Recurrent Arthritis and Anti-cyclic Citrullinated Peptide Positivity during Interferon-beta 1a Treatment in Two Patients with Multiple Sclerosis

Interferon (IFN) beta is the most widely prescribed disease-modifying drug for multiple sclerosis (MS). However, some adverse reactions are observed in course of IFN-beta therapy. This article presents two cases of female patients diagnosed with relapsing-remitting MS who developed inflammatory musculoskeletal manifestations, following IFN-beta 1a therapy. In the first patient recurrent arthritis developed a week after initiation of IFN-beta, which improved few weeks after a switch to glatiramer acetate. The second patient developed recurrent arthritis 1 month after IFN-beta 1a therapy who suffered painful arthritis despite discontinuation of the medication. Both patients were seropositive for anti- cyclic citrullinated peptide; the first patient was a positive rheumatoid factor (RF) and the second patient was both positive RF and anti-Ro. The role of IFN-beta in the setting of inflammatory musculoskeletal disease remains unclear. To minimize its side effects, review of these antibodies may be required in patients who are candidates for this therapy.