Multi-centre evaluation of HLA-B*5701 allele detection by SSP-PCR typing: a quality assurance initiative

Hammond, E., Almeida, C., Mamotte, C., Nolan, D., Phillips, E., Schollaardt, T., Gill, M.J., Angel, J.B., Neurath, D., Li, J., Giulivi, T., McIntyre, C., Koultchitski, G., Wong, B., Reis, M., Rachlis, A., Cole, D.E., Chew, C.B., Neifer, S. and Mallal, S. (2007) Multi-centre evaluation of HLA-B*5701 allele detection by SSP-PCR typing: a quality assurance initiative. In: 4th International AIDS Conference on HIV Pathogenesis, Treatment and Prevention, 22 - 25 July, Sydney, Australia.

Abstract

Objectives: HLA-B*5701 strongly and specifically predicts susceptibility to abacavir hypersensitivity (ABC HSR), however implementation of routine genetic screening into clinical practice requires that testing be both practical and accurate. We assessed the proficiency of HLA-B*5701 typing among numerous laboratories using a sequence specific primer (SSP)/ PCR assay.

Methods: DNA was distributed to 6 laboratories for blinded typing of the HLA-B*5701 allele. Panel A (n=10 samples; n=6 laboratories) included 3 HLA-B*5701 positives as well as other closely related HLA-B alleles and B17 subtypes (B*5702, B*5703, B*5704 and B*5801). Panel B (n=96 samples; n=4 laboratories) included 36 B*5701 positives among a broad spectrum of other B alleles. Result interpretation was based on the presence of 3 amplicons (growth hormone control, generic HLA-B*57 and HLA-B*5701 specific amplicons). Laboratories A and B also submitted 96 routine samples, typed by the same methodology, to the reference centre for additional analysis by sequence based typing (SBT).

Results: All laboratories correctly typed panel A samples for HLA-B*5701 carriage, and also correctly identified non-B*5701 alleles within the HLA-B57/58 group. Laboratories A, B and C identified HLA-B*5701 alleles in panel B with 100% sensitivity and 100% specificity. Laboratory D reported one false negative B*5701 result due to an error in sample selection.

Five and four percent of the routine samples typed by laboratories A and B respectively, were positive for HLA-B*5701. The results obtained by both laboratories and that generated by the reference laboratory using SBT were fully concordant

Conclusions: Detection of HLA-B*5701 alleles among laboratories was 100% specific and 99.4% sensitive, indicating that participating HIV providers were currently offering effective screening for individuals who might benefit from abacavir. Accurate reporting of HLA-B*5701 status is critical for the safe administration of this drug and participation in QA programs by all sites who report HLA-B*5701 status should be promoted.

Item Type:	Conference Item
Murdoch Affiliation(s):	Institute for Immunology and Infectious Diseases
Conference Website:	http://www.iasociety.org/
URI:	http://researchrepository.murdoch.edu.au/id/eprint/15726

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