IL17A and type 1 diabetes mellitus: On the other hand, serum levels of IL-17 or IL-23 – a cytokine known to maintain Th17 cells (14, 15), as well as genetic variants in other cytokine genes within the Th17 pathway, such as IL-17 (14), IL-21 (16), and IL-27 (17), were found by our group not to influence T1D susceptibility, clinical phenotype or presence of autoantibodies.