Table 1-1. Possible mechanisms... | American Society of Hematology

Table 1-1.

Possible mechanisms underlying an increased risk of postoperative infection in association with white-cell–containing allogeneic blood transfusion

Hypothesis	Reduction in the risk of postoperative infection following the implementation of prestorage WBC reduction?	Increased risk of postoperative infection as the length of storage of the transfused cellular blood components increases?
Hypothesis		Before the implementation of prestorage WBC reduction?	After the implementation of prestorage WBC reduction?
1. Transfusion of older RBCs results in tissue hypoxia, which predisposes to postoperative infection.	No	Yes	Yes
2. Biologic response modifiers, released from deteriorating WBCs and accumulating in the supernatant fluid of cellular blood components, mediate adverse TRIM effects.	Yes	Yes	No
3. Immunologically active, intact allogeneic WBCs mediate adverse TRIM effects.	Yes	No	No

Hypothesis	Reduction in the risk of postoperative infection following the implementation of prestorage WBC reduction?	Increased risk of postoperative infection as the length of storage of the transfused cellular blood components increases?
Hypothesis		Before the implementation of prestorage WBC reduction?	After the implementation of prestorage WBC reduction?
1. Transfusion of older RBCs results in tissue hypoxia, which predisposes to postoperative infection.	No	Yes	Yes
2. Biologic response modifiers, released from deteriorating WBCs and accumulating in the supernatant fluid of cellular blood components, mediate adverse TRIM effects.	Yes	Yes	No
3. Immunologically active, intact allogeneic WBCs mediate adverse TRIM effects.	Yes	No	No

Expected results from observational comparisons of patients transfused before or after the implementation of universal WBC reduction.