Screening for and management of hepatitis B virus reactivation in patients treated with anti-B-cell therapy

Reactivation of hepatitis B virus (HBV) is a potentially fatal complication after anti-B-cell therapy. It can develop not only in patients seropositive for hepatitis B surface antigen (HBsAg), but also in those with resolved HBV infection who are seronegative for HBsAg but seropositive for antibodies against hepatitis B core antigen (anti-HBc) and/or antibodies against HBsAg (anti-HBs). The risk of HBV reactivation depends on the balance between replication of the virus and the immune response of the host. Anti-CD20 monoclonal antibody-rituximab in combination with steroid-containing chemotherapy (R-CHOP: rituximab + cyclophosphamide + hydroxydaunorubicin + vincristine + prednisone/prednisolone)-is an important risk factor for HBV reactivation in HBsAg-negative patients. More obviously, HBsAg-positive patients are considered to be at very high risk for HBV reactivation and, in the rituximab era, 59%-80% of these patients develop HBV reactivation after R-CHOP-like chemotherapy. Patients with resolved HBV infection should also be considered at high risk of HBV reactivation, the incidence of which is reported to be 9%-24% in such lymphoma patients. All patients should be screened to identify risk groups for HBV reactivation before initiating anti-B-cell therapy by measuring serum HBV markers including HBsAg, anti-HBc and anti-HBs. To prevent the development of hepatitis due to HBV reactivation after anti-B-cell therapy, antiviral prophylaxis is recommended for HBsAg-positive patients and/or patients in whom HBV DNA is detectable at baseline, whereas regular monitoring of HBV DNA-guided preemptive antiviral therapy is a reasonable and useful approach for patients with resolved HBV infection.