Duration and predictors of CD4 T-cell gains in patients who continue combination therapy despite detectable plasma viremia

    loading  Checking for direct PDF access through Ovid


BackgroundSustained elevations in CD4 cell counts commonly occur despite incomplete viral suppression with protease inhibitor-based antiretroviral therapy.ObjectivesTo determine the incidence and risk factors associated with return of CD4 cell count to pre-therapy levels in patients experiencing virologic failure of protease inhibitor therapy.DesignThis is a clinic-based cohort study of HIV-infected adults who failed to maintain durable viral suppression on a protease inhibitor-based regimen.Main outcome measuresVirologic failure was defined as persistent plasma HIV RNA level > 500 copies/ml. Immunologic failure was defined as return of CD4 cell count to pre-therapy levels.ResultsA total of 291 patients experienced virologic failure on a protease inhibitor-based regimen and had a treatment-mediated CD4 cell increase above pre-therapy levels at the time of virologic failure. If patient data were censored at the time a successful salvage regimen was initiated, then the median time to immunologic failure after the onset of virologic failure was 3 years. If patient data were also censored at the time therapy was discontinued, then 36.8% of the cohort experienced immunologic failure after 3 years of continuous virologic failure. The change in viral load from a pre-treatment baseline, and not the absolute level of viremia achieved, was a strong and independent predictor of immunologic failure. Discontinuing therapy was associated with immunologic failure independent of viral load changes.ConclusionReduction in T CD4+ cell numbers may eventually occur during prolonged virologic failure of a protease inhibitor-based regimen and is predicted by the degree of virologic suppression below a pre-therapy ‘set-point'.

    loading  Loading Related Articles