| Cryopreserved cell dose |
| Number of cells in the UCB unit for malignant disease |
| a. Single UCBT TNC/kg: ≥2.5-3 × 107 and/or CD34+/kg ≥1.5 × 105* |
| b. Double UCBT: TNC/kg: ≥1.5 × 107 for each unit and/or CD34+/kg ≥1 × 105 for each unit |
| HLA typing |
| a. High-resolution typing for HLA-A, -B, -C, and -DRB1 of patients and UCB units |
| b. Avoid UCB units with >2 HLA mismatches and avoid HLA-C mismatches |
| c. In double UCBT, unit-to-unit HLA match is not required |
| Adapt cell dose and HLA matching to graft indication |
| a. Nonmalignant diseases: increase cell dose (>5.0 × 107 TNC/kg) and find the best HLA match. If the criterion for the minimum number of cells in a single UCB unit is not achieved, a double UCBT should be considered also in nonmalignant diseases |
| b. Cell dose should be considered first over HLA match for high–body weight patients |
| Perform anti-HLA antibody screening in patients and avoid CBU against which patient has DSA, when possible, especially in those with nonmalignant diseases (due to the risk of rejection) |
| Cord blood bank accreditation status (favor units from accredited cord blood banks) |
| Selection of UCB unit with attached segment for confirmatory identity testing is mandatory |
| If several UCB units are available, choice of the best one should be also guided by the following: |
| a. ABO compatibility |
| b. NIMA and KIR status† |
| c. Avoid RBC-replete units (or accept only if no RBC-depleted unit is available) |
| d. Cryovolume (to be considered in case of further dilution needed after thaw) |
| e. Select more recent units because they may be linked to optimal banking practices |
| Cryopreserved cell dose |
| Number of cells in the UCB unit for malignant disease |
| a. Single UCBT TNC/kg: ≥2.5-3 × 107 and/or CD34+/kg ≥1.5 × 105* |
| b. Double UCBT: TNC/kg: ≥1.5 × 107 for each unit and/or CD34+/kg ≥1 × 105 for each unit |
| HLA typing |
| a. High-resolution typing for HLA-A, -B, -C, and -DRB1 of patients and UCB units |
| b. Avoid UCB units with >2 HLA mismatches and avoid HLA-C mismatches |
| c. In double UCBT, unit-to-unit HLA match is not required |
| Adapt cell dose and HLA matching to graft indication |
| a. Nonmalignant diseases: increase cell dose (>5.0 × 107 TNC/kg) and find the best HLA match. If the criterion for the minimum number of cells in a single UCB unit is not achieved, a double UCBT should be considered also in nonmalignant diseases |
| b. Cell dose should be considered first over HLA match for high–body weight patients |
| Perform anti-HLA antibody screening in patients and avoid CBU against which patient has DSA, when possible, especially in those with nonmalignant diseases (due to the risk of rejection) |
| Cord blood bank accreditation status (favor units from accredited cord blood banks) |
| Selection of UCB unit with attached segment for confirmatory identity testing is mandatory |
| If several UCB units are available, choice of the best one should be also guided by the following: |
| a. ABO compatibility |
| b. NIMA and KIR status† |
| c. Avoid RBC-replete units (or accept only if no RBC-depleted unit is available) |
| d. Cryovolume (to be considered in case of further dilution needed after thaw) |
| e. Select more recent units because they may be linked to optimal banking practices |
DSA, donor-specific antibodies; KIR, killer cell immunoglobulin-like receptor; KIR-L, killer cell immunoglobulin-like receptor ligand; NIMA, noninherited maternal antigen; RBC, red blood cells; TNC, total nucleated cell dose; UCB, umbilical cord blood; UCBT, umbilical cord blood transplantation.
If the minimum number of cells for a single UCBT is not achieved, a double UCBT should be considered, as well as a clinical trial investigating the use of ex vivo expanded CBU or the addition of another cellular product.
No sufficient data to support unit selection on the basis of NIMA or KIR-L status.