Association between HLA antigens and periodontal disease.

HLA-A, B and DR antigen frequencies were determined in three groups of periodontally diagnosed subjects: 49 patients with rapidly progressive periodontitis, 40 elderly subjects with minimal disease (considered as a resistant group) and 30 young subjects with minimal disease. The relative risk for HLA-A9 (previously reported to be associated with periodontal disease) was 15.5. HLA-A9 was present in 36.7% of the patients and 2.5% of the resistant group. HLA-A10 showed a significantly increased incidence in the resistant group (30.0%) compared to a non-periodontally diagnosed control population (9.0%), and was absent from the patient group. These findings provide additional evidence for the involvement of HLA-A9 in susceptibility to periodontitis, and suggest that A10 may play a role in resistance to the disease.