A pioneering new project has shown that it may be possible to create universal donor organs that can be accepted by transplant recipients of any blood type, as reported in the journal Science Translational Medicine. The research is still in its early days and only considered a proof-of-concept study, but it could open the way towards shorter waiting lists for much-needed donor organs. Blood type is all to do with antigens found on the surface of red blood cells: type A blood has the A antigen, type B has the B antigen, AB blood has both antigens, and O has neither. Antigens can spark an immune response if they are foreign to our bodies. Other than people with AB positive blood type – known as the “universal recipient” – you can only receive blood from donors with the same blood type as yours, or type O which is universal. These antigens are also on the surfaces of blood vessels in our organs, meaning doctors also have to correctly match donor organs to recipients. If a patient with type A blood receives an organ from a type B, for example, then there’s a much higher chance that the transplant will be rejected. “This translates into mortality. Patients who are type O and need a lung transplant have a 20 percent higher risk of dying while waiting for a matched organ to become available,” Dr Aizhou Wang, the first author of this latest study, said in a statement. In a bid to overcome this hurdle, scientists at the University Health Network in Canada added an extra element to the Ex Vivo Lung Perfusion System used to pump nourishing fluids through organs, enabling them to be warmed to body temperature and ready for transplantation. The team pumped a lung from a type A donor full of enzymes (sourced from the human gut) into the perfusion fluid, which helped to clear the A antigens from the surface of the organ, effectively converting it into a type O lung. They then ran type O blood through the lung. Typically, this blood type would react badly to an organ from a type A blood donor, but their study appeared to show it was well tolerated with no signs of rejection. The researchers believe this is a very promising step towards universal donor organs, a feat that could significantly reduce transplant waiting times and save lives. None of their work has been tested on humans or other animals just yet, but the team hopes to launch a clinical trial within the next 12 to 18 months. “With the current matching system, wait times can be considerably longer for patients who need a transplant depending on their blood type,” explains Dr Marcelo Cypel, Surgical Director of the Ajmera Transplant Centre and the senior author of the study. “Having universal organs means we could eliminate the blood-matching barrier and prioritize patients by medical urgency, saving more lives and wasting less organs,” Dr Cypel adds. Source
