Association of dental caries with HLA Class II allele in Brazilian adolescents.

The purpose of this study was to evaluate the association between the frequencies of DR and DQ HLA class II alleles and the prevalence of dental caries in Brazilian adolescents. The study sample consisted of 164 adolescents aged 15- 19 years. For the assessment of caries experience the DMFT index was used, according to World Health Organization criteria. DNA samples of the adolescents were extracted from oral mucosa cells. The amplification of the alleles HLA-DR and HLA-DQ was carried out by polymerase chain reaction with sequence-specific primers (PCR-SSP). The products of PCR-SSP were electrophoresed and analyzed in agarose gel. Statistical analysis was performed using simple and multiple logistic regression to test the association between the adolescents' caries experience and the presence of HLA-DR and -DQ alleles. Sociodemographic covariates were included in the model. The significance level for all analyses was p < 0.05. The prevalence of caries was 60.4% and the mean DMFT was 2.41 ± 2.53. Adolescents positive for HLA-DQ2 allele were less likely to have dental caries than their counterparts who were negative for this allele (OR = 0.33, CI 0.16-0.66), and those whose mothers presented low levels of education were 2.01 (CI 1.02-3.97) times more likely to have dental caries. There was no statistical difference between HLA-DR4, -DQ4, -DQ5, -DQ6 and dental caries. Our data provide evidence that genes within the MHC, especially the DQ2 group, may influence susceptibility to dental caries in Brazilian adolescents.