Table 7.
Association of High–Low CC16 mRNA Expression Levels in Bronchial Epithelial Cells in Asthmatics with Asthma Phenotypes
| SARP (Asthmatics, n = 242) | CC16 High* (n = 108) |
CC16 Low* (n = 134) |
P Value |
|||
|---|---|---|---|---|---|---|
| n | Mean ± SD | n | Mean ± SD | Unadjusted† | Adjusted‡ | |
| Age at enrollment, yr | 108 | 36 ± 13 | 134 | 42 ± 13 | 0.0003 | NA |
| Age of asthma onset, yr | 106 | 13 ± 13 | 132 | 16 ± 15 | 0.29 | NA |
| Sex, n (%) female | 108 | 76 (70) | 134 | 84 (63) | 0.22 | NA |
| Race (% White/African American/other§) | 103 | 73/22/5 | 130 | 52/32/15 | 0.0026 | NA |
| Body mass index, kg/m2 | 108 | 29 ± 7.3 | 134 | 32 ± 8.1 | 0.025 | NA |
| Baseline Pre-BD FEV1% predictedǁ | 108 | 80 ± 20 | 134 | 69 ± 20 | <0.0001 | 0.0005 |
| Baseline Pre-BD FEV1/FVCǁ | 108 | 0.74 ± 0.11 | 133 | 0.67 ± 0.11 | <0.0001 | <0.0001 |
| Maximal FEV1% predicted | 96 | 91 ± 18 | 124 | 83 ± 20 | 0.0006 | 0.013 |
| Maximal reversibility | 108 | 16 ± 18 | 134 | 25 ± 25 | 0.0001 | 0.0042 |
| PC20 methacholine, mg/ml, median (IQR) | 58 | 1.5 (0.5–3.1) | 49 | 0.58 (0.28–2.0) | 0.0053 | 0.016 |
| Total serum IgE concentrations, IU/ml, median (IQR) | 94 | 99 (29–307) | 120 | 159 (86–336) | 0.042 | 0.024 |
| FeNO, ppb, median (IQR) | 97 | 22 (15–42) | 120 | 36 (19–63) | 0.0024 | 0.0011 |
| Blood eosinophils, cells/μl, median (IQR) | 95 | 183 (100–300) | 121 | 200 (100–374) | 0.024 | 0.082 |
| Blood neutrophils, cells/μl, median (IQR) | 95 | 3,800 (2,900–5,008) | 121 | 3,800 (2,906–5,548) | 0.53 | 0.39 |
| Sputum % eosinophils, median (IQR) | 61 | 0.4 (0.001–2.2) | 85 | 1.2 (0.2–4.4) | 0.011 | 0.019 |
| Sputum % neutrophils, median (IQR) | 61 | 59 (33–78) | 85 | 45 (30–63) | 0.034 | 0.28 |
| Serum or plasma IL-6 concentrations, pg/ml, median (IQR) | 47 | 1.2 (0.68–2.3) | 64 | 1.4 (0.74–3.0) | 0.52 | 0.45 |
| Serum sIL-6R concentrations, ng/ml, median (IQR) | 49 | 37 (30–42) | 73 | 37 (31–47) | 0.21 | 0.10 |
| High-dose ICS (%) | 86 | 40 | 117 | 61 | 0.0043 | 0.040 |
| Oral or systemic CS (%) | 97 | 28 | 124 | 48 | 0.0035 | 0.015 |
| Exacerbations in the last 12 mo, n (%) | 106 | 33 (31) | 132 | 65 (49) | 0.0055 | 0.046 |
| ACQ-6 | 42 | 0.95 ± 1.21 | 69 | 1.61 ± 1.40 | 0.0058 | 0.031 |
| ATS-ERS severe asthma, n (%) | 108 | 37 (34) | 134 | 78 (58) | 0.0003 | 0.0033 |
Definition of abbreviations: ACQ-6 = asthma control questionnaire-6; CS = corticosteroids; ATS-ERS = American Thoracic Society-European Respiratory Society; FeNO = fractional exhaled nitric oxide; ICS = inhaled corticosteroids; Pre-BD = prebronchodilator; SARP = Severe Asthma Research Program.
High and low CC16 mRNA expression levels in asthmatics were categorized using the standardized median value of CC16 mRNA expression levels as described in the Methods section.
Unadjusted P value was generated using Kruskal-Wallis test.
Adjusted P value was generated using a generalized linear model adjusted for age, sex, body mass index, race, and batch effect.
Other races include Hispanic, Asian, American Indian, and mixed.
Pre-BD pulmonary function was presented.