Research Article HLA Haplotypes and Genotypes Frequencies in Brazilian Chronic Periodontitis Patients

License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Human leukocyte antigens (HLA) have a pivotal role in immune response andmay be involved in antigen recognition of periodontal pathogens. However, the associations of HLA with chronic periodontitis (CP) have not been previously studied in the Brazilian population. In an attempt to clarify the issue of genetic predisposition toCP, we examined the distribution ofHLA alleles, genotypes, and haplotypes in patients from Southern Brazil. One hundred and eight CP patients and 151 healthy and unrelated controls with age-, gender-, and ethnicity-matched were HLA investigated by polymerase chain reaction with sequence specific oligonucleotides. To exclude smoking as a predisposing factor, statistical analyses were performed in the total sample and in nonsmoking individuals. The significant results showed a positive association of the A∗02/HLA-B∗40 haplotype with CP (total samples: 4.2 % versus 0%