Chimerism and Solid Organ Transplantation

Trenches in Transplant Surgery · Oct 1, 2025 · 48m

Chimerism—the coexistence of donor and recipient hematopoietic cells—has become central to understanding and inducing immune tolerance in solid organ transplantation. Early work by Owen, Medawar, and later Starzl revealed that donor “passenger leukocytes” can persist as microchimerism in recipients, reshaping the once one-way host-versus-graft paradigm into a bidirectional model. Stable mixed chimerism can induce central and peripheral tolerance by deleting or regulating donor-reactive lymphocytes, while microchimerism may help sustain long-term graft acceptance but is not uniformly…