In conclusion, the hyperglycemia caused by diabetes can directly or indirectly reduce the expression level of anti-inflammatory cytokines such as IL-4, IL-10, and TGF-β1 and increase the expression level of proinflammatory cytokines such as IL-1β, IL-6, IL-8, IL-17, and TNF-α, all of which together enhance the periodontal inflammatory performance (79, 80). Here, IL4 is linked to diabetes mellitus.