The case of a 46-year-old woman with chronic hepatitis C who was prescribed subcutaneous pegylated interferon once a week and oral ribavirin once a day is presented. Within 24 h after the first injection to her left arm, the patient developed pruritus and erythematous papules at the injection site and painful papules on her hands. After immediate administration of antihistamines, the pruritus and papules remitted. One wk later, after injection in the right arm, skin lesions and pruritus were seen. After the third injection to the abdomen, the patient developed a rash, and after the fourth and fifth injections to other areas of the abdomen, injection-site papules were seen. The patient had no skin reactions for the next 12 mo, with the exception of injection-site papules. Hepatitis C virus RNA was negative after 12 mo of treatment. Clearly, patience is important during hepatitis C therapy in order to avoid unnecessary examinations and to promote successful outcomes.
Aims This study was conducted to clarify the resistance profile of a novel mutation pattern emerging during lamivudine (3TC) therapy and showing cross-resistance to adefovir dipivoxil (ADV) in a patient with chronic hepatitis B. Methods and results Successful suppression of hepatitis B virus (HBV) replication by sequential therapy of 9 MU thrice weekly interferon (IFN) and 3TC was followed by genotypical resistance detected at month 28 of therapy (month 19 of lamivudine treatment). ADV was added to 3TC therapy on month 44 of antiviral treatment. Neither alanine aminotransferase normalization nor a stable decrease in HBV viral load was observed, although ADV was used for more than 40 months. The HBV pol region was amplified from serum samples obtained before and after ADV treatment. The complete genome was cloned into a TA vector. PCR products and 7–10 clones from each cloned vector were sequenced. A novel mutation, A181S, in the reverse transcriptase gene leading to a conversion of W172C in the overlapping surface antigen gene was detected along with a M204I mutation. The complete genome comprising the A181S+M204I pattern was cloned into an expression vector and its in vitro susceptibility to 3TC, ADV, tenofovir (PMPA), clevudine (l-FMAU) and emtricitabine (FTC) were determined in transiently transfected Huh7 cells. This mutation pattern displayed more than 1,000-fold resistance to the nucleoside analogues 3TC and FTC and approximately sixfold resistance to l-FMAU, while it confers 28.23- and 5.57-fold resistance for the nucleotide analogues ADV and PMPA, respectively. Conclusion A new mutation pattern, A181S+M204I, arising under lamivudine treatment confers cross-resistance to ADV both in vivo and in vitro.
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