THU0398 Efficacy of rituximab and other immunosuppressants for IgG4-related disease

Background IgG4-related disease (IgG4-RD) is considered a systemic, chronic and inflammatory disorder that is characterized by elevated levels of serum IgG4 and abundant infiltration of IgG4-bearing plasmacytes and storiform fibrosis in the involved organs. It includes autoimmune pancreatitis type I, Mikulicz’s disease (MD; IgG4-related dacryoadenitis and sialadenitis), and a part of tubulointerstitial nephritis (IgG4-related tubulointerstitial nephritis). It is necessary to manage this disease as soon as possible to prevent permanent organ damages. Glucocorticoid treatment is currently performed in most cases of IgG4-RD and could lead to the clinical remission at once, but we often experience the flare-up by reducing steroid. We have to add on immunosuppressants in that case, but we don’t know what is the most effective drug. Objectives To evaluate the efficacy of rituximab and other immunosuppressant treatment for IgG4-RD. Methods The study subjects included 80 patients with IgG4-RD who had been referred to our hospital and the related institutes (registered to SMART database: Sapporo Medical university And Related institutes database for investigation and best Treatments of IgG4-RD), and performed some therapies since April 1997. Out of the 80 patients, 55 were diagnosed with MD, 16 with Kuttner’s tumor (IgG4-related sialadenitis), 9 with IgG4-related dacryoadenitis. We analyzed the treatments performed for IgG4-RD, and the response to each drug. Results Oral glucocorticoid treatment (≥0.4 mg/kg/day) is significantly effective for all cases with IgG4-RD. Enlargement of involved glands and their gland function was improved in the short term. There were three patients with complete remission and drug-free condition, but 21 patients presented with recurrent in decreasing steroid. In the relapse cases, the same organs were re-affected, or new involvements appeared in the other organs. Almost patients needed glucocorticoid (5∼15 mg/day) for their symptoms. The amounts of steroid were increased to 17 patients. Azathioprine were added on to five patients, cyclosporine A to four patients, mizoribine to three patients, and methotrexate and cyclophosphamide to each one patient. Rituximab was prescribed to two patients. Increase of glucocorticoid was effective for clinical remission, but almost cases presented with the resistant to reducing steroid again. Other oral immunosuppressants could not improve steroid-dependency. Rituximab could reduce the amounts of steroid, but the cases presented with relapse within a year. Conclusions We realize that glucocorticoid is effective for the relief of symptoms in IgG4-RD, but it is difficult to lead to drug-free or long term remission by only steroid in almost cases. Oral immunosuppressants have little efficacy for reducing steroid. It is possible that rituximab improves steroid-dependency, but it is necessary for the maintenance therapy. This suggests that new therapeutic approaches are necessary for IgG4-RD. Disclosure of Interest None Declared