IL17A and combined immunodeficiency: However, anti-IL-17 was ineffective in preventing T1D in NOD–SCID (nonobese diabetic/severe combined immunodeficiency) mice13,14 and we cannot rule out a relevant effect of the IL-12-blocking component of ustekinumab to stop a diversion to the TH1 cell pathway after TH17 cell inhibition or effects on other T cell subsets such as mucosa-associated invariant T cells57, which may play a role in T1D58.