Abstract
Resistance to HIV-1 infection and delayed disease progression have been associated with a 32-bp deletion (Delta32) in the gene encoding the CCR5 chemokine receptor. In the present study we describe the modification of a nucleic acid sequence-based amplification (NASBA)-based CCR5 genotyping assay for a NucliSens Basic Kit (Organon Teknika, Durham, N.C.) format using a new target-specific sandwich oligonucleotide detection methodology. The new method permitted the use of generic electrochemiluminescent probes supplied in the NucliSens Basic Kit, whereas the original NASBA method required expensive target-specific ruthenium detection probes. The Basic Kit CCR5 Delta32 genotypic analysis was in 100% concordance with both the original NASBA assay and DNA PCR results. This study also evaluated the use of multiple specimen types, including peripheral blood mononuclear cells (PBMC), whole blood, dried blood spots, buccal scrapings, and plasma, for CCR5 genotype analysis. The sensitivities of the three assays were comparable when PBMC or whole blood was the specimen source. In contrast, when dried blood spots, buccal scrapings, or plasma was used as the sample source, the sensitivity of DNA PCR was 80.95, 42.8, or 0%, respectively, compared to 100% sensitivity obtained with the original NASBA and Basic Kit NASBA assays. Our study indicates that the NucliSens Basic Kit NASBA assay is very sensitive and specific for CCR5 Delta32 genotyping using multiple sample types.