Transplant Patients Show Good Immunity After 20 Years

A study has found that patients who had bone-marrow and stem-cell transplants 20-30 years ago now have effective immune systems and live normal lives, free of frequent infections. Conducted by researchers at the Fred Hutchinson Cancer Research Center (Seattle, WA, USA), the study was reported in the December 15, 2001, issue of Blood.

The quality of life following hematopoietic transplantation has been a concern, especially for patients who were among the first to undergo this treatment. Today, hematopoietic transplantation is considered to provide the best chance for curing leukemia, but it works by destroying the patient's damaged marrow and replacing it with healthy marrow or stem cells. The high-dose chemotherapy and radiation therapy given to these patients cause cell counts to drop to very low levels, creating a highly immune-compromised state. It can take a long time for the immune system to function normally again. During this time, patients are susceptible to debilitating and life-threatening infections.

For the study, the researchers evaluated 591 patient-years for 72 patients. They found a total of 41 infections reported, for an average of one infection every 14 years, discounting common colds. For people transplanted before the age of 18, the rate was only one infection every 18 years, and for those transplanted after 18, the rate was one every 11 years. The researchers studied immune cells in blood samples in 33 of the patients, concluding that most had recovered normal immunity by 20 years after the transplant.

"We believed we captured a significant majority of serious infections,” said Dr. Jan Storek, a member of the research team and an assistant professor at the University of Washington (Seattle, USA). "However, it is possible that minor infections were underreported due to the patients not recalling these infections.”




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