Eventually, this meta-analysis included 91 articles involving 138 case-control studies of 5642 T2DM patients and 7378 healthy controls: 13 for IL-6 [34–46], 22 for TGF-β [23, 47–67], 7 for TNF-α [34–36, 38, 45, 68, 69], 6 for CD4+CD25+Foxp3+Treg [70–75], 15 for IL-10 [76–90], 18 for CD4+CD25+Treg [70, 72, 74, 75, 91–104], and 10 for IL-17 [105–114]. This evidence concerns the gene IL17A and type 2 diabetes mellitus.