In smoking and systemically healthy patients, IL-7, IL-12, and IL-23 showed increased concentrations, while concentrations of IL-2, IL-7, IL-12, IL-17, IL-21, IL-23, MIP-1α, and TGF-β were higher in smoking DM patients (p < 0.05) (Table 5). This evidence concerns the gene IL21 and diabetes mellitus.