Subcutaneous immunoglobulin G in idiopathic inflammatory myopathies: therapeutic implications.

Polymyositis (PM) and dermatomyositis (DM) are systemic autoimmune diseases of unknown etiology that primarily affect the skeletal muscle. Despite the improvement achieved in recent years with new therapeutic options, the prognosis remains poor, with high rates of morbidity and mortality. Conventional first-line treatment is based on glucocorticoids. However, their use in many patients requires long-term administration, which increases the probability of side effects developing. Thus, there is often the need to add immunosuppressive or immunomodulatory agents to improve the disease’s response to treatment and to reduce the longterm complications linked to glucocorticoid. Among the treatment options, the use of immunoglobulin, by both the intravenous (IVIg) and the subcutaneous (SCIg) route, is still under debate We describe here our experience with the use of SCIg in patients with PM and DM.