PHILADELPHIA – Selected U.S. organ donors should undergo testing for infection by Trypanosoma cruzi, the etiologic agent of Chagas’ disease, before organs are taken for transplantation, recommended an expert panel initiated by the United Network for Organ Sharing.
U.S. blood donations already undergo routine screening for T. cruzi, Dr. Peter V. Chin-Hong said at the American Transplant Congress, which was sponsored by the American Society of Transplant Surgeons. As of early 2011, infectious disease experts estimate that about 300,000 Americans were infected with T. cruzi, and the panel learned of about 30 confirmed cases of T. cruzi transmission from infected donors to U.S. organ recipients, he added.
Dr. Peter V. Chin-Hong
Dr. Chin-Hong and his fellow panel members also recommended that when an organ donor – either living or deceased – is positive for T. cruzi infection, most organs are still usable for transplant as long as the recipient gives informed consent, is closely monitored for 6 months for signs of infection, and is treated promptly with an appropriate drug regimen if infection starts. The panel’s only exception to this policy was a recommendation that hearts from organ donors that are infected with T. cruzi not be used at all because the pathogen specifically targets the myocardium, and hearts that harbor T. cruzi risk eventually developing cardiomyopathy.
The panel backed an aggressive approach to the use of organs from infected donors because "we were concerned that people were discarding these organs "needlessly," Dr. Chin-Hong said in an interview. He estimated that patients who received a kidney or liver from a donor infected by T cruzi had about a 20%-30% risk of becoming infected by the pathogen, and even if infection occurred, reliable treatment exists with the primary agent, benznidazole, or with the second-line drug, nifurtimox.
"We have not seen any negative outcomes using T. cruzi treatment," he said.
"We do the same thing, except all our donors are screened for T. cruzi," commented Dr. Roberta Lattes, coordinator of transplant infectious diseases at the Institute of Nephrology in Buenos Aires. The only difference is that in Argentina, every organ donors is screened because T. cruzi is endemic in Mexico and in Central and South American. The U.S. panel suggested that U.S. organ donors undergo selection for screening by first asking if the donor was born in any of those regions.
"There is insufficient evidence for universal screening" in the United States, although individual U.S. organ procurement agencies might decide to apply universal screening to donors based on local T. cruzi epidemiology, said Dr. Chin-Hong, director of the transplant and immunocompromised host infectious diseases program at the University of California, San Francisco.
"We don’t use drug prophylaxis" on recipients of organs from infected donors "because the drugs are very toxic, and transmission is not that high," Dr. Lattes said. "But you must monitor, and at the least sign of infection you have to treat." She also agreed that hearts from T. cruzi–infected donors should not be used for transplants.
Organ donors who were born in Mexico or Central or South American should receive screening by a T. cruzi test that is approved by the Food and Drug Administration. Patients who receive an organ from a positive donor should undergo periodic testing with the same tests, weekly for the first 2 months after transplant, followed by every other week for the third month, and then monthly for another 3 months. Blood specimens should also be drawn and monitored microscopically for T. cruzi at the same times, and even more frequent specimens should be drawn, tested, and examined if organ recipients develop fever or signs of rejection. Confirmed infection must be treated promptly.
The panel published their recommendations in April (Am. J. Transplant. 2011;11:672-80).
The United Network for Organ Sharing is a private, nonprofit organization that manages the nation’s organ transplant system under contract with the federal government.
Dr. Chin-Hong said he had no relevant financial disclosures.