Abstract
DILI: drug-induced liver injury, HBV: Hepatitis B virus, LFT: liver function test, RRMS: Relapsing-remitting multiple sclerosis, UDCA: ursodeoxycholic acid. Rituximab is a human chimeric monoclonal antibody that targets CD20 on B cells. The incidence of rituximab-associated drug-induced liver injury (DILI) is 19 cases per 100 000 people annually. This condition is characterized by a rapid increase in aminotransferase levels and hepatocellular injury, primarily due to reactivation of the hepatitis B virus (HBV). Nevertheless, there have been rare cases of DILI occurring in the absence of HBV reactivation. This case presents a 25-year-old male with relapsing-remitting multiple sclerosis (RRMS) that was treated with rituximab. After treatment, the patient demonstrated a hepatocellular damage pattern and biopsy confirmed the diagnosis. Following the administration of ursodeoxycholic acid (UDCA), the patient's liver function tests (LFTs) returned to normal levels, demonstrating that DILI from rituximab can occur after any infusion, regardless of therapy duration or dosage.