In situ hybridization studies of bronchial biopsy specimens from steroid responsive asthmatics versus steroid resistant asthmatics treated with one week of prednisolone demonstrated a decrease in IL-13 mRNA+ cells after treatment in the steroid responsive group that correlated with asthma clinical improvement in contrast to the steroid resistant group that maintained IL-13 mRNA+ cells and no clinical response [66]. This evidence concerns the gene IL13 and asthma.