The main finding of the present study was that H2S stimulated the secretion of IFN-γ, IL-6, IL-17, TNF-α, IL-12p40, and IL-12p70, from PBMCs of both periodontitis patients and healthy controls, while the reverse was seen for IL-1Ra, that is, H2S decreased the secretion. Here, IL17A is linked to periodontitis.