:03 | 30.49 ± 14.12 | 23.08 ± 7.79 | — | — | 6.76 | <0.05 b | 0.29 | >0.05 | |
| DRB1*04:04 | 29.58 ± 13.58 | — | 23.05 ± 8.05 | 23.40 ± 4.10 | — | 13.18 | <0.05 d | 2.60 | >0.05 |
| DRB1*04:05 | 30.48 ± 14.17 | 25.33 ± 11.59 | 22.58 ± 7.44 | 25.70 ± 9.38 | <0.05 b | 14.01 | <0.05 a , d , e | 2.78 | >0.05 |
| DRB1*04:06 | 30.30 ± 14.07 | 29.33 ± 15.95 | 22.98 ± 7.82 | — | — | 6.58 | >0.05 | 6.92 | >0.05 |
| DRB1*04:07 | 30.26 ± 14.03 | — | 23.15 ± 7.90 | — | — | 7.86 | <0.05 b | 1.90 | >0.05 |
| DRB1*04:08 | 30.26 ± 14.03 | — | 23.03 ± 7.76 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| DRB1*04:10 | 30.46 ± 14.13 | — | 23.08 ± 7.79 | — | — | 7.73 | <0.05 b | 1.64 | >0.05 |
| DRB1*06:02 | 23.08 ± 7.79 | — | — | — | — | 8.84 | <0.05 b | 0.89 | >0.05 |
| DRB1*07:01 | 30.11 ± 14.45 | 31.38 ± 11.07 | 23.55 ± 7.69 | 21.31 ± 8.20 | <0.05 b , c | 7.25 | >0.05 | 7.49 | >0.05 |
| DRB1*08:01 | 30.26 ± 14.03 | — | 23.23 ± 7.76 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| DRB1*08:02 | 30.34 ± 14.12 | — | 23.33 ± 7.79 | — | — | 7.32 | >0.05 | 3.91 | >0.05 |
| DRB1*08:03 | 31.28 ± 14.38 | 24.30 ± 10.47 | 23.36 ± 8.02 | 21.44 ± 6.39 | <0.05 b , c | 6.62 | >0.05 | 1.81 | >0.05 |
| DRB1*09:01 | 31.21 ± 13.32 | 28.39 ± 15.46 | 22.70 ± 7.68 | 24.67 ± 8.40 | <0.05 b | 9.87 | <0.05 e | 3.19 | >0.05 |
| DRB1*09:06 | 30.49 ± 14.00 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.39 | >0.05 |
| DRB1*10:01 | 30.60 ± 13.84 | — | 23.08 ± 7.79 | — | — | 8.84 | <0.05 b | 0.39 | >0.05 |
| DRB1*11:01 | 30.85 ± 14.42 | 24.17 ± 7.14 | 22.68 ± 7.60 | 27.60 ± 9.37 | <0.05 b | 7.59 | >0.05 | 1.90 | >0.05 |
| DRB1*12:01 | 29.98 ± 13.36 | — | 23.21 ± 7.91 | 21.25 ± 6.50 | <0.05 b | 10.61 | <0.05 b | 1.75 | >0.05 |
| DRB1*12:02 | 29.56 ± 14.48 | 34.30 ± 10.77 | 23.85 ± 7.71 | 20.43 ± 7.75 | <0.05 b , c , d , e | 8.19 | <0.05 b | 8.66 | <0.05 f |
| DRB1*13:01 | 30.25 ± 14.24 | — | 22.98 ± 7.89 | — | — | 6.99 | >0.05 | 5.16 | >0.05 |
| DRB1*13:02 | 29.48 ± 13.88 | 40.00 ± 13.51 | 23.08 ± 7.85 | — | — | 7.13 | >0.05 | 2.77 | >0.05 |
| DRB1*13:50 | 30.26 ± 14.03 | — | 23.03 ± 7.84 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| DRB1*14:04 | 29.70 ± 13.84 | 39.25 ± 16.07 | 22.97 ± 7.80 | — | — | 7.29 | >0.05 | 3.67 | >0.05 |
| DRB1*14:05 | 29.91 ± 14.38 | 35.75 ± 3.40 | 22.68 ± 7.52 | — | — | 9.30 | <0.05 b | 2.27 | >0.05 |
| DRB1*14:07 | 30.02 ± 14.00 | — | 23.08 ± 7.79 | — | — | 8.84 | <0.05 b | 0.89 | >0.05 |
| DRB1*14:10 | 30.22 ± 14.13 | — | 23.08 ± 7.79 | — | — | 7.09 | <0.05 b | 0.89 | >0.05 |
| DRB1*14:12 | 30.26 ± 14.03 | — | 23.21 ± 7.78 | — | — | 6.58 | <0.05 b | 1.88 | >0.05 |
| DRB1*14:54 | 29.72 ± 13.42 | — | 22.69 ± 7.74 | 30.67 ± 4.93 | — | 11.67 | <0.05 b | 2.16 | >0.05 |
| DRB1*15:01 | 30.46 ± 14.41 | 29.18 ± 14.42 | 23.00 ± 14.62 | 23.33 ± 8.57 | <0.05 b , c | 7.73 | >0.05 | 0.86 | >0.05 |
| DRB1*15:02 | 30.78 ± 14.09 | 21.88 ± 11.35 | 23.26 ± 8.01 | 20.50 ± 2.08 | <0.05 b | 7.12 | >0.05 | 0.29 | >0.05 |
| DRB1*15:04 | 30.26 ± 14.03 | — | 23.03 ± 7.84 | — | — | 6.58 | <0.05 b | 1.01 | >0.05 |
| DRB1*16:02 | 29.50 ± 13.80 | 36.86 ± 15.38 | 23.18 ± 7.88 | — | <0.05 b | 6.81 | >0.05 | 0.64 | >0.05 |
Note: One‐way ANOVA with post hoc multiple comparisons were used to analysis age at AS onset. Independent samples Kruskal–Wallis test for gender distribution and disease site analysis. p < 0.05 was considered to be statistically significant.
Represents the comparison between the HLA‐B*27(−) Allele (−) group and HLA‐B*27(−) Allele (+).
Represents the comparison between the HLA‐B*27(−) Allele (−) group and HLA‐B*27(+) Allele (−).
Represents the comparison between the HLA‐B*27(−) Allele (−) group and HLA‐B*27(+) Allele (+).
Represents the comparison between the HLA‐B*27(−) Allele (+) group and HLA‐B*27(+) Allele (−).
Represents the comparison between the HLA‐B*27(−) Allele (+) group and HLA‐B*27(+) Allele (+).
Represents the comparison between the HLA‐B*27(+) Allele (−) group and HLA‐B*27(+) Allele (+).
In the HLA‐B*27(+) group, the presence/absence of the other HLA alleles had no significant effect on the age at AS onset, suggesting that the timing of AS onset in this group was mainly affected by HLA‐B*27 (Table 3), and that patients with the HLA‐B*27 allele may develop AS at a younger age.
Gender distribution also significantly differed between the HLA‐B*27(−) and HLA‐B*27(+) groups, with the latter group having a lower proportion of female AS patients. This suggested that the gender distribution of AS was mainly related to the HLA‐B*27 allele (Table 3).
In the HLA‐B*27(−) group, the A*32:01, C*08:01, and DRB1*04:05 alleles were associated with the gender distribution of AS patients. Among AS patients without A*32:01, there were 45 male patients and 20 female patients, while the three patients carrying the A*32:01 allele were all female (H‐value = 16.53, p < 0.05). There were 37 male and 17 female patients without the C*08:01 allele, while eight male and six female patients carried the C*08:01 allele (H‐value = 15.23, p < 0.05). There were 42 male and 23 female DRB1*04:05(−) patients, and 3 female DRB1*04:05(+) patients (H value = 14.01, p < 0.05). Thus, in the HLA‐B*27(−) group, women who carried the A*32:01, C*08:01, and DRB1*04:05 alleles may be more likely to develop AS than women without these alleles. In the HLA‐B*27(+) group, there were 44 male and 4 female DQB1*03:02(−) patients, and four male and five female DQB1*03:02(+) patients, suggesting that HLA‐B*27(+) women who carry the DQB1*03:02 allele may be more prone to AS than HLA‐B*27(+) women without this allele (Table 3).
There was no significant difference between the HLA‐B*27(−) and HLA‐B*27(+) groups, (comparison of HLA‐B*27(−) allele(−) and HLA‐B*27(+) allele(−) group, and comparison of HLA‐B*27(−) allele(+)and HLA‐B*27(+) allele(+) group) in terms of the distribution of disease sites. This suggested that HLA‐B*27 had no significant correlation with the sites of AS involvement, which is consistent with the chi‐square test results in Table 1. The results of the H test showed that there was an interaction between DRB1*12:02 and HLA‐B*27 that affected the pathogenesis of AS (Table 3). The distribution of disease sites in patients who were HLA‐B*27(+) and DRB1*12:02(−) was as follows: trunk, 30 patients; peripheral joints, 5 patients; both trunk; peripheral joints, 13 patients. The corresponding results for HLA‐B*27(+) and DRB1*12:02(+) patients were as follows: trunk, two patients; peripheral joints, six patients; both trunk and peripheral joints, six patients (H‐value = 8.66, p < 0.05). This suggested that among HLA‐B*27(+) AS patients, those carrying the DRB1*12:02 allele are more likely to have peripheral joint involvement than those who are negative for this allele.
4. DISCUSSION
Ankylosing spondylitis is a chronic inflammatory rheumatic disease that mainly involves the axial skeleton and sacroiliac joints. If left untreated, it will lead to vertebral fusion. 1 The epidemiological incidence of AS in the Chinese population is approximately 0.3%, that is, there are about 4 million patients with AS in China. 11 Unlike most immune diseases, AS affects men more often, with a male‐to‐female ratio of approximately 1.5–3:1 in European countries 12 , 13 and 2:1–4:1 in Chinese AS patients. 14 In our study, the total number of male Chinese Han AS patients (98/130, 75.38%) was significantly higher than the number of female patients (32/130, 24.62%), with a male‐to‐female ratio of 3:1, which is in line with the male‐to‐female ratio reported for AS patients in China.
An individual's susceptibility to AS is almost entirely determined by genetic factors, whose heritability is estimated to be 90% or more. The strongest association is with the MHC, 15 and most of this genetic association is driven by HLA‐B*27. Nevertheless, in the HLA‐B*27(+) population, approximately 80% of people do not develop AS; we have also found in our clinical practice that about 10% of AS patients are HLA‐B*27 negative. These findings suggest that HLA regions other than HLA‐B*27 are also involved in the pathogenesis of AS. 5 , 16 , 17 , 18 , 19 , 20
Large‐scale case–control studies of HLA and other MHC genes in AS suggest that the genetic association of this locus is more complex than initially thought. Since the discovery of the association of HLA‐B*27 with AS, many studies have shown that additional MHC‐related variants are involved in the development of AS. 21 , 22 , 23 Until now, 113 loci have been identified as contributing approximately 30% to the heritability of AS, 24 , 25 exceeding the effect of HLA‐B*27, which determines about 20% of the genetic risk.
To study the correlation of HLA regions other than HLA‐B*27 with AS, the present study specially selected 68 HLA‐B*27‐negative AS patients, 62 HLA‐B*27‐positive AS patients, and 70 normal controls. Sanger sequencing was used to detect alleles of typical MHC class I regions (HLA‐A, HLA‐B, and HLA‐C) and MHC class II regions (HLA‐DQB1 and HLA‐DRB1), and a correlation analysis was carried out. In general, MHC class I and class II loci were clearly associated with AS. Due to linkage disequilibrium between HLA‐B and easily confused with MHC class II loci, in this study, we performed a stratified analysis of AS patients with HLA‐B*27 as the main cause, and explored the correlations of alleles of other MHC class I regions (HLA‐A, HLA‐B, and HLA‐C) and MHC class II regions (HLA‐DQB1 and HLA‐DRB1) with the occurrence of AS, age at AS onset, gender distribution, sites of involvement, etc. We further analyzed whether there was an interaction between each allele and HLA‐B*27.
Among HLA‐A alleles, we observed that the presence of HLA‐A*02:01 was associated with a risk of developing AS in the HLA‐B*27(−) group (OR: 2.54), which is consistent with the results using the imputation method in a large‐scale study. 24 Similar results were found in a study of AS patients including HLA‐B*27(+) and HLA‐B*27(−) patients. 22 , 26 , 27 Compared with the controls, the frequency of A*11:02 was increased in the HLA‐B*27(+) group which was consistent with Aaron et al. who performed a synergistic effect of HLA‐A*11 and HLA‐B*27 on the pathogenesis of AS. 22 HLA‐A*33:03 may be a protective allele for AS in the Chinese Han population which has been found to have protective effects for cervical cancer patients in the Xinjiang population in China. 22 HLA‐A*24:02 and A*24:03 may be also protective factors for AS and HLA‐A*24:02 is relatively common in Chinese Han 23 which is also positively associated with chronic hepatitis B virus infection. 28 HLA‐A*24:03 is a risk factor for leukemia in the Zhuang ethnic group in Guangxi, China. 29
Our study found that in the Chinese Han population, in addition to the confirmed positive correlation of HLA‐B*27:04 and HLA‐B*27:05 with the incidence of AS, other HLA‐B genes are involved in the occurrence of AS. HLA‐B60 correlates with HLA‐B*40:01 at the DNA level, 29 which has a major genetic association with AS in many major ethnic groups. 5 , 27 In this study, we did not confirm an association of HLA‐B*40:01 with AS, though it has been inferred in studies of white populations by direct typing 26 and in Taiwanese Chinese. 19
In AS patients (mixed samples) and the HLA‐B*27(+) group, we found that the frequencies of HLA‐C*02:02 and HLA‐C*12:02 were significantly increased relative to the controls, and these alleles were positively correlated with the occurrence of AS. Reveille et al. found that the frequency of HLA‐C*02 was increased in white AS patients. 8 In a study of Macedonian and Moroccan AS populations, HLA‐C*02 was found to be positively correlated with the occurrence of AS. 30 , 31 HLA‐C*12:02 has been confirmed to be closely related to late‐onset psoriasis in the Japanese population. Recent studies have found that AS patients often have concomitant psoriasis and/or inflammatory bowel disease. 32 A study in the Taiwanese population found that the HLA‐C*12:02:02 allele strongly increases the risk of AS (43.42% vs. 3.31%; p < 0.00001, OR: 16.88; 95% CI: 11.27–25.28). 33 Therefore, HLA‐C*12:02 may be closely related to the occurrence of AS in Chinese Han population or Asian population.
Stratified analysis revealed that in the HLA‐B*27(+) group, the frequency of C*07:02 was decreased, and this allele was negatively correlated with the incidence of AS. This is consistent with the reduction in HLA‐C*07 frequencies in AS patients found in the white Prospective Study of Ankylosing Spondylitis and North American Spondylitis Consortium cohorts as compared with the controls. 8
The mean age at AS onset was significantly greater in the HLA‐B*27(−) group (30.03 ± 15.15 years) than in the HLA‐B*27(+) group (23.08 ± 7.79 years, p < 0.01), suggesting that those who carry the HLA‐B*27 gene may develop AS earlier. In the HLA‐B*27(−) group, the alleles A*01:01, B*13:01, B*13:02, C*01:02, C*04:01, DQB1*02:01, DQB1*06:01, and DRB1*03:01 were associated with a significantly earlier onset of AS compared to patients without the above alleles (p < 0.05). In contrast, the B*40:02, C*07:02, C*12:02, C*15:02, DQB1*05:02, and DQB1*05:03 alleles significantly delayed AS onset in the HLA‐B*27(−) group (p < 0.05).
The proportion of male patients was significantly lower in the HLA‐B*27(−) group (45/68, 66.18%) than in the HLA‐B*27(+) group (53/62, 85.48%, p < 0.05), suggesting that men carrying the HLA‐B*27 allele are more likely to develop AS than women carrying this allele. In the HLA‐B*27(−) group, the proportion of female patients was higher among AS patients carrying the HLA‐A*32:01, C*08:01, and DRB1*04:05 alleles than among patients without these alleles, suggesting that HLA‐B*27(−) female patients carrying the above alleles may be more prone to AS. In the HLA‐B*27(+) group, there were 44 male and 4 female DQB1*03:02(−) patients, and four male and five female DQB1*03:02(+) patients, suggesting that women with both the HLA‐B*27(+) and DQB1*03:02 alleles may be more prone to AS. However, due to our small sample size, the results may not be completely reliable, and a larger sample size may be required for follow‐up observations.
In the HLA‐B*27(+) group, 14 patients carried the DRB1*12:02 allele, of which two patients (14.28%) had axial joint involvement, six patients (42.86%) had peripheral joint involvement, and six patients (42.86%) had both axial and peripheral joint involvement. Among the 48 patients without the DRB1*12:02 allele in the HLA‐B*27(+) group, 30 patients (62.5%) had axial joint involvement, 5 patients (10.42%) had peripheral joint involvement, and 13 patients (27.08%) had both axial and peripheral joint involvement. The above findings suggest that HLA‐B*27(+) AS patients with DRB1*12:02 may be more likely to have peripheral joint involvement rather the classic axial joint involvement of AS, which may be beneficial for the clinical diagnosis of AS. We did not have a sufficient sample size to study the alleles associated with uveitis in the Chinese Han population due to relatively small number of cases with uveitis in the sample.
In this study, we detected major HLA class I and class II alleles, including HLA‐B*27, by using Sanger sequencing, and analyzed their association with AS in the Chinese Han population. Stratified analysis was carried out according to whether patients carried the HLA‐B*27 allele, and we identified some alleles that were related to the age at AS onset, gender distribution, and involved sites in the Chinese Han population. There are some very interesting findings for the clinical diagnosis and treatment of AS. Most of the results are consistent with the findings of other researchers, but a small number of results are not supported by relevant literature, which may be related to the following reasons. First, in different populations, the distribution frequency of HLA alleles is not the same. Second, although patients and controls were from the Chinese Han population, ancestry information markers were not checked, and whether the family carried the relevant gene was not registered, so potential stratification problems cannot be ruled out. Finally, our sample size was relatively small; some low‐frequency alleles were too small to be statistically analyzed, which may affect the results of the study.
FUNDING INFORMATION
This study was supported by the National High Level Hospital Clinical Research Funding, Elite Medical Professionals project of China‐Japan Friendship Hospital (Grant no: ZRJY2021‐GG03); Horizontal Scientific Research Project (Grant no: 2021‐HX‐39); Key Clinical Specialty Project of Beijing (Grant no: 2020); the National Natural Science Foundation of China (Grant no:82074221).
CONFLICT OF INTEREST STATEMENT
All authors declare that there is no conflict of interest.
Jiang Y, Liu Q, Kong X, et al. Role of HLA class I and II alleles in susceptibility to ankylosing spondylitis in Chinese Han. J Clin Lab Anal. 2023;37:e24964. doi: 10.1002/jcla.24964
First authors: Yongwei Jiang and Qian Liu
Contributor Information
Yongtong Cao, Email: caoyongtong92@sina.com.
Liang Ma, Email: liangma321@163.com.
DATA AVAILABILITY STATEMENT
The data that support the findings of this study are openly available in “figshare” at https://figshare.com/articles/dataset/data_for_1076038_xlsx/21391509, reference number (DOI: 10.6084/m9.figshare.21391509).
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Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Data Availability Statement
The data that support the findings of this study are openly available in “figshare” at https://figshare.com/articles/dataset/data_for_1076038_xlsx/21391509, reference number (DOI: 10.6084/m9.figshare.21391509).