title: Antiretroviral treatment monitoring with an improved HIV-1 p24 antigen test: an inexpensive alternative to tests for viral RNA.
abstract: Monitoring of viral RNA has become indispensable for the management of HIV-1 infection, but is expensive. This study investigated whether a highly improved test for p24 antigen could serve as an alternative. Thirty-four patients enrolled during 1997 into two treatment studies were tested prospectively for viral RNA by the Roche HIV-1 Monitor and for p24 antigen using signal-amplification-boosted ELISA of heat-denatured plasma. P24 antigen was detectable in 75.8% of 178 samples and HIV RNA in 73.9% of 138 samples. The half-life of p24 antigen in the first phase of effective treatment was 1.6 +/-.4 days (RNA, 1.7 +/-.8). An apparent second, slower decay phase had a half-life of 42 +/- 16 days. Treatment failure occurred in 14 patients. Secondary treatment failures with RNA rebounds from undetectable levels to < or = 10(3) copies/ml in two patients with an undetectable viral load and 10(3) HIV RNA copies/ml, respectively, at baseline were not detected by p24 antigen but carried a low risk for secondary resistance mutations. The other 12 failures were on average detected 29 days earlier by p24 antigen than by RNA (P =.0204), owing to slightly more frequent testing for p24 than for RNA (2.7 vs. 2.4 tests). Average costs for p24 antigen testing up to a failure were only 20.5% of those for RNA (P <.0001). These results indicate that heat-denatured, amplification-boosted p24 antigen measurement can be used as a simple and inexpensive alternative to HIV RNA testing for monitoring treatment.
authors.affiliation: Swiss National Center for Retroviruses, University of Zürich, Zürich, Switzerland. jschupb@immv.unizh.ch
authors.forename: J
authors.initials: J
authors.lastname: Schüpbach
authors.forename: J
authors.initials: J
authors.lastname: Böni
authors.forename: M
authors.initials: M
authors.lastname: Flepp
authors.forename: Z
authors.initials: Z
authors.lastname: Tomasik
authors.forename: H
authors.initials: H
authors.lastname: Joller
authors.forename: M
authors.initials: M
authors.lastname: Opravil
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D004359:Drug Therapy, Combination; D004797:Enzyme-Linked Immunosorbent Assay / Q000191:economics / Q000379:methods*; D016655:HIV Core Protein p24 / Q000097:blood*; D015658:HIV Infections / Q000097:blood / Q000188:drug therapy* / Q000821:virology; D015497:HIV-1 / Q000302:isolation & purification*; D006207:Half-Life; D006801:Humans; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012367:RNA, Viral / Q000097:blood*; D011933:Reagent Kits, Diagnostic / Q000191:economics; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D019380:Anti-HIV Agents; D015415:Biomarkers; D016655:HIV Core Protein p24; D012367:RNA, Viral; D011933:Reagent Kits, Diagnostic