A randomized double-blind trial of intravenous immunoglobulin for bullous pemphigoid

Background Patients with steroid-resistant bullous pemphigoid (BP) require an appropriate treatment option. Objective A multicenter, randomized, placebo-controlled, double-blind trial was conducted to investigate the therapeutic effect of high-dose intravenous immunoglobulin (IVIG; 400 mg/kg/day for 5 days) in BP patients who showed no symptomatic improvement with prednisolone (≥0.4 mg/kg/day) administered. Methods We evaluated the efficacy using the disease activity score on day15 (DAS15) as a primary endpoint, and changes in the DAS over time, the anti-BP180 antibody titer, and safety for a period of 57 days as secondary endpoints. Results We enrolled 56 patients in this study. The DAS15 was 12.5 points lower in the IVIG group than in the placebo group (p = 0.089). The mean DAS of the IVIG group was constantly lower than that of the placebo group throughout the course of observation, and a post hoc analysis of covariance revealed a significant difference (p = 0.041). Furthermore, when analyzed only in severe cases (DAS ≥ 40), the DAS15 differed significantly (p = 0.046). The anti-BP180 antibody titers showed no difference between the two groups. Conclusion IVIG provides a beneficial therapeutic outcome for patients with BP who are resistant to steroid therapy.