Grant Medal awardee Andreas Greinacher: Pioneering platelet researcher shapes future of hematology
Andreas Greinacher, M.D., is a natural critical-thinker.
Throughout his professional career, his curiosity has led him to skillfully analyze, conceptualize and generate groundbreaking scientific discoveries that have had a profound impact on the field of hematology.
Greinacher is the recipient of the ISTH Robert P. Grant Medal, the highest honor of the Society, in recognition of his outstanding accomplishments in the field of thrombosis and hemostasis.
A distinguished expert in transfusion medicine, immunohematology and hemostasis, Greinacher held the position of Professor and Department Head at the University of Greifswald in Germany until his retirement in December 2023.
Looking back on a professional career spanning more than 35 years, Greinacher reflects on his research, clinical work and leadership with the ISTH, while offering a behind-the-scenes perspective at some of the most defining moments of his career.
A bold career start and an unexpected discovery
In the late 1980s, Greinacher was in his final years as a medical student in Germany. He had two patients with immune thrombocytopenia (ITP), but something did not seem right with their diagnosis. Greinacher did not think that these patients had ITP.
He read a paper about a similar case that was authored by Jim White, M.D., in Minneapolis, USA, so Greinacher contacted him for guidance.
“It was a time before the Internet, so I wrote Dr. White an actual letter in the mail,” Greinacher recalls. “Even international phone calls were prohibitively expensive for students at that time.”
White responded, and with White’s support, Greinacher sent him a sample of reagents, which confirmed the diagnosis of Sebastian platelet syndrome (MYH9-related disorders) and led to Greinacher’s first published paper.
In 1987, Greinacher was eager to meet Jim in person, so he registered to attend his first ISTH Congress in Belgium. At that congress, he also met Christian Mueller-Eckhardt, his future mentor who shaped his career.
"When I first joined the ISTH, I was a young medical student. This was a big society," he recalled. "The ISTH always had been and still is the scientific society reflecting most of what I am doing in my professional and my research life."
Greinacher’s curiosity took a new turn a few years later, when, during his first year as a trainee, he cared for a patient with thrombosis and thrombocytopenia after having hip replacement surgery. The patient was treated with heparin, but died shortly after heparin was increased to the therapeutic dose to treat the thrombosis.
“It was a shocking event for me as a trainee,” Greinacher said. “You have one of your first patients and you do what you are supposed to do, but the outcome is fatal. Then, by coincidence, a very similar situation happened a few weeks later. That was the moment I knew something was wrong.”
Prof. Beng Chong from Sydney, Australia had published about an an adverse drug effect, heparin-induced thrombocytopenia (HIT). When Greinacher’s mentor Christian Mueller-Eckhardt contacted him, he sent Greinacher 7 mL of serum of one of his HIT patients.
Greinacher began work developing a lab assay and exploring alternative anticoagulants to treat these patients. He led the compassionate use program on danaparoid in Germany, and he later became the principal study investigator, which led to international approval of recombinant hirudin as the first non-heparin/warfarin anticoagulant.
Looking back, Greinacher recalls that his tenacity as an early career professional helped to propel his career forward.
“It was unbelievable. I was naïve enough to not feel scared about the prospect of what could happen. I just did it. It was an incredible time for me, and it all happened at an incredible velocity,” he said.
A new career amid an ever-evolving Germany
In early 1993, Greinacher’s career was about to take a new turn. He was 34-years-old with a young family when he was offered a position to serve as Department Chair at the University of Greifswald’s Institute of Transfusion Medicine.
It was a big step. Over the past several years, Greinacher’s home country of Germany had experienced a political transformation, with the fall of the Berlin Wall in late 1989. In October 1990, Soviet-occupied East Germany, known as the German Democratic Republic, reunited with West Germany, creating a reunified country.
Greinacher had spent his entire childhood and adult life thus far in western parts of Germany. The move to Greifswald, which had been formerly been part of East Germany just a few years prior, was an exciting change that came with its own challenges. It was also an opportunity to be a small part of history as Germany unified together after many years.
“It was an enormous privilege to live in the middle of a rapidly changing part of German society by moving to the former East Germany. Being in the middle of the process, it was sometime extremely demanding, but also very rewarding,” he shared.
After nearly 50 years of previous division, society and culture were very different from what he was accustomed.
“When I came in to establish the blood service and thrombosis clinic, there was little infrastructure. The blood donor clinic was in need of repair, the next major city was five hours away…everything was different. We had to tackle these things together and the staff there were incredibly willing,” he said.
Over the years, Greinacher has taken on a variety of roles at the University of Greifswald, supporting its growth and development by establishing the blood service to cater to the entire region. He later served as Chief of Staff and CEO, building a new 1,000 bed University hospital within the newly developing life science campus, before becoming Associate Dean of Research.
ISTH leadership and engagement
Greinacher's leadership with the ISTH spans more than 35 years, from his early days as a trainee to eventually serving as a member of the ISTH Council.
One of his initial leadership roles was serving on the ISTH Scientific and Standardization (SSC) Subcommittee on Platelet Immunology. He also made significant contributions as Chair of the ISTH Education Committee, which oversees the educational direction and program development of the Society and served as an Associate Editor of the Journal of Thrombosis and Haemostasis.
“The most interesting and satisfying work for me personally was the work for the Education Committee,” he shared. “I enjoyed the networking, international contacts and organizing sustainable programs for education, as well as training to support those who are really interested in changing and developing their systems.”
His leadership with the ISTH Education Committee even led to new philanthropic efforts in Africa. In 2016, he and other ISTH Education Committee leaders attended the ISTH education workshop in Nigeria. The first ISTH educational program of its kind held in Africa, it was an exciting milestone for the Society.
During his time in Nigeria, he learned that bleeding is a leading cause of maternal death due to the lack of blood that is safe to transfuse. This inspired Greinacher to help improve the safety and quality of blood transfusion in Nigeria, which eventually led to a collaboration project between his university and one in Nigeria that continues to this day. Read more about Greinacher and his team’s efforts in Nigeria in an April 2024 article published in The Lancet Hematology.
VITT: A race against the clock
Greinacher paved the way on international understanding and treatment of vaccine-induced immune thrombocytopenia and thrombosis (VITT), which came to fruition amid the start of COVID-19 vaccinations during the pandemic. He recalled the intensity of that time.
“I remember the exact day. It was a Sunday, March 14, 2021. A colleague in Vienna contacted me about a patient with a low platelet count and very unusual thrombotic complications. She had no risk factors. The only thing of note was that the patient had received the COVID-19 vaccine two weeks before,” he said.
That same day he received a call from a national agency asking him to participate in an emergency meeting the following day on Monday. He knew at that moment that something significant was happening.
By Tuesday, he received the sample from Austria and ran the first assay, which was strongly positive. However, the confirmatory functional assay was negative, which was highly unusual. Greinacher called his colleague Ted Warkentin, M.D., at McMaster University in Canada, who suggested they use platelet factor 4 (PF4) in the assay. By Wednesday, they did so, and the assay came back positive. They had identified the first patient with VITT.
They had to move quickly.
He shared how the global team worked around the clock—quite literally—taking advantage of varying time zones to each work on the project at different hours in during the day. In an unpreceded one week, Greinacher and colleagues submitted a paper with the inaugural VITT clinical picture, diagnostic assay and mode of treatment to the New England Journal of Medicine.
He collaborated with other ISTH members to issue guidance for the diagnosis and treatment of VITT on behalf of the ISTH, receiving major attention by the scientific community and the public.
“It was one of the most absolute stellar experiences in my entire career. It was unbelievable,” he said. "It was a true scientific collaboration and international cooperation to solve one of the most acute and burning questions at the forefront of that time."
The understanding of VITT placed a spotlight on the significance of anti-PF4 disorders and Greinacher hopes to continue this research in the future.
Charting a remarkable career: Shaping tomorrow’s frontiers
With more than 500 publications and numerous national and international awards, Greinacher's contributions to the field are profound. His recognition as a recipient of the ISTH Grant Medal, the Society’s highest honor, highlights Greinacher’s accomplishments in research and groundbreaking discoveries that have transformed science and understanding in the field.
“It is very rewarding that the colleagues with whom I have worked with for many years, who probably know my work the best, feel that I am worthy of this honor,” he shared. “There are so many other colleagues who have done excellent and important work, who would all deserve this award as much as I do. I am honored and humbled.”
Greinacher retired from his clinical obligations at the University of Greifswald in December 2023. Despite retirement, he continues to serve in a Senior Professorship position and can continue his research projects as grant funding allows. He also looks forward to continuing his blood transfusion safety work in Nigeria.
“At the end of my professional career, this recognition is a special moment. I always tried to select carefully what I want to do. If I commit to something, then I want to do it right, even if the workdays are long,” he said. “I have had the privilege to work with fantastic colleagues over the years. For the ISTH Grant Award, I am the front man of what is really a super team.”
Click here to read the ISTH official announcement.