Sera from 7 patients with paraneoplastic opsoclonus were examined for antineuronal autoantibodies. An antibody against neuronal nuclei was found in serum from a patient with breast cancer, opsoclonus, and ataxia. This antibody recognized 53- to 61-kDa and 79- to 84-kDa antigens in immunoblots of neurons. Antineuronal antibodies were not found in other patients with paraneoplastic opsoclonus.

The partial D of the Rh D phenotype, DFR, is recognized by its pattern of reactions with monoclonal anti-D and its association with the low-incidence antigen FPTT, FPTT has now been numbered Rh50.