Use of the ELISpot assay to detect abacavir- and nevirapine-induced IFN-g responses in PBMC from HIV-infected patients with abacavir or nevirapine hypersensitivity reactions
Keane, N., Lucas, A., Netto, J., Almeida, C., Martin, A., Marriott, D., Kelleher, A., Phillips, E., Nolan, D. and Mallal, S. (2007) Use of the ELISpot assay to detect abacavir- and nevirapine-induced IFN-g responses in PBMC from HIV-infected patients with abacavir or nevirapine hypersensitivity reactions. In: 4th International AIDS Conference on HIV Pathogenesis, Treatment and Prevention, 22 - 25 July, Sydney, Australia.
Objectives: Abacavir and nevirapine drug hypersensitivity reactions are common causes for early discontinuation of both drugs in patients initiating antiretroviral therapy. Rapid and severe reactions on rechallenge and associations with HLA alleles support the involvement of immunogenetic mechanisms for both these syndromes. The ELISpot assay detects antigen-induced IFN-g responses within 24-48 hours after blood collection. Our study investigated the use of the ELISpot assay to detect abacavir- and nevirapine- induced IFN-g responses in HIV-infected patients who had previously experienced a clinically diagnosed hypersensitivity reaction.
Methods: Peripheral Blood Mononuclear Cells isolated from six HIV-infected patients with a previous abacavir hypersensitivity reaction (6/6 HLA-B*5701), ten patients with a previous nevirapine hypersensitivity reaction (8/10 HLA-DR*01) characterized by fever, rash or hepatitis within 8 weeks of initiating the drug, healthy controls and drug tolerant patients were also included in the IFN-g ELISpot assay (n=10).
Results: Anti-CD3-induced IFN-g responses were detected in samples from all HIV-infected patients. Abacavir-induced IFN-g responses were detected in two patients with abacavir hypersensitivity (105 and 490 spot forming units/million cells respectively) and three sequential samples from a patient with nevirapine hypersensitivity (245, 195 and 710 spot forming units/million cells). Two of three patients with positive drug-induced IFN-g responses had samples collected within two months of experiencing their hypersensitivity reaction. No drug-induced IFN-g responses were detected in samples from tolerant patients or healthy controls.
Conclusions: The ELISpot assay is a novel technique for exploring the immunopathogenesis of abacavir and nevirapine associated hypersensitivity. While numerous pharmacological and immunological explanations exist for negative responses, longitudinal follow up of positive responses and CD4+ and CD8+ T cell depletion studies will give further insight into the mechanism of abacavir and nevirapine immune mediated hypersensitivity.
|Publication Type:||Conference Item|
|Murdoch Affiliation:||Institute for Immunology and Infectious Diseases|
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