CD4 and colitis: Wang et al described the cases of 2 patients with therapy-refractory ICH colitis undergoing fecal microbiota transplantation (FMT).117 These patients, in addition to developing complete resolution after 1 and 2 procedures respectively, presented a substantial reduction in CD8+ T-cell density with a concomitant increase in CD4+ FoxP3+ T-cells after transplantation, offering the authors speculation on the potential mechanism by which FMT would reduce ICI-associated toxicity.