Mono-arthritis in a chronic hepatitis B patient after alpha-interferon treatment.

A 28 year old woman with hepatitis B (HB) related chronic active hepatitis was treated with a 12 week course of alpha-interferon (alpha-IFN). She developed acute mono-arthritis 1 week after completion of treatment. Her rheumatoid factor (RF) was positive before alpha-IFN and fell steadily during therapy. This was followed by a rebound of RF level with the associated arthritis occurring 1 week after completion of the course of alpha-IFN. In absence of any medication RF gradually fell and became negative at the end of 1 year. This observation is thought to be related to the immunomodulatory effect of alpha-IFN either directly on RF production or indirectly through the control of hepatitis.