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Open Access Short Report

Emergence of HBV resistance to lamivudine (3TC) in HIV/HBV co-infected patients in The Gambia, West Africa

Balint Stewart1, Modou L Jobarteh1, Ramu Sarge-Njie1, Abraham Alabi12, Thushan de Silva1, Kevin Peterson1, Ingrid Peterson1, Hilton Whittle1, Sarah Rowland-Jones13, Assan Jaye1, Matthew Cotten14 and Maimuna Mendy15*

Author Affiliations

1 Medical Research Council, Fajara, P O Box 273, Banjul, The Gambia, West Africa

2 Medical Research Unit, Albert Schweitzer Hospital, Lambarene, Gabon

3 Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK

4 Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK

5 International Agency For Research on Cancer (IARC), 150 Cours Albert Thomas, Lyon 69372, France

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BMC Research Notes 2011, 4:561  doi:10.1186/1756-0500-4-561

Published: 23 December 2011

Abstract

Background

Lamivudine (3TC) is a potent inhibitor of both Hepatitis B virus (HBV) and Human Immunodeficiency Virus (HIV) replication and is part of first-line highly active antiretroviral therapy (HAART) in the Gambia. Unfortunately, the effectiveness of 3TC against HBV is limited by the emergence of resistant strains.

Aim

The aim of this retrospective study was to characterise 3TC-resistant mutations in HBV from co-infected patients receiving HAART, by generating HBV polymerase sequence data and viral loads from HBV genotype E infected patients, both at initiation and during a course of 3TC therapy.

Method

Samples from 21 HBV chronic carriers co-infected with HIV-1 (n = 18), HIV-2 (n = 2) and HIV-dual (n = 1) receiving HAART for a period of 6-52 months were analysed for the emergence of 3TC-resistance mutations.

Findings

Sixteen out of 21 HBV/HIV co-infected patients responded well to HAART treatment maintaining suppression of HBV viraemia to low (≤ 104 copies/mL) (n = 5) or undetectable levels (< 260 copies/ml) (n = 11). Out of the 5 non-responders, 3 had developed 3TC-resistant HBV strains showing mutations in the YMDD motif at position 204 of the RT domain of the HBV polymerase. One patient showed the M204V+ L180M+ V173L+ triple mutation associated with a vaccine escape phenotype, which could be of public health concern in a country with a national HBV vaccination programme. All except one patient was infected with HBV genotype E.

Conclusions

Our findings confirm the risk of 3TC mutations in HAART patients following monotherapy. This is a novel study on 3TC resistance in HBV genotype E patients and encourage the use of tenofovir (in association with 3TC), which has not shown unequivocally documented HBV resistance to date, as part of first-line therapy in HIV/HBV co-infected patients in West Africa.

HBV- hepatitis B infection; HIV- human immunodeficiency virus; HAART- antiretroviral therapy.