Lewy body-like hyaline inclusions in sporadic motor neuron disease are ubiquitinated

Round eosinophilic hyaline inclusion bodies with halos in the somata of anterior horn cells from a case of sporadic lower motor neuron disease (MND) were intensely immunostained with the monoclonal anti-ubiquitin antibody (DF2). A few similar, DF2-positive inclusions were also observed in the nerve cell processes of anterior horn cells or in the neuropil. Most inclusions showed intense homogeneous staining of the entire inclusion, whereas a few had intense staining of their periphery with no or pale staining of the central areas. Other DF2-positive structures in the somata of anterior horn cells included cytoplasmic granular structures, eosinophilic thread-like or reticular structures, and small eosinophilic profiles different from Bunina bodies. The DF2-staining intensity of Bunina bodies and spheroids did not exceed the background level. These results suggest that ubiquitination is associated with a pathological process of anterior horn cell degeneration in this MND case.