Changes in CD4 lymphocyte counts after interruption of therapy in patientswith viral failure on protease inhibitor-containing regimens

Objective: To describe the short-term changes in CD4 lymphocyte counts afte r the interruption of antiretroviral HIV therapy in order to increase the u nderstanding of CD4 lymphocyte dynamics, and so that appropriate monitoring strategies can be designed. Methods: We studied 35 HIV-infected patients with late-stage disease who ha d therapy interruptions leading to high viral load levels, median greater t han 750 000 RNA log(10) copies/ml, and in whom two CD4 cell counts (median 28 days apart) were available before beginning a salvage regimen. Results: Overall, there was a substantial decline in CD4 cell counts from a median of 125 to 83 cells/mm(3) in the average 28 day period, with median proportionate and absolute losses of 26% and 24 cells/mm(3) per month, resp ectively (P < 0.008). This tended to be greater in individuals studied soon er after interrupting therapy (P = 0.03) and in those with CD4 cell counts above the pre-therapy baseline (P = 0.06). There was a strong negative corr elation between the proportionate increase in viral load and the absolute c hange in CD4 cell count (-0.66, P = 0.0002). Conclusion: Patients with relatively advanced HIV infection interrupting an tiretroviral therapy after failing a protease inhibitor-containing regimen require frequent monitoring because CD4 cell counts appear to fall quite ra pidly, at least in the first few weeks after interruption (C) 2000 Lippinco tt Williams & Wilkins.