Leukoreduction

Leukoreduction is the removal of white blood cells (or "leukocytes") from the blood or blood components supplied for blood transfusion. After the removal of the leukocytes, the blood product is said to be "leukoreduced".

Benefits and costs

It is theorized that transfusions which contain white blood cells may cause adverse effects through multiple mechanisms. White blood cells may themselves harbor infectious disease and some pathogens will be more concentrated in white blood cells than the rest of the blood product. It is also theorized that the donor white blood cells may suppress the recipient's immune system by interacting with it.

An April 2007 meta-analysis by Dr. Neil Blumberg and others and covering 3093 patients who received leukoreduced blood was published in the scientific journal Transfusion. According to the meta-analysis, use of leukoreduced blood reduced the frequency of post-transfusion infection by 50%. cite journal|journal=Transfusion|month=April | year=2007|title=The intention-to-treat principle in clinical trials and meta-analyses of leukoreduced blood transfusions in surgical patients|author=Blumberg N, Zhao H, Wang H, Messing S, Heal JM, Lyman GH|volume=47|issue=4|pmid=17381614|pages=573–81|doi=10.1111/j.1537-2995.2007.01158.x] In a previous study, Blumberg and others reported that a change to universal use of leukoreduced blood at Strong Memorial Hospital at University of Rochester reduced post-transfusion infection by 33-45%. [cite journal|journal=Transfusion|month=October | year=2005|title=Decreased sepsis related to indwelling venous access devices coincident with implementation of universal leukoreduction of blood transfusions|volume=45|issue=10|author=Blumberg N, Fine L, Gettings KF, Heal JM|pmid=16181215|pages=1632–9|doi=10.1111/j.1537-2995.2005.00565.x]

However, other scientific studies question the effectiveness of leukoreduction. A March 2007 study by researchers at University of South Alabama Medical Center found no reduction of mortality or length of hospital stay in 439 trauma patients who received leukoreduced transfusions compared to 240 patients who did not.cite journal|journal=Journal of Surgical Research|title=Leukoreduction before red blood cell transfusion has no impact on mortality in trauma patients|author=Phelan HA, Sperry JL, Friese RS|month=March | year=2007|volume=138|issue=1|pmid=17161430|pages=32–6|doi=10.1016/j.jss.2006.07.048] University of Washington researchers reported in October 2006 that a study of 286 transfused injury patients showed no reduction in mortality or length of stay, although a 16% reduction in rate of infection was shown with marginal statistical significance.cite journal|journal=Shock|month=October | year=2006|title=The effects of leukoreduced blood transfusion on infection risk following injury: a randomized controlled trial|author=Nathens AB, Nester TA, Rubenfeld GD, Nirula R, Gernsheimer TB|volume=26|issue=4|pmid=16980879|pages=342–7|doi=10.1097/01.shk.0000228171.32587.a1]

Leukoreduction has the inadvertent effect of removing approximately 10% of red blood cells from a processed unit of Red Blood Cells.cite web|url=http://www.nytimes.com/2001/01/28/health/28BLOO.html?ex=1176091200&en=e7c57579415fdef5&ei=5070|title=Donated Blood Needs Filtering, Panel Advises|publisher=New York Times|date=January 28, 2001|accessdate=2007-04-07|author=Associated Press] Because blood from persons who possess the Sickle cell mutation is difficult to filter, leukoreduction is often not performed on donors who may have the sickle cell gene, which is most common in people of African descent.

Dr. Blumbeth, the lead author of the meta-analysis covering 3093 patients, stated in the press that the cost savings due to universal leukoreduction exceed the cost of performing the leukoreduction.cite web|url=http://www.sciencedaily.com/releases/2007/04/070403134553.htm|title=Transfusion Expert Urges Wider Use Of Filtered Blood|accesseddate=7 April 2007|date=April 5, 2007|publisher=Science Daily|author=University of Rochester Medical Center] The cost of leukoreduction is an increase of approximately US$30 per unit of blood product.

History of availability

Universal leukoreduction is currently not practiced in all countries.

As of 2005, most developed nations have adopted universal leukoreduction of transfusions with the notable exception of the United States. Canada, Britain and Franceadopted universal leukoreduction in the late 1990s. Leukoreduced products are commonly available in the United States and some hospitals use only leukoreduced blood while others only use leukoreduced products in certain patient populations. For example, Strong Memorial Hospital began universal use of leukoreduced blood in July 2000; University of South Alabama Medical Center began use in January 2002.Woodlands Medical Centre is beginning a randomised controlled trial to look into the benefits of transfusing leukoreduced whole blood for the ICCU patients.

Notes