[How intravenous immunoglobulin therapy works in pemphigus]

High-dose intravenous immunoglobulin (HD-IVIg) is one of potential therapy to accelerate the pathogenic antibody degradation in pemphigus. Advantage and benefits of this therapy are non-immunosuppressive and less adverse effects. The clinical trial of HD-IVIg for pemphigus has proved that 400mg/kg/day for 5 days administration of IVIg is effective as an adjuvant therapy with systemic steroid therapy and/or immunosuppressive agents. Among the several mechanisms to explain the mode of action of IVIg, the neonatal Fc receptor for IgG (FcRn) plays important role for rapid clearance of pathogenic antibody in pemphigus induced by HD-IVIg. To monitor the serum IgG levels is necessary to predict the timing that the titer of anti-Dsg1 antibody starts to increase. Furthermore, the sufficient suppression of the antibody production in patients with severe disease activity is a key point for successful treatment with IVIg.