TNF and necrotizing enterocolitis: The expression of IL-2 and TGF-β (transforming growth factor β) was unchanged, but levels of IL-1β, -6, -8, and -10, MMP3 (matrix metalloproteinase 3), MMP9, and TNF-α were increased, supporting the hypothesis that cytokines have an inhibitory effect on Treg development, and that increased inflammatory cytokine expression results in decreased Treg, thus contributing to the development of NEC [32].