The effect of large-dose prednisone therapy on IgG subclasses in multiple sclerosis

The effect of large-dose prednisone therapy (3960 mg over 56 days) on IgG subclasses in the cerebrospinal fluid and sera, as well as on their intrathecal synthesis, was studied in 15 patients with clinically definite multiple sclerosis. The concentration of IgG subclasses was measured using ELISA with monoclonal antibodies against human IgG subclasses, secondary biotinylated antibody and avidin-biotin-peroxidase complex. There was a decrease of IgG1, IgG3 and IgG4 in the CSF of MS patients after the treatment, but the differences did not reach statistical significance. The IgG index was decreased about 34% (p < 0.01) after the therapy. This was mainly due to diminished synthesis of IgG1 and IgG3. The significance of IgG subclasses in the pathogenesis of MS is discussed.