New research from the University of Texas Southwestern Medical Center at Dallas has detailed a new technique that may be able to boost patients' acceptance rates of corneal transplants. This is according to a study published in the American Journal of Transplantation.
A corneal transplant, also referred to as a corneal graft, is an operation involving the removal of all or part of a damaged cornea. Using healthy corneal tissue from a suitable donor, the damaged cornea is replaced.
According to the Eye Bank Association of America, approximately 42,624 corneal transplants were carried out in the US last year.
The research team, led by Dr. Khrishen Cunnusamy, says that for approximately 10% of patients who undergo corneal transplants, their bodies reject the donor. Because of this, they say the chances of a second transplant being successful for these patients are poor.
With this in mind, the team conducted a mouse study in an attempt to develop a method to increase patients' acceptance rate of corneal transplants.
Deactivation of IFN-y and MHC matching '90% successful'
The investigators found that when they blocked the action of interferon-gamma (IFN-y) - an immune system molecule - corneal transplants were accepted in 90% of cases for mice who had the same major histocompatibility complex (MHC) genotype as their donor.
Previous studies have suggested that IFN-y triggers immune system rejection of corneal transplants, and that deactivating the molecule may improve transplant acceptance rates.
But the investigators explain that this most recent study suggests otherwise. They found that when IFN-y was deactivated and the MHC of the mice were not matched, this resulted in a 100% rejection rate. This indicates that IFN-y can both activate and suppress the immune system, but its action relies on the MHC genotype.
Commenting on the findings, Dr. Jerry Niederkorn, professor of Opthalmology and Microbiology at the University of Texas Southwestern and senior author of the study, says:
"Our findings indicate that neither MHC matching alone nor administration of anti-IFN-γ antibody alone enhances graft survival. However, we found that when MHC matching is combined with anti-IFN-γ therapy, long-term corneal transplant survival is almost guaranteed."
Dr. Niederkorn adds that the technique detailed in their study would be most appropriate for patients who are at risk of corneal transplant rejection, or those who have already rejected a cornea, rather than individuals who are receiving a corneal transplant for the first time.
However, he notes that further research is required before the method can be put forward to clinical trials.
"We are working to develop an IFN-γ antibody in eye-drop form," says Dr. Niederkorn. "Then we need to test whether this antibody will work in animal models."
Medical News Today recently reported on a study suggesting that corneal reflections in photos may help solve crimes.