The researchers studied 20 patients who as infants underwent heart transplantation and had their thymus removed. As a result the infants were deficient in T cells, the cells depleted in AIDS patients that are crucial to fighting viruses and cancer tumors. The researchers found that over a 10-year-period the infant transplant patients resisted the same infections that often kill adult AIDS patients. The transplant patients maintained their health even with low T cell counts. The finding could help improve treatments of AIDS, cancers and diseases of aging related to declining function of the immune system.
"We are very excited by this result," says Jeffrey Platt, M.D., the Mayo transplant researcher who led the team. "This will be the first step to discovering how to make the immune system work in patients who have severe defects in their immune systems or who have cancer."
The Mayo Clinic researchers report results comparing T cell function between transplant patients 1-10 years post transplant and healthy people matched to the transplant patients by age and gender. To compare T cell function, they measured the T cell response to select viral immunization. This comparison enabled them to see that infant heart transplant patients had more help from the immune system post transplant -- even though some had a 10,000-fold reduction in T cells -- compared to the healthy control group. The nature of the compensat