Background: The genes encoding the human leukocyte antigens (HLAs; major histocompatibility complex [MHC]) have been considered candidate markers for periodontitis because they are involved in regulating immune responses. Several studies have examined this association, and despite the inconclusive results, the antigens HLA-A9 and HLA-B15 have been found to be consistently associated with the destructive forms of periodontitis in many populations. Ethnic factors are considered to be a major variable for evaluating the predisposition to the disease. The purpose of the present study was to: 1) assess the association of HLA-A*9 and HLA-B*15 with generalized aggressive periodontitis (GAgP) and 2) evaluate the role of these genetic risk factors in influencing the severity of GAgP in a South Indian population.
Methods: Forty GAgP patients (cases) and 80 periodontally and systemically healthy subjects (controls) participated in this study. HLA-A*9 and HLA-B*15 typing was carried out using the polymerase chain reaction with sequence specific primers (PCR-SSP)-based molecular method.
Results: HLA-B*15 was a significant risk factor for GAgP and was positively correlated with the disease severity, whereas HLA-A*9 had no association with the disease. The haplotype of HLA-A*9:B*15 did not impart any additional risk for GAgP compared to that imparted by HLA-B*15 alone.
Conclusions: To our knowledge, this is the first report on HLA-B*15 association with GAgP in an Indian population. The finding of HLA-B*15 as a risk factor may have potential use in the future management of GAgP. The precise disease-causing mechanism of this HLA disease association and whether this association is "causal" or "casual" need to be evaluated further.