Controlled studies with high-dose intravenous immunoglobulin in the treatment of dermatomyositis, inclusion body myositis, and polymyositis

There are three major subsets of the inflammatory myopathies: polymyositis (PM), dermatomyositis (DM), and inclusion-body myositis (IBM). High-dose in travenous immunoglobulin (IVIg) has been tried in controlled clinical trial s in patients with DM and IBM but not with PM. In patients with DM that is resistant or partially responsive to conventional therapies, Mg was very ef fective. The treated patients experienced dramatic improvement not only in muscle strength but also of their skin rash. Repeated muscle biopsies with quantitative histologic studies showed the Mg-treated patients had a statis tically significant improvement of the muscle cytoarchitecture, with resolu tion of the aberrant immunopathologic parameters. In two controlled clinica l trials conducted in IBM patients, Mg showed marginal improvements in musc le strength which were nonsignificant. However, a few IBM patients had a de finite clinical improvement with increased activities of daily living, but when analyzed within the entire Mg-treated group, their total gains in musc le strength did not reach statistical significance compared to the placebo- treated group. Of interest is that certain muscle groups in the Mg-treated patients, such as the muscles of swallowing, showed significant improvement compared to those of the placebo-treated patients, implying mild regional effects. In PM, uncontrolled trials have shown improvements in muscle stren gth, but the controlled clinical trial is still ongoing.