Markers of HIV Infection Prior to IgG Antibody Seropositivity

Abstract

During a 1-year period of study at two plasma collection centers, 7 of 35,000 plasma donors seroconverted to the human immunodeficiency virus (HIV) and had stored plasma samples that predated or antedated the seroconversion period. From each donor, three to eight plasma samples that had been collected at 2- to 7-day intervals were tested for IgG and IgM antibodies to HIV with enzyme immunoassays, Western blot testing, and radioimmunoprecipitation assays. The presence of an HIV viremic phase was demonstrated by the infectivity of plasma on normal, phytohemagglutinin-stimulated peripheral blood mononuclear cells and by the detection of HIV antigen. In 5 of these donors, HIV antigen was detected prior to or simultaneously with IgG to HIV; these HIV-antigen-positive samples overlapped an IgM immune response. The disappearance of detectable HIV antigen, and to a lesser extent plasma infectivity, was concurrent with the development of an IgG immune response. Although the improved sensitivity of a recombinant DNA-derived anti-HIV screening assay shortened the "window period" between initial HIV infection and antibody detection, HIV antigen and plasma HIV viremia were the only markers of HIV infection for several days in 2 donors. These results demonstrate that HIV plasma viremia and antigenemia occur prior to seroconversion in healthy plasma donors.

The Efficiency of HIV p24 Antigen Screening of US Blood Donors: Projections versus Reality

“…These studies were based on analyses of stored blood specimens from seroconverting plasma donors or from subjects enrolled in high-risk cohort studies [1,2]. Similar results were subsequently reported for patients presenting with symptomatic primary HIV-1 infection (the acute HIV syndrome) [3].…”

“…Studies reporting detection of HIV-1 p24 antigen in serum prior to detection of antibody first appeared in 1986 [1][2][3]. These studies were based on analyses of stored blood specimens from seroconverting plasma donors or from subjects enrolled in high-risk cohort studies [1,2].…”

Blood Donations Indeterminate in HIV-1 Western Blot Analysed by IgM Immunoblot and Polymerase Chain Reaction

“…It was our initial hypothesis that because the produc tion of IgM antibodies is an early response to HIV-1 in fection [8], their determination by an IgM-specific immu noblot [9] could provide a possibility for early confirma tion of infection. In several screening studies of high-risk groups IgM antibodies to HIV-1 were detected in the early phase of infection, sometimes markedly before the ap pearance of IgG antibodies [10,11], The findings of other groups are not in agreement with these quoted studies [12]. They found that IgM antibody response overlaps the preence of HIV antigen during an approximately 10-day period preceding the development of IgG response.…”

Detection of Antibodies to Human Immunodeficiency Virus (HIV) That Recognize Conformational Epitopes of Glycoproteins 160 and 41 Often Allows for Early Diagnosis of HIV Infection

“…In addition, in some early infected EIA-negative patients, B cells, which make anti-HIV antibodies, can be expanded from peripheral blood in vitro [33]. Antibodies to HIV Nef and p17 proteins have are present before seroconversion in EIA [75,76]. Consequently, several studies indicate that immune responses occur early after infection and these do not necessarily involve induction of antibodies that react to linear epitopes of HIV proteins.…”