Disappearance of hepatitis B virus core deletion mutants and successful combined kidney/liver transplantation in a patient treated with lamivudine

Efficiency and safety of lamivudine therapy in patients with chronic HBV infection, dialysis or after kidney transplantation

AIM: To analyze the effectiveness and safety of lamivudine treatment in patients with chronic HBV infection undergoing hemodialysis or after kidney transplantation, and to study the frequency of tyrosine - methionine - aspartate - aspartate (YMDD) mutation occurrence after lamivudine treatment.

METHODS: We analyzed 91 patients with chronic hepatitis B, among whom, 16 patients underwent hemodialysis, 7 patients had kidney transplantation and 68 patients had normal function of kidney. The hemodialysis patients were treated by lamivudine 300 mg/wk. Patients after kidney transplantation and patients with normal function of kidney were treated with lamivudine 100 mg/d. Therapy lasted for 12 mo. HBV-DNA, HBsAg, HBeAg and anti-HBe, and anti-HCV antibodies were assessed in sera of patients. The analysis was performed before and 6 mo after the end of lamivudine treatment. Before, during and after the lamivudine therapy, the number of erythrocytes, leukocytes, platelets and hemoglobin concentration, ALT and AST activity, as well as bilirubin, urea and creatinine concentrations were analyzed in sera from patients.

RESULTS: After the 12-mo lamivudine treatment, elimination of HBV - DNA was observed in 56% patients undergoing hemodialysis and in 53% patients with normal kidney function. Only 1 from 7 (14%) kidney-transplanted patients eliminated HBV-DNA. Furthermore, HBeAg elimination was observed in 36% hemodialysis patients, in 51% patients with normal function of kidneys and in 43% kidney-transplanted patients. Among the patients undergoing dialysis, no YMDD mutation was found after 12 mo of therapy, while it was detected in 9 patients (13%) with normal function of kidney and in 2 kidney-transplanted patients (29%, P<0.006). We did not observe significant side effects of lamivudine treatment in studied patients.

CONCLUSION: Effectiveness of lamivudine therapy in dialysis patients is comparable with that in patients with normal function of kidney. Lamivudine treatment is well tolerated and safe in patients with renal insufficiency undergoing hemodialysis and kidney-transplantation. However, in the latter group, high incidence of YMDD mutation after lamivudine treatment was observed.

Replication of naturally occurring woodchuck hepatitis virus deletion mutants in primary hepatocyte cultures and after transmission to naive woodchucks

Woodchuck hepatitis virus (WHV) mutants with core internal deletions (CID) occur naturally in chronically WHV-infected woodchucks, as do hepatitis B virus mutants in humans. We studied the replication of WHV deletion mutants in primary woodchuck hepatocyte cultures and in vivo after transmission to naive woodchucks. By screening 14 wild-caught, chronically WHV-infected woodchucks, two woodchucks, WH69 and WH70, were found to harbor WHV CID mutants. Consistent with previous results, WHV CID mutants from both animals had deletions of variable lengths (90 to 135 bp) within the middle of the WHV core gene. In woodchuck WH69, WHV CID mutants represented a predominant fraction of the viral population in sera, normal liver tissues, and to a lesser extent, in liver tumor tissues. In primary hepatocytes of WH69, the replication of wild-type WHV and CID mutants was maintained at least for 7 days. Although WHV CID mutants were predominant in fractions of cellular WHV replicative intermediates, mutant covalently closed circular DNAs (cccDNAs) appeared to be a small part of cccDNA-enriched fractions. Analysis of cccDNA-enriched fractions from liver tissues of other woodchucks confirmed that mutant cccDNA represents only a small fraction of the total cccDNA pool. Four naive woodchucks were inoculated with sera from woodchuck WH69 or WH70 containing WHV CID mutants. All four woodchucks developed viremia after 3 to 4 weeks postinoculation (p.i.). They developed anti-WHV core antigen (WHcAg) antibody, lymphoproliferative response to WHcAg, and anti-WHV surface antigen. Only wild-type WHV, but no CID mutant, was found in sera from these woodchucks. The WHV CID mutant was also not identified in liver tissue from one woodchuck sacrificed in week 7 p.i. Three remaining woodchucks cleared WHV. Thus, the presence of WHV CID mutants in the inocula did not significantly change the course of acute self-limiting WHV infection. Our results indicate that the replication of WHV CID mutants might require some specific selective conditions. Further investigations on WHV CID mutants will allow us to have more insight into hepadnavirus replication.