Viral load in asymptomatic patients with CD4+ lymphocyte counts above 500 × 106/l

Abstract

Background: HIV-1-infected patients with a CD4+ lymphocyte count ≥500×10⁶/l may be selected for antiretroviral treatment when viral load is above a given cut-off point. Objectives: To assess the stability of viral load measurement at CD4+ T-cell counts above 500×10⁶/l, and the proportion of patients selected for treatment if a cut-off point of 10 000 or 30 000 RNA copies/ml is used. Design and methods: Seventy-eight consecutive asymptomatic antiretroviral-naive HIV-1-infected patients with CD4+ lymphocyte counts ≥500 × 10⁶/l, presenting for previously scheduled medical visits as outpatients, were enrolled. None of the patients had suffered from symptomatic primary infection or seroconverted within 6 months before enrolment. Two blood samples separated by a 1-month interval [day −30 (screening) and day 0 (enrolment)] were collected in an EDTA tube. Plasma was separated and frozen at −70°C within 4 h of collection. HIV-1 RNA was quantified by polymerase chain reaction. CD4+ T cells were measured by flow cytometry. Results: Viral load was fairly stable, and only four (13%) out of 30 pairs had a variation ≥0.5 log₁₀. At day −30 and day 0, log₁₀ HIV RNA levels (mean ± SD) were 4.24 ± 0.7 and 4.35 ± 0.87 log₁₀ copies/ml plasma (P= 0.23). The difference of the mean was −0.11 (95% confidence interval, −0.28 to 0.07). At day 0 (n = 78) mean ± SD value was 35730 ± 73700 RNA copies/ml (range, 30 000 RNA copies/ml. Only two of the 13 patients with CD4+ T-cell counts >750 × 10⁶/l had viral load >10 000 copies/ml. Conclusions: A single-point viral load assessment is enough in asymptomatic patients with CD4+ lymphocytes counts ≥500 × 10⁶/l since plasma HIV RNA measurements obtained 1 month apart are fairly stable. Approximately 25% of these patients (including some patients with LTNP criteria) will be selected for treatment if 30 000 RNA copies/ml is used as cut-off point, and approximately 50% if the cut-off point is 10 000 RNA copies/ml. Viral load ≥10 000 is very unusual in patients with CD4+ T-cell counts >750 × 10⁶/l.