An antibody called immunoglobulin E causes allergic reactions by stimulating cells to churn out histamines and other inflammatory agents. Despite the new finding, transplant recipients need not worry about dangerous allergies, says J. Harold Helderman, an immunologist at Vanderbilt University Medical Center in Nashville and president of the American Society of Transplant Physicians. The result in this case, he notes, was a skin rash, not a systemic, life-threatening reaction. Thousands of patients have received livers without developing allergies. More important, he says, the study sheds light on the debate over microchimerism, the theory that immune cells from a donor eventually work alongside those of the recipient and perhaps mitigate rejection.
Doctors disagree on how much immune system suppression is needed after a transplant.
In rare cases, recipients have been taken off suppressant drugs and done fine, Legendre says. Legendre, C., et al. 1997. Ezzell, C. 1992. Antibody combo nixes graft rejection. Lipkin, R. 1995.