Interleukin-1 gene polymorphism and periodontal status. A case-control study.

OBJECTIVES: This case-control study examined polymorphisms at the interleukin-1 gene in relation to periodontal status, subgingival bacteria and systemic antibodies to periodontal microbiota.

METHODS: 132 periodontitis patients were age- and gender-matched with 73 periodontally intact controls. Full-mouth clinical assessments of the periodontal tissues were performed. Subgingival plaque samples (2440 in total) were analyzed by genomic DNA probes, and serum IgG antibodies to periodontal microbiota were assessed by an immunoassay. Polymorphisms in the IL-1A gene at position +4845 and the IL-1B gene at position +3953 were studied by PCR. A composite positive genotype was defined as at least one rare (#2) allele present at each locus.

RESULTS: No skewed distribution of the composite genotype was observed between cases and controls (45.2% vs 41.7%). In cases, both the composite genotype and the number of #2 alleles were positively correlated with the severity of attachment loss. No relationship between genotype and subgingival microbial profiles was observed. Genotype positive patients revealed both overall lower serum antibody levels and specific titers against selected bacteria.

CONCLUSIONS: The composite genotype failed to distinguish between periodontitis patients and controls but correlated in patients with the severity of the disease and the antibody responses to periodontal microbiota.