Adverse effects of transfusions caused by leukocytes.

The tremendous complexity of blood products gives rise to a range of adverse reactions. Transfusion reactions caused by leukocytes range from subtle and discomforting to dramatic and fatal. Although leukocyte-mediated events usually are harmful, some effects are beneficial. Leukoreduction can prevent most, but not all, adverse reactions. Awareness of the array of leukocyte-mediated transfusion complications and the appropriate preventive and therapeutic measures to be taken is a critical component of sound clinical transfusion practice.