Identifying the immunologic and virologic consequences of discontinuing antiretroviral therapy in HIV-infected patients is of major importance in developing long-term treatment strategies for patients with HIV-1 infection. We designed a trial to characterize these parameters after interruption of highly active antiretroviral therapy (HAART) in patients who had maintained prolonged viral suppression on antiretroviral drugs. Eighteen patients with CD4 ؉ T cell counts > 350 cells͞l and viral load below the limits of detection for >1 year while on HAART were enrolled prospectively in a trial in which HAART was discontinued. Twelve of these patients had received prior IL-2 therapy and had low frequencies of resting, latently infected CD4 cells. Viral load relapse to >50 copies͞ml occurred in all 18 patients independent of prior IL-2 treatment, beginning most commonly during weeks 2-3 after cessation of HAART. The mean relapse rate constant was 0.45 (0.20 log 10 copies) day ؊1 , which was very similar to the mean viral clearance rate constant after drug resumption of 0.35 (0.15 log 10 copies) day ؊1 (P ‫؍‬ 0.28). One patient experienced a relapse delay to week 7. All patients except one experienced a relapse burden to >5,000 RNA copies͞ml. Ex vivo labeling with BrdUrd showed that CD4 and CD8 cell turnover increased after withdrawal of HAART and correlated with viral load whereas lymphocyte turnover decreased after reinitiation of drug treatment. Virologic relapse occurs rapidly in patients who discontinue suppressive drug therapy, even in patients with a markedly diminished pool of resting, latently infected CD4 ؉ T cells.HIV-1 infection ͉ antiretroviral drugs ͉ viral load ͉ relapse ͉ CD4

To investigate the extent to which drug resistance mutations are missed by standard genotyping methods, we analyzed the same plasma samples from 26 patients with suspected multidrug-resistant human immunodeficiency virus type 1 by using a newly developed single-genome sequencing technique and compared it to standard genotype analysis. Plasma samples were obtained from patients with prior exposure to at least two antiretroviral drug classes and who were on a failing antiretroviral regimen. Standard genotypes were obtained by reverse transcriptase (RT)-PCR and sequencing of the bulk PCR product. For single-genome sequencing, cDNA derived from plasma RNA was serially diluted to 1 copy per reaction, and a region encompassing p6, protease, and a portion of RT was amplified and sequenced. Sequences from 15 to 46 single viral genomes were obtained from each plasma sample. Drug resistance mutations identified by single-genome sequencing were not detected by standard genotype analysis in 24 of the 26 patients studied. Mutations present in less than 10% of single genomes were almost never detected in standard genotypes (1 of 86). Similarly, mutations present in 10 to 35% of single genomes were detected only 25% of the time in standard genotypes. For example, in one patient, 10 mutations identified by single-genome sequencing and conferring resistance to protease inhibitors (PIs), nucleoside analog reverse transcriptase inhibitors, and nonnucleoside reverse transcriptase inhibitors (NNRTIs) were not detected by standard genotyping methods. Each of these mutations was present in 5 to 20% of the 20 genomes analyzed; 15% of the genomes in this sample contained linked PI mutations, none of which were present in the standard genotype. In another patient sample, 33% of genomes contained five linked NNRTI resistance mutations, none of which were detected by standard genotype analysis. These findings illustrate the inadequacy of the standard genotype for detecting low-frequency drug resistance mutations. In addition to having greater sensitivity, single-genome sequencing identifies linked mutations that confer high-level drug resistance. Such linkage cannot be detected by standard genotype analysis.

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Changes in CD4+ T-cell surface marker phenotype and antigen receptor (TCR) repertoire were examined during the course of HIV infection and following therapy. A preferential decline in naive CD4+ T cells was noted as disease progressed. Following protease inhibitor therapy, naive CD4+ T cells increased only if they were present before initiation of therapy. Disruptions of the CD4+ TCR repertoire were most prevalent in patients with the lowest CD4+ T-cell counts. Antiviral or IL-12 therapy-induced increases in CD4+ T-cell counts led to only minor changes in previously disrupted repertoires. Thus, CD4+ T-cell death mediated by HIV-1 infection may result in a preferential decline in the number of naive CD4+ T cells and disruptions of the CD4+ T-cell repertoire that are not immediately corrected by antiviral or immune-based therapies.

Herbal therapies are widely used, but there are few data on their interactions with conventional medications. This study evaluated the effect of garlic supplements on the pharmacokinetics of saquinavir. Ten healthy volunteers received 10 doses of saquinavir (Fortovase) at a dosage of 1200 mg 3 times daily with meals for 4 days on study days 1-4, 22-25, and 36-39, and they received a total of 41 doses of garlic caplets taken 2 times daily on study days 5-25. Blood samples were obtained on study days 4, 25, and 39 for determination of saquinavir plasma pharmacokinetic parameters. In the presence of garlic, the mean saquinavir area under the curve (AUC) during the 8-h dosing interval decreased by 51%, trough levels at 8 h after dosing decreased by 49%, and the mean maximum concentrations (Cmax) decreased by 54%. After the 10-day washout period, the AUC, trough, and Cmax values returned to 60%-70% of their values at baseline. Patients should use caution when combining garlic supplements with saquinavir when it is used as a sole protease inhibitor.

Intermittent courses of interleukin-2 can improve some of the immunologic abnormalities associated with HIV infection in patients with more than 200 CD4 cells per cubic millimeter.

In patients with HIV infection and base-line CD4 counts above 200 cells per cubic millimeter, intermittent infusions of interleukin-2 produced substantial and sustained increases in CD4 counts with no associated increase in plasma HIV RNA levels.