In T2DM patients, significant positive immune system effects were observed after 3 months of 5 g X 3/day oral glycine ingestion, including decreased proinflammatory cytokines such as interleukin-6 (IL-6), interferon-gamma (IFN-γ), tumour necrosis factor- receptor 1 (TNF-RI), resistin, and interleukin-1 beta (IL-1β) [13] (Table 1, Fig. 2, Supplementary Table A). Here, RETN is linked to type 2 diabetes mellitus.