Polymorphisms of Fcγ-receptors RIIa, RIIIa, and RIIIb in patients with adult periodontal diseases

Abstract

Polymorphisms influencing the binding affinity between the Fcγ receptors and IgG of different subclasses are thought to be of importance in the individual susceptibility to infections with Gram-negative bacteria contributing to periodontal disease. One hundred and fifty-four Caucasian subjects were clinically and radiographically examined for their periodontal status and genotyped for their allelic pattern of FcγRIIa, FcγRIIIa, and FcγIIIb polymorphism. In assessing periodontitis according to mean probing depth and attachment loss, no differences were found in allele frequencies or combined allotypes between the subjects with mild or moderate and those with severe signs of periodontitis. However, the extent and severity of bone loss were significantly associated with the genotype of the receptor FcγRIIIa. An increased risk of severe bone destruction was observed in individuals carrying the FcγRIIIa-VV genotype (OR = 5.3; 95% Cl 1.4-26.2). FcγRIIIb is in linkage disequilibrium with FcγRIIIa. Hence it is also related to periodontal disease. There is no indication of an association between the polymorphism of FcγRIIa and periodontitis. The results are evidence that the FcγRIIIa genotype coding for the high affinity receptor imposes an additional risk of bone loss as does the FcγRIIIb genotype coding for the low affinity receptor.