CORRELATION BETWEEN CHANGES IN PLASMA HIV RNA LEVELS AND IN PLASMA INFECTIVITY IN RESPONSE TO ANTIRETROVIRAL

We evaluated the degree of correlation between the variation of differ ent HIV-1 viral load measures in response to antiretroviral therapy, A quantitative reverse transcriptase polymerase chain reaction (RT-PCR) for plasma HIV-RNA, and HIV plasma infectivity titration, were perfor med on prospective samples obtained from 86 antiretroviral-naive patie nts with symptomatic infection and CD4(+) < 300/mm(3), enrolled in a r andomized double-blind trial of the HIV protease inhibitor saquinavir (SQV) in combination with zidovudine (ZDV), Subjects were stratified a ccording to plasma virus infectivity and examined for correlations bet ween distinct response categories with respect to CD4 count and HIV RN A copy number changes, Infectious virus could be titrated in 72% of pa tients at baseline. A significant reduction (>1 log(10)) in HIV plasma infectivity titer was observed during the study in 69% of these patie nts, The reduction in plasma infectivity was a good predictor of susta ined CD4(+) cell increases and of sustained decrease in HIV RNA plasma copies. A decrease of at least 0.5 log(10) in HIV RNA copy number was observed in 82% of the treated patients, A good correlation was found between HIV plasma infectivity titer and plasma HIV RNA copy number v ariations (p < 0.001), However, 10 of 17 patients with unchanged plasm a infectivity titer showed a significant reduction in HIV RNA copies, While a good correlation was found between plasma infectivity and RNA plasma copies variations, only a minor correlation was found between C D4(+) cell count variation and plasma infectivity titer variation, How ever, reduction in plasma infectivity was a very good predictor of hig h CD4 changes.