engraftment
The process by which transplanted stem cells establish themselves in the bone marrow and begin producing new blood cells.
Full Definition
Engraftment represents the successful establishment and proliferation of transplanted hematopoietic stem cells within the recipient's bone marrow microenvironment, resulting in sustained production of functional blood cells. Neutrophil engraftment is typically defined as achieving an absolute neutrophil count ≥500/μL for three consecutive days, while platelet engraftment requires platelet counts ≥20,000/μL without transfusion support for seven days. The timing of engraftment varies by stem cell source, conditioning regimen intensity, and patient factors, typically occurring 14-21 days post-transplant for peripheral blood stem cells. Delayed or failed engraftment represents a serious complication requiring intervention.
Usage
Usage note: Neutrophil engraftment typically precedes platelet engraftment. Chimerism studies confirm donor cell engraftment at the molecular level.
In Context
- "Neutrophil engraftment occurred on day +16 following allogeneic stem cell transplantation." — Transplant follow-up
- "Delayed platelet engraftment required additional supportive care measures." — Complication management