Human leukocyte antigen class II alleles in white Brazilian patients with celiac disease

Background: Celiac disease (CD) is a permanent gluten intolerance disorder characterized by malabsorption, intestinal mucosa villus atrophy, and crypt hyperplasia. Clinical and histologic features improve in persons consuming a gluten free diet. The pathogenesis of CD involves environmental, genetic , and immunologic factors. Methods: The frequencies of human leukocyte antigen (HLA) class II alleles were evaluated in white Brazilian patients who had CD and compared with tho se observed in healthy individuals from the same geographical area (Ribeira o Preto, Sao Paulo) and of similar ethnic background. Twenty-five patients with CD, 11 females and 14 males, and 91 control individuals were studied. The HLA class II alleles were typed using amplified DNA hybridized with seq uence-specific primers. Statistical analysis was performed using the two-ta iled Fisher exact test. The relative risk (RR), etiologic fraction (EF), an d preventive fraction (PF) were also estimated. The EF represents the attri butable risk for the development of CD at the population level, whereas PF represents the protective risk. Results: The frequency of the HLA-DRB1*03, HLA-DRB1*07, and HLA-DQB1*02 all eles was significantly increased in patients. The RR conferred by these all eles was 5.35, 7.15, and 10.6, respectively, and the EF was 48.7%, 44.7%, a nd 76%, respectively. The frequency of HLADQB1*06 alleles was significantly decreased in CD patients, conferring an RR of 0.08 and a PF of 48%. Conclusions: The results show that HLA-DRB1*03, HLA-DRB1*07, and HLA-DQB1*0 2 alleles conferred susceptibility to CD in Brazilian patients. In contrast , HLADQB1*06 alleles conferred protection against development of the diseas e.