(CNN) Scientists have transfused lab-made red blood cells into a human volunteer in a world-first trial that experts say has major potential for people with hard-to-match blood types or conditions such as sickle cell disease. The research could someday mean an end to long searches for compatible donors or dangerous transfusion reactions.
The experimental transfusion was done at Addenbrooke's Hospital in Cambridge, England, as part of a collaborative effort among UK scientists to understand how lab-made blood transfusions could work.
The scientists took whole blood from donors in a UK database and separated out the stem cells. These are the body's raw materials -- the cells from which all specialized cells, like a red blood cell, can generate.
The researchers grew red blood cells from those stem cells and transfused them into two healthy volunteers.
The transfusions involved only a tiny amount of blood: the equivalent of one or two teaspoons. A standard blood transfusion would involve many hundred times that amount.
This stage of the trial involves two mini transfusions at least four months apart, one with a standard donation of red cells and the other with lab-made cells from the same donor.
The researchers are closely monitoring the volunteers to determine whether the process was safe. They say there have been with "no untoward side effects" so far.
They're also watching how long the lab-grown cells last compared with an infusion of standard red blood cells. Red blood cells typically last about 120 days, but a transfusion from a standard donation contains cells that are a variety of ages because the bone marrow continuously makes these cells.
Previous tests have shown that manufactured cells function like normal cells and that these lab-made cells are likely to survive longer overall while in circulation. This study will determine for the first time whether that's true.
Further trials will be necessary to determine whether there could be a clinical use of this lab-grown product.
The research could eventually make a difference for people with sickle cell disease, those who develop antibodies against most donor blood types, or those with genetic disorders in which their body can't make red blood cells or the blood cells they make don't work well.
Red blood cells are the helper cells that carry oxygen from the lungs to the body's tissues, which use this oxygen to produce energy. The process also generates waste in the form of carbon dioxide that the red blood cells take to the lungs to be exhaled out.
With sickle cell disease -- also called sickle cell anemia -- red blood cells take on a folded shape that can clog tiny blood vessels and cause organ damage and pain. People with sickle cell often need multiple transfusions over the course of their lives.
"This world leading research lays the groundwork for the manufacture of red blood cells that can safely be used to transfuse people with disorders like sickle cell," Dr. Farrukh Shah, a researcher on the study and medical director of transfusion for NHS Blood and Transplant, said in a news release. "The need for normal blood donations to provide the vast majority of blood will remain. But the potential for this work to benefit hard to transfuse patients is very significant."
Dr. Glenn Ramsey, medical director of the blood bank at Northwestern Memorial Hospital and a professor of pathology at Northwestern University Feinberg School of Medicine, said he has had many patients over the years who are extremely difficult to transfuse and would have benefited from a therapy like the one in this study.
Often, if there is not a local blood match, he has to turn to the American Rare Blood Donor Program -- and even then won't always find an appropriate donor. In one case a few Thanksgivings ago, it was so difficult to find a match for one patient that they had to turn to a world database and bring in blood from Canada.
"This doesn't come up very often, and it's an extreme example, but this would be the kind of problem that these kinds of cells could try to solve," said Ramsey, who was not involved in the new research.
He found the work "quite exciting" and its potential enormous.
Scientists have been working on this issue for many years, he said.
"Down the road in years to come, this might be a way to replace transfusions as we know it," Ramsey said. "It's still a long way from getting to that point, but it certainly starts us down the road to see if this will even be feasible."
Dr. Cheryl Maier, an assistant professor of pathology and laboratory medicine and a medical director at the Emory Center for Transfusion and Cellular Therapies, said the experiment is a "really exciting advancement."
She is particularly interested in the possibilities of lab-made red blood cell for people with sickle cell.
"There hasn't been a lot of attention on some of these diseases, especially sickle cell, which mostly affects African American patients, and it can be really frustrating and disheartening that there isn't more attention to it," said Maier, who wasn't involved in this study.
"For certain patients, especially patients with sickle cell disease or other patients that need some kind of chronic transfusion therapy, if you gave them incompatible blood, they would have oftentimes a very strong bad transfusion reaction," she said.
The research could lay the groundwork for studies of things like platelets, which are often in critically short supply, she said. If scientists find that lab-made red blood cell products last longer, it may also improve the quality of life for people who wouldn't have to be transfused as regularly.
"Even in 2022, there are patients that we almost can't find units for, and they get a delay in their treatment because we can't find matching units for them," Maier said. "I think it definitely has the ability to revolutionize how we support some patients that are really difficult to support with blood products currently."