Elevated IL-12 production and higher rate of CD4+ T conventional (Tconv) cell proliferation in NOD mice have been implicated in the progression of type 1 diabetes.However, the underlying mechanisms remain largely unknown, even though enhanced activation of the IκB kinase (IKK)/NF-κB pathway has been revealed to mediate IL-12 overproduction.Here, we report that deviated p38 MAPK activation also contributes to elevated IL-12 production with a mechanism involving MAPK-activated protein kinase-2 (MK-2)-mediated stabilization of IL-12p40 mRNA.