Scientists Are Calling Monkey’s Two-Year Survival After a Pig Kidney Transplant “Unprecedented”


The xenotransplant involved transplanting Yucatan miniature pig kidneys into macaque monkeys with 69 genetic modifications.

One monkey survived for over two years, offering hope to the team of Harvard Medical and eGenesis researchers regarding the potential use of pig kidneys in humans. Pigs are considered the most suitable donor animals due to their availability, gene-editing compatibility, and organ similarities. Nevertheless, it has taken over four decades to even begin to address the issue of pig organ rejection by the human immune system.

NHS statistics reveal that in the UK, 5,562 individuals are currently waiting for a kidney transplant. This figure accounts for over three-quarters of the people in the UK who are seeking various types of transplants.

About the Edits

The genetic modifications were substantial, involving the elimination of pig viruses, the addition of specific human genes, and the removal of three antigen (marker) coding genes, which are partially responsible for transplant rejection.

Previous studies have shown that the human immune system targets specific antigen genes. Therefore, for the purposes of this study, these genes were edited out.

A significant portion of the genetic modifications focused on removing the PERV gene. Although the PERV gene does not appear to be responsible for diseases in pigs, there is some evidence suggesting that human cells can become infected.

The researchers found that the addition of human genes to the pigs resulted in prolonged survival.

About the Transplantation

A total of twenty-one monkeys received pig transplants.

  • Six monkeys received kidneys with the PERV and antigen genes removed.
  • Eight were modified by the removal of antigen genes in addition to the incorporation of human genes.
  • Seven donor kidneys were modified in all three ways.

It was evident to the team that the addition of human genes improved survival rates.

According to the study, the genetic modifications involved kidneys that were believed to have minimal chances of graft survival. Those kidneys that carried seven human genes exhibited survival rates seven times greater than the rates of the other cohorts (176 days). Notably, one monkey survived for 758 days.

The study demonstrates success in maintaining kidney function in non-human primates for over two years.

Tatsuo Kawai, a Harvard professor, noted three noteworthy achievements:

  1. Editing the porcine genome to minimize rejection.
  2. Improving recipient compatibility.
  3. Minimizing the risk of viral transmission from the donor to the host.

The study has opened doors and holds promise for the future.


Rose Duesterwald

Rose Duesterwald

Rose became acquainted with Patient Worthy after her husband was diagnosed with Acute Myeloid Leukemia (AML) six years ago. During this period of partial remission, Rose researched investigational drugs to be prepared in the event of a relapse. Her husband died February 12, 2021 with a rare and unexplained occurrence of liver cancer possibly unrelated to AML.

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