IL23A and colitis: Analysis of cytokines predicted to activate Ifng expressing CD4+ T cells in CPI colitis included IL2 (z score 4.7, P < 1.0 × 10−27), IL7 (z score 3.8, P < 9.8 × 10−19), IL15 (z score 3.4, P < 5.2 × 10−34), IL18 (z-score 2.0, P < 4.0 × 10−25) and IL23A (z-score 2.6, P < 2.1 × 10−31) (Fig. 8a, Supplementary Table 2).