IL-10-deficient mice develop spontaneous colitis due to host immune dysregulation, which closely mimics the pathogenesis of human IBD.33 Here, a similar effect was observed in IL-10-deficient mice given elderly microbiota transplantation, as evidenced by increased weight loss, colonic shortening, and histopathological scores (Figure S2A-K). The gene discussed is IL10; the disease is colitis.