The ancestry of the HLA-DRB1*15 allele predisposes the Mexican mestizo to the development of aplastic anemia

Abstract

Aplastic anemia (AA) is a hematological disorder characterized by pancytopenia in peripheral blood and hypoplasia in the bone marrow; the majority of cases have no known etiology, but it is thought that genetic and environmental factors can be involved in its pathogenesis. From the genetic viewpoint, it has been reported a significant increase frequency of the human leukocyte antigen HLA-DRB1(∗)15 in patients with AA as compared to ethnically matched healthy controls, this is true in different populations worldwide, which would suggests that this allele participates in the immune regulation of the disease.

Objective: To determine gene frequencies of HLA-DRB1 alleles in Mexican mestizo patients with AA.

Methods: We analyzed and compared the HLA-DRB1 alleles in 36 Mexican mestizo patients (female gender, n=13; male gender, n=23) with AA to those present in 201 umbilical cord blood (UCB) samples as a control group, this was done by means of the polymerase chain reaction-single specific primer (PCR-SSP) technique.

Results: Analysis of gene frequencies of HLA-DRB1(∗) alleles exhibits a significant increase of HLA-DRB1(∗)15 allele in the group of patients with AA as compared to those present in the control group (15.27% vs. 2.23%, respectively; p=1×10(-5); odds ratio [OR]=9.3; 95% confidence interval [95% CI]=3.2-27.8).

Conclusions: Our results showed a positive association of the DRB1(∗)15 allele in Mexican patients with aplastic anemia, which coincides with that reported internationally. In addition, we think that this allele was introduced to the Mexican population structure inherited from European ancestry.