Th2 cells are higher in women, but not men, with severe asthma
Examining asthmatics stratified by sex and severity showed, as expected, both women and men with severe asthma were taking higher daily doses of ICS than those with mild/moderate disease (Table 2). Women with severe asthma, however, were more likely to be hospitalized for their asthma, to have more neutrophils, higher serum IL-13 and more circulating peripheral blood Th2 cells than women with mild/moderate asthma (Table 2, Fig. 1A). In contrast, comparison of men with mild/moderate and severe asthma showed no differences in type 2 inflammation (Table 2, Fig. 1A). Women with severe asthma had more hospitalizations and higher proportions of circulating Th2 cells than men with severe asthma (Table 2; Fig. 1A). Women also had more Th2 cells when those on oral CS (>50% of the year) or anti-type 2 biologic therapy (anti-IgE or anti-IL-5) were removed from the analysis (Fig. 1B). Though men and women with asthma were taking similar amounts of ICS (Table 1), only women exhibited positive correlations between total daily dose of ICS and circulating Th2 cells, while CRTh2 mRNA and eosinophils (Fig. 1C, 1E and Table S1) were inversely correlated with FEV1(Fig. 1G). No relationships between these parameters were observed in men (Figs. 1D, F, H). Collectively, these observations suggest that asthma severity in women associates with type 2 inflammation.