Hepatitis B virus variants with natural resistance to adefovir and lamivudine and S-escape mutants isolated from children in Argentina.

CUESTAS ML, MATHET VL, MINASSIAN ML, TRINKS J, RIVERO C, ANDREETTA AM, CASTILLO A, GENTILE E, LEZAMA C, GALOPPO M, GIACOVO G, GALOPPO C, OUBIÑA JR.

Buenos Aires, Argentina

Congreso; The 6th World Congress of the World Society for Pediatric Infectious Diseases; 2009

Abstract: Despite the availability of therapeutic and preventive strategies, Hepatitis B virus (HBV) infection is still the most common cause of liver cirrhosis and hepatocellular carcinoma. The unique genomic structure and the replication cycle of HBV together with the high error-prone of its viral polymerase provide much opportunity for mutations to occur. Emergence of different viral variants or “escape” mutants is thus inevitable. In this connection, several reports have documented the appearance of S-escape mutants from protective anti-HBs antibodies, the occurrence of drug-resistant mutants to the current nucleos(t)ide analogues approved for the treatment of chronic hepatitis B; and the presence of pre-core/core and X mutants that may cause severe and progressive liver disease. The aim of this study is to report three cases of chronically HBV-infected children in Argentina who developed natural antiviral resistance to adefovir, and one of them to lamivudine as well. Two of the patients studied are also carriers of S-escape mutants.