IgM anti-GM1 antibody titers in patients with monomelic amyotrophy

Abstract

Background: Monomelic amyotrophy (MMA) is a benign motor neuron disorder, which particularly affects young people and the etiology is still unknown. Gangliosides are located on the outer surface of motor neurons. Anti-GM1 antibodies have been found to be elevated in multi-focal motor neuropathy with conduction block and other neurological diseases, which may have therapeutic implication.

Aim: To evaluate IgM anti-GM1 antibody titers in patients of monomelic amyotrophy.

Setting and design: prospective controlled study.

Materials and methods: Forty-six clinically and electrophysiologically diagnosed cases of MMA were assessed for IgM anti-GM1 antibody titers by enzyme-linked immunosorbent assay (ELISA) method and compared with titers in healthy controls, cases of amyotrophic lateral sclerosis (ALS) and acute inflammatory demyelinating polyneuropathy (AIDP). Titer of 800 units was taken as upper limit of normal (Buhlmann Laboratories AG, Switzerland).

Statistical analysis used: one-way ANOVA.

Results: The mean age of 46 patients with MMA was 24.5 (+/- 7.3) years, with male female ratio of 44:2. The mean age of 19 healthy controls was 24.1 (+/- 3) years with male: female ratio of 18:1. Five (26%) individuals in the healthy control group, 22 (48%) patients of MMA, four (30%) of ALS and five (50%) of AIDP had high titers of IgM anti-GM1 antibody (P> 0.05).

Conclusions: Although larger number of patients with MMA had higher IgM anti-GM1 antibody titers, the difference was not statistically significant from titers of healthy individuals and of patients in the ALS and AIDP group.