Jean Dausset. Portrait of Jean Baptiste Gabriel Joachim Dausset (born 1916), French immunologist and transplant pioneer. Dausset investigated the responses of patients to blood transfusions. He discovered that patients who have had many transfusions or certain drug treatments had abnormal responses. This reaction was directed against the white blood cells in the transfused blood. He then investigated tissue-rejection in transplant patients. He found that the human lymphocyte antigen (HLA) group caused the rejection. His work led to the development of tissue-typing which reduced the chance of transplant rejection. He shared the 1980 Nobel Prize for Physiology or Medicine.