Antineuronal antibodies in patients with neuroblastoma and paraneoplastic opsoclonus-myoclonus

Purpose: To identify serologic markers in children with paraneoplastic opso clonus-myoclonus (POM). Materials and Methods: We examined the sera of 64 children with neuroblasto ma (16 with POM and 48 age-matched anti stage-matched controls) by immunohi stochemistry of rat brain and human cerebellum, and by Western blot analysi s of protein extracts from human Purkinje cells, cortical neurons, neurobla stoma cell lines, and HuD. Results: Using immunohistochemistry, IgG reactivity against neurons was ide ntified in 13 of 16 POM sera (81%), and 12 of 48 non-POM sera (25%; P < 0.0 01). IgM antineural antibodies were present in 3 of 16 POM sera (19%) and 1 1 of 48 (23%) non-POM sera. Except for anti-Hu antibodies detected in 10 se ra (4 with POM), no other specific reactivities were identified by Western blot analysis of neuronal or of neuroblastoma protein extracts. Conclusions: We conclude that: 1) patients with neuroblastoma and POM are m ore likely to harbor antineuronal antibodies than patients without POM; 2) no specific serologic marker of POM was identified, but the frequent presen ce of antineuronal antibodies suggests that POM is immune-mediated; and 3) anti-Hu antibodies are present in some sera from patients with neuroblastom a, irrespective of the presence of POM.