IL17A and crescentic glomerulonephritis: Accordingly, patients with ANCA-associated vasculitis presented elevated serum levels of IL-17A and other Th17-related cytokines, such as IL-23 [89], whereas in ANCA-associated crescentic glomerulonephritis patients, only serum IL-17C but not IL-17A, F, or E levels were increased [90].