SERUM AUTOANTIBODIES IN CHILDHOOD OPSOCLONUS-MYOCLONUS SYNDROME - AN ANALYSIS OF ANTIGENIC TARGETS IN NEURAL TISSUES

Objective: Opsoclonus-myoclonus (OM) is a rare neurologic syndrome aff ecting children and adults, in children it occurs as a parainfectious process or a paraneoplastic syndrome in association with neuroblastoma , Evidence for an immune mechanism includes the presence of serum auto antibodies to several neural antigens and improvement of symptoms with immunosuppressive therapy, We studied the neural antigenic targets of serum IgM and IgG autoantibodies from nine children with OM, Design: We studied sera from nine children with OM, three with associated neur oblastoma and six with a prodromal viral illness, Control subjects (n = 77) included four children with neuroblastoma but not OM, 32 childre n with other neurologic disorders, and 41 with nonneurologic illnesses , We studied the neural antigenic targets of serum IgM and IgG autoant ibodies by the following methods: (1) immunostaining of human cerebell ar sections and peripheral nerve, and (2) Western blot analysis with h uman brain fractions including white matter, gray matter, and cerebell ar Purkinje cells and nuclei, Results: Sera from all nine children wit h OM had IgM and IgG binding to the cytoplasm of cerebellar Purkinje c ells and to some axons in white matter. In peripheral nerve, IgM and I gG from all nine OM sera bound to large and small axons. Western blot analysis showed a distinctive pattern of binding to several neural pro teins, including a 210 kd antigen identified as the high molecular wei ght subunit of neurofilament. No control serum showed a similar patter n of reactivity. Conclusion: Opsoclonus-myoclonus syndrome in childhoo d is associated with a distinctive pattern of serum IgM and IgG bindin g to neural tissues and antigens.