After the workup request form is received, it is checked for completeness and correctness. If it contains all necessary information, the workup request is assigned to a case manager. The case manager will then contact the donor as soon as possible to discuss all details and coordinate the collection.
The following details will be discussed with the donor:
If patients have a relapse or a graft failure, a subsequent donation (HSC apheresis or HSC bone marrow) of the same donor can become necessary.
A donor can also be requested as best match for a different recipient; this happens in approximately 2-3 % of our cases. To protect donors, stem cell collections per donor are limited.
After an HSC donation (the donor can suffer from side effects for some time. Therefore, there is a defined minimal interval between two donations.
We observe a huge range in requested CD34+ cell counts for HSC apheresis from 1.5 x 106 / kg to 50 x 106 / kg bodyweight of the recipient. Generally, a CD34+ cell count of 5 x 106 / kg recipient bodyweight is considered sufficient. However, there are protocols in use that require higher numbers of CD34+ cells.
For HSC bone marrow, the requested TNC usually is within a range of 3-5 x 108 / kg bodyweight of the recipient. For children with rare diseases (e.g., SCID, other congenital disorders or metabolic diseases) as well as for patients with SAA, a higher cell count may be reasonable, as there is a higher possibility of graft failure.
As nowadays HLA results from donor registry typing are very accurate, a Transplant Center can very often identify a match for a patient immediately on the search list. Therefore, in urgent cases or in cases where the donor was already requested multiple times for confirmatory typing, the confirmatory typing can be shifted to the workup process. In these cases, it is possible to request CT and workup in parallel. The Transplant Center has to consider that CT unavailability varies between 20-40% depending on the DKMS entity. A health and availability check (HAC) should be requested instead of a CT to assure the donor’s availability and medically suitability. HAC does not include IDM testing which will be performed during workup in these cases.
At DKMS the workup unavailability rate is approximately 15% globally.
If, in urgent cases, there is an increased risk that the preferred donor will not be available, DKMS may, in exceptional cases, plan with both donors simultaneously.
With a DKMS donor pool of more than 10 million donors, many patients have more than one potential DKMS donor.
In case a donor becomes unavailable for the patient during workup, DKMS starts a replacement donor search within all DKMS donors.
Research studies for better treatment or outcome of the patients are important. DKMS therefore generally supports studies if they can result in a benefit for patient care and the additional burden on the donor is acceptable.
Stem cell products from unrelated donors are normally transplanted fresh, immediately after the product has arrived in the Transplant Center. Under certain circumstances, a cryopreservation of the product can become necessary.
If the information stated above has not been provided before the start of the mobilization, the Collection Center, Donor Center or the donor may not proceed with the donation.
Donor MHC products usually are portioned and most parts are cryopreserved. One portion should be infused freshly.
A Transplant Center needs to inform DKMS if they plan to cryopreserve the complete product and not infuse a fresh portion within 14 days. A reason and any plans for infusion should be communicated so that the donor can be informed correctly.
If an infusion seems very unlikely, the Transplant Center should consider postponing the MHC apheresis.
DKMS will follow-up with the Transplant Center on the date of the first infusion and inform the donor accordingly.
If the stem cell product contains more cells than needed, the Transplant Center can cryopreserve residues of the HSCs or MHCs for a later use.
In cases in which DKMS agreed to cryopreservation of a stem cell product and the product cannot be used for the intended patient, the stem cell product usually has to be discarded.
For recipient safety, Transplant Centers can cryopreserve the stem cell product after arrival and before patient conditioning if a donor is only available for one stem cell source (HSC apheresis or HSC bone marrow).
DKMS recommends to infuse cells fresh wherever possible and to have a backup plan for each transplantation (e.g. other donor or cell source).
T-cell or red cell depletion is a common manipulation method before stem cell transplantation. Transplant Centers are usually responsible to perform T-cell or red cell depletion.
In some countries, Transplant Centers have to perform additional tests, which are not relevant for donor clearance in the donor country.
Pre-collection samples of donors are often requested in a workup request. Transplant Centers can perform specific tests required before transplantation.
If the physical examination reveals that donation bears no increased risk for the donor but the potential transmission of a condition or disease to the recipient as specified in the responsible official guidelines of the donor country, such a donor may only be cleared after written acceptance from the Transplant Center.
Examples: travel history, sexual high-risk behavior, enzyme deficiency (G6PDH)
As subsequent donations occur in 10.5% of all our cases (HSC apheresis or bone marrow: 2.5% and MHC apheresis: 8%), donors are reserved for the patient for whom they donated.