Filter design sifts deadly prions from blood supply
08/01/2004
BY STEVE SMITH
EAST HILLS, N.Y.—For the second time this summer, a major advance has been unveiled in the battle against infectious prions associated with Mad Cow Disease, Creutzfeldt-Jakob Disease (vCJD). The latest, announced last month by Pall Corp. (www.pall.com), is a proprietary filter technology that's said to reduce deadly prions from the blood supply before it is used for transfusions.
Earlier this summer, Serologicals Corp. (Atlanta, Ga.; www.serologicals) was granted a patent on its proprietary purification process that clears the Mad Cow prions from bovine-based pharmaceuticals. More than 60 percent of pharmaceuticals on the market have involved bovine-based products in their development or manufacture.
Prion transmission via blood transfusion, though reduced in recent years, remains a concern for the public blood supply—particularly overseas. In December 2003, a case of vCJD was identified in a person who received a blood transfusion six years earlier from a donor who later died of the disease. In announcing its breakthrough to the International Society for Blood Transfusion annual meeting, Pall Corp. officials noted that since vCJD has an unknown and lengthy incubation period that is asymptomatic, there is no way to know how many have transmitted the disease via transfusion.
The Leukotrap affinity prion reduction filter, however, is designed to offer a multi-targeted approach to blood safety by reducing leukocytes and infectious prions that are cell or non-cell associated. According to the company, about 60 percent of prions in blood resides in cell-associated leukocytes and about 40 percent in non-cell associated plasma. Pall says its research indicates that the Leukotrap filter has an affinity to all types of prions, including aggregated, denatured and normal.
"We are moving this technology forward rapidly," reports Pall Corp. chairman and CEO Eric Krasnoff. "Blood centers and hospitals will soon be able to combine both prion and leukocyte reduction in a single, simple step."
Pall says it will also investigate broadening the technology to help identify Mad Cow Disease in cattle before it reaches the food supply.
With hopes of introducing the Leukotrap filter to hospitals by early next year, Pall says it expects that its technology will meet the requirements of the Council of Europe and will be ready for operational trials in Europe, where vCJD is most prevalent.
Because a majority of blood transfusions in the industrialized world is leukocyte-reduced, Pall is hopeful that its filtration development can swiftly fit into routine operating practice already in use in blood centers around the world.
Meanwhile, testing on the filter continues. With support from the New York Institute of Basic Research, Pall is studying the Leukotrap filter using Western blot assay, bioassay and animal models of prion disease to validate reduction of the infectious prions. Additional results on the animal model research are expected in the coming months.