Table 1 Definitions of hematopoietic recovery, graft rejection, graft failure, poor graft function, and donor chimerism in allogeneic hematopoietic cell transplantation [7,8,9,10]
Term | Definition | |
|---|---|---|
Graft failure* | Lack of hematopoietic cell engraftment after allogeneic or autologous HSCT | |
Primary graft failure (PrGF) | MAC allo-HSCT | Graft source is peripheral blood (PB) or bone marrow (BM): Failure to achieve a threshold absolute neutrophil count (ANC) of 0.5 × 109/L for 3 consecutive days by day 28 after HSCT with associated pancytopenia and absence of initial donor cell engraftment (donor cells less than 95%; Mixed or full recipient chimerism) |
Graft source is umbilical cord blood (UCB): Failure to achieve a threshold absolute neutrophil count (ANC) of 0.5 × 109/L for 3 consecutive days by day 42 after HSCT with associated pancytopenia and absence of initial donor cell engraftment (donor cells less than 95%; Mixed or full recipient chimerism) | ||
RIC allo-HSCT | ANC < 0.5 × 109/L by day + 28/ + 42, and assay confirming ≥ 5% donor type cells Failure to surpass the 5% donor type threshold, even if essentially normal blood counts | |
Secondary graft failure | Loss of previously functioning graft (may involve hemoglobin and/or platelets and/or neutrophils) associated with loss of full donor chimerism RIC allo-HSCT: Loss of donor hematopoiesis to < 5% | |
Graft rejection | GF caused by an immune-mediated process; rejection of donor cells mediated by host cells | |
Poor graft function (PGF) | Severe cytopenia of at least two cell lines and/or frequent dependence on blood and/or platelet transfusions and/or growth factor support with full donor chimerism Absence of other explanations such as disease relapse, drugs or infections Poor graft function Primary PGF: incomplete hematological recovery Secondary PGF: decrease of blood counts after prompt recovery | |