HIV-1 p24 antigen is a significant inverse correlate of CD4 T-cell change in patients with suppressed viremia under long-term antiretroviral therapy.
An HIV-1 p24 antigen test involving signal amplification-boosted ELISA of heat-denatured plasma was evaluated prospectively in 55 patients whose viral RNA in plasma had previously been suppressed for at least 6 months under antiretroviral combination therapy. During a median follow-up of 504 days, CD4 counts increased by a median of 62 cells per year. By univariate and multivariate linear regression analysis, the level of p24 antigen as expressed by the absorbance/cutoff ratio was a significant inverse correlate of both the CD4 count in a sample (p =.013) and its annual change in a patient (p <.0001). The p24 antigen retained significance even among 48 individuals whose HIV-1 RNA, apart from occasional blips, remained below 400 copies/mL. Batch-wise retesting of 70 samples from 5 such patients with a further improved procedure showed measurable p24 antigen in all but 1 sample and an inverse correlation with both the CD4 count (p =.0331) and percentage (p <.0001), thus confirming the prospectively generated data. Comparison of p24 antigen and HIV-1 RNA concentrations indicate that the p24 antigen detected in these samples is not associated with viral RNA-containing particles and may originate from other compartments of virus expression.
Schüpbach
Jörg
J
Swiss National Center for Retroviruses, University of Zurich, Zurich, Switzerland. jschupb@immv.unizh.ch
Böni
Jürg
J
Bisset
Leslie R
LR
Tomasik
Zuzana
Z
Fischer
Marek
M
Günthard
Huldrych F
HF
Ledergerber
Bruno
B
Opravil
Milos
M
D000328:Adult; D019380:Anti-HIV Agents / Q000008:administration & dosage* / Q000627:therapeutic use*; D018791:CD4 Lymphocyte Count; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D005260:Female; D016655:HIV Core Protein p24 / Q000032:analysis* / Q000097:blood; D015658:HIV Infections / Q000188:drug therapy* / Q000276:immunology* / Q000821:virology; D015497:HIV-1; D006801:Humans; D008297:Male; D008875:Middle Aged; D014766:Viremia / Q000188:drug therapy
D019380:Anti-HIV Agents; D016655:HIV Core Protein p24