Intravenous immunoglobulin therapy in vasculitis: speculation or evidence?

Initially, intravenous immunoglobulins (IVIgs) were used as replacement therapy in primary and secondary antibody-deficiency syndromes. The clinical use of IVIg has been extended during the past decade to a wide variety of clinical conditions, such as infectious processes, neuroimmunological diseases, and different systemic autoimmune diseases. The mode of action of IVIg is complex, involving modulation of the Fc receptors, interference with the complement and cytokine network, and effects on the activation and differentiation of T and B-cells. Kawasaki disease (KD) was one of the first diseases within the group of primary vasculitides in which IVIg were used. Today, there is a clear evidence of benefit for IVIg in the treatment of coronary artery abnormalities related to KD. Subsequently, various reports have suggested a beneficial effect in other vasculitides; however, there are few data from controlled studies. For antineutrophil cytoplasmic antibody-associated vasculitis (AAV) one placebo-controlled and several open-label studies have shown a beneficial effect on the disease activity in patients with Wegener's granulomatosis or microscopic polyangiitis refractory to standard therapy with prednisone and cyclophosphamide. For other vasculitides, such as polyarteritis nodosa or Henoch-Schonlein purpura, only case reports have described an inhibition of a disease progression by IVIg so far. However, the effect was partly only temporary. In conclusion, KD and AAV are the only vasculitides with a definite beneficial use of IVIg. For other vasculitides, the efficacy of IVIg has not been proven properly but may be useful in single cases.