The idea for the symposia with our partners worldwide was born in 2018 for a good reason: "We all have the common mission to enable as many patients as possible to receive the optimal, life-saving stem cell donation,” says Gabi Rall, head of DKMS Transplant Center Services and the International Medical Team. “In doing so, we come from different directions: Day after day, the transplant coordinators move heaven and earth to find a suitable donor for their patients via the respective search unit. The medical departments of the DKMS in Tuebingen are the ones who support them in the confirmation typing as well as the coordination of the donation, organize everything and are in direct contact with them for this purpose. In order to continuously optimize our processes, it is incredibly important and valuable for us to know the perspective, needs and challenges of our partners at the clinics." Ute Leipprand, who together with her colleagues Maria Schmiing and Lisa-Marie Besemer has been involved in organizing the event since the beginning of the year, added: "Personal contact promotes mutual understanding and good, trusting cooperation."

Reason for exclusion no. 1: vein status

Burkhardt Schleipen of the DKMS Physicians Team kicked off the event with some surprising facts about donor availability: of the 8,024 workup requests, 532 suitable donors were not accepted for donation - most of them because of a problematic vein status (15%). "So, it is often not necessarily severe or chronic diseases that lead to exclusion, but apparent trivialities," said Burkhardt Schleipen. Another relatively common reason for exclusion was iron deficiency anemia (5%). "The availability of donors has decreased overall, but this only seems problematic at first glance," explained Thilo Mengling, Director International Medical Science of DKMS. If the figures are interpreted correctly, they even contain good news: "In the past, when there were far fewer registered donors, there was usually no alternative donor available," said Mengling. "For example, you would have had to wait until an iron deficiency anemia was resolved. Today, fortunately, there are often alternative donors to choose from, especially if the transplant is very time-critical."

Cryopreservation: safe transport in uncertain times

Deborah Buk, head of donor-patient contacts, provided information on a topic that has gained enormous importance during the pandemic: cryopreservation. Stem cell donations are frozen in liquid or fuming nitrogen. They can then be sent on their way to the patient and conditioning can begin once the donation has arrived intact at the site of the planned transplantation. In times of unreliable transportation, this is a huge, often life-saving advantage. While only 4.9% of stem cell donations were cryopreserved in 2019, at the beginning of the COVID-19 pandemic - due to the unclear transport situation, border closures, concerns about declining donor availability, etc. - the figure was as high as 88.3%. Amazingly, hindsight shows that donor availability was not affected by the pandemic. "However, when the incidence finally rose sharply due to Omicron, the age group of our donors was increasingly affected," Buk reported. "Therefore, to be on the safe side, we made a clear recommendation in January 2022 to cryopreserve all stem cell donations." Today, we recommend that transplant clinics decide on a case-by-case basis whether cryopreservation is necessary and appropriate for a certain patient. Still, 52% of donations worldwide, and 36.3% in Germany, are cryopreserved.

More partner clinics for larger collection capacities

There is currently a total of 18 collection centers in Germany where stem cells from all German donors are collected. As Sandra Bochert, head of our Workup department, reported in her presentation, collection capacities have become increasingly scarce in recent years for various reasons (e.g., several donors are requested for one patient or T-cell therapies with apheresis in patients). In order to counteract this, DKMS has held many discussions and has finally been able to win new partner clinics for stem cell collections: Since March 1, DKMS has been cooperating with the collection centers of the DRK Mannheim and the University Hospital Duesseldorf; since the middle of May also with the collection centers in Leipzig and Dessau. In addition, she said, negotiations with other clinics were already underway. "We always do our best to make your desired dates for the transplantations possible," says Bochert.

Unique worldwide: the DKMS Stem Cell Bank

Deborah Buk informed about a worldwide unique project that DKMS will start soon: the DKMS Stem Cell Bank. This newly founded subsidiary of the DKMS aims to help patients even better. Stem cells from donors with common HLA characteristics who have voluntarily agreed to donate to the Stem Cell Bank are cryopreserved and stored. Afterwards, they are immediately available for patients with corresponding HLA characteristics. Confirmation typing, preliminary examinations, etc. are not necessary, since they have already taken place. This is particularly advantageous for patients who need a transplant particularly urgently and promptly. "With the DKMS Stem Cell Bank, we can significantly shorten the time to transplantation," says Buk. DKMS only asks donors to donate to the Stem Cell Bank if they are already planning a collection for an acute patient. An additional collection day is not necessary, because only excess cells resulting from the normal collection are stored anyway.

T cells - a double-edged sword

A stem cell transplant contains about 40 times as many T cells as stem cells. However, T cells are a double-edged sword in stem cell transplantation: On the one hand, they can cause the dreaded graft-versus-host disease and thus act as destructive contaminants. On the other hand, they provide patients with adaptive immunity and enable the graft-versus-leukemia effect. Is it possible to use only the positive effects of T cells and to eliminate the negative effects? This was the subject of the exciting presentation by Dr. Halvard Bönig, Professor of Translational Development of Cell Therapeutics at Goethe University Frankfurt. He described a study in collaboration with the DRK Blutspendedienst Baden-Württemberg-Hessen, which concluded: Yes, separation of GvHD- and GvL-T cell memory is possible.

Family donors abroad - often DKMS can help

What to do if there is a suitable family donor for a patient in the USA, but the donor lives in India, for example, and cannot obtain a visa for the USA? In many such and similar cases, DKMS can help. "If the family donor lives in a country where we have a DKMS entity, it is usually not a problem," Gabi Rall explained. "We then take care of his or her HLA typing on site, organize the physical examination and finally also the collection." DKMS is represented in seven countries worldwide, including India, Chile and South Africa.

Things can get much more complicated if a family donor lives in a country without a DKMS entity. A real-life example: A patient in the USA had a matching family donor in the Dominican Republic. DKMS took care of her flight to Chile to accompany her from the DKMS site there and to assist her in all preparations. But when these steps were all completed, all flights were cancelled due to the pandemic. The donor was stuck in Chile for weeks. "The challenges can also be the language barrier or certain cultural requirements, such as when family donors are from very remote villages and have never seen an airplane up close," Rall said. Her offer to the transplant clinics: "If you are confronted with such problems, talk to us! We can't promise that the family donation will always work out then - but I promise we'll do everything we can!"