Table 8.
Association of a Combination of CC16 mRNA Expression Levels in Bronchial Epithelial Cells and Blood IL-6 Protein Concentrations in Asthmatics with Asthma Phenotypes
| SARP (Asthmatics, n = 111) | HH (n = 19) |
HL (n = 28) |
LH (n = 31) |
LL (n = 33) |
P Value |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | Mean ± SD | n | Mean ± SD | n | Mean ± SD | n | Mean ± SD | Unadjusted* | Adjusted† | |
| Age at enrollment, yr | 19 | 41 ± 11 | 28 | 33 ± 11 | 31 | 44 ± 13 | 33 | 42 ± 11 | 0.004 | NA |
| Age of asthma onset, yr | 19 | 13 ± 12 | 28 | 12 ± 12 | 31 | 17 ± 15 | 33 | 16 ± 12 | 0.49 | NA |
| Sex, n (%) female | 19 | 12 (63) | 28 | 20 (71) | 31 | 26 (84) | 33 | 13 (39) | 0.002 | NA |
| Race (% White/African American/other‡) | 19 | 53/47/0 | 28 | 89/11/0 | 31 | 42/42/16 | 33 | 48/33/18 | 0.002 | NA |
| BMI, kg/m2 | 19 | 35 ± 8.1 | 28 | 27 ± 5.6 | 31 | 36 ± 10 | 33 | 27 ± 5.4 | <0.0001 | NA |
| Obesity (BMI ⩾30 kg/m2), % | 19 | 74 | 28 | 21 | 31 | 77 | 33 | 21 | <0.0001 | NA |
| Baseline Pre-BD FEV1% predicted§ | 19 | 72 ± 19 | 28 | 87 ± 13 | 31 | 72 ± 17 | 33 | 67 ± 22 | 0.0002 | 0.029 |
| Baseline Pre-BD FEV1/FVC§ | 19 | 0.70 ± 0.09 | 28 | 0.75 ± 0.08 | 31 | 0.69 ± 0.08 | 33 | 0.64 ± 0.1 | 0.0004 | 0.0026 |
| Maximal FEV1% predicted | 19 | 84 ± 16 | 28 | 96 ± 14 | 31 | 87 ± 15 | 33 | 83 ± 21 | 0.009 | 0.33 |
| Maximal reversibility | 19 | 20 ± 23 | 28 | 11 ± 9.0 | 31 | 24 ± 21 | 33 | 27 ± 26 | 0.002 | 0.042 |
| PC20 methacholine, mg/ml, median (IQR) | 12 | 1.9 (0.49–3.2) | 15 | 0.99 (0.39–2.4) | 13 | 0.37 (0.17–0.71) | 8 | 0.32 (0.18–0.60) | 0.007 | 0.067 |
| Total serum IgE concentrations, IU/ml, median (IQR) | 19 | 140 (41–374) | 27 | 139 (42–337) | 30 | 168 (69–345) | 32 | 153 (90–335) | 0.97 | 0.99 |
| FeNO, ppb, median (IQR) | 19 | 17 (14–33) | 27 | 22 (14–44) | 28 | 40 (27–66) | 32 | 25 (13–46) | 0.093 | 0.036 |
| Blood eosinophils, cells/μl, median (IQR) | 19 | 180 (68–252) | 27 | 183 (100–300) | 31 | 294 (100–400) | 33 | 150 (100–304) | 0.17 | 0.24 |
| Blood neutrophils, cells/μl, median (IQR) | 19 | 4,402 (3,825–5,280) | 27 | 3,031 (2,300–4,095) | 31 | 4,116 (2,777–5,969) | 33 | 3,658 (3,088–5,044) | 0.02 | 0.060 |
| Sputum % eosinophils, median (IQR) | 17 | 0.8 (0.3–2.6) | 19 | 0.8 (0.1–3.2) | 20 | 0.8 (0.2–7.9) | 24 | 2.0 (0.5–4.0) | 0.52 | 0.62 |
| Sputum % neutrophils, median (IQR) | 17 | 64 (33–88) | 19 | 59 (48–76) | 20 | 46 (32–76) | 24 | 45 (30–69) | 0.51 | 0.89 |
| High-dose ICS (%) | 15 | 47 | 22 | 36 | 29 | 48 | 31 | 52 | 0.74 | 0.89 |
| Oral or systemic CS (%) | 19 | 42 | 28 | 21 | 31 | 42 | 33 | 42 | 0.28 | 0.61 |
| Exacerbations in the last 12 mo, n (%) | 19 | 7 (37) | 28 | 5 (18) | 31 | 14 (45) | 33 | 15 (45) | 0.1 | 0.29 |
| ACQ-6 | 11 | 0.91 ± 1.22 | 21 | 0.67 ± 0.80 | 19 | 1.68 ± 1.45 | 26 | 1.62 ± 1.47 | 0.022 | 0.13 |
| ATS-ERS severe asthma, n (%) | 19 | 7 (37) | 28 | 5 (18) | 31 | 14 (45) | 33 | 16 (48) | 0.07 | 0.55 |
Definition of abbreviations: ACQ-6 = asthma control questionnaire-6; BMI = body mass index; CS = corticosteroids; ATS-ERS = American Thoracic Society-European Respiratory Society; FeNO = fractional exhaled nitric oxide; HH = high CC16 mRNA expression levels in bronchial epithelial cells and high blood IL-6 protein concentrations; HL = high CC16 and low IL-6; ICS = inhaled corticosteroids; LH = low CC16 and high IL-6; LL = low CC16 and low IL-6; Pre-BD = prebronchodilator; SARP = Severe Asthma Research Program.
Unadjusted P value was generated using Kruskal-Wallis test.
Adjusted P value was generated using a generalized linear model adjusted for age, sex, BMI, race, and batch effect.
Other races include Hispanic, Asian, American Indian, and mixed.
Pre-BD pulmonary function was presented.