Human immunodeficiency virus type 1 quasi species that rebound after discontinuation of highly active antiretroviral therapy are similar to the viral quasi species present before initiation of therapy.

In an effort to identify the sources of the viruses that emerge after discontinuation of therapy, analyses of human immunodeficiency virus (HIV) quasi species were done for 3 patients with sustained levels of HIV RNA of <50 copies/mL for 1-3 years. The sequences found in the rebounding plasma virus were closely related to those of the actively replicating form of viruses present before the initiation of combination therapy. All quasi species found in the rebounding plasma virus were also present in proviral DNA, cell-associated RNA in peripheral blood mononuclear cells (PBMC), and virion RNA derived from PBMC coculture during periods when plasma HIV RNA levels were <50 copies/mL. These findings suggest that the rapid resurgence of plasma viremia observed after discontinuation of therapy and the viruses cocultured from PBMC are derived from a relatively stable pool of the replicating form of virus rather than from activation of a previously latent pool.

Comparison of the Quantiplex version 3.0 assay and a sensitized Amplicor monitor assay for measurement of human immunodeficiency virus type 1 RNA levels in plasma samples.

This study evaluated correlation and agreement between version 3 of the Quantiplex human immunodeficiency virus type 1 (HIV-1) RNA assay (v3 branched DNA [bDNA]) and a sensitized Amplicor HIV-1 Monitor assay (reverse transcription [RT]-PCR) for the measurement of HIV RNA. Three hundred eighteen samples from 59 randomly selected, HIV-1-seropositive persons on various drug protocols from the National Institute of Allergy and Infectious Diseases HIV outpatient clinic were studied. The results indicate that v3 bDNA and RT-PCR are highly correlated (r = 0.98) and are in good agreement (mean difference in log(10) copies/ml +/- 2 standard deviations = 0.072 +/- 0.371). The relationship between values obtained by both assays is given by the following equation: log(10)v3 bDNA = -0.0915 + 1. 0052. log(10)RT-PCR. This represents a 1.026-fold difference between log(10)RT-PCR values and log(10)v3 bDNA values.

Prospective studies on nasopharyngeal carcinoma in Epstein-Barr virus IgA/VCA antibody-positive persons in Wuzhou City, China.

A serological mass survey was carried out in Wuzhou City in 1980, 1,136 IgA/VCA-positive persons being followed up for 4 years. Altogether 35 NPC cases were detected, of which 15 (43%) were in stage I and 17 (48.5%) in stage II, early cases (I + II) thus amounting to 91.5%. The detection rate of early cases was 2.9 times higher than in our outpatient clinic. IgA/VCA antibody could be detected 16-41 months prior to clinical diagnosis of NPC. We conclude that, if IgA/VCA-positive individuals are examined routinely once a year, NPC can be detected in the early stages of evolution. The annual detection rate of NPC in IgA/VCA antibody-positive individuals was 31.7 times higher than that of the annual incidence of NPC in the general population in the same age group, while during the 4-year follow-up period the incidence was 7.5 times higher than in the general population for the same age group. These results further indicate that EB virus plays an important role in the development of NPC, and that serological screening and follow-up studies are valuable for the early detection of NPC.