FDA Meets on Blood Filtration Mandate

N E W   Y O R K, Jan. 25 -- In all likelihood, you don't know about leukocytes or why you should worry about them, but government health officials are meeting this week to discuss filtering them from the national blood supply.

So, what are they and why would we want to get rid of them?

Leukocytes are white blood cells that are part of the immune system and help fight off foreign substances in the body, such as bacteria, viruses and abnormal cells. But since leukocytes are personalized for each individual's body, they can cause adverse reactions in blood transfusion recipients, such as chills, fever and shaking.

Adverse reactions affect about 150,000 patients a year, and can occur regardless of the type of blood transfusion a patient receives. There are three kinds of transfusions: red blood cells to restore blood volume, platelets to help clot blood and plasma to replace fluids. Leukocytes are found in all three types of transfusion if unfiltered.

Foreign leukocytes in a patients' blood can also make their immune systems reject future transfusions. The new white blood cells form an antibody that makes an immune system sensitive to further foreign invasions.

While the adverse reactions from foreign leukocytes are not life-threatening, they are impossible to anticipate unless a patient has already received blood transfusions. Currently, it is up to individual doctors to decide whether a patient should receive leukoreduced blood, and many hospitals only offer filtered transfusions to very sick patients. Rhode Island is the only state with a universal blood filtering policy.

Many experts agree, however, that universally filtering leukocytes from the national blood supply is safer for patients and could reduce length of hospital stays, ultimately lowering public health expenses.

"The American Red Cross believes that all patients should be able to avoid unforeseen adverse reactions to transfusion, and they should not be limited in their ability to access a safer, purer product," Jacquelyn Frederick, executive vice president of American Red Cross Biomedical Services, told a Food and Drug Administration advisory committee today.