Long-term persisting interferon beta-1b neutralizing antibodies after discontinuation of treatment.

ABSTRACT

OBJECTIVES: Neutralizing antibodies (NAB) against interferon beta (IFNB) with presumably negative impact on treatment outcome have been described in up to 42% of patients undergoing IFNB treatment. However, in most cases NAB decrease despite continuation of IFNB therapy. Observations on NAB after discontinuation of IFNB therapy are lacking. Here, we report for the first time on NAB which now persist for several years following discontinuation of IFNB treatment. MATERIALS AND METHODS: We present two multiple sclerosis patients followed over 8 and 10 years. NAB have been measured repeatedly and are presented together with clinical data. NAB developed after 2 years of treatment and persisted despite discontinuation of treatment at high titers for more than 4 years. CONCLUSION: Our data indicate that IFNB therapy may induce long-term NAB production which persists even after discontinuating IFNB treatment. Possible immunological mechanisms are discussed.