title: Ethnicity-dependent association of HLA DRB1-DQA1-DQB1 alleles in Brazilian multiple sclerosis patients.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Neurology Department, Federal University of Rio de Janeiro State (UNIRIO), Rio de Janeiro, Brazil. sonizavleon@globo.com
authors.forename: S V
authors.initials: SV
authors.lastname: Alves-Leon
authors.forename: R
authors.initials: R
authors.lastname: Papais-Alvarenga
authors.forename: M
authors.initials: M
authors.lastname: Magalhães
authors.forename: M
authors.initials: M
authors.lastname: Alvarenga
authors.forename: L C S
authors.initials: LC
authors.lastname: Thuler
authors.forename: O
authors.initials: O
authors.lastname: Fernández y Fernandez
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D044383:Black People / Q000235:genetics* / Q000706:statistics & numerical data; D001938:Brazil / Q000453:epidemiology; D004351:Drug Resistance / Q000235:genetics; D005260:Female; D018740:Genetic Heterogeneity; D006683:HLA-DQ Antigens / Q000235:genetics*; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; D006684:HLA-DR Antigens / Q000235:genetics*; D059811:HLA-DRB1 Chains; D006801:Humans; D007372:Interferons / Q000627:therapeutic use; D008297:Male; D009103:Multiple Sclerosis / Q000188:drug therapy / Q000208:ethnology* / Q000235:genetics*; D010641:Phenotype; D044465:White People / Q000235:genetics* / Q000706:statistics & numerical data; D001741:Black or African American
chemical_list: D000970:Antineoplastic Agents; D006683:HLA-DQ Antigens; D059848:HLA-DQ alpha-Chains; D059866:HLA-DQ beta-Chains; C069050:HLA-DQA1 antigen; C069051:HLA-DQB1 antigen; D006684:HLA-DR Antigens; D059811:HLA-DRB1 Chains; D007372:Interferons