Mad cow disease prions can be removed from blood

New research results released today confirm that infectious variant Creutzfeldt-Jakob Disease (vCJD) prions that cause the human form of "mad cow disease" can be removed from blood.

The study, presented today at the annual meeting of the AABB, found that a new filtration technology from Pall Corporation reduces infectious vCJD prions from red blood cell concentrates, the most commonly transfused blood component.

The study, conducted at a leading prion research institute in Europe, found that the Pall Leukotrap® Affinity Prion Reduction Filter reduces infectious vCJD prions from red blood cell concentrates below the limit of detection of the Western blot assay. The investigators concluded that these results suggest that the new filter can be used to remove different strains of infectious prions, including vCJD.

Samuel O. Coker, Ph.D., Principal Scientist and Technical Director of Pall Medical, who presented the results also reported on the newest findings of additional research, conducted with the New York Institute of Basic Research, confirming that the same technology reduces infectious scrapie prions from blood. Both vCJD and scrapie are transmissible spongiform encephalopathies (TSEs) that cause fatal, neurorodegenerative prion diseases in humans and animals.

"The outcomes of these new studies are fortuitous in respect to the recent cases of transfusion-transmitted vCJD. The possibility of further increases in the number of human cases is of an uncertain magnitude, and the adverse impact that current donor deferral measures has on availability of the blood supply creates a serious public health issue" says Eric Krasnoff, Chairman and CEO, Pall Corporation. "We are moving forward as quickly as possible so that this new technology can be made available worldwide. This is part of our ongoing commitment to blood safety and our ongoing prion research program."

There have been two probable cases of human-to-human vCJD transmission via blood transfusions reported in the past year. Since there are no clinical signs or symptoms of the disease for many years, and the only reliable tests to determine who has the disease are performed post-mortem, there is no way of knowing how many people may be harboring vCJD and donating blood.

These events have spurred increasing concern about the possibility of a second and bigger wave of mad cow disease in humans. Public health officials and risk assessment experts believe that the problem is not limited to the UK, where a majority of the early cases of vCJD have been identified, or to Europe, but is a potential global threat that includes the U.S. and Canada. They urge that in addition to maintaining existing precautionary measures, additional risk assessments should be conducted for blood products in the U.S.

Reduction of vCJD and other TSEs from Blood The study of vCJD used human red blood cell concentrates contaminated with about 108 infectious units of human vCJD from transgenic mice. The concentration of infectious vCJD prions in the red cell concentrates was measured before and after filtration with the Pall Leukotrap Prion Affinity Reduction Filter using a Western blot assay.

The research with infectious scrapie prions was a follow-up study that evaluated the efficacy of the filter to determine whether a test group of animals receiving the filtered red blood cells had the prion disease versus a control group that received the unfiltered red cells. The study confirmed that three (3) of the animals in the control group, which received the unfiltered scrapie infected blood, contracted scrapie as determined by post-mortem autopsy. None of the test group, which received the filtered blood, was found to have scrapie. Of the three controls where scrapie was confirmed, only two had previously displayed clinical symptoms of the disease. No animals in the test arm had any clinical signs of the disease.

"This latest research further confirms results from previous infectivity studies where it was found that this new technology removes TSE-infected prions below the limit of detection of the Western blot assay," said Dr. Coker. "We are excited and optimistic about these results because it brings us much closer to helping ensure the safety of blood transfusion and preventing this insidious and devastating disease from escalating."

The Leukotrap Affinity Prion Reduction Filter's innovative proprietary technology is designed to provide the dual benefit of reducing both leukocytes (white blood cells) and infectious prions -- cell-associated and non-cell associated -- in a single step. About 60 percent of prion infectivity in blood resides in leukocytes (cell-associated) and about 40 percent in plasma (non-cell associated). The new filter also has an affinity to all types of prions including aggregated, denatured and normal.

Pall expects to launch the new filter in Europe in early 2005 with a Council of Europe (CE) mark. It is also developing a dossier and documentation to meet regulatory requirements for submission to the U.S. Food and Drug Administration in midyear 2005. Additionally, the Company is studying the filter as a device to aid in the detection of bovine spongiform encephalopathy (BSE) in cattle before entering the food supply.

The new filter is an integral component of the Pall Life Sciences technology platform, which provides several products to enhance the safety of the world's blood supply. Pall is the global leader in leukocyte reduction technology and also provides the enhanced Bacterial Detection System to test platelets for contamination prior to transfusion. The Company also provides products to remove infectious agents including viruses, bacteria and prions from biologicals used for the manufacture of medicines.