Effect of intravenous immunoglobulin with or without cytotoxic drugs on pemphigus intercellular antibodies

Background: Intravenous immunoglobulin (IVIg)-a relatively new approach to treat pemphigus-lowers serum levels of pemphigus antibodies; however, the optimal way to use this agent is unknown. Objective: We sought to examine whether coadministration of a cytotoxic drug to patients with pemphigus improves the ability of IVIg to decrease serum levels of intercellular (IC) antibodies. Methods: In this retrospective study, we analyzed changes in IC antibody levels in 20 patients with pemphigus who were treated with 24 courses of IVIg administered alone (n = 10) or with a cytotoxic drug (n = 14). Each course of IVIg consisted of 400 mg/kg daily of immunoglobulin given over 5 days every other week; this cycle was repeated 3 to 4 times. Serum levels of IC antibodies were measured at baseline, before treatment, and 1 week and 1 month after the last IVIg cycle. Results: One week after the last IVIg cycle IC antibodies decreased by an average of 77% in the group treated with IVIg and cytotoxic drug compared with 48% in the group treated with IVIg alone (P = .54), and by 90% versus 43% 1 month later (P = .03). Limitations: A larger sample size is suggested for future studies. Conclusions: These observations confirm that IVIg can rapidly lower serum levels of autoantibodies in patients with pemphigus and its ability to do so is improved by the coadministration of a cytotoxic drug. These findings imply that the clinical effectiveness of IVIg in treating pemphigus, and possibly other autoantibody-mediated diseases, may be improved by the concurrent administration of a cytotoxic drug.