Four cases of anti-ganglioside antibody-positive neuralgic amyotrophy with good response to intravenous immunoglobulin infusion therapy.

Neuralgic amyotrophy (NA), which is an idiopathic disorder in the peripheral nerves, is characterized by an acute onset of unilateral pain in the proximal limbs followed by muscular weakness and wasting. Some cases of NA are thought to be related to immune pathogenic disorders such as Guillain-Barré syndrome (GBS). We report the case of four patients with NA who were positive for anti-N-acetylgalactosaminyl GD1a (anti-GalNAc-GD1a) antibodies, had a preceding infection, and showed a good response to intravenous immunoglobulin infusion therapy. Anti-ganglioside antibodies, especially the anti-GalNAc-GD1a antibody, may be a useful marker for predicting response to immune therapy.