The use of leukocyte-reduced cellular blood components has been advocated as a means of lowering the risk of Non-Hemolytic Febrile Transfusion Reactions (NHFTRs), HLA alloimmunization and disease transmission.

The designation leukocyte-reduced red blood cells applies to RBCs prepared by a method known to retain at least 80% of the red cells originally present. When intended for prevention of febrile reactions, a unit should contain no more than 5 x 10⁸ (number normally present is >/= 5 X 10⁸); for other purposes such as preventing transmission of CMV or alloimmunization to HLA antigens, the number of leukocytes should be no more than 5 X 10⁶ (1). The most effective way to remove leukocytes is the use of specially designed filters (up to 99% WBC removal).

1. Prevention of Febrile Non-Hemolytic Transfusion Reactions:

Multitransfused and/or multiparous patients may be come alloimmunized to HLA or leukocyte antigens and may experience FNTR’s when transfused with blood components containing WBCs. The use of blood components with a residual leukocyte count below 5 X 10⁸ often, but not always, prevents such reactions. (2)

2. Prevention of HLA Alloimmunization:

Prevention of HLA alloimmunization may be desirable for patients who require long-term platelet support or who may require eventual transplantation. Leukocyte reduction has been proposed as a way to achieve this (2).

3. Prevention of Transfusion-Transmitted Viruses and Bacteria:

CMV transmission can be prevented either by administration of components from seronegative donors or by vigorous leukocyte reduction of blood components from random donors. The transmission of EBV and HTLV I/II may also be reduced with the use of leukocyte reduced components. For certain indications prestorage leukocyte reduction may decrease multiplication of Yersinia and other bacteria during refrigerated storage or red cells. (2)

Therefore, it is recommended, that patients meeting the criteria below, receive leukocyte reduced blood and/or blood products if transfusion(s) is/are required:

1. All patients who have had two documented mild to moderate or one severe Febrile Non-Hemolytic Transfusion Reaction.
2. All transplant or potential transplant patients.
3. All chemotherapy patients (since they may require multiple platelet transfusions and to help reduce transmission of CMV and other viruses).
4. All neonates, infants and children.
5. All multiparous (3 or more pregnancies) since they may be alloimmunized to leukocyte antigens or plasma proteins.

REFERENCES

1. American Association of Blood Banks, Technical Manual, 12 ed., pages 141-142.

2. American Association of Blood Banks, Technical Manual, 12 ed.., 1996, pages 423-424.

Please contact the Department of Pathology and Laboratory Medicine:

Pathologists

Dr. Turjman Ext. 6196

Dr. Joyce Ext. 6197

Blood Bank Department

Ms. Misty McClanahan

Blood Bank Section Leader

Ext. 5144