The Impact of Methylprednisolone Pulses during Relapses of Multiple Sclerosis on the Kinetics of Anti-Interferon-Beta Antibodies.

Background/aims: We assessed the, hitherto unknown, impact of intravenous methylprednisolone (ivMP) pulses during relapses of multiple sclerosis (MS) on the kinetics of anti-interferon-beta neutralizing antibodies (Nabs) and binding antibodies (Babs).

Methods: Babs (ELISA) and Nabs (antiviral cytopathic effect assay) titers were evaluated before, immediately after and at 1 month following ivMP in 60 MS patients.

Results: ivMP reduces Nabs and Babs titers for at least 1 month. Baseline titers determine Nabs and Babs seronegativity at the end of ivMP. Clinical response to ivMP tends to be better in Nabs(+) patients.

Conclusion: Sampling for Nabs/Babs should be avoided during or shortly after ivMP to avoid transient positive or negative results that may obscure the decision to switch treatment.