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.