Researchers monitoring children who received heart transplants report that common viral infections of the implants can send these patients on a downward spiral.
Tests reveal that the viruses dont arrive with the donated organ but rather infect the recipient sometime after transplantation. Research on adult and child recipients of either a heart or a pair of lungs had hinted that when viral infections settle into a donated organ, immune rejection and other problems can result.
Jeffrey A. Towbin of the Baylor College of Medicine in Houston and his colleagues tracked the progress of 149 heart-transplant recipients under age 18. During a series of checkups over 4 years on average, physicians threaded a flexible device tipped with a tiny scope and clipping tool through a vein to the heart. They took snippets of heart muscle for analysis.
The heart tissue of 34 children tested positive at some point during the study for at least one of six types of virus. Surprisingly, the researchers report, 24 of the infections included adenovirus, the common pathogen that causes problems ranging from colds to viral pneumonia.
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Of these 34 patients, 29 experienced at least one severe heart problem–including 16 cases of strong organ rejection–within 3 months of detection of an infection, the researchers report in the May 17 New England Journal of Medicine. Of the 115 transplant patients without infections, 39 had severe heart problems, including eight cases of strong organ rejection, within 3 months of a checkup.
After 5 years, the transplanted heart continued to function in 96 percent of the patients who were free of virus. In contrast, the heart remained healthy in only 65 percent of patients who had shown a viral infection.
When the researchers focused specifically on adenovirus, they found that such an infection placed a patient at nearly five times the risk of transplant loss compared with people free of that virus.
The children with virus-infected hearts were more likely to develop narrowed coronary arteries and other warning signs of heart disease.
The study is the largest to date detailing the role of viral infections in heart transplants, says Kenneth O. Schowengerdt of the University of Florida College of Medicine in Gainesville. It suggests that viruses, especially adenoviruses, contribute to long-term coronary disease in heart-transplant patients. However, he says, it remains unclear whether the virus itself or a transplant recipients overactive immune system causes this damage.