[Intravenous immunoglobulins in polymyositis and dermatomyositis]

Polymyositis (PM) and dermatomyositis (DM) are inflammatory idiopathic myopathies of dysimmune origin. Studies have shown two different pathogenic mechanisms: a primitive vascular mechanism mediated mainly by a humoral mechanism responsible for a muscular ischemia in juvenile DM; and a primitive injury of muscle cells mediated by a cytotoxic cellular mechanism, directed against the myofibrillae, in PM.

Oral corticosteroids are the treatment of first choice in patients with PM/DM. This therapy has transformed the prognosis of these diseases. The efficacy of polyvalent human intravenous immunoglobulin (IVIG) was first described in an open study with severe refractory PM and DM, and confirmed by a controlled study in DM.

We present our experience about the interest of intravenous immunoglobulin (IVIG) in refractory PM and DM and discuss the different mechanisms of action of this new immunotherapy.