Bugs in the blood

By Stephaine L. Perry, M.D., and Thomas L. Ortel, M.D.,Ph.D.

The American Society of Hematology has been holding annual meetings since about 100 hematologists first met in 1958. The American Association of Blood Banking was established in 1947, and the 57th Annual Meeting of AABB was held here in San Diego earlier this year. Today, in the first Joint Educational Session by ASH and AABB (4:15 p.m. – 6:00 p.m.), the speakers will address the “magnitude and clinical relevance” of Bacterial Contamination of Blood Components. This session will cover the (1) risks of transfusion complications, (2) strategies to decrease bacterial contamination, and (3) regulatory approaches to address this important concern.

The realization that viral diseases such as human immunodeficiency virus, hepatitis C, and hepatitis B were being transmitted through transfusions led to screening the blood for these viruses. Now that these viral transmissions have declined through rigorous screening procedures, the risk of recipients receiving a blood product contaminated by bacteria is now an increasing concern among the blood banking community.

The first speaker, Dr. Christopher D. Hillyer from Emory University Hospital, will discuss the risk of bacterial contamination in the cellular blood components, with emphasis on the problem encountered in platelets. Platelets are stored at room temperature, increasing the potential for bacterial contamination. Dr. Hillyer will point out the offending “bugs” and their potential sources. The signs and symptoms of “transfusion-associated sepsis” will also be outlined which will help clinicians better identify and report this often unrecognized cause of morbidity and mortality.

In the second part of this session, Dr. Morris A. Blajchman from McMaster University will relay the different approaches to prevent and detect bacterial contamination, with the ultimate goal of decreasing the exposure to transfusion recipients. The different methods range from simple techniques of improving ‘skin disinfection’ to the more complicated task of “pre-transfusion detection” of bacteria. Novel approaches using photodynamic or photochemical methods to reduce not only bacteria, but also viruses and protozoa will also be discussed.

The third speaker, Dr. Jaroslav Vostal, from the Food and Drug Administration (FDA) will address the efforts that both the FDA and the blood industry have made to decrease the bacterial contamination of blood components and to increase the detection rate prior to transfusion. Dr. Vostal will present data on the FDA-approved devices to decrease the risk of contamination during blood collection as well as “bacterial detection devices.” Additionally, safety and efficacy concerns of these devices and of “pathogen reduction technologies” will be discussed.

In addition to today’s “Joint ASH and AABB Educational Session,” this problem will be discussed again Sunday, December 7th, from 7:30 a.m. – 9:15 a.m. For related issues of “bugs in the blood” the reader is referred to two important abstracts to be presented during the Simultaneous Session in Transfusion Medicine on Monday, December 8th from 7:30 a.m. – 9:00 a.m. The recognition of West Nile Virus transmission through blood transfusion and organ transplant and the subsequent implementation of nucleic acid amplification technology to detect this virus in human blood will be reported on in Abstract #4867 (Presenter: S. Caglioti). In addition, using a murine model, the role of monocytes in the transmission of cytomegalovirus is evaluated in Abstract #5164 (Presenter: Dr. C Hillyer).