Human Immunodeficiency Virus-Specific CD8⁺T-Cell Responses Do Not Predict Viral Growth and Clearance Rates during Structured Intermittent Antiretroviral Therapy

Abstract

There is a continuing search for better ways to use existing drugs against human immunodeficiency virus (HIV). One idea is to use short therapy interruptions to "autovaccinate" HIV-infected patients. A group of 13 chronically HIV-infected patients enrolled in a trial of such so-called structured treatment interruptions (STIs) were intensively studied with respect to their viral load (VL) and HIV-specific CD8+ T-cell (cytotoxic T-lymphocyte [CTL]) responses. We found that 10 of the 13 patients had plateau VLs after STIs that were lower than their pretreatment VLs. While viral rebound rates became lower over STIs, there were no changes in clearance rates. Although numbers of CTLs did increase over the same time that viral rebounds decreased, there was no correlation between CTL count and either viral rebound rates or clearance rates. Finally, we asked whether absolute numbers of or changes in numbers of CTLs predict plateau VLs after STIs. No measure of CTLs was able to predict plateau VLs. Thus, there was no signature in these data of an important contribution to virological control from HIV-specific CD8+ T lymphocytes.