A Phase II Study of Umbilical Cord Blood Transplantation

Inclusion Criteria:

Patients meeting eligibility criteria for unrelated allogeneic stem cell transplantation may be considered for participation on this clinical trial if and only if they meet each of the following criteria:

* Patients must have one of the following diagnoses
* Relapsed or refractory hematologic malignancy, or
* High risk hematologic malignancy in first remission, or
* Refractory acquired marrow failure state, or
* Inherited disorder of metabolism or marrow failure state without alternative curative therapy.
* Patients must not have a 6/6 or 5/6 HLA-matched related donor.
* Patients must not have a HLA-A, -B and -DRB1 high resolution matched unrelated donor following registry search, or cannot (in the opinion of the treating physician) wait the median 3 months to receive a MUD unit.
* Patients must demonstrate an ability to understand and willingness to sign the informed consent document

Patients considered for myeloablative conditioning must satisfy the following additional criteria:

* Patients must be up to age 55 (inclusive)
* Patients must have serum direct bilirubin ≤ 2.0 mg/dl and transaminases ≤ 2x institution upper limit of normal
* Patients must have serum creatinine ≤ 2 mg/dl with creatinine clearance ≥ 60 ml/min (either calculated or measured).
* Patients must have MUGA scan or echocardiogram normal for the institution, but not less than 45% left ventricular ejection fraction and no clinical evidence of cardiac dysfunction.
* Patients must have an ECOG performance status of 0 or 1 (see Appendix C).
* Patients must have adequate pulmonary function when corrected for hemoglobin and alveolar volume as evidenced by a diffusion capacity and FEV1 \> 50% of predicted.

Patients considered for reduced-intensity conditioning must satisfy the following additional criteria:

* Patients must not be candidates for myeloablative conditioning due to any one of the following: Prior myeloablative stem cell transplantation, Age \> 50, Co morbid illness
* In opinion of treating physician, unable to comply with or withstand rigors of myeloablative conditioning
* Patients with leukemia must have circulating and bone marrow blast counts \< 5%, all other patients must have chemotherapy responsive disease
* Patients must be between the ages of 18 and 70 (inclusive)
* Patients must have serum direct bilirubin ≤ 2.0 mg/dL and transaminases ≤ 3x institution upper limit of normal
* Patients must have creatinine clearance ≥ 30 ml/min (either calculated or measured).
* Patients must have MUGA scan or echocardiogram documenting left ventricular ejection fraction of no less than 35% and no clinical evidence of cardiac dysfunction.

Patients must have an ECOG performance status of 0 or 1 (see Appendix C).

Patients must have adequate pulmonary function when corrected for hemoglobin and alveolar volume as evidenced by a diffusion capacity and FEV1 ≥ 40% of predicted.

Exclusion Criteria:

Patients are ineligible for participation on this trial if they meet any of the following criteria:

* Patients with a history of myocardial infarction within the preceding 6 months, significant arrhythmia within the preceding 3 months, uncontrolled hypertension or congestive heart failure are ineligible.
* Patients with unstable angina are not eligible.
* Pregnant or lactating women are ineligible.
* Male and female patients who do not agree to practice approved methods of birth control for the duration of the study are ineligible.
* Patients with uncontrolled infection are ineligible.
* Patients who are HIV positive or have evidence of chronic viral hepatitis are ineligible.
* Patients unable to comply with requirements for compliance with therapeutic plan and/or scheduled evaluations