IL-17 mRNA and numbers of IL-17–positive lymphocytes are also increased in BAL from patients with asthma.10, 11, 40 A recent study that has investigated the TH17 high phenotype in adult asthma has shown that a TH17 high signature is associated with steroid-dependent moderate-to-severe asthma and eosinophilia.41 The gene discussed is IL17A; the disease is asthma.