Autologous Unselected Hematopoietic Stem Cell Transplantation for Refractory Crohn's Disease

Inclusion Criteria: 1. Age between 14 and 50 years (patients aged 50 - 70 can participate at the principal investigators discretion). 2. Confirmed diagnosis of active Crohn's disease: * Diagnosis of Crohn's disease based on typical radiological findingsand or typical histology at least 6 months prior to screening. * Active disease at the time of registration to the trial, defined as \*Crohn's Disease Activity Index (CDAI) \> 150, and ii) Two of the following: * Harvey Bradshaw Index \> 4 * Endoscopic evidence of active disease confirmed by histology * Clear evidence of active small bowel Crohn's disease on computed tomography (CT) or magnetic resonance (MR) enterography. 3. Unsatisfactory course despite immunosuppressive agents (usually azathioprine, methotrexate and two biologic agents (normally infliximab, adalimumab and/or certolizumab) in addition to corticosteroids. Patients should have relapsing and refractory disease despite thiopurines, methotrexate and/or infliximab/adalimumab/certolizumab maintenance therapy or clear demonstration of intolerance / toxicity to these drugs. 4. Current problems unsuitable for surgery or patient at risk for developing short bowel syndrome. 5. Informed consent: * Prepared to undergo additional study procedures as per trial schedule * Patient has undergone intensive counseling about risks Exclusion Criteria: 1. Pregnancy or unwillingness to use adequate contraception during the study, in women of childbearing age. Unwillingness of using appropriate contraceptive measures in males. 2. Concomitant severe disease * renal: creatinine clearance \< 30 mL/min (measured or estimated) * cardiac: clinical evidence of refractory congestive heart failure; left ventricular ejection fraction \< 40% by multigated radionuclide angiography (MUGA) or cardiac echo; chronic atrial fibrillation necessitating oral anticoagulation; uncontrolled ventricular arrhythmia; pericardial effusion with hemodynamic consequences as evaluated by an experienced echo cardiographer. * pulmonary: diffusion capacity \<40% * psychiatric disorders including active drug or alcohol abuse * concurrent or recent history of malignant disease (excluding non-melanoma skin cancer) * uncontrolled hypertension, defined as resting systolic blood pressure ≥ 140 and/or resting diastolic pressure ≥ 90 despite at least 2 anti-hypertensive agents. * uncontrolled acute or chronic infection with HIV, Human T-lymphotropic virus (HTLV-1 or 2), hepatitis viruses or any other infection the investigators consider a contraindication to participation. * other chronic disease causing significant organ failure.