Evaluation of the Roche COBAS® TaqMan® HIV-1 test for quantifying HIV-1 RNA in infected cells and lymphoid tissue

Lymphoid tissue is the main reservoir of HIV-1 in infected individuals. In this study the COBAS® TaqMan® HIV-1 test was evaluated for use with the High Pure System (HPS), for quantifying HIV-1 RNA in infected cells and lymphoid tissue specimens. Serial dilutions of 8E5-LAV1 infected T-cells into SUP-T1 cells and 44 tonsil specimens were examined. Some modifications of the test were required, such as the removal of residual DNA and the HIV-1 RNA output copies were adjusted to the sample input and expressed as HIV-1 RNA copies/μg of total RNA. The Roche COBAS® TaqMan HIV-1® (HPS) test proved to be a robust, sensitive, specific and reproducible method for quantifying HIV-1 RNA in infected cells and lymphoid tissue. Linearity and reproducibility were observed in serial dilutions of 8E5-LAV1 infected T-cells (R2 > 0.86). High reproducibility was found in clinical tonsil specimens (Wilcoxon test p > 0.05). rDNase I treatment was essential to avoid false positives caused by residual HIV-1 DNA, mainly in tonsil specimens obtained from infected patients receiving effective antiretroviral treatment. Probit analysis determined the limit of detection as 22 HIV-1 RNA copies/μg of total RNA. The Roche COBAS® TaqMan® HIV-1 (HPS) test thereby proved to be a helpful tool for measuring the HIV-1 viral load in infected cells and lymphoid tissue reservoirs.