Immune responses to abacavir in antigen-presenting cells from hypersensitive patients

Annalise M. Martin, Coral Ann Almeida, Paul Cameron, Anthony W. Purcell, David Nolan, Ian James, James McCluskey, Elizabeth Phillips, Alan Landay, Simon Mallal

Research output: Contribution to journalArticlepeer-review


OBJECTIVES: A potentially life-threatening hypersensitive reaction accompanies the use of HIV nucleoside analogue abacavir (ABC) in 4-8% of Caucasian individuals. HLA-B*5701 and Hsp70 493T alleles have been shown to predict susceptibility to this hypersensitivity. DESIGN AND METHODS: This study was undertaken to provide a mechanistic understanding of the highly significant genetic association of HLA Class I and Hsp70 alleles with ABC hypersensitivity. RESULTS: In this study an ABC-induced localization of intracellular HSP70 to endosomal vesicles of antigen-presenting cells was demonstrated. This ABC-stimulated redistribution of endogenous HSP70 was substantially higher in the genetically homogenous HLA-B*5701, Hsp70 493T ABC-hypersensitive individuals and ABC-naive individuals in comparison with the heterogenous tolerant patients (P = 0.023). Increased expression of HSP70 was also detected in the hypersensitive group as measured by flow cytometry (P = 0.032). Blocking of HSP70 and HSP70 cell surface receptors CD14 and TLR2 abrogated ABC-stimulated HSP70 redistribution in sensitized individuals to basal levels (P < 0.004). In addition, the use of TcRαβ and HLA-B57/58 antibodies also ablated the expression of HSP70. Cells expressing the activation markers CD40 were increased after ABC stimulation in the hypersensitive patients (P = 0.006). ABC-stimulated interferon-gamma levels were higher in hypersensitive patients in comparison with ABC-tolerant individuals with a mean of 123.54 versus 0 pg/ml (P = 0.001). CONCLUSION: The present data indicates that ABC stimulates an innate immune response and activates antigen-presenting cells via the endogenous HSP70-mediated Toll-like receptor pathway in genetically susceptible individuals potentially initiating the immuno-pathological hypersensitive response.

Original languageEnglish (US)
Pages (from-to)1233-1244
Number of pages12
Issue number10
StatePublished - Jun 2007
Externally publishedYes


  • Abacavir hypersensitivity
  • Cell activation
  • HLA-B*5701
  • Interferon gamma
  • Monocytes

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology
  • Infectious Diseases


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