Characterization of CRF56_cpx, a new circulating B/CRF02/G recombinant form identified in MSM in France
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Updated: May 6, 2026
Generation, Amplification, and Titration of Recombinant Respiratory Syncytial Viruses
Published on: April 4, 2019
Marie Leoz1, Felix Feyertag, Charlotte Charpentier
1aLaboratoire associé au CNR du VIH, hôpital Ch. Nicolle, CHU de Rouen bGRAM EA 2656, Faculté de Médecine-Pharmacie, Université de Rouen, Rouen, France cComputational and Evolutionary Biology research group, Faculty of Life Science, University of Manchester, Manchester, UK dAssistance Publique - Hopitaux de Paris, Groupe Hospitalier Bichat Claude Bernard, Service de Virologie eAssistance Publique - Hopitaux de Paris, Groupe Hospitalier Saint Louis, Service de Virologie, fAssistance Publique - Hopitaux de Paris, Groupe Hospitalier Pitié Salpêtrière, Service de Virologie, Paris, France.
Abstract:
Several B/CRF02_AG Unique Recombinant Forms (URFs) have previously been identified in France. Here we show that one of them (URF5_B/02/G) is emerging in MSM, a high-risk population where HIV incidence and number of superinfections are increasing. We describe this new Circulating Recombinant Form, CRF56_cpx, estimate the time to its most recent common ancestor, investigate its origins and show that it probably shares common ancestors with strains from the East Mediterranean.
Insights
A new HIV variant, CRF56_cpx, is emerging in men who have sex with men (MSM) in France. This circulating recombinant form likely originated from strains in the East Mediterranean region.
Area of Science:
- Virology
- Epidemiology
- Public Health
Background:
- Previous identification of unique recombinant forms (URFs) of Human Immunodeficiency Virus type 1 (HIV-1) B/CRF02_AG in France.
- Increasing HIV incidence and superinfections observed in men who have sex with men (MSM), a population at high risk.
Purpose of the Study:
- To identify and characterize a newly emerging HIV-1 circulating recombinant form (CRF) in France.
- To investigate the origins and evolutionary history of this new CRF, specifically CRF56_cpx.
- To assess the potential epidemiological impact in the MSM population.
Main Methods:
- Molecular epidemiology techniques to identify and sequence the novel recombinant form.
- Phylogenetic analysis to estimate the time to the most recent common ancestor (TMRCA).
- Recombination analysis to determine the genetic origins of CRF56_cpx.
Main Results:
- Identification of a novel circulating recombinant form, designated CRF56_cpx, previously known as URF5_B/02/G.
- Evidence suggests CRF56_cpx is emerging within the MSM population in France.
- Phylogenetic analysis indicates probable shared ancestry with HIV strains from the East Mediterranean region.
Conclusions:
- CRF56_cpx represents a new and emerging HIV-1 variant in France, particularly within the MSM community.
- The emergence of CRF56_cpx highlights the dynamic nature of HIV-1 evolution and recombination.
- Understanding the origins and spread of CRF56_cpx is crucial for targeted prevention and treatment strategies in high-risk populations.
