Increased frequency of FcγRIIIb-NA1 allele in periodontitis-resistant subjects in an elderly Japanese population

Many elderly people show minimum periodontal tissue destruction, which might be partly due to genetic advantages in host immune response against periodontopathic bacteria. The human IgG Fc receptor IIIb on neutrophils bears a NA1-NA2 polymorphism. The Fc gamma RIIIb-NA1 displays a more efficient interaction with IgG1- and IgG3-opsonized bacteria, compared with the Fc gamma RIIIb-NA2. We investigated a 70-year-old Japanese population (n = 599) to determine whether the Fc gamma RIIIb polymorphism was associated with resistance to periodontitis. Among subjects with greater than or equal to 20 teeth present, periodontitis-resistant (n = 46) and periodontitis-susceptible groups (n = 73) were selected based on the percentage of sites with greater than or equal to 4 nim probing attachment loss in the entire dentition. The Fc gamma RIIIb-NA1 allotype was overrepresented in the periodontitis-resistant group, compared with the periodontitis-susceptible group (chi (2) = 4.89, p = 0.03, odds ratio = 1.87, 95% CI, 1.07 to 3.28). This suggests that Fc gamma RIIIb-NA1 may be associated with resistance to periodontitis.