New Kaposi's sarcoma-associated herpesvirus variant in men who have sex with men associated with severe pathologies.

BACKGROUND: Kaposi's sarcoma-associated herpesvirus (KSHV) subtype depends mostly on patient origin. This study aimed to assess KSHV-diversity in a population of MSM living in France. METHODS: We included 264 patients; (i) 65 MSM: 57 HIV-infected with Kaposi's sarcoma (KS), multicentric Castleman disease (MCD) or primary effusion lymphoma (PEL), and 8 HIV-uninfected on HIV-pre-exposure prophylaxis (PrEP) to perform KSHV-typing by ORF-K1 Sanger and KSHV-whole-genome sequencing, (ii) 199 other patients for real-time PCR screening for the new variant. RESULTS: We found that 51% of KSHV-strains were subtype C (85% C3) and 33% were subtype A. Four patients with severe KSHV-disease (2 visceral KS, 1 MCD, 1 PEL) and one asymptomatic PrEP user had a new variant resembling the Ugandan subtype F, but with different ORF-K1 and KSHV-whole-genome sequences and a different epidemiological context (MSM versus African population). Its prevalence was 4.5% in Caucasian MSM and absent in other epidemiological groups. CONCLUSIONS: Subtype C predominated among MSM living in France. The new F-variant was identified in Caucasian MSM and associated with severe KSHV-disease, suggesting that subtype F could be split into F1 and F2 variants. Careful screening for this variant may be required in MSM given the severe clinical presentation of associated diseases.