Dr. Maillard is a hematologist and immunologist with a longstanding interest in the regulation of hematopoiesis, bone marrow transplantation, T and B cell immunity, and lymphomagenesis. Born and raised in Switzerland, he earned his M.D. at the University of Lausanne, Switzerland, and a Ph.D. in Immunology from the Swiss Academy of Medical Sciences under the direction of Heidi Diggelmann. He subsequently completed a postdoctoral fellowship with Warren S. Pear at the University of Pennsylvania. In 2007, Dr. Maillard joined the Faculty at the University of Michigan, where he was affiliated with the Life Sciences Institute as well as with the Division of Hematology-Oncology in the Department of Medicine and the Department of Cell and Developmental Biology. In 2018, Dr. Maillard relocated to the University of Pennsylvania Perelman School of Medicine as a Professor fo Medicine and Vice-Chief for Research in the Division of Hematology/Oncology. In 2024, he was recruited to Memorial Sloan Kettering Cancer Center in New York as Head of the Division of Hematologic Malignancies. Dr. Maillard’s research is focused on the role of Notch signaling in hematopoiesis and T cell immunity. In particular, the Maillard laboratory identified new essential functions of Notch signaling in the regulation of pathogenic T cells mediating graft-versus-host disease after allogeneic bone marrow transplantation. These findings are being explored both for their fundamental immunobiological relevance and for their translational potential in the prevention of graft-versus-host disease and in the treatment of T cell–mediated immune disorders. Other laboratory interests include the role of Notch signaling and lymph node fibroblastic reticular cells in immunity and in blood disorders. Dr. Maillard’s research has been supported by multiple awards, including from the Damon Runyon Cancer Research Foundation, the American Society of Hematology, the Kimmel Foundation, the Leukemia and Lymphoma Society, and the NIH. Besides his research interests, Dr. Maillard maintains an active clinical practice in the care of patients with hematologic malignancies.