Interferon β is the first-line treatment for relapsing-remitting multiple sclerosis. Patients treated with interferon β may develop neutralizing antibodies that can reduce or abolish its efficacy.
Interferon-inducible Myxovirus resistance protein A has been proven to be a sensitive marker of biological response to interferon β. Neutralizing antibodies and the levels of Myxovirus resistance protein A mRNA are sensitive measures of biological response to interferon β; their levels should be investigated in all interferon-treated patients.