PLASMA VIREMIA TITRATION AND RNA QUANTITATION IN ICD-P24 NEGATIVE HIVTYPE-1-INFECTED PATIENTS

Quantitative culture of human immunodeficiency virus (HIV) was perform ed on 202 plasma samples obtained from asymptomatic and early symptoma tic HIV-1 infected patients (mean CD4(+) count: 186/mm(3)) before anti retroviral therapy was started. HIV could be isolated from 84% of the plasma samples (titers ranging from 10(0) to 10(2.75) TCID50/ml). Immu ne complex dissociated p24 antigen (ICD-p24) was detected in 66% of th e samples. Only 23 samples (11%) were negative for both ICD-p24 as wel l as HIV culture. Discordant results were obtained in 55 samples, and 45 samples negative for ICD-p24 were positive for HIV culture. A signi ficant proportion (42%) of patients that were negative for ICD-p24 bel onged to a very advanced group with very low CD4(+) cell count. Howeve r, almost 90% of these ICD-p24 negative samples were positive for HIV plasma viremia, stressing the value of this virological marker in pati ents with low CD4(+) cell count and without any detectable ICD-p24 ant igenemia. HIV-1 RNA was detected in all ICD-p24 negative plasma sample s tested by the branched DNA (bDNA) assay. A very good correlation was found between high RNA copy number and HIV plasma isolation in sample s obtained from patients with low CD4(+) cell count, suggesting that H IV-1 RNA quantitation may also reflect viral infectivity of plasma.