ABSTRACT
Systemic lupus erythematosus (SLE) is an autoimmune disease in which polymorphisms within the human leukocyte antigen (HLA) region have been associated to its etiology. For this study, HLA-DQB1, DQA1, and DRB1 genes were typed by polymerase chain reaction-sequence-specific primer in 237 individuals, taken from 74 families, who had a member with SLE, and who had their residence in the western region of Mexico; as well as in 159 ethnically matched healthy volunteers taken from 32 families. Genotype and allele frequency analysis was performed in 74 SLE patients and 54 unrelated controls. Precise three-loci identification of independent haplotypes was performed in 48 patients and 54 controls by familial segregation. Genotype distribution at each loci was concordant with Hardy-Weinberg's equilibrium in the control group. In general, no genotype effect was observed in SLE patients. Allele distribution comparison showed in the SLE group a significant increase of HLA-DQA1*0102, DQB1*0402, and DRB1*15; whereas alleles HLA-DQB1*0303 and *0501 were significantly decreased. SLE patients showed haplotype DQB1*0602-DQA1-*0102-DRB1*15 increased. As expected, patients with SLE have a reduced haplotype genetic diversity. The associations found in this study are related to an ancestral haplotype that has been observed in SLE populations of different origins.
