New tests aim to spot bone marrow graft failure early

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: General * Ability to undergo 18F FLT imaging without sedation * Patients \> 4 years of age and less than 80 years of age at highest risk for graft failure: cord blood HSCT, haplo HSCT, or lack of engraftment by day 28. * Diagnosed with a condition for which hematopoietic stem cell transplant (HSCT) is standard of care and HSCT is planned (Arm A) or occurred (Arm B) * In morphologic remission prior to HSCT * Patient or guardian able to give informed consent * Investigational therapies within past 28 days or planned on protocol are pre-approved by the PI or Site PI * Karnofsky or Lansky performance status \> 60% Arm A * A1 Cord blood recipients: Absence of donor specific antibodies to cord HLA * Haplo-identical recipients: ≥ 5/10 and \< 7/8 allele mismatch donor * A2- myeloablative Haplo-identical transplant is planned * A3- reduced intensity Haplo-identical transplant is planned (non-myeloablative is excluded) * A1- myeloablative or reduced intensity transplant is planned (non-myeloablative is excluded) * Diagnosed with a condition for which hematopoietic stem cell transplant (HSCT) is standard of care and HSCT is planned * Total bilirubin \< 2.5 mg/dL (unless documented Gilbert's syndrome) and transaminases (ALT and AST) \< 5 x the upper limit of normal * Creatinine clearance or GFR \> 60 ml/min/1.73 m2. (performed pre-HSCT) * FEV1 \> 80% pre or post-bronchiolator whichever is higher and DLCO Adj \> 70% (performed pre-HSCT if age appropriate) and Sa02 \> 94% on room air * Ejection fraction \> 50% (performed pre-HSCT) Arm B • Non-engraftment recipients of HCT with any donor source (related or unrelated): primary graft failure as defined by ANC not \> 500 for 3 consecutive days and at least 20 days after HSCT. Inclusion Criteria - Donors * 1-2 cords and \>.4/6 match to recipient for each (as per current National Marrow Donor guidelines), with a dose \>2 x 10e6 CD34 cells/kg for each cord OR \> 5/10 and \<7/8 allele mismatch related donor * Institutional guidelines met for donor suitability Exclusion Criteria: * History of psychiatric disorder which may compromise compliance with transplant protocol, or which does not allow for appropriate informed consent * Clinically significant systemic illness with manifestations of significant organ dysfunction which, in the judgment of the PI, or Co-I, would render the patient unlikely to tolerate the protocol therapy or complete the study * Presence of active malignancy from an organ system other than hematopoietic * Pregnant or lactating females * Patients who are unable or unwilling to use effective form (s) of contraception during the course of the study * Prior history of fluorothymidine allergy or intolerance * Decline enrolment on CIBMTR research protocol