Successful treatment of idiopathic colitis related to XIAP deficiency with allo-HSCT using reduced-intensity conditioning.

Recently, it has been reported that Crohn's-like intractable colitis occurred in approximately 20% of the patients with XIAP deficiency, also known as X-linked lymphoproliferative disease type 2. Because treatment used for Crohn's disease is not always effective for Crohn's-like colitis related to XIAP deficiency, more effective treatment should be established. Although several studies reported allo-HSCT might be promising even for Crohn's-like colitis related to XIAP deficiency, the outcome of allo-HSCT using MAC for XIAP deficiency is extremely poor due to frequent TRM. In addition, there is little information about the outcome of allo-HSCT for intractable colitis related to XIAP deficiency. Herein, we describe a patient with intractable colitis related to XIAP deficiency who was successfully treated with allo-HSCT using a reduced-intensity conditioning regimen. Although allo-HSCT using the RIC regimen might be a curative therapeutic option for intractable colitis with XIAP deficiency, the prognostic factors that will determine the success of allo-HSCT require further clinical information of more patients.