Evaluation of residual viral replication for optimization of HAART

Shuzo Matsushita, Tetsuya Kimura, Noriko Shirai, Atsushi Koito, Kazuhisa Yoshimura. Division of Clinical Retrovirology and Infectious Diseases, Center for AIDS Research, Kumamoto University, 2-2-1 Honjo, Kumamoto (Japan)

Background: Even in patients whose plasma viral load were undetectable for certain period of time by HAART, persistence of proviral DNA (pDNA) of HIV-1 in PBMCs has been reported. The persisting pDNA was mainly derived from a residual virus replicated in lymphoid organ. Using highly sensitive assay to detect pDNA and turnover of T lymphocytes, we are attempting to optimize HAART to minimize the residual viruses in patients with undetectable plasma viremia. Methods: The pDNA levels in PBMCs from HIV-1⁺ patients were measured using a novel hypersensitive nested PCR in the LTR region. Quantitative real-time PCR fluorogenic assay was performed to detect pDNA after conventional first PCR. We also investigated CD4⁺ and CD8⁺ T cell turnover by measuring the nuclear antigen Ki-67 with four-color flow cytometry analysis. Results: We measured the HIV pDNA level in PBMCs of 390 samples from viremic or aviremic patients. Among the patients who had undetectable plasma viremia by HAART, the CD4⁺ T cell count and CD4/8 ratio were significantly higher in patients who achieved undetectable pDNA than in patients with detectable pDNA (p<0.01). We also followed a group of patients who have an option to choose treatment optimization by getting the results of pDNA and T-cell turnover. Significant decline of the pDNA level was observed when the regimen of HAART was optimized to more potent combination. Normalization of accelerated turnover of CD4⁺ and CD8⁺ subset was followed after the decline of pDNA. Conclusions: Our study suggests that the measurement of both pDNA and T-cell turnover is suitable candidate for evaluating the residual replication of HIV-1 in patients. Long-term successful treatment can be achievable by providing these results with an informed choice of potent combination of antiretrovirals.