TABLE 2

Biomarkers in the Yale Center for Asthma and Airways Disease (YCAAD), Severe Asthma Research Programme (SARP) and New York University/Bellevue Asthma Registry (NYUBAR) cohorts by YKL-40 asthma cluster

Total cohortCluster 1Cluster 2Cluster 3Cluster 4p-value
YCAAD
 Subjects15676 (49)30 (19)20 (13)30 (19)
 Sputum YKL-40 ng·mL−1#15 (0–40)10 (0–37)10 (0–26)28 (5–58)32 (8–43)0.16
 Serum IgE IU·mL−191 (25–277)77 (23–220)85 (17–328)163 (48–341)72 (30–351)0.40
FENO ppb28 (19–53)25 (18–55)43 (23–60)20 (15–35)32 (21–50)0.02
 Absolute blood eosinophil count cells·μL−1165 (86–335)136 (84–276)170 (101–322)192 (86–399)170 (91–338)0.69
 Eosinophils in sputum %#3 (1–7)2 (1–5)4 (2–8)2 (1–4)5 (2–12)0.08
 Neutrophils in sputum %#37 (27–48)34 (27–44)37 (24–45)46 (34–55)43 (29–50)0.15
 Macrophages in sputum %55 (42–65)60 (51–67)51 (42–67)47 (35–55)44 (35–58)<0.01
SARP
 Subjects16784 (50)57 (34)14 (8)12 (7)
 Serum IgE IU·mL−1116 (34–301)73 (24–191)177 (60–354)162 (18–262)270 (200–333)0.03
FENO ppb25 (16–50)21 (11–52)29 (23–63)27 (16–40)52 (16–111)0.04
 Blood eosinophils %3 (2–5)2.5 (1.8–4.0)4.0 (2.0–6.0)5.1 (4.0–7.5)4.5 (2.3–9.8)<0.01
NYUBAR
 Subjects341205 (60)97 (28)15 (4)24 (7)
 Serum IgE IU·mL−1129 (41–345)119 (31–328)197 (74–443)130 (52–278)94 (46–173)0.02

Data are expressed as n, n (%) or median (interquartile range). FENO: exhaled nitric oxide fraction. #: data available for n=113 (C1, n=54; C2, n=17; C3, n=18; C4, n=24).