Do Low Titers of Antibody Against Hepatitis B Surface Antigen Carry a Risk of Viral Reactivation During Immunosuppressive Therapy for Rheumatic Diseases?

Abstract

To the Editor: I read with great interest the article by Kato, et al regarding hepatitis B virus (HBV) reactivation in patients receiving immunosuppressive therapy for autoimmune diseases1. The authors had performed a followup study on 35 patients who were negative for hepatitis B surface antigen (HBsAg) and positive for antibody against hepatitis B core antigen (anti-HBc). During the 8- to 124-week period of followup, 6 patients (17%) experienced reactivation of viral replication. The authors showed that baseline titers of antibody against HBsAg (anti-HBs) were significantly lower in these patients than in the others (median 2.83 mIU/ml, range 0.24–168.5 vs median 99.9 mIU/ml, range 0.00–5343; p = 0.036). Accordingly, they suggested that low baseline anti-HBs titers may be a risk factor for viral reactivation in this clinical setting. Among the 6 patients with viral reactivation, however, 1 had a relatively high titer of serum anti-HBs at baseline (168.5 mIU/ml). The presence of anti-HBs following natural HBV infection indicates recovery and immunity against reinfection. This antibody can also be acquired as an immune response to active vaccination or passively transferred by administration of hepatitis B immunoglobulin (HBIG). A serum anti-HBs … E-mail: moris{at}saisyunsou1.hosp.go.jp