Clinical and endoscopic remission was associated with a greater reduction in CCR9 expression on circulating T cells and monocytes.45 This led to a subsequent double-blind placebo-controlled trial of leukapheresis to deplete CCR9+ monocytes in ulcerative colitis, which was associated with improvement in the endoscopic Mayo score compared with placebo (Table 2).56 The gene discussed is CCR9; the disease is ulcerative colitis.