Recombination confounds the early evolutionary history of human immunodeficiency virus type 1: subtype G is a circulating recombinant form.

Human immunodeficiency virus type 1 (HIV-1) is classified in nine subtypes (A to D, F, G, H, J, and K), a number of subsubtypes, and several circulating recombinant forms (CRFs). Due to the high level of genetic diversity within HIV-1 and to its worldwide distribution, this classification system is widely used in fields as diverse as vaccine development, evolution, epidemiology, viral fitness, and drug resistance. Here, we demonstrate how the high recombination rates of HIV-1 may confound the study of its evolutionary history and classification.

A combination of poor adherence and a low baseline susceptibility score is highly predictive for HAART failure.

The relationship between adherence, virological response to highly active antiretroviral therapy (HAART) and the presence and development of genotypic resistance was assessed in 41 HIV-infected patients on HAART. Four adherence parameters (drug taking adherence, dosing adherence, timing adherence and drug holidays) were scored prospectively using electronic event monitoring. Genotypic resistance at baseline and after therapy failure was scored retrospectively and a genotype-based susceptibility score was calculated.

Laboratory guidelines for the practical use of HIV drug resistance tests in patient follow-up.

HIV drug resistance is one of the major limitations in the successful treatment of HIV-infected patients using currently available antiretroviral combination therapies. When appropriate, drug susceptibility profiles should be taken into consideration in the choice of a specific combination therapy. Guidelines recommending resistance testing in certain circumstances have been issued.

Baseline HIV type 1 genotypic resistance to a newly added nucleoside analog is predictive of virologic failure of the new therapy.

We evaluated the predictive value of baseline HIV-1 genotypic resistance mutations for failure of a nucleoside reverse transcriptase inhibitor (NRTI) containing therapy. The change in therapy of 88 HIV-1-infected patients was analyzed retrospectively, relating the genotypic resistance profile at baseline to the evolution of viral load and CD4+ T cell counts. Genotypic resistance at baseline and at 6 months was evaluated with the LiPA HIV-1 RT, which detects mutations at codons 41, 69, 70, 74, 184, and 215.

Anti-hepatitis G E2 antibody detection and its relation to serum HGV-RNA in patients with clotting disorders: high prevalence of HGV infection and spontaneous remission.

In a previous study, we have determined the prevalence of serum HGV-RNA in patients with congenital clotting disorders. Twenty-six (15%) of 175 patients investigated were serum HGV-RNA positive. In addition, HGV-RNA was detectable in peripheral blood mononuclear cells (PBMC) in ten percent of the cases, three of these patients were serum HGV-RNA negative.

Failure to quantify viral load with two of the three commercial methods in a pregnant woman harboring an HIV type 1 subtype G strain.

The level of HIV-1 RNA in plasma has become one of the most important markers in the follow-up of HIV-infected patients. Three techniques are commercially available: both the Amplicor HIV Monitor and the NASBA HIV-1 RNA QT are target amplification methods, whereas the Quantiplex HIV RNA assay is a branched DNA signal amplification technique. Detection in both target amplification techniques is based on a single primer pair and a single probe in the gag region, whereas multiple probes capture the pol region of the viral RNA in the branched DNA assay.

A primate T-lymphotropic virus, PTLV-L, different from human T-lymphotropic viruses types I and II, in a wild-caught baboon (Papio hamadryas).

Searching for clues to the evolution of the primate T-lymphotropic viruses (PTLVs), which include the human and the simian T-lymphotropic viruses (HTLV and STLV), we have identified another PTLV, which differs sufficiently from the known PTLV-I and PTLV-II types to be designated here PTLV-L. The virus was isolated from a wild-born baboon (Papio hamadryas) from Eritrea. In a cDNA library a 1802-bp-long fragment was identified that extends from the env region, including the complete transmembrane protein gene, to part of the tax/rex gene.

Polymerase chain reaction (PCR) as a diagnostic tool in HIV infection.

We set up a PCR laboratory for the diagnosis of HIV-1. Probably due to the variability of the HIV-genome, classical primers that performed well in some laboratories in the past, did not suffice for detection of HIV-1 strains in Belgian hospitals. Two new primer sets amplifying a fragment in the LTR-gag gene and in the env gene, which perform better on strains seen in Belgium, have been developed and evaluated.

HTLV-II seroprevalence in pygmies across Africa since 1970.

HTLV-II-specific antibodies, with patterns similar to those in the Americas, were present in sera collected about 1970 from Bambuti pygmies in Zaire (14/102; 14%) and from pygmies in Cameroon (5/214; 2.3%), and were more prevalent than HTLV-I. In the Central African Republic, 504 pygmies were HTLV negative.