Breakthrough in the manufacture of platelets

Researchers at NHS Blood and Transplant and the University of Cambridge have developed a new method to produce platelets in the laboratory in large numbers for the first time.

Billions of platelets are circulating in our blood and they are vital to us because they stop bleeding, for instance when you cut your finger. They may be given to patients having cancer chemotherapy, transplants, major surgery and trauma.

How are platelets made?


Platelets are formed from giant ‘mother cells’ known as megakaryocytes that are themselves formed from stem cells in the bone marrow.  The platelets ‘bud’ off the megakaryocytes – they are the round objects on the surface of the Megakaryocyte in the picture – and eventually join the blood circulation by passing through the small vessels in the bone marrow.

Our researchers have found a novel way to switch stem cells grown in a laboratory into these megakaryocytes with a very high efficiency  making it possible to produce large numbers of platelets outside the body.

This breakthrough is important for a number of reasons. Firstly, donated human platelets only last seven days, which is why we ask our platelet donors to donate as regularly as possible. Also, whenever a patient receives a platelet transfusion, there is always some risk, although it is very low, of transferring an infection.  Finally, patients who receive regular platelet transfusions may become sensitised to them, making it difficult to find suitable donors in future. The production of platelets in strictly controlled conditions in the laboratory could make them more available, safer and precisely matched to the patient, stopping them becoming sensitised.

Cedric Ghevaert, a consultant haematologist at NHS Blood and Transplant said “Making megakaryocytes and platelets from stem cells for transfusion has been a long standing challenge because of the sheer numbers we need to produce to make a single unit for transfusion.  We have found a way to 'rewire' the stem cells to make them become megakaryocytes a lot faster and more efficiently. It’s a major step forward towards our goal to one day make blood cells in the laboratory to transfuse to patients.”

But please don’t stop donating platelets! It will take many years to develop the production of laboratory platelets to the scale required for transfusion and we still need more platelet donors to donate as regularly as possible.

Platelets helped save my life!


When Andy Jackson was 18 he was diagnosed with chronic myeloid leukaemia. He was told that a bone marrow transplant was his only option.

Andy takes up the story…

“About 3 months after I was diagnosed with chronic myeloid leukaemia I was fortunate enough to find a suitable donor. When I received my bone marrow transplant it was just like having a blood transfusion; it was over in a couple of hours. Then it was a case of having to wait and hope the donor stem cells would accept my body.

“In the weeks and months following the transplant, I received platelet transfusions to help bolster my levels which had been depleted by my treatment.

“Platelets and blood transfusions are easy to take for granted, but they were vital for me in my recovery. I can’t thank my bone marrow donor, or the donors who donated platelets enough for their generosity.

”I now work for Bloodwise, a charity that has been working to beat blood cancer since 1960. In April this year we became the official charity partner for NHS Blood and Transplant. We are really looking forward to working with NHS Blood and Transplant to raise awareness of the need for blood and platelet donors and raising awareness about blood cancers.”

More A negative platelet donors needed

You may have heard O negative blood can be given to any patient. Well, A negative platelets can also be given to any patient requiring a platelet transfusion.

We particularly need more A negative blood donors to start donating platelets at one of our donor centres.

For more information visit: or call 0300 123 23 23


In this issue of The Donor magazine

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A chance conversation

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A day to remember

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Competing thanks to you