We identified suggestive associations between 2 immune cell traits and IBD risk (P = 4.18 × 10–5 for human leukocyte antigen-DR on CD14+ monocytes, OR: 0.902; 95% CI: 0.859–0.947; for CD39+ CD4+ T cells, P = 6.24 × 10–5; OR: 1.042; 95% CI: 1.021–1.063). Here, CD4 is linked to irritable bowel syndrome.