title: A simple screening approach to reduce B*5701-associated abacavir hypersensitivity on the basis of sequence variation in HIV reverse transcriptase.
abstract: BACKGROUND
  Abacavir hypersensitivity is strongly associated with the human leukocyte antigen (HLA)-B*5701 allele; however, the cost of routine high-resolution HLA typing before initiation of therapy remains prohibitive. We propose a simple approach to reduce B*5701-associated abacavir hypersensitivity based on the screening of human immunodeficiency virus (HIV) reverse transcriptase (RT) for a signature B*5701-associated cytotoxic T lymphocyte escape mutation at RT codon 245.
  
  
  METHODS
  The correlation between HLA-B*5701 and RT codon 245 variation was investigated in 392 HIV-infected, antiretroviral-naive adults who were initiating highly active antiretroviral therapy. The relationship between codon 245 variation and premature abacavir discontinuation was investigated in a larger cohort of treated individuals (n=982). Associations between HLA-B*5701 and codon 245 variants were determined using Fisher's exact test or the chi (2) test.
  
  
  RESULTS
  A very strong association between HLA-B*5701 and RT codon 245 variation was observed. Only 1 (4.2%) of 24 subjects with B*5701 harbored virus with the clade B "wild-type" amino acid 245V, compared with 278 (75.5%) of 368 who did not have B*5701 (P<.001). The sensitivity and specificity of codon 245 substitutions for predicting HLA-B*5701 were 96% and 75%, respectively, and the positive and negative predictive values were 20% and 99.6%, respectively. This association remained robust even after antiretroviral treatment was administered (negative predictive value, 100%; n=269). In abacavir-treated individuals (n=982), codon 245 substitutions were predictive of premature abacavir discontinuation (P=.02).
  
  
  CONCLUSIONS
  As HIV RT sequence is incidentally obtained as a part of routine drug-resistance testing, the examination of sequence variation at RT codon 245 could be adopted as a simple, low-cost screening method to identify individuals who could be safely treated with abacavir and/or who could benefit from HLA characterization.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, University of British Columbia, Vancouver, Canada.
authors.forename: Celia K S
authors.initials: CK
authors.lastname: Chui
authors.forename: Zabrina L
authors.initials: ZL
authors.lastname: Brumme
authors.forename: Chanson J
authors.initials: CJ
authors.lastname: Brumme
authors.forename: Benita
authors.initials: B
authors.lastname: Yip
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Phillips
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
authors.forename: P Richard
authors.initials: PR
authors.lastname: Harrigan
mesh_terms: D000328:Adult; D000483:Alleles; D019380:Anti-HIV Agents / Q000009:adverse effects*; D023241:Antiretroviral Therapy, Highly Active / Q000009:adverse effects; D000075202:Contraindications; D015224:Dideoxynucleosides / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000235:genetics*; D005260:Female; D005820:Genetic Testing / Q000191:economics / Q000379:methods*; D005838:Genotype; D054303:HIV Reverse Transcriptase / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics*; D015235:HLA-B Antigens / Q000235:genetics*; D006801:Humans; D008297:Male; D009154:Mutation; D015995:Prevalence; D018894:Reverse Transcriptase Inhibitors / Q000009:adverse effects*; D012680:Sensitivity and Specificity; D017423:Sequence Analysis, RNA; D000099227:Abacavir
chemical_list: D019380:Anti-HIV Agents; D015224:Dideoxynucleosides; D054303:HIV Reverse Transcriptase; D015235:HLA-B Antigens; D018894:Reverse Transcriptase Inhibitors; D000099227:Abacavir; C484830:HLA-B*57:01 antigen