Efficacy of Intravenous Immunoglobulin Therapy in Refractory Polymyositis and Dermatomyositis

Lee, Sang Heon; Yoh, Kyung Ah; Cho, Young Suk; Yang, Hyung In; Park, Sung Hwan; Cho, Chul Soo; Kim, Ho Youn

Abstract

OBJECTIVES
Polymyositis (PM) and dermatomyositis (DM) are inflammatory muscle diseases of presumed autoimmune origin. Many interventions including corticosteroids, immunosuppressive drug, and plasmapheresis to treat patients with PM/DM are not always effective, and may be associated with certain serious side effects. Intravenous immunoglobulin(IVIG) has been useful in a number of autoimmune diseases. An attempt was made to evaluate the efficacy of IVIG in refractory PM/DM.
METHODS
Six patients with conventional treatment-refractory PM/DM [ 1 man and 5 women; mean age of 27(7-49)years ; PM(2), DM(2), juvenile DM(2)] received high doses of IVIG(2 mg/kg) dividing over consecutive 2 or 5 days. The IVIG infusion was conducted each month for 6 months. Clinical evaluations, including proximal muscle power, functional grading, and biochemical studies(creatine kinase(CK), aldolase) were performed before each or every IVIG infusion. Clinical evaluations were considered successful if more than 20% improvement of initial score was obtained. Biochemical results were considered "good" if muscle enzymes decreased more than 30% of initial values.
RESULTS
Clinical improvement of proximal muscle power was noted in 5 patients after 6 courses of IVIG infusion. Timed stand test and functional grading score were also improved in all patients. All patients showed good response of biochemical results, except two cases with normal initial CK levels. Mean daily prednisolone dosage was significantly reduced(before IVIG: 39.2+/-9.2 mg/day vs after 6th IVIG: 7.3+/-2 mg/day, p<0.01). One patient experienced mild dyspnea and sweating during the course of IVIG infusion, which were disappeared with the reduction of daily IVIG dosage.
CONCLUSIONS
These results suggest that IVIG is a safe and effective therapy in patients with PM/DM, who are resistant to traditional therapies or have limitations for their use.