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X4 tropic viruses are on the rise in recent HIV-1 seroconverters in Spain

Sierra-Enguita, Rocíoa; Rodriguez, Carmenb; Aguilera, Antonioc; Gutierrez, Felixd; Eiros, Jose M.e; Caballero, Estrellaf; Lapaz, Marianaa; Soriano, Vicentea; del Romero, Jorgeb; de Mendoza, Carmena,g

doi: 10.1097/QAD.0000000000000269
Clinical Science

Background: Transmission of HIV-1 with drug resistance mutations (DRMs) in Spain remains stable around 13%. However, the profile of recent HIV-1 seroconverters has experienced significant changes.

Methods: Retrospective analyses of all individuals with HIV-1 infection acquired within the past 12 months recruited at a national registry since year 1997.

Results: A total of 1032 recent HIV-1 seroconverters were examined (92.2% men; median age 31 years; 84% homosexual men). At the moment of diagnosis, median plasma HIV-RNA and CD4+ cell counts were 4.5 log copies/ml and 558 cells/μl, respectively. A total of 136 individuals (13.8%) carried non-B subtypes. Major primary DRMs were found in 13.4%, being 7.7% for nucleoside reverse transcriptase inhibitor (NRTI), 5.8% for nonnucleoside reverse transcriptase inhibitor (NNRTI) and 2.9% for protease inhibitor. NRTI DRM significantly declined from 23.7% in 1997–2000 to 5.7% in 2010–2012 (P < 0.01). Overall, X4 viruses were found in 19.7% of HIV-1 seroconverters, increasing from 11.5% before 2001 to 23.3% since year 2010 (P = 0.04). Interestingly, median CD4+ cell counts were significantly lower in seroconverters diagnosed during the last period after adjusting for potential confounders. In multivariate analyses, X4 tropism, high HIV-RNA, foreigners and non-B subtypes were independent predictors of lower CD4+ cell counts.

Conclusion: Transmission of NRTI DRM has declined significantly in recent HIV-1 seroconverters in Spain. Conversely, X4 tropic viruses are on the rise and currently account for 23.3% of new HIV-1 infections. These individuals present with lower CD4+ cell counts suggesting that circulating HIV-1 strains might have gained virulence.

aHospital Carlos III

bCentro Sanitario Sandoval, Madrid

cHospital Conxo-CHUS, Santiago

dHospital General, Elche & Universidad Miguel Hernández, Alicante

eHospital Rio Hortega, Valladolid

fHospital Vall d’Hebron, Barcelona

gHospital Universitario Puerta de Hierro & Puerta de Hierro Research Institute, Madrid, Spain.

Correspondence to Dr Carmen de Mendoza, Department of Internal Medicine, Hospital Universitario Puerta de Hierro & Puerta de Hierro Research Institute, Calle Joaquin Rodrigo 2, Majadahonda 28222, Madrid, Spain. E-mail:

Received 21 December, 2013

Revised 24 February, 2014

Accepted 24 February, 2014

This work was presented orally at the International Workshop on HIV & Hepatitis Virus Drug Resistance and Curative Strategies, which was held in Toronto, Canada, on 4–8 June 2013 (abstract #14).

© 2014 Lippincott Williams & Wilkins, Inc.