[The high-dose gamma-globulin therapy for inflammatory demyelinating peripheral neuropathy: evaluations of clinical effects and serum IgG subclasses].

PURPOSE OF THE STUDY: To clarify the clinical effects and the influence of high-dose therapy of gamma-globulin for inflammatory demyelinating peripheral neuropathy, we have investigated changes of serum IgG subclass distribution of the patients with these diseases by this therapy. SUBJECTS AND METHODS: gamma-Globulin (20g/day) was intravenously administrated for 5 days in 4 cases of CIDP, 2 cases of Fisher syndrome and 1 case of Guillain-Barré syndrome. The IgG subclass was measured by sandwich ELISA method four times, namely before the treatment, immediately after, and 2 and 4 weeks after the treatment. RESULTS: Marked symptomatical improvement was observed in all cases. Serum levels of all IgG subclasses were highest just after the therapy, and all subclasses recovered to the pretherapeutic levels in 4 weeks. Attitude of changes in all IgG subclasses of all cases was fairly similar each other. CONCLUSION: These results suggest that high-dose therapy of gamma-globulin is an effective therapy for inflammatory demyelinating peripheral neuropathy with little influences on IgG production and metabolism of IgG.

[IgG subclasses in the patients with myotonic dystrophy].

Low serum concentration of IgG in myotonic dystrophy (MyD) has been well documented and has been considered to be due to accelerated breakdown of IgG. However, the catabolic rate of IgG is tightly regulated by serum IgG level and basal metabolic rate. The serum IgG level and basal metabolic rate in the patient with MyD is reported to be significantly low. One possible explanation for this fact is presence of disproportion in IgG subclasses; if the level of one or some subclasses is high, catabolism of total IgG could be accelerated regardless of decreased total IgG. In this study, we examined serum concentration of all four IgG subclasses by sandwich ELISA methods in 43 patients with MyD and 24 healthy age- and sex-matched controls. Serum levels of al IgG subclasses were lower in MyD than those in normal controls, especially the levels of IgG1 and IgG3 were significantly low (p < 0.01) as compared to those in normal controls. These results, combined with our previous studies, suggest that accelerated catabolism is inadequate as a cause of low serum concentration of IgG in MyD. Further studies are required to approach the mechanism of low serum concentration of IgG in the patients with MyD.