CLINICAL AND ELECTROPHYSIOLOGIC CORRELATES OF ELEVATED ANTI-GM(1) ANTIBODY-TITERS

We reviewed the clinical and electrophysiologic features of 36 patient s with increased titers of IgM anti-GM, antibodies. Mildly elevated ti ters of up to 3,200 were not associated with any particular clinical s yndrome or disease. Clinically, 14 of 16 patients with highly elevated titers of 6,400 or higher had progressive weakness with lower motor n euron signs; six had active tendon reflexes and eight had absent refle xes, but none had definite upper motor neuron signs. Electrophysiologi c studies showed spontaneous activity in all 14 patients, one or more motor conduction blocks in nine, slowed motor conductions in one, and normal conductions in four patients. None had abnormal sensory conduct ions. These patients presented with a syndrome that has features of, b ut is distinct from, both motor neuron disease and demyelinating neuro pathy.