What serum antibodies and other laboratory findings are commonly seen with HBV infection and arthritis?
In acute hepatitis B, aspartate transaminase (AST) and alanine transaminase (ALT) are significantly elevated (1000s IU/mL) and HBsAg is present. With the onset of jaundice and resolution of arthritic symptoms, the HBsAg titer falls and IgG HBsAb and IgM HBcAb titers increase. As the remainder of the virus is cleared, IgG HBcAb appears. Other abnormal laboratory findings include a positive RF (25% of patients) and depressed C3 and C4 levels (as much as 40% of patients). Synovial fluid is typically inflammatory.