Late postpoliomyelitis muscular atrophy: clinical, virologic, and immunologic studies.

Seventeen relatively young patients, ages 31-65 years (average, 45) with prior poliomyelitis, who after a number of years of stability had experienced new neuromuscular symptoms, were studied. Seven patients had deterioration of functional capacity and then stabilization without new muscular weakness. The other 10 had late postpoliomyelitis muscular atrophy (late PPMA ) characterized by focal progressive muscle weakness, wasting, fasciculations, and muscle pains affecting previously spared muscles or muscles previously affected but recovered. Four patients with late PPMA had lymphorrhages or lymphocytic infiltrates in their biopsied muscle; three of three patients had oligoclonal IgG bands in their spinal fluid, and five had variable peripheral T lymphocyte-subset ratios. In one patient with late PPMA , antibodies to poliovirus were specifically elevated in the cerebrospinal fluid. Our findings indicate that new motor-neuron disease can occur in patients with prior poliomyelitis and that immunopathologic mechanisms may play a role.