After the workup request form is received, it is checked for completeness and correctness. The following information must be provided by the transplant center at the time of a formal request for a stem cell donation:
If the workup request form contains all necessary information, it 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 donors during the workup procedure:
If patients have a relapse or a graft failure, a subsequent donation of HSC from the same donor can become necessary. This happens in approximately 2-3 % of our cases. A donor can also be requested as best match for a different recipient (<1% of cases). To protect donors, the number of donations for HSC Apheresis or HSC Bone Marrow is limited to two collections per donor for each product type. There is no defined maximum number of donations for MNC Apheresis. However, when the donor is requested for MNC Apheresis the third time, a medical advisor will be contacted to evaluate the indication.
After an HSC donation the donor may 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 body weight of the recipient. Generally, a CD34+ cell count of 5 x 106 / kg recipient body weight 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 body weight 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 results list. Therefore, in urgent cases or in cases where the donor was already requested multiple times for CT, the HLA verification typing can be shifted to the workup process. In these cases, it is possible to request CT and workup at the same time. The transplant center has to consider that CT unavailability varies between 20-40% depending on the DKMS entity. For this reason, it is recommended that a Health and Availability Check (HAC) has been completed before a simultaneous CT and workup is requested to verify the donor’s availability and medically suitability. A HAC does not include IDM testing which will be performed only during workup in these cases.
At DKMS, the workup unavailability rate is approximately 15 % globally, including temporary reasons.
If there is an increased risk that the primary donor will be unavailable, DKMS may, in exceptional, plan collection dates with both donors simultaneously. Further exceptions can be made in individual cases, e.g. if several donors have already failed for a patient and the urgency is given.
With a global DKMS donor pool of more than 11 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 supports studies if they can result in a benefit for patient care or increase safety of donors and the additional burden on the donor is acceptable.
If the stem cell product contains more cells than needed, the transplant center should cryopreserve residues of the HSCs or MNCs for a later use.
It is not allowed to use the product for research or any other purposes without approval of DKMS and the donor.
Donor MNC products usually are portioned and most parts are cryopreserved. One portion should be infused freshly.
For recipient safety, transplant centers can request approval for cryopreservation of the stem cell product 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 therapeutic cell source).
In some countries, transplant centers have to perform additional tests, which are not relevant for donor clearance in the donor’s country.
Pre-collection samples of donors are often requested as part of the 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 respective official guidelines of the donor’s country, such a donor may only be cleared after written acceptance by the transplant center.
Examples: travel history, sexual high-risk behavior, enzyme deficiency (G6PDH).
As subsequent donations for the same patient occur in about 10% of all our cases (HSC Apheresis or Bone Marrow: 2.8% and MNC Apheresis: 7.8%), donors are reserved for the patient for whom they donated.