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In India: (i) HBV infection is the predominant factor for the development of HCC, often related to mutant forms of HBV; (ii) a majority of the HCC patients have overt cirrhosis of the liver; and (iii) HCV and alcohol per se are uncommonly associated.

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Lamivudine results in the selection of resistant hepatitis B virus (HBV) variants. Because the surface gene of HBV overlaps completely the polymerase gene, the incidence and profile of surface and polymerase gene mutations were investigated prospectively in chronic HBV patients who were on lamivudine therapy. Twenty-six patients with chronic liver disease confirmed histologically were included in this study. Extracted HBV DNA from sera samples were subjected to PCR amplification for the mutation prone regions of the surface and polymerase genes of the HBV genome. The emergence of mutant forms and biochemical derangements were studied carefully during the course of the therapy. In six of 26 (23%) patients, mutations emerged on lamivudine therapy. YM552I/VDD resistant mutants were observed in one (6%) and five (29%) patients at Month 12 and 18, respectively, out of 17 patients, who had completed more than 9 months of therapy. The mean time of emergence of resistance was 16.4 +/- 6.8 months. In three of the five patients, emergence of YM552I/VDD mutation was accompanied with a rise in HBV DNA levels. In two patients, mutations were noticed at the end of the viral breakthrough; when the DNA level went down to undetectable levels (<0.5 pg/mL). In two patients, normal ALT levels were found at the time of emergence of the YMDD mutation. YM552I/VDD mutations were observed in 43% of HBeAg positive and 20% of anti-HBe positive patients (P = ns). Although the 'a'-determinant region was found to be unaffected; in one patient, a novel pattern due to emergence of YIDD mutant was observed; the corresponding aa in the S-ORF turned to a stop codon. In summary, the frequency of emergence of YM552I/VDD mutations was 29% at Month 18 in the Indian patients. The presence of normal ALT and low levels of HBV DNA do not exclude the existence of resistant mutants. Novel mutations in the S-ORF, which lead to premature surface gene termination might affect the production of HBsAg and need further study.

Our results demonstrate that sequential therapy is superior to lamivudine monotherapy in achieving sustained seroconversion, ALT normalization, and HBV DNA loss. Compared to 80% with sequential therapy, only 20% Indian patients with CHB did not relapse after stopping lamivudine monotherapy.

There is limited data on the patterns of HBV mutation in family contacts of chronic liver disease (CLD) patients in India. DNA sequence analysis is an important tool to study this viral epidemiology. Transmission and prevalence of mutations in the S and pre-C gene region in HBV infected close family contacts of HBV-related CLD patients were studied. Twelve HBsAg(+) index patients and their 20 HBV DNA contacts were studied in detail. The S ORF and the pre-C region were sequenced using direct PCR products. S-gene sequencing included 32 specimens (12 index cases and all 20 contacts). Pre-C gene sequencing included 26 specimens (12 index cases and all the 14 HBsAg(+) contacts irrespective of their HBeAg status). More than 98% sequence homology was found between the index patients and their contacts. The in-depth study of 12 families revealed that the transmission pattern was primarily horizontal in 6 (50%) and vertical in 2 (17%) families (P < 0.05). The remaining four families had evidence of both horizontal and vertical transmission. Mutations in the S-gene were found in 80% of HBsAg(+) and 17% HBsAg(-) subjects (P < 0.05). A total of 22-point mutations at different nucleotide positions were found. In these, 16 (72%) were mutation of the "a" determinant region and 14 (64%) resulted in missense mutations. The commonest S-gene mutations were T118V and A128V, present in 44 and 38% specimens, respectively. T143M and G145R mutations in the second loop of the "a" determinant were found in 9% of the specimens. Novel mutations, C137stp and C138stp were found in only one HBsAg(-) subject. Mutations in the pre-C gene were common (91%) in patients with HBeAg(-) phenotype. G1896A mutation was found in 7 of 11 (64%) specimens changing amino acid tryptophane (W) to stop codon. Other mutations were at codons 25 and 29. The results of the study, demonstrate (1) clustering of Pre-C and S-gene mutations in the families, (2) horizontal mode of transmission and a common source infection appears to be frequent as evidenced by sequence homology and detailed history, (3) T118V and A128V were the commonest mutations in the S-gene region, while (4) M2 (G1896A) was the commonest pre-C gene mutation, and (5) long-term follow-up evaluation of these mutations suggested.