In particular, the analysis revealed that the levels of IL-1α, IL-1β, IL-4, IL-8, IL-10, IL-12p70, IL-17, CCL2/MCP-1, CCL3/MIP-1α, and TNF-α in the saliva of patients with periodontal disease were more than twice as high as those in the saliva of subjects without periodontal disease (data not shown). The gene discussed is CCL2; the disease is periodontal disorder.