In a series of bronchial biopsy studies using in situ hybridization and/or immunohistochemistry, both atopic and nonatopic asthma were characterised by increased infiltration of Th2 cells secreting IL-4, the presence of FcεRII+ cells and cells that expressed mRNA for the ε germ-line transcript (Iε), and ε heavy chain of IgE (Cε) compared to nonasthmatic controls (Table 4) [44]. This evidence concerns the gene IL4 and asthma.