Distribution of HLA-DRB1 alleles in a mixed population with insulin-dependent diabetes mellitus from the Southeast of Brazil

Abstract

HLA class II genes are strongly associated with susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM). The present study reports the HLA-DRB1 genotyping of 41 IDDM patients and 99 healthy subjects from the Southeast of Brazil (Campinas region). Both groups consisted of an ethnic mixture of Caucasian, African Negro and Amerindian origin. HLA-DRB1*03 and *04 alleles were found at significantly higher frequencies among IDDM patients compared to the controls (DRB1*03: 48.8% vs 18.2%, P<0.005, RR = 4.27; DRB1*04: 43.9% vs 15.1%, P<0.008, RR = 4.37) and were associated with a susceptibility to the disease. DRB1*03/*04 heterozygosity conferred a strong IDDM risk (RR = 5.44). In contrast, the HLA-DRB1*11 allele frequency was lower among IDDM patients (7.3% vs 26.3% in controls), but the difference was not significant. These data agree with those described for other populations and allow genetic characterization of IDDM in Brazil.

HLA‐DQB1 Alleles May Influence the Surface Expression of DQ Molecules in Lymphomononuclear Cells of Type 1 Diabetes Mellitus Patients

“…Immunogenetic susceptibility to type 1 diabetes mellitus in Brazilians is associated with HLA-DRB1*03, -DRB1*04, -DQB1*0201 and -DQB1*0302 alleles, and protection against the development of the disease is associated with the DQB1*0602 allele [7,8]. This susceptibility pattern is similar to that seen in other populations [2].…”

Rapid genetic screening for major human leukocyte antigen risk haplotypes in patients with type 1 diabetes from Northeastern Brazil

“…This higher frequency of the DQ8 haplotype in the northeastern Brazilian population can be possibly explained by the contribution of Amerindian genome, known to be characterized by higher frequen- cies of the DQ8 [30]. It is noteworthy that the distribution of the DQ2.5 and DQ8 haplotypes in the healthy controls from Sao Paulo (Southern Brazil, mostly Caucasian ethnicity) [29] are substantially different with respect to the healthy individuals from Recife, and those in the study by Koskinen et al [22].…”

“…The presence of the DRB1*03/*04 heterozygous combined haplotype was also associated with a strong risk to develop T1D, in T1D patients from the Southeast of Brazil [29].…”

Prevalência dos marcadores imunológicos Anti-GAD e Anti-IA2 em parentes de primeiro grau de diabéticos do tipo 1 em amostra da população da Grande São Paulo

“…Observouse que haplótipos HLA-DR3 e DR4 estão presentes em 90 a 95% dos diabéticos do tipo 1 europeus caucasianos 12 . Em amostra da população brasileira com DM1, caracterizada por um alto grau de miscigenação 13-15 , evidenciouse igualmente associação desses haplótipos com a presença da doença [16][17][18] .Há aproximadamente três décadas, com a descoberta dos auto-anticorpos anti-ilhotas pancreáticas 19 , o papel da auto-imunidade na etiopatogenia do DM1 foi reforçado. Os primeiros auto-anticorpos descritos foram os anti-ilhotas (islet cell antibody -ICA) 20 e os antiinsulina (AAI) 21,22 .…”