VIP and autoimmune thrombocytopenic purpura: In summary, VIP/PACAP levels in the model control group of ITP mice were decreased in brain, colon, and serum, and P53 protein expression and apoptosis rate in mesenteric lymph node lymphocytes were abnormally increased, and cytokine changes such as elevated IFN-γ, decreased IL-4 and IL-10, and elevated IL-17A were observed.