VIRAL LOAD IN ASYMPTOMATIC PATIENTS WITH CD4+ LYMPHOCYTE COUNTS ABOVE500X10(6) 1/

Background: HIV-1-infected patients with a CD4+ lymphocyte count great er than or equal to 500 x 10(6)/l may be selected for antiretroviral t reatment when viral load is above a given cut-off point. Objectives: T o assess the stability of viral load measurement al CD4+ T-cell counts above 500 x 10(6)/l, and the proportion of patients selected for trea tment if a cut-off point of 10 000 or 30 000 RNA copies/ml is used. De sign and methods: Seventy-eight consecutive asymptomatic anti retrovir al-naive HIV-1-infected patients with CD4+ lymphocyte counts greater t han or equal to 500 x 10(6)/l, presenting for previously scheduled med ical visits as outpatients, were enrolled. None of the patients had su ffered from symptomatic primary infection or seroconverted within 6 mo nths before enrolment. Two blood samples separated by a 1-month interv al [day -30 (screening) and day 0 (enrolment)] were collected in an ED TA tube. Plasma was separated and frozen at -70 degrees C within 4 h o f collection. HIV-1 RNA was quantified by polymerase chain reaction. C D4+ T cells were measured by flow cytometry. Results: Viral load was f airly stable, and only four (13%) out of 30 pairs had a variation grea ter than or equal to 0.5 log(10). At day -30 and day 0, log(10) HIV RN A levels (mean +/- SD) were 4.24 +/- 0.7 and 4.35 +/- 0.87 log(10) cop ies/ml plasma (P = 0.23). The difference of the mean was -0.11 (95% co nfidence interval, -0.28 to 0.07). At day 0 (n = 78) mean +/- SD value was 35730 +/- 73700 RNA copies/ml (range, <200-438480; median, 9331; 25th and 75th percentiles, 1518 and 37193, respectively). In 13 patien ts (16%) the viral load was <200 copies RNA/ml. Seven out of 10 patien ts, who fulfilled the criteria of long-term non-progressors (LTNP), ha d viral load >10 000 RNA copies/ml, and two patients had >30 000 RNA c opies/ml. Only two of the 13 patients with CD4+ T-cell counts >750 x 1 0(6)/l had viral load >10 000 copies/ml. Conclusions: A single-point v iral load assessment is enough in asymptomatic patients with CD4+ lymp hocytes counts greater than or equal to 500 x 10(6)/l since plasma HIV RNA measurements obtained 1 month apart are fairly stable. Approximat ely 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 c opies/ml. Viral load greater than or equal to 10 000 is very unusual i n patients with CD4+ T-cell counts >750 x 10(6)/l.