We then examined the individual subpopulations in these clusters; in CD4 cluster 16, we identified a significantly higher frequency of CD4+ CRTH2+ cells among T effector memory (TEM) and T central memory (TCM) cells in T2 groups with and without asthma (Figure 2A–D; Supporting Information S1: Figure S3). The gene discussed is PTGDR2; the disease is asthma.