Open Access Case Report

High number of CD56bright NK-cells and persistently low CD4+ T-cells in a hemophiliac HIV/HCV co-infected patient without opportunistic infections

Giulia Fregni128, Anaenza Freire Maresca6, Valérie Jalbert3, Anne Caignard12, Daniel Scott-Algara7, Elisabeth Bordé Cramer1234, Elisabeth Rouveix46, Marie C Béné5 and Claude Capron1234*

Author Affiliations

1 Inserm U1016, Institut Cochin, Département d’Hématologie et d’Immunologie, Paris, France

2 Université Paris Descartes Sorbonne Paris Cité, CNRS (UMR8104), Paris, France

3 Service d’Hématologie et d’Immunologie, Hôpital Ambroise Paré, Boulogne-Billancourt, France

4 UFR des Sciences et de la Santé Paris Ile-de-France Ouest, Université de Versailles St Quentin en Yvelines, St Quentin en Yvelines, France

5 Laboratoire d’Hématologie, Hôtel-Dieu-CHU, Nantes, France

6 Service de Médecine Interne, Hôpital Ambroise Paré, Boulogne-Billancourt, France

7 Unité de Régulation des Infections Rétrovirales, Institut Pasteur, Paris, France

8 Institute of Pathology, Centre Hospitalier Universitaire Vaudois, Faculty of Biology and Medecine, University of Lausanne, Lausanne, Switzerland

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Virology Journal 2013, 10:33  doi:10.1186/1743-422X-10-33

Published: 26 January 2013

Abstract

Background

Both the human immunodeficiency virus (HIV) and hepatitis C virus (HCV), either alone or as coinfections, persist in their hosts by destroying and/or escaping immune defenses, with high morbidity as consequence. In some cases, however, a balance between infection and immunity is reached, leading to prolonged asymptomatic periods. We report a case of such an indolent co-infection, which could be explained by the development of a peculiar subset of Natural Killer (NK) cells.

Results

Persistently high peripheral levels of CD56+ NK cells were observed in a peculiar hemophiliac HIV/HCV co-infected patient with low CD4 counts, almost undetectable HIV viral load and no opportunistic infections. Thorough analysis of NK-subsets allowed to identify a marked increase in the CD56bright/dim cell ratio and low numbers of CD16+/CD56- cells. These cells have high levels of natural cytotoxicity receptors but low NCR2 and CD69, and lack both CD57 and CD25 expression. The degranulation potential of NK-cells which correlates with target cytolysis was atypically mainly performed by CD56bright NK-cells, whereas no production of interferon γ (IFN-γ) was observed following NK activation by K562 cells.

Conclusions

These data suggest that the expansion and lytic capacity of the CD56bright NK subset may be involved in the protection of this « rare » HIV/HCV co-infected hemophiliac A patient from opportunistic infections and virus-related cancers despite very low CD4+ cell counts.

Keywords:
HIV; HCV; Opportunistic infections; CD4; NK cells