Blood. According to a saying it is “thicker than water”, and for one poet it is “a very peculiar juice”. We know that blood consists of plasma, red and white blood cells, and platelets. And we know that each component plays a different role: Platelets enable clotting, white blood cells are part of the immune system, red blood cells carry oxygen and carbon dioxide, plasma carries nutrients and waste.

With the onset of the COVID-19 pandemic, blood plasma got special attention as it might play a role in the treatment of an infection with the coronavirus.

On the occasion of World Blood Donor Day on June 14 we turned to a specialist, who was among the first to study the effect of convalescent plasma. Professor Andreas Buser is Director of the Regional Blood Transfusion Service of the Swiss Red Cross and head of Transfusion Medicine, Hematology at Basel University Hospital in Switzerland. He teaches at the University of Basel.

Professor Buser, please tell us about the study of convalescent plasma as a treatment for COVID-19 patients you took part in: What is the aim of this study? Who initiated it? When did it start? What are the findings so far?

The idea in essence: Antibodies against Sars-CoV-2 are naturally produced by the immune system during an infection with the coronavirus. Convalescent plasma, i.e. plasma from donors who have Sars-CoV-2 antibodies, is administered to severely ill COVID-19 patients in the hope that the antibodies in the transfused plasma will act in the body and accelerate recovery and prevent a fatal outcome in affected COVID-19 patients.

Time was extremely short, the virus was on the rise. No one knew at the time whether the idea would work. There were no information or facts about COVID-19 anywhere in the world.

We have only treated a few patients in our hospital and cannot draw any definitive conclusions. However, numerous studies have been carried out worldwide, some of them very well controlled, but with divergent results. There are large consortia that are now trying to draw conclusions for possible new waves of SARS Cov-2 or other viruses from the published and non-published data and experiences.

What else is blood and/or plasma being used for with regard to medical treatment?

Blood products are used for various medical conditions. Red blood cell concentrates (RBCs) are used to improve the oxygen supply to the organs in cases of anaemia. Anaemia can be caused by iron deficiency, haemorrhage, or reduced blood production due to diseases affecting the bone marrow (site of blood production).

Platelets are used to prevent or treat bleeding when there are too few platelets (e.g. in patients with leukaemia and its treatment) or when platelets are not functioning properly.

Plasma is used when bleeding occurs and the clotting factors that are needed cannot be replaced in any other way.

How have blood transfusions and the use of blood components developed from the first documented transfusion in 1818 until now?

Since the first human-to-human blood transfusion in 1818, many important inventions have been made that have led to the current form of transfusion therapy.

Undoubtedly, the most important discovery was that of blood groups (the AB0 blood group system), as was first described by Karl Landsteiner in 1900. Today, 43 blood group systems are known and their knowledge and the current forms of diagnostic possibilities make it possible to find the best compatible blood product for the vast majority of patients. Other very important milestones were of course the possibility of storing the blood products and components, testing for infectious diseases which can be transmitted by blood and the technology of pathogen reduction of blood components.

What developments are you expecting in blood transfusion in the next 10 years?

I expect more knowledge about when to transfuse and when not to transfuse.

Especially “personalized” blood products will be increasingly used to ensure optimal patient care. Securing the blood supply will certainly be a major challenge. In addition, we are moving in an environment that is becoming more and more regulated, which brings with it a challenge for blood establishments.

The use of artificial organs and bone replacement has developed into a standard procedure over the years. Why has it not yet been possible to create artificial blood? Do you expect this to happen one day?

Artificial blood substitutes or blood from bioreactors (blood pharming) will certainly experience further development and will represent a therapy option at least for individual patients with complex blood group constellations, at least in rich countries.

If you were granted one wish for “World Blood Donor Day”, what would it be?

My wish is that, with the great help of donors, we can provide the right blood product at the right time for all patients. And I hope that the blood supply can also be sustainably improved in countries with fewer resources.

Thank you very much for your time and your insight.