Idiopathic Eosinophilic Esophagitis and Eosinophilic Gastroenteritis Successfully Treated with Azathioprine or 6-Mercaptopurine

Abstract

Background: Idiopathic eosinophilic esophagitis (EE) is an increasingly recognized inflammatory disorder of the esophagus. The inflammatory pattern of EE is predominately associated with a TH 2-type allergic response. The disease has often chronic recurrent character and requires long-term treatment with topical or systemic corticosteroids. The aim of our study was to determine whether in severe cases with long-term systemic corticosteroid-dependency an immuno-modulating treatment may have a steroid-sparing effect? Methods: In three patients with proven severe idiopathic EE (1/3 also suffered from eosinophilic gastroenteritis) and chronically corticosteroid-dependency, we prospectively studied the clinical and histological response under treatment with azathioprine (2mg/kg BW po/die) or 6-mercaptopurine (1mg/kg BW po/die). Results: All patients experienced both symptomatical and histological relapse once steroid doses were tapered on several occasions. After administration of azathioprine in 2 patients and 6-mercatopurine in one patient, steroids could be stopped in all 3 patients without clinical relapse. Subsequent histological examinations showed complete disappearance of eosinophilic infiltration over a time span of months up to 8 years. One patient who stopped his treatment with azathioprine relapsed and became again steroid-dependent. In the follow-up, steroids could be stopped again after azathioprine had been reinstituted. In one patient, high blood counts of eosinophilic cells had been originally measured which also disappeared under azathioprine treatment. Conclusions: In severe steroid-dependent cases of idiopathic eosinophilic esophagatis and eosinophilic gastroenteritis, an immuno-modulationg treatment with purine analogues may be an helpful alternative to glucocorticoid therapy. At least in our patients, long-term use of immuno-modulating drugs was overall well tolerated and decreased morbidity due to EE. It could be speculated that the beneficial effect of azathioprine/6-mercaptopurine in treating EE is associated with their pro-apoptotic effect on T-lymphocytes.