The main effects of IL-12 are A critical role in Th1 differentiation Induction of proliferation of Th1 cells, CD8 T cells, gamma-delta T cells, and NK cells and their production of IFN-gamma Enhancement of NK and CD8 T-cell cytotoxicity Clinical relevance of IL-12 includes For anti-IL-12 mAb, treatment of plaque psoriasis and psoriatic arthritis IL-13 is produced by mast cells and Th2 cells.