Overall, the numbers of IL-17-positive cells in each bronchial biopsy was low and only 5 IL-17 positive cells were identified from 13 healthy biopsies and 11 IL-17 positive cells identified from 25 severe asthma biopsies (representative photomicrograph from both a healthy individual and a severe asthma patient shown in Fig. 1a), although 15 out of 25 severe asthma bronchial biopsies (60%) contained IL-17 positive cells compared to 6 out of 13 biopsies from healthy volunteers (46%). The gene discussed is IL17A; the disease is asthma.