Importantly, among CD4− T cells, the fraction that was TH17/type 3-polarized was sixfold increased (78% vs 13%; P < 0.001) in NEC compared to adults (Fig. 5c), and, albeit not significantly, the same was the case in CD4+ T cells (1.5-fold in WT NEC and threefold in IL-37tg NEC, Supplementary Fig. 5i). Here, CD4 is linked to necrotizing enterocolitis.