Lack of evidence of occult human immunodeficiency virus in seronegative individuals at very high risk of infection

HIV heterosexual transmission to stable sexual partners of HIV-infected Brazilian hemophiliacs

Nineteen Brazilian HIV-infected hemophiliacs and their stable heterosexual sexual partners were studied with the aim of assessing the rate of HIV transmission in this at risk group. The mean length of relationship between couples was 7.4 years. The hemophiliac men were Class II (n = 6), III (n = 11) and IVa (n = 2) of the CDC classification. They had decreased CD4+ and elevated CD8+ cell numbers; five had p24 antigenemia. We found 3 HIV-infected women (15.8 percent) by routine and confirmatory tests, a prevalence similar to that seen in other countries. They were asymptomatic and had no detectable p24 antigenemia. The 3 seropositive women's partners were Class II and III-CDC, and had normal CD4+ and CD8+ values and no p24 antigenemia. All seronegative women also had normal CD4+ and CD8+ numbers, except for elevated CD8+ cells in three of them, but immune abnormalities had already been seen in some seronegative partners at high risk for HIV infection. Our results reinforce previous suggestions that heterosexual transmission to stable female partners occurs preferentially early after initiation of sexual exposure, and possibly when the transmitter had high levels of viremia and regular sexual activity.

P24 antigen detection, viral isolation, DNA-PCR and in vitro antibody production for the diagnosis of HIV-1 latent infection in heterosexual women at high risk for HIV-1 infection

INTRODUCTION

The report of the existence of at-risk seronegative subjects, latently infected with HIV-1 and producing "in vitro" HIV-1 specific antibodies, prompted the authors to evaluate extensively twenty-five heterosexual HIV-1 seronegative women at high risk for HIV-1 infection.

MATERIAL AND METHODS

The capability of peripheral blood mononuclear cells from such subjects to produce "in vitro" HIV-1 specific antibodies after pokeweed-mitogen stimulation, was studied. Silent HIV-1 infection was investigated by HIV-1 DNA PCR, viral isolation and serum p24 Ag detection at entry and after 6 and 12 months.

RESULTS

Three seroconversions took place within 12 months, but no HIV-1 infections were found in the absence of detectable serum anti HIV-1 antibodies, even in subjects who apparently produced such antibodies in vitro. The antibodies produced in vitro by the seronegative women studied appeared of narrow specificity, reacting mainly with gp 160/120 envelope glycoproteins.

CONCLUSIONS

A strong concordance was found between the serological status and the other markers for HIV-1 infection, suggesting that the phenomenon of HIV-1 "latent infection" is a very rare event, if it occurs at all. Seronegative women sexually exposed to the virus may produce in vitro anti HIV-1 antibodies of narrow specificity in the absence of other signs of infection and this phenomenon might be related to an anamnestic response to the virus.

Absence of prolonged immunosilent infection with human immunodeficiency virus in individuals with high-risk behaviors

PURPOSE

The presence in some individuals of a prolonged phase of infection with human immunodeficiency virus type 1 (HIV-1) before seroconversion remains controversial. This study was undertaken to determine with a sensitive in vitro amplification technique, the polymerase chain reaction (PCR), whether seronegative individuals with high-risk behaviors could harbor HIV-1 sequences in their peripheral blood mononuclear cells (PBMCs) and remain seronegative for more than 6 months.

PATIENTS AND METHODS

Seronegative individuals who engaged in unprotected anogenital intercourse with HIV-1-infected partners or with more than 10 individuals per year, and seronegative individuals who shared needles with seropositive partners, were recruited prospectively over 18 months. HIV-1 DNA and RNA sequences were detected in PBMCs of these individuals with three PCR assays using SK38/SK39, SK145/SK431, and SK68/SK69. Seronegative but PCR-positive patients were also evaluated with p24 antigen capture assay, radioimmunoprecipitation assay, and Western blot. The latter patients were followed prospectively to reproduce PCR-positive results and monitor serologic responses.

RESULTS

Sixty-one men and 18 women, with an average age of 34.1 +/- 7.6 years, were recruited: 56 were homosexual men, 18 were heterosexual women, and 5 were heterosexual men. Amplification reactions for HIV-1 of 104 PBMC specimens from 79 patients with negative or indeterminate serologies revealed that 4 patients (5.1%) were positive with PCR for HIV-1 DNA and RNA at the time of enrollment. Positive amplification reactions could not be reproduced in prospective samples for one patient. The analysis of a variable human genomic locus in this patient's PBMCs demonstrated that the first PCR-positive sample and following PCR-negative samples originated from different patients, suggesting a specimen mix-up. Two of the three PCR-positive seronegative patients had symptoms suggestive of acute retroviral disease. Sera from all three patients contained p24 antigen. Two patients seroconverted within 1 month whereas one patient could not be followed prospectively.

CONCLUSION

Prolonged infection with HIV-1 without seroconversion was not found in our population of patients at very high risk for HIV-1 infection. All PCR-positive patients seroconverted in less than 1 month.