Hepatitis B Virus Reactivation Following Salazosulfapyridine Monotherapy in a Patient with Rheumatoid Arthritis

A 72-year-old man was diagnosed with rheumatoid arthritis (RA) and prior hepatitis B virus (HBV) infection. He began treatment with salazosulfapyridine (SASP). Several months later, his blood tests reflected a slightly elevated liver function. Serum tests were positive for hepatitis B surface antigen and HBV-DNA, and the diagnosis of de novo HBV hepatitis was made. A genetic analysis showed that he had polymorphisms of ABCG2 and NAT2, which could lead to high plasma concentrations of SASP and sulfapyridine. To the best of our knowledge, this is the first report of de novo hepatitis developing during SASP monotherapy for RA.