Cluster analysis of sputum cytokine-high profiles reveals diversity in T(h)2-high asthma patients

Respiratory Research

Table 3 Characteristics of patient clusters

CLUSTER	1	2	3	4	5	P value
Subjects (n=)	24	16	8	25	132
Age (years)	44.0 ± 13.4	47.3 ± 14.1	39.0 ± 15.4	38.0 ± 12.7	40.2 ± 12.7	0.14
Gender (M/F)	12/12	6/10	4/4	11/14	62/70	0.95
Body Mass Index	22.5–26.8–28.8	21.2–25.4–29.9	20.7–23.5–30.9	21.9–23.6–26.0	21.8–24.3–28.7	0.55
Active smoking (%)	9	0	0	19	19	0.27
Atopy (%)	73	62	88	73	80	0.54
Steroid-naive (%)	8	18	12	20	23	0.82
Inhaled steroids only (%)	79	75	50	68	68	0.58
Inhaled and oral steroids (%)	13	7	38	12	9	0.15
FEV₁, % predicted	86.0 ± 17.7^†	93.9 ± 17.5	95.6 ± 18.8	95.2 ± 21.4	96.1 ± 18.7	0.21
FEV₁/FVC	69.0 ± 12.0	72.5 ± 8.1	71.3 ± 13.1	71.3 ± 13.4	73.1 ± 11.3	0.57
PEF, % predicted	90.0 ± 19.7	91.8 ± 18.5	96.9 ± 26.6	88.8 ± 26.7	97.5 ± 19.5	0.30
FEF_25–75, % predicted	53.5 ± 25.6	55.5 ± 23.0	67.2 ± 41.4	67.8 ± 35.4	67.2 ± 30.6	0.29
F_ENO (ppb)	16.8–27.2–48.1^†	12.1–6.7–29.5	16.1–27.9–43.3	13.9–24.3–55.1	13.3–21.2–37.2	0.46
Sputum eosinophils (%)	0.6–2.0–31.1^†	0.2–1.0–8.0	0.0–1.0–4.0	0.0–0.8–2.0	0.0–1.0–4.0^†††	0.36
Sputum neutrophils (%)	23.5–51.9–81.6^*,†	29.5–64.0–73.8	22.0–32.0–62.4	37.0–55.0–77.9^**,††	11.8–24.8–49.5^†	<0.0001

Clinical, lung function and inflammatory parameters in different asthma patients clusters defined by their sputum cytokine profile. Cluster 1: n = 24; IL-5-high and IL-17A-high, cluster 2: n = 16; IL-5-high and IL-10-high and IL-17 F-low, cluster 8: n = 15; IL-6-high, cluster 4: n = 25; IL-22-high, cluster 5: n = 132; normal levels of the previous cytokines with or without an IL-1β or TNF low profile. Normally distributed data were represented as mean ± standard deviation and analyzed by ANOVA. Data that were not normally distributed were represented as median and 25–75% (interquartile range) percentile and analyzed by Kruskal-Wallis test. Dunn’s Multiple Comparison test was used as a post hoc test. ^*,** p < 0.05, p < 0.01 respectively compared to cluster 5, ^{†,††,†††} p < 0.05, p < 0.01 and p < 0.001 respectively compared to mean/median level in asthmatics. FEV ₁ Forced Expiratory Volume in 1 second, FVC Forced Vital Capacity, PEF Peak Expiratory Flow, FEF _25–75% Forced expiratory Flow at 25–75% interval, F _E NO Fraction of exhaled Nitric Oxide

ISSN: 1465-993X