Prevalência dos alelos de risco do complexo HLA DQ2 e DQ8 em celíacos no sul do Brasil

Abstract

Celiac disease (DC) is characterized as an autoimmune disorder triggered by the ingestion of prolamins present in gluten, being its main manifestation the intestinal lesion. This disorder is consequence of genetic factors, the most known and correlated with DC would be those found in the Human Leukocyte Antigen (HLA), chromosome region 6p21.31, class II (HLA-DQ). The objective of the present study was to evaluate the prevalence of HLA-DQ2 (DQA1*05 e DQB1*02) and HLA-DQ8 (DRB1*04) alleles, which are associated with increased risk of DC, and compare these results with other findings related to the diagnosis, symptoms and the presence of other related diseases, in celiac patients living in southern Brazil. A total of 140 celiacs living in the states of Santa Catarina and Rio Grande do Sul were enrolled. After signing a consent form, forms were obtained for obtaining clinical data and collected samples of oral cells for subsequent extraction of genomic DNA and genotyping of alleles by reaction in polymerase chain. Ninety eight percent of patients had at least one of the analyzed alleles. The DQ2-AB genetic profile was present in 75% of celiac patients, while the allele for DQ8 presented a prevalence of 21%. There was a significant association between the total absence of the alleles (p=0.003) and the DQ8 profile (p = 0.003) with the degree of intestinal lesion 4 by the Marsh classification. Anti-gliadin (p = 0.037), Antiendomysium (p<0.001) and Anti-transglutaminse (p=0.032) were also associated with the DQ2-AB genetic profile. These data show a high prevalence of risk alleles related to the HLA system in the population of the two southern states of Brazil. In addition, an association between the genetic profile and severity of the intestinal lesion was found, as well as the association of the DQ2-AB profile with serological test results, indicating that the genetic profile besides influencing the susceptibility of CD can influence the severity of the disease.