Lab-grown blood transfusion: The many problems it could address if it works

It could end shortages of rare groups, and drastically cut the risk of infections from transfusions

A clinical trial in the UK has grown blood in the laboratory and transfused it into two volunteers in a research project carried out jointly by the University of Cambridge, the University of Bristol and the Blood and Transplant Department of the UK’s National Health Service. The experiment will be repeated with more volunteers.

This has huge implications for the treatment of certain congenital blood-related disorders such as sickle cell anaemia and thalassemia. It could also make it considerably easier to arrange treatments and transfusions for patients with rare blood groups.

An ability to generate blood in the lab could end shortages of rare groups, and drastically cut the risk of infections from transfusions. It could reduce the complexity of finding donors, and stocking different types of blood in banks.

The experiment

Here’s what the experimental trial (called Restore) does. It starts with a donation of around 500 millilitres (ml) – one standard unit – of blood. Everyone’s blood contains stem cells, which can develop into mature red blood cells. Red blood cells contain iron in the haemoglobin (the combination of iron and oxygen gives them the characteristic rust colour).  

These stem cells can be collected by using a magnetic device. They are then placed in nutrient cultures where they grow. Over 18-21 days, an initial pool of half a million stem cells (which 500 ml of blood contains) multiplies into 50 billion red blood cells. This is further filtered to collect around 15 billion red blood cells, which are at the right stage of maturity, and those can be transfused back into the body of volunteers. 

The researchers say they are hoping that the newly-generated red blood cells from the lab will work as well – or even better – than blood produced within the body. Right now, extremely small quantities – around 5-10 ml – are being transfused and the subjects are being studied for responses or complications.

If this works without side-effects or mishaps, a blood donation could be scaled and multiplied using this procedure to many times the original volume. The lab-grown blood in the study is tagged with a (harmless) radioactive tracer dye, as typically used in medical procedures, to track its activity and longevity inside the body.

At least 10 volunteers are expected to receive two mini transfusions each, with a gap of four months between transfusions. One transfusion will be of standard donated blood and the other will be of lab-grown cells.

If it's a success

Red blood cells have a lifespan of about 120 days and they are continuously renewed, which is why stem cells are contained in blood. A normal blood sample will contain cells of varying ages. Instead, groups of fresh, new lab-grown blood cells should last longer. This could reduce frequency of transfusions for patients who regularly need blood, and also avoid iron overload – in repeated transfusions, excess iron accumulates and has to be removed.

People with blood disorders like thalassemia or sickle cell disease depend on transfusions– some require 12 units of blood every 4-6 weeks. If the patient has a rare group, there is a supply problem since blood transfusions can be rejected.  

Assuming Restore works, there would have to be a scale up and experimentation with tweaks. For individuals with rare groups, this could be a boon. While there are eight main blood groups, there are at least 36 very rare groups. AB negative is the rarest of the major eight groups. But it is found in 1 per cent (one in 100) of the population, which means for blood banks to get donors. The Bombay blood group is found in one out of a million persons. Transfusions are very, very hard to arrange.   

Blood disorders like sickle-cell anaemia and thalassemia are caused by genetic disorders and these could conceivably be cured or alleviated by a combination of gene-therapy and lab-grown blood. Experimental procedures have been tried to cure sickle cell anaemia, which is caused by misshapen red blood cells.

Stem cell modification vs lab-grown blood

Red blood cells are manufactured by stem cells within the bone marrow. Scientists have extracted stem cells, modified them using gene-editing techniques to generate healthy blood cells and put the modified stem cells back into the body. While this procedure shows promise, it’s highly risky. The unhealthy (original) stem cells have to be killed using chemotherapy, and the entire blood supply has to be replaced, with massive transfusions. If blood can be manufactured in the lab, it would be a far less risky procedure.

But this will always be an expensive procedure. The culture has to be kept within controlled lab conditions and growth must be overseen by skilled technicians.  It’s unlikely to replace the normal donation-transfusion cycle for common groups. But it could be a huge game-changer in the cases such as those outlined above.