Researchers have found the potential to create a universal ABO blood group system for transplantation

Elizabeth Ostlander stayed on the waiting list for organ transplants for two years, worried about oxygen levels whenever she left home, and wondered if she could get the lungs she needed.

Residents of Niagara, who were diagnosed with chronic obstructive pulmonary disease (COPD) in 2016, successfully had a double lung transplant in November. But she approached to schedule her surgery a few times earlier-she is often one with her B-positive blood just to discover the lungs she was set to receive. I didn’t do it.

Ostrander’s waiting time is much longer than most lung transplant recipients, and depending on where you are in the country, new organs will be available within a few months. Patients in large city transplant centers often have short waiting times.

She’s fine now, but Ostlander still wants her surgery to come sooner.

“I’ve been using oxygen for six years, and I’ve always been worried about running out, getting tangled in tubes, and falling out at night,” said Surgery at the University Health Network’s Ajmera Transplant Center. A 57-year-old woman said. In Toronto.

A new study by Canadian researchers offers hope for more time on the waiting list, such as potential transplant recipients, especially Ostlanders with rare blood types and other physical factors. increase.

A proof-of-concept study presented at Science Translational Medicine on Wednesday suggests that organ blood types can be converted to universal O. Save on surgery.

UHN researchers treated eight untransplantable lungs with a pair of enzymes that convert the blood type of an organ from A to O without causing pulmonary toxicity. The enzyme removed more than 97% of blood group A antigen within 4 hours.

Antigens in the blood can provoke an immune response to foreign bodies in the body and reject organs unless they match the blood type of the recipient or come from a universal type O donor.

Dr. Marcelo Cypel, a thoracic surgeon at UHN and one of the authors of the study, said the enzymatic process was to convert red blood cells for transfusion by Dr. Stephen Withers, a biochemist at the University of British Columbia, and his team in 2018. Said it was developed in.

Cypel’s team tested the enzyme in the blood and then in the human aorta. When they saw success, they moved throughout the organ.

Three of the converted lungs were tested for rejection by introducing blood containing the A and AB antigens, and Cypel said the results were good.

“Based on previous studies with Dr. Wizards’ blood cells, this was found to be very efficient (but) those who take a bag of blood, put an enzyme in it … and distribute it quickly. Is much easier, “saipel said. “To reach all other aspects of organ tissue, we didn’t know if we would reach that point.

“So it was a nice surprise to be able to deplete these antigens so efficiently. And when we reintroduced blood into the system … we had it adversely affected the organs. I could clearly see that it did not reach. This was very different from the organs that were not treated with enzymes. “

The study focused on the lungs, but Cypel said it was likely to work in other organs. The team is then expanding its research to the kidney, aiming to advance to human clinical trials within 12-18 months.

A proof-of-concept study can help you determine if something is feasible before conducting further analysis. Cypel said the study is a promising first step for people waiting for a particular blood group organ.

Currently, people with A or B blood can receive O-type organs, while those with O blood can only receive from other O donors. Cypel said that it means that patients who are most in need of a transplant are skipped for patients on the waiting list who are less ill but may match the blood type of the organ.

According to researchers, patients with type O take an average of twice as long to receive a lung transplant as patients with type A. It also increases your chances of dying while waiting for a transplant by 20%.

Cypel, an Ostrander doctor, said B donors are rare in other blood types, including Ostrander’s B-positive, which can lead to longer waiting times.

According to the Canadian Blood Services website, O-positive is 39% of Canada’s most common blood types, and A-positive makes up 36% of the population. Less than 8% of Canadians are B-positive and 0.5% are AB-negative, making it the rarest blood type in the country.

Cypel added that Ostlander also had to wait for a lung size that matched her small frame. This further dilutes the options from donors.

“If you start (including) other factors, it will take a long time to find a small B donor,” he said. “Therefore, B patients will also benefit from now on, because … A donors converted to O donors can be used with any A, B, or O.”

By changing the blood type of the organ to make it suitable for all patients, Ostlander said he could avoid waiting for years of transplantation.

“It would have made a big difference in my life,” she said. “I would have had more freedom. I would be able to go out with my family and go camping. I can no longer do what I used to do.”

This report by Canadian Press was first published on February 16, 2022.