Zundler et al. investigated the presence of TRM in IBD patients using core characteristics of TRM (as summarized in Table 1) and observed enrichment of CD69+CD4+ T cells in the lamina propria of IBD patients with increased expression of CXCR6, CD103 and CD101, and decreased expression of KLF2 [24]. This evidence concerns the gene CD69 and inflammatory bowel disease.