IL21 and type 1 diabetes mellitus: The current study suggests that the protective role of probiotics among people with T1DM is most likely related to modulation of IL-21 and IL-22 levels, as shown by the improvement in their levels after probiotic supplementation; patients with T1DM who received probiotic supplementation had markedly decreased IL-21 and significantly higher IL-22 at the end of the follow-up compared with baseline levels or the placebo.