High-dose immunoglobulin therapy in sporadic inclusion body myositis: a double-blind, placebo-controlled study

Sporadic inclusion body myositis (s-IBM) is an acquired inflammatory muscle disease of unknown cause. In general, s-IBM presents with slowly progressi ve, asymmetric weakness, and atrophy of skeletal muscle. There is a mild tr ansitory or nil responsiveness to standard immunosuppressive treatment. A c ontrolled cross-over study of 22 s-IBM patients over 3 months showed a part ial improvement in those heated with high-dose intravenous immunoglobulin t herapy (IVIG) versus placebo. The present study included 22 patients aged 3 2-75 years and with a mean duration of disease of 5.2 +/- 3.6 years. They w ere randomized by a double-blind, placebo-controlled, cross-over design to monthly infusions of 2 g/kg bodyweight IVIG or to placebo for 6 months each , followed by the alternative treatment. After 6 and 12 months the response to treatment was evaluated, using a modified Medical Research Council scal e, Neuromuscular Symptom Score (NSS), the patient's own assessment of impro vement, arm outstretched time, and electromyography. No serious side effect s were seen, in particular no viral infection and no major cardiac or neuro logical complications. Overall there was no progression of the disease in 9 0% of patients, unlike that which might have been expected in untreated pat ients. A mild and significant improvement (11%) in clinical symptoms was fo und using NSS, but not with other test procedures. There was a trend to mil d improvement in treated patients when using other tests. Individual respon ses to treatment was heterogeneous. The validity of this study may be reduc ed by mismatch of groups with regard to age at onset and variability in dis ease expression. The findings of this study largely confirm those of a prev ious IVIG; trial. Treatment with IVIG may be mildly effective in a-IBM by p reventing dis ease progression or inducing mild improvement. Long-term stud ies are needed to evaluate further the benefit of IVIG therapy in s-IBM.