Based on periodontal status, the group with periodontitis (smokers and nonsmokers) had significantly higher plasma sRANKL, TNF, a proliferation-inducing ligand (APRIL and BAFF) and lower OPG (P < 0.01) [101], and higher salivary OC (P < 0.05) [102] than the healthy control group (smokers and nonsmokers without periodontitis). The gene discussed is TNFSF13B; the disease is periodontitis.