Re-appearance of hepatitis B virus following therapy with rituximab for lymphoma is not rare in Japanese patients with past hepatitis B virus infection

Background and aim De novo hepatitis B virus (HBV)-related hepatitis is a well-known fatal complication following chemo-immunosuppressive therapy in patients with past HBV infection (HB surface antigen and serum HBV DNA negative, but HB core antibody and/or HB surface antibody positive). This research was conducted to evaluate the incidence of and clinical features associated with re-appearance of serum HBV DNA following chemo-immunosuppressive therapy in Japanese patients with past HBV infection. Methods This is a retrospective review. Forty-five patients with past HBV infection who had received chemo-immunosuppressive therapy for haematological disease were followed up for > 6 months, to determine whether the serum test for HBV changed from negative to positive (i.e. re-appearance of serum HBV DNA following chemo-immunosuppressive therapy). Results Re-appearance of serum HBV DNA was confirmed in five (20.8%) of the 24 patients who had received treatment regimens containing rituximab, but in none of the 21 patients who had not received treatment regimens containing rituximab (P=0.035). The HBV genotype could be determined in four of the five aforementioned patients, and in all four, HBV genotype C, which is the most prevalent genotype in Japan, was identified. Conclusion This research showed that re-appearance of serum HBV DNA is not rare in Japanese patients treated with chemotherapy regimens containing rituximab, and no other factors related to such re-appearance of serum HBV DNA could be identified. Well-designed clinical studies, including immunological and genetic analyses of the host and of the HBV, are required for further elucidation.