Genomic characterization of HBV genotype F variants by S gene analysis in a patient with previous anti HBs antibodies

MATHET V; FELD M; VERDUN R; QUARLERI JF; FENILI C; MANDÓ O; CARBALLAL G; SANCHEZ DO; OUBIÑA JR

Atlanta, USA

Simposio; 10th International Symposium on Viral Hepatitis and Liver Disease; 2000

Objective: To investigate HBV genomic factors associated with a severe course of chronic hepatitis in a patient who previously exhibited anti HBs antibodies. Patient and Methods: Adult male with severe chronic hepatitis and cirrosis since 1995. HCV, HAV and HBV serologic markers were determined. HBV viral DNA (S gene) was detected by PCR ang characterized by RFLP and SSCP. Amplicons were cloned and sequenced. Sequences were aligned with prototypes downloaded from GenBank (Genotypes A to F). A phylogenetic analysis was performed. Results: Viral markers proved positive only for HBV. HBs Ag remained positive since 1995 to date, while anti HBs was detected until july 1996. Several consecutive serum samples were ascribed to genotype F by RFLP, sequencing and phylogenetic analysis (20 clones). SSCP confirmed multiple quasispecies cocirculation. HBs Ag exhibited all characteristic aminoacids ascribed to genotype F in 4 of 20 clones, while the remaining 16 exhibited one or two changes. Within the `a´ determinant two clones had either C124R or C124Y; other mutations were Q129R, C138R, C139R and S140T (one clon each). Outside the `a´ determinant, several substitutions were documented. Conclusions: Co-circulation of quasispecies ascribed to HBV (genotype F) including variants with mutations at the main HBs neutralizing epitope was observed.