Serum immunoglobulin G level reduction is a predictor of short-term improvement in patients with myasthenia gravis undergoing plasmapheresis.

OBJECTIVES: The aim of the study was to investigate the serological factors in predicting symptom improvement in myasthenia gravis (MG) patients who underwent plasmapheresis (PP).

METHODS: The relationship between symptom improvement and change in immunoglobin G (IgG) and acetylcholine receptor antibody (AchR-Ab) levels in 21 MG patients after PP was analyzed.

RESULTS: Patients were divided into two groups: the favorable (n = 11) or unfavorable (n = 10) response groups around the median MG composite improvement rate (50 [29, 56]%) 2 weeks after a PP course. In all patients, the IgG reduction rate before and after PP was higher in the favorable than the unfavorable response group. In AChR-Ab-positive patients, IgG and AChR-Ab reduction rates were higher in the favorable than the unfavorable response group.

CONCLUSION: IgG reduction rate is a predictor of symptom improvement in MG patients who underwent PP.