Background: Reactivation of hepatitis B virus (HBV), characterized by increased levels of serum HBV DNA, abnormal liver function and hepatic failure, is a frequent complication of immunosuppressive therapy and chemotherapy in patients with HBV infection. However, reactivation of occult HBV infection with immunosuppressive therapy or chemotherapy is rare.
Case presentation: A 77-year-old man was diagnosed with nephrotic syndrome and IgM nephropathy with unclear pathogenesis. Liver function was normal, HBV-related serum markers were negative and HBV DNA titer was below the upper limits of normal. Two months following the start of prednisone therapy for his nephrotic syndrome, laboratory tests revealed a substantial increase in serum transaminase levels (ALT: 490 IU/L; AST: 149 IU/L) and an elevation of HBV DNA level (3.42×10(6) copies/ml). We tested stored kidney tissue for HBsAg and HBcAg using immunohistochemistry and found the sample to be HBcAg positive, allowing us to confirm the etiology of nephropathy as an occult HBV infection. The cause of the hepatitis was thought to be HBV reactivation, so we immediately administered lamivudine. One month after the initiation of daily lamivudine treatment, laboratory tests revealed that serum levels of transaminases had improved (ALT: 35 IU/L; AST: 17 IU/L). Patient examination one year later showed that HBeAg had decreased with a concomitant increase of HBeAb, the quantity of HBV DNA was undetectable, and liver function and renal function had stabilized.
Conclusion: This is the first report describing HBV reactivation in an occult HBV infection patient treated with oral prednisone for nephrotic syndrome. HBV-associated antigen should be regularly tested for in patients with unknown etiological glomerulonephritis in areas with high HBV viral popular and even in those with no clinical evidence for diagnosis of HBV.