IL31 and asthma: Spearman’s rank correlation analysis showed that serum IL-31 levels in patients with asthma correlated positively with serum total IgE levels and negatively with FEV1 (r = 0.437, p < 0.01 and r = −0.431, p < 0.01, respectively), but not with the percentage of peripheral blood eosinophils (r = 0.254, p = 0.096) (Fig. 5).