CD4 and asthma: Other microarray studies have found that (1) genes involved in interferon response, including GSDMB, one of the genes in the 17q21 locus whose variants are strongly associated with asthma, distinguish severe asthma epithelial cells [87], and (2) CD8+, but not CD4+, T cells have gene expression changes that distinguish severe asthma vs. mild asthma [88].