First line therapy of aGVHD > grade I consists of steroids at a dose of 2 mg/kg. The response rates to this treatment are only 15-35%4. In case of a steroid refractory aGVHD different therapeutic strategies have been evaluated, but with no satisfactory results so far. The mortality of patients suffering from steroid refractory aGVHD remains at 75-80%, although numerous studies with different treatment strategies have been conducted2-5. Therefore, it remains important to search for new therapeutical strategies for the treatment of aGVHD.