High-dose i.v.
immunoglobulin (HD-
IVIG) has several distinguishing therapeutic characteristics including rapid clearance of pathogenic antibody, non-immunosuppressive and less adverse effects. In 2009, the first multicenter, randomized, placebo-controlled, double-blind trial of HD-
IVIG for
pemphigus was conducted in Japan. This clinical trial has proved that 400 mg/kg per 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, several lines of evidence have suggested that
neonatal Fc receptor for
immunoglobulin (Ig)G (FcRn) plays an important role for rapid clearance of pathogenic antibody in
pemphigus induced by HD-
IVIG. Additionally, the long suppression of
IgG production induced by HD-
IVIG has been observed in some cases. Taking these characteristics into consideration, HD-
IVIG, which leads to decreased pathogenic
IgG, is recommended to use in combination with oral
corticosteroids or other
immunosuppressants, which suppress the production of pathogenic
IgG. This review summerizes experimental and clinical evidences for major mechanism of action in HD-
IVIG and how to use it.