Immunoglobulin therapy in inflammatory myopathies

A prospective open label trial of add on therapy with intravenous immunoglobulin (IVIg) was carried out in 16 patients with inflammatory myopathy who had continued to deteriorate or had relapsed on conventional therapy. The response was assessed using isometric myometry, functional scales, MRC grading, and serum creatine kinase concentrations with a three month run in period before commencement of IVIg. Five of seven patients with isolated dermatomyositis or polymyositis and all four patients with an overlap syndrome responded to IVIg with partial or complete remission of disease and normalisation of serum creatine kinase concentrations. None of five patients with inclusion body myositis showed any functional improvement although myometry scores improved in some muscles in one case. It is concluded that IVIg is an effective therapeutic option in patients with drug resistant polymyositis or dermatomyositis. However, further controlled trials are required to confirm the efficacy of this form of treatment and to establish optimal doses and administration regimes.