Scientists say among organ transplant patients, those receiving new lungs face a higher rate of organ failure and death compared with people undergoing heart, kidney and liver transplants, and one of the culprits is inflammation that damages the newly transplanted lung.
Researchers at Washington University School of Medicine in St. Louis and Northwestern University Feinberg School of Medicine have uncovered the precise cells that flow into and harm the lung soon after transplant.
Studying mice that had undergone lung transplants, the researchers found that monocytes are rapidly released from the spleen after lung transplantation.
These cells infiltrate the newly transplanted lung and then produce a protein called interleukin one beta, which in turn invites in the tissue-damaging white blood cells known as neutrophils.
“More than 50 percent of lung transplant patients experience some lung damage after a transplant,” said Daniel Kreisel, a Washington University professor of surgery and of immunology and pathology.
“Understanding the mechanisms of this damage is important in developing novel therapeutic agents to treat or prevent the condition in lung transplant patients,”
Early lung damage typically occurs in the 72 hours following surgery.
When a lung is removed from a donor, it is flushed with a cold preservation fluid and placed on ice, where it is deprived of blood and oxygen.
The damage typically occurs after the lung is surgically implanted and the recipient’s blood enters the lung for the first time.
The recipient’ s white blood cells seep into the transplanted lung and trigger inflammation that harms the organ’ s tissue.
The condition is a big reason why the success of lung transplants trails behind other solid organ transplants.
Five years after lung transplantation, only about half of the transplanted lungs are still functioning, according to the U.S. Organ Procurement and Transplantation Network, as against the five-year organ survival rates of about 70 to 80 per cent for liver, heart and kidney transplants.
The study was published online in the Journal of Clinical Investigation.