title: HLA-B Bw4 alleles and HIV-1 transmission in heterosexual couples.
abstract: BACKGROUND
  Genetic factors may play a role in the transmission of HIV-1. Because HLA-B alleles influence HIV-1 disease progression and viral levels, they might also influence HIV-1 transmission.
  
  
  OBJECTIVE
  To investigate if the presence of HLA-B alleles with the Bw4 epitope in HIV-1-infected men decreased the risk of transmission to their female sex partners.
  
  
  METHODS
  The study comprised 304 HIV-1-infected men with hemophilia and 325 female sex partners. HLA class I genes were amplified using sequence-specific primers. Products of the polymerase chain reaction were blotted on nylon membranes and hybridized with sequence-specific oligonucleotide probes. Logistic regression models were used to calculate odds ratios (OR) and 95% confidence intervals (CI) for HIV-1 infection among the women.
  
  
  RESULTS
  Among the 325 women, 44 (13.5%) were infected with HIV-1. HIV-1 infection in the women was associated with the HLA-B genotype of their male partner [Bw6/Bw6, 22/118 (18.6%); Bw4/Bw6, 18/154 (11.7%); Bw4/Bw4, 4/53 (7.6%)]. Compared with men who were homozygous for Bw6, men who carried Bw4 were about half as likely to have transmitted HIV-1 to their female partner (OR, 0.52; 95% CI, 0.27-0.98; P = 0.04). Transmission was higher among couples in which the man's ethnicity was other than White (OR, 2.60; 95% CI, 1.25-5.40; P = 0.01), but the association between HIV-1 transmission and HLA-B genotype was not confounded by race.
  
  
  CONCLUSIONS
  The presence of HLA-Bw4 in HIV-1-infected men was associated with a decreased risk of male-to-female HIV-1 transmission, which suggests that these alleles reduce infectivity for HIV-1.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, MD 20892, USA.
authors.forename: Tania M
authors.initials: TM
authors.lastname: Welzel
authors.forename: Xiaojiang
authors.initials: X
authors.lastname: Gao
authors.forename: Ruth M
authors.initials: RM
authors.lastname: Pfeiffer
authors.forename: Maureen P
authors.initials: MP
authors.lastname: Martin
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: O'Brien
authors.forename: James J
authors.initials: JJ
authors.lastname: Goedert
authors.forename: Mary
authors.initials: M
authors.lastname: Carrington
authors.forename: Thomas R
authors.initials: TR
authors.lastname: O'Brien
mesh_terms: D000293:Adolescent; D000328:Adult; D000483:Alleles; D018562:Disease Transmission, Infectious; D004812:Epidemiologic Methods; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D015658:HIV Infections / Q000235:genetics* / Q000635:transmission*; D015497:HIV-1; D015235:HLA-B Antigens / Q000235:genetics*; D006467:Hemophilia A / Q000150:complications; D020010:Heterosexuality; D006650:Histocompatibility Testing; D006801:Humans; D008297:Male
chemical_list: D015235:HLA-B Antigens; C042388:HLA-Bw4 antigen