Transient or occult HIV-1 infection in high-risk adults

Infection of humans with HIV-1 results in a persistent, and usually progressive, infection, resulting in the loss of T helper lymphocytes and immunodeficiency. The diagnosis of HIV-1 infection has been based upon the detection of serum anti-HIV-1 antibodies by commercial enzyme immunoassays (EIA) employing denatured HIV antigens, with confirmation by Western blot or fixed-cell immunofluorescence. However, the transient appearance of either anti-HIV-1 antibodies in sera or polymerase chain reaction (PCR)-amplifiable HIV-1 DNA in peripheral blood mononuclear cells (PBMC), or both, has been described in a small number of adults at risk of HIV-1 infection. Although conversion from HIV-1 antibody-positive to negative status is the norm for infants born to infected mothers once maternal IgG in the newborns has cleared, virological data based on HIV-1-DNA amplification by PCR in infant blood specimens at early and later time-points have indicated that clearance of HIV-1 may occur in some infected infants. However, a recent analysis of HIV-1 sequences in some of those infants and their mothers raised doubts about the suspected cases of transient HIV infection. The question thus remains as to whether transient HIV infection occurs. During a prospective study of seronegative sexual partners of known HIV-1-infected patients, we identified two apparently transiently infected individuals (nos. 1 and 2) using a live-cell immunofluorescence assay (IFA) as a test for serum anti-HIV-1 antibodies, HIV-1 DNA amplification by PCR, and HIV-1 culture from the PBMC of the subjects.