Analysis of the requirement for IL-23 in colitis-associated changes in extramedullary hematopoiesis showed a significantly reduced, although not completely absent, accumulation of GMP in the BM and periphery of T cell transferred Rag1−/−Il23p19−/− mice that developed mild intestinal inflammation (Figure S6D; Hue et al., 2006). This evidence concerns the gene IL23A and colitis.