Furthermore, the gene expression levels of tumor necrosis factor-α (TNF-α), chemokine (C-C motif) ligand 2 (CCL-2), inducible nitric oxide synthase (Nos2) and IL-17A displayed no statistical differences among the control and obese group, while the levels were elevated in the periodontitis group and combination group. The gene discussed is IL17A; the disease is periodontitis.