MAP3K8 and Thrombocytopenia: The TPL-2/ERK1/2 signaling pathway regulates cytokine and chemokine production in inflammatory responses.9, 10, 11 Studies with TPL-2–deficient Map3k8−/− mice have indicated that TPL-2 promotes inflammation in models of endotoxin shock, pancreatitis, liver fibrosis, and thrombocytopenia.9, 12, 13, 14 TPL-2 is also required for proficient immunity to intracellular bacterial and protozoan infection.15, 16