Frequency and predictors of HIV-1 co-receptor switch in treatment naive patients.

Background: Determination of HIV-1 co-receptor use is a necessity before initiation of a CCR5 antagonist but the longevity of a CCR5-use prediction remains unknown.

Methods: Genotypic co-receptor tropism determination was performed in 225 newly diagnosed individuals consulting an AIDS Reference Centre. Samples were collected at diagnosis and at initiation of antiretroviral therapy or just before closure of the study for patients who did not initiate therapy.

Presence of CXCR4-using HIV-1 in patients with recently diagnosed infection: correlates and evidence for transmission.

Background: The prevalence and correlates of CXCR4-use in recently diagnosed patients and the impact of X4/DM transmission remain largely unknown.

Method: Genotypic coreceptor use determination on the baseline sample of 539 recently diagnosed individuals. Correlation of coreceptor use with clinical, viral and epidemiological data and with information on transmission events as obtained through phylogenetic analysis of protease and reverse transcriptase sequences.

Epidemiological study of phylogenetic transmission clusters in a local HIV-1 epidemic reveals distinct differences between subtype B and non-B infections.

Background: The number of HIV-1 infected individuals in the Western world continues to rise. More in-depth understanding of regional HIV-1 epidemics is necessary for the optimal design and adequate use of future prevention strategies. The use of a combination of phylogenetic analysis of HIV sequences, with data on patients' demographics, infection route, clinical information and laboratory results, will allow a better characterization of individuals responsible for local transmission.

Impact of Delta 32-CCR5 heterozygosity on HIV-1 genetic evolution and variability--a study of 4 individuals infected with closely related HIV-1 strains.

A cluster of four patients acutely infected with a genetically almost identical virus, allowed us to investigate genetic variability and disease progression in early HIV-1 infection with minimal interference of virus specific factors. Two of the patients were heterozygous for the 32-bp deletion in the CCR5 coreceptor gene. Both showed a slower disease progression with lower viral load levels and a reduced rate of genetic evolution compared to the patients with normal CCR5 alleles.