Autoimmune neuropathy by anti-ganglioside GD-1b antibodies associated with primary Sjögren's Syndrome

Abstract

The terms axonal or demyelinating, traditionally disseminated in the classification of polyneuropathies, are electrophysiological interpretations that guide us to determine the pathogenic locus where the neuropathic lesion originates; this is an objective contribution to the knowledge of the etiology of the corresponding neuropathy. However, in some circumstances, a bimodal interpretation initially does not allow determining the possibility of involvement at the axolemma level, as can be identified in some immune-mediated polyneuropathies that compromise the Ranvier node or its different domains; These neuropathies are of autoimmune origin and are characterized by the presence of anti-ganglioside antibodies directed against antigenic epitopes at this anatomical locus. This is a case report of a 66-year-old male patient with progressive weakness in all four limbs leading to prostration over a few weeks; no prior systemic infections were reported. Initially diagnosed with Guillain-Barré Syndrome (GBS), he was evaluated with electrophysio- logical studies that confirmed the existence of a sensorimotor demyelinating polyneuropathy and treated with intravenous immunoglobulin (IVIg), with partial clinical improvement. Two weeks later, he was readmitted with a new episode of global muscle weakness, due to a fluctuating response of GBS to immunomodulatory treatment; therefore, he received two cycles of IVIg with little response. Complemen- tary immunological studies confirmed a diagnosis of Sjögren's syndrome and showed positive IgM anti-GD1b antibodies.