Jeffrey L. Platt received his M.D. from the University of Southern California in 1977. He is a professor of surgery, immunology and pediatrics at the Mayo Clinic and the head of the clinic's Transplantation Biology Program. Address: Mayo Clinic, Transplantation Biology, 200 First Street S.W., Medical Sciences 2–66, Rochester, MN 55905. Internet: platt.jeffrey@mayo.edu" "00774573