Overexpression of IL-12, IL-23 or their receptors is implicated in the development of several autoimmune diseases IL-23 IL-12 IL-23 IL-12 IL-23 IL-12 IFNγ Naive T cell IFNγ Th1 IFNγ Th1 IL-17F IL-22 Naive T cell IL-17F IL-22 Naive T cell IFNγ Th17 Th17 Naive T cell IFNγ IFNγ IL-17A IL-17A Autoimmune disorders eg psoriasis

Ustekinumab blocks binding of IL-12 and IL-23 to their receptors, thereby reducing the autoimmune response IL-12 IL-23 IL-23 IL-12 IL-23 IL-12 IFNγ Naive T cell Th1 IL-17F IL-22 Naive T cell Naive T cell IFNγ Th17 Naive T cell IFNγ IL-17A Autoimmune disorders eg psoriasis