Failure of bone marrow engraftment could be due to all of the following except?

The assertion that failure of bone marrow engraftment could be due to ABO-mismatched donor cells is not accurate. While ABO incompatibility can complicate transfusions and may lead to hemolytic reactions, in the context of bone marrow transplantation, the engraftment process is predominantly driven by immunological compatibility as defined by the major histocompatibility complex (MHC) and the presence of CD34+ hematopoietic stem cells. ABO blood group differences typically do not prevent engraftment from occurring, as the adaptive immune response primarily focuses on MHC discrepancies rather than ABO antigens.

In situations where an engraftment failure occurs, a positive crossmatch indicates that the recipient's immune system recognizes the donor's cells as foreign, which actively leads to graft rejection. Graft failure may also result from a low number of CD34+ cells, as these cells are essential for hematopoietic reconstitution. Additionally, if the preparative chemotherapy regimen is insufficient, it may not adequately suppress the recipient's immune response, leaving the donor cells vulnerable to rejection.

Thus, while ABO mismatches can create certain challenges, they are not a determining factor for the actual failure of bone marrow engraftment when other more critical factors are considered