A comparison of immunocomplex-dissociated serum HIV-1 p24 antigenemia and plasma HIV-1 viral load: assessment of 3,129 paired assays.

In order to compare HIV-1 p24 antigenemia and plasma HIV-1 RNA levels as markers of viral replication, 3,129 paired determinations of alkaline immunocomplex-dissociated serum HIV-1 p24 antigenemia (performed with an immunoenzymatic assay), and plasma HIV-1 RNA levels (carried out with a branched DNA method, a reverse transcriptase-coupled polymerase chain reaction, and a nucleic acid sequence-based assay) were assessed over a two-year-period. When excluding samples with undetectable plasma HIV-1 RNA levels (which tested negative or borderline positive at serum p24 antigen assay in 97.9% of cases), immunocomplex-dissociated p24 antigenemia proved significantly less sensitive than viral load at all considered HIV-1 RNA reference levels, although the profile of positive serum p24 antigen assays (values above 10 pg/ml) paralleled the trend of plasma HIV-1 viral load, especially at higher levels. However, serum HIV-1 p24 antigenemia (even after immunocomplex dissociation) can be longer suggested as a the sole virological tool in the laboratory management of HIV-1 infection, due to its significantly lower sensitivity levels compared with viral load assessment.