Ethnicity-dependent association of HLA DRB1-DQA1-DQB1 alleles in Brazilian multiple sclerosis patients

The present study focused on human leukocyte antigen (HLA) DQB1, DQA1 and DRB1 allelic variation according to ethnicity and analyzed whether susceptibility to multiple sclerosis (MS) depends on population characteristics.

Eighty-eight healthy African-Brazilians and 92 healthy white Brazilians living in Rio de Janeiro City were selected and the HLA phenotype between the two ethnic groups was compared with 44 MS patients of African descent and 40 patients of European descent. HLA class II genes were performed using polymerase chain reaction (PCR) and PCR-sequence-specific primer amplification.

DQA1*0201-0301 alleles were associated with the white Brazilian population (P < 0.001). The DRB*1501 allele was present in White Brazilians (P=0.003), and DRB1*03-1503 in African-Brazilians. The DRB1*1501 allele confers an ethnicity-dependent MS susceptibility in White patients and the DQB1*0602 allele confers genetic susceptibility regardless of ethnicity.

Heterogeneous phenotypes occur in both Brazilian ethnic groups. Taking into account that the response to immunomodulator drugs for MS treatment changes according to the DRB1*1501 allele and African-American MS patients presented poor response to the interferons, phenotype heterogeneity of HLA loci found in this study could influence therapeutic decisions in the Brazilian MS population.