Performance comparison of an in-house integrase genotyping assay versus the ViroSeq™ Integra48, and study of HIV-1 integrase polymorphisms in Hong Kong

Abstract Background Integrase inhibitors are recently prescribed to multi-class drug resistant HIV-1 patients in Hong Kong. Unlike pol gene, there are no FDA-approved genotypic resistance tests available for int . Limited studies compared the performance between an in-house and commercial integrase genotyping system. Information on baseline polymorphisms was also insufficient in our region. Objectives To compare integrase genotyping data obtained from an in-house and ViroSeq™ Integra48 assay, and to illustrate integrase polymorphisms on HIV-1 B and non-B subtypes in Hong Kong. Study design A total of 283 HIV-1 patients were recruited during 2006–2012 in Hong Kong. All samples were genotyped by an in-house assay for pol and int separately, and 46 of them were further genotyped by ViroSeq™ Integra48. Polymorphisms and resistance mutations were analyzed by Stanford HIV Drug Resistance Database. Results The included patients were mainly infected by HIV-1 subtype B (38.9%) and CRF01_AE (43.1%), followed by CRF07_BC (5.3%), C (3.9%), CRF02_AG (2.8%), D (1.4%), CRF08_BC (1.1%) or others (3.5%). Of 46 samples genotyped by ViroSeq™ and the in-house assays, all major and minor resistance mutations were concordant. Integrase major resistance mutations were identified in two CRF01_AE raltegravir-treated patients. Integrase minor resistance mutations were observed in subtypes B and CRF01_AE. Conclusions With 25% of the commercial cost, the in-house integrase genotyping assay managed to regenerate over 96% concordant results as good as the RUO ViroSeq™ assay. Further investigations are required to understand the effect on integrase minor mutations, which are present in many subtype B and CRF01_AE samples.