Transient MOG antibody seroconversion associated with immunomodulating therapy.

Immunoglobulin G (IgG) autoantibodies targeting myelin oligodendrocyte glycoprotein (MOG) have recently been associated with autoimmune CNS demyelination. We present the case of a 35-year-old patient who was seronegative for MOG-IgG (as confirmed by means of three independent immunoassays) during two corticosteroid-responsive attacks of brainstem encephalitis and optic neuritis, respectively, but turned positive for MOG-IgG under treatment with interferon-beta (IFN-beta), which was commenced 6 months after onset of the first attack. MOG-IgG serum levels declined after therapy was switched to glatiramer acetate. The fact that seroconversion was first observed under treatment with IFN-beta is in accordance with previous evidence suggesting a role of IFN-beta in disease exacerbation in antibody-mediated disorders.