Hepatitis B reactivation in hematopoietic stem cell transplanted patients: 20 years of experience of a single center from a middle endemic country.

Hematopoietic stem cell transplantation (HSCT) is a risk factor for viral hepatitis reactivations because it affects lymphocyte number and functions. Latent hepatitis B virus (HBV) may stay in dormant form in hepatocytes and may be reactivated in prolonged immunosuppression. This study analyzes the incidence of reactivation of HBV infections in HSCT patients in a middle endemic country like Turkey. Five hundred and sixty-one HSCT patients from 1994 to 2015 were retrospectively evaluated. Sixty-six patients had a serologic feature of HBV infection. Fifteen patients were hepatitis B surface antigen (HBsAg)-positive patients (3 allogeneic and 12 autologous) while 51 of them were anti-hepatitis B core IgG (anti-HBc IgG)-positive patients (22 allogeneic and 29 autologous). Although under lamivudine prophylaxis, reactivation was seen in three of 12 (25%) chronic HBV (HBsAg positive) patients who received autologous HSCT and in two of the three HBsAg-positive patients who received allogeneic HSCT. Rate of reactivation in the whole HBsAg-positive group was 33%. Reactivation occurred on median 270th day (range: 60-730). Reverse seroconversion incidence was 10% on 133th day for HBsAg negative, but anti-HBc IgG-positive patients, which increased to 17% on 360th and to 23% on 1500th day. Cumulative incidence increased to 41% on 2280th day for isolated anti-HBc IgG-positive patients. Hepatitis B surface antibodies (anti-HBs) were found to be protective as reactivation did not exceed 11% on 5050th day when anti-HBs was positive. When anti-HBc IgG-positive cases were analyzed according to their transplantation types, allogeneic HSCT was found to have higher cumulative incidence (45% on 3258th day) for HBV reactivation than autologous HSCT (7% on 5050th day). Besides, HBV reactivation in anti-HBc IgG-positive patients who received allogeneic transplantation was related to mortality. Findings of this study suggest that HBV prophylaxis extending over 1 year should be prescribed for HBsAg-positive patients independent of the transplantation type. Prophylaxis should also be given to anti-HBc IgG-positive patients if an allogeneic HSCT is to be performed.