Adult Donor Cryopreserved Unit (ADCU): An unrelated adult donor-derived HSC product (generally PBSC) that is cryopreserved (frozen) prior to transplant. These donations are not collected on behalf of a specific patient (undirected donation); products are available on behalf of any patient seeking transplant, may be searched alongside donor and CBU options, and offer an expedited path to transplant.

Apheresis: A procedure in which the blood is collected, passed through an apparatus that separates and retains a specific component, and the remaining portion returned to circulation. HSC collected from the peripheral blood of a donor following G-CSF stimulation are referred to as HPC, APHERESIS or HPC(A) per ISBT 128 Standard.

Blood sample: Newly drawn sample of blood from a potential donor and shipped to the tissue-typing laboratory designated by the transplant centre responsible for a patient.

Bone marrow (BM): Spongy, flexible tissue found in the medullary (interior) cavity of bones. In adults, it is the primary location of hematopoiesis (process by which cellular components of the blood are made) and is thus a rich source of HSC. HSC harvested from the bone marrow of a donor by a surgical procedure are referred to as HPC, MARROW or HPC(M) per ISBT 128 Standard.

CD34 molecule: Cell surface glycoprotein that present on HSC and hematopoietic progenitors. Enrichment and selection of CD34+ cells have applications in HSCT, and CD34+ content is a parameter used in the evaluation of CBU for transplant.

Cord blood bank (CBB): Organisation involved in the recruitment, collection, processing, testing, cryopreservation, and storage, listing, reservation, release, and distribution CBU. A private CBB stores CBU on behalf of an individual (i.e. family of the infant from whom the CBU was collected) for potential future use as directed by that individual. Public CBB inventory is searchable on behalf of unrelated individuals seeking HSCT.

Cord blood unit (CBU): Cryopreserved cord blood donation that has been tested for safety (IDM, sterility) and HLA genotype and stored (banked) for future use, including as a source of HSC for transplantation.

Donor: Source of cells or tissue for a cellular therapy product; donors are altruistic volunteers who are unrelated to the patient seeking transplant. The term is used throughout the search and transplant process (i.e. recruitment through donation) regardless of whether a product is collected.

Donor lymphocyte infusion (DLI): Post-transplant therapy in which lymphocytes are collected from the hematopoietic cell donor’s peripheral blood and infused into the recipient to manage relapse. 

Extended HLA typing (ET): HLA testing, typically performed on repository samples stored by the donor registry or CBB, that is requested in order obtain typing results at one or more missing or ambiguous HLA locus/loci so that match level between a patient and donor/CBU can be assessed. This typing can also serve as a VT if performed on a fresh donor sample or attached segment of a CBU.

Health and Availability Check (HAC): an alternative to verification typing in which a donor is contacted, offered information and counseling, administered a health history questionnaire, and availability to donate determined. Verification typing is performed at workup on pre-collection blood samples. HAC is offered under specific circumstances (i.e. known HLA match level, transplant urgency) by some organisations.

Hematopoietic progenitor cells (HPC): Immature blood cells that are restricted in their ability to differentiate and lack the capacity self-renewal in compared to HSC.

Hematopoietic stem cells (HSC): Immature blood progenitor cells that give rise to all cells of the blood and immune systems including red blood cells, white blood cells, and platelets. In contrast with HPC, these cells demonstrate a capacity for self-renewal and potential to produce all types of blood cells. HPC are found in bone marrow, peripheral blood, and umbilical cord blood.

Human Leukocyte Antigen (HLA): Large, evolutionarily conserved complex of genes also known as the major histocompatibility complex (MHC). Located on the short arm of chromosome six, HLA genes are imperative to immune function in humans. A subset of HLA genes whose products include antigen-presenting molecules present on cell surfaces are considered when determining a donor’s suitability for transplant; degree of HLA match between donor and recipient is the largest determinant of post-transplant outcome.

Hybrid Cord Blood Banking: A CBB business model whereby privately banked CBU are included among public inventory; hybrid CBU are thus searchable on behalf of unrelated patients in need of HSCT. If a hybrid CBU is identified as a possible candidate for transplant, the CBB must investigate whether the person for whom the unit was privately collected would be willing to release the unit for unrelated transplant.

ISBT 128: Global Information Standard for Medical Products of Human Origin: ISBT 128 is the global standard for the terminology, identification, coding and labeling of medical products of human origin. The standard has been designed to ensure the highest levels of accuracy, safety, and efficiency for the benefit of donors and patients worldwide by providing international consistency to support the transfer, traceability and transfusion/transplantation of blood, cells, tissues, and organs.

Issuing Organisation Number (ION): Four-digit number between 1000 and 9999 assigned to an organisation that issues GRID to adult unrelated stem cell donors. Assigned by ICCBBA in its capacity as an issuing agency under ISO 15459, the ION is encoded and interpreted by reference to the ICCBBA GRID Issuing Organization Number Table published and maintained by ICCBBA. The ION comprises the first 4 characters of a GRID.

Key Performance Indicator (KPI): a quantifiable measurement used to assess the performance of an organisation. The WMDA has established five KPIs to gauge registry performance in four areas: HLA typing discrepancy incidence, VT sample shipment timeframe, proportion of donors available at VT and at workup and SPEAR incident reporting.

Locus (plural: loci): The specific location of a gene or DNA sequence on a chromosome.

Major Histocompatibility Complex: Large, multigene complex of polymorphic genes encoding components of the of adaptive immune system across vertebrate species; also known as HLA in humans (see above).

Mononuclear cell (MNC) apheresis: Apheresis collection of donor lymphocytes for DLI infusion (see above)

Nomenclature: A system of naming in arts or science.

Patient: A person for whom allogeneic HSCT has been indicated and for whom an unrelated donor, CBU, or cellular therapy product is sought. After receiving HSCT, the patient may also be referred to as a recipient or transplant recipient.

Peripheral Blood Stem Cells (PBSC): HSC present in the peripheral blood; the amount of PBSC in circulation can be augmented via administration of G-CSF in a process often referred to as ‘mobilization’. HSC collected from the peripheral blood of a donor following G-CSF stimulation are referred to as HPC, APHERESIS or HPC(A) per ISBT 128 Standard.

Product: A cellular therapy containing HSC and/or other nucleated cells that is intended for therapeutic use. Adult donor-derived HSC donations, CBU, and cellular therapy products are referred to as products.

Registry: An organisation responsible for coordination of the search for HSC from donors (including cord blood) unrelated to the potential recipient (patient). The patient registry, also known as the requesting registry, is the registry that acts on behalf of their domestic transplant centres. The donor registry, also known as providing registry, is the registry that provides the HSC product.

Serology: The scientific study of plasma serum and other bodily fluids. Applications of serology in HSCT include HLA typing and identification of anti-HLA antibodies (alloimmunization) in patients.

Search status: Refers to the current search status of an HPC product with the options: AV = Available for transplantation purposes, TU = Temporarily unavailable, RS = Reserved, DE = Deleted/permanently unavailable.

Total nucleated cell count (TNC): The number of immature blood cells present in a cord blood unit. This value could be presented pre-freeze or post-thaw and is required to establish whether a CBU would provide the requisite cell dose for a patient seeking cord blood transplant.

Transplant centre (TC): A medical facility (i.e. hospital) where a patient receives HSCT. The TC oversees the immediate medical treatment and provides long-term follow-up of the recipient.

Verification typing (VT): HLA testing performed on a fresh blood sample (donor) donor or attached segment (CBU) confirm identity and concordance of existing HLA assignment prior to transplant. Also known as ‘confirmatory typing (CT)’.

Workup: The final stages of donor testing and medical clearance prior to HSC collection. A donor who has agreed to proceed to transplant will be provided information and counselling and have their medically eligibility to proceed evaluated. Further testing of HLA and/or IDM could also be required.