"The availability of our prion reduction filter is a seminal event heralding a new era in blood safety," says Eric Krasnoff, Chairman and CEO of Pall Corporation. "We are working very closely with health authorities, starting with the nations hardest hit by vCJD, to help protect the safety of the blood supply and prevent the spread of this insidious disease."
The new prion reduction filter will be evaluated by the United Kingdom (UK) National Blood Service and the Irish Blood Transfusion Service with results expected to be available later this year or in early 2006. Of the 40 million red cell units collected annually across the industrialized world, 2.5 million are collected in the UK and 130,000 in Ireland.
Since the first human case of vCJD was identified in the UK in 1994, there has been a total of 172 cases worldwide in Ireland, France, Italy, the Netherlands, Canada, the United States (US), Japan and Saudi Arabia, with the vast majority (155) in the UK. Since vCJD can be asymptomatic for about 10 to 16 years, there is no accurate way to determine how many people could currently be harboring the disease or the magnitude of future cases. Variant CJD is transmitted by eating contaminated beef and may also be transmitte d by a contaminated blood transfusion.
Dr. Adrianno Aguzzi of the Institute of Neuropathology, University Hospital of Zurich, and one of the pre-eminent prion biologists in the world says, "There have been two probable cases of human-to-human vCJD transmission via blood transfusion. Since there are no clinical signs or symptoms of the disease for many years, a proportion of the UK population could be incubating vCJD and acting as blood donors. The most direct action to reduce the risk of transmission may come from new methods to provide prion protection."
The Leukotrap Affinity Prion Reduction Filter removes all types of prions in addition to leukocytes (white blood cells) from red blood cells. Prions can be either cell-associated (on white blood cells) or non-cell associated. Studies with the new prion filter show that it removes 99.9 percent of the infectious agent from red cells.
A filtration approach to prion protection offers significant advantages over other potential technologies. Filtration is currently an integral part of standard blood processing and handling in the UK and many other countries. This enables easier and more cost effective implementation of the new prion reduction filter into established good manufacturing practices.
Unlike pathogen inactivation, the new filter does not rely on chemical additives, which could damage or compromise the therapeutic value of a blood transfusion such as the oxygen carrying properties of red cells. A filtration approach also avoids the ethical issues associated with diagnostic testing, such as alerting a blood donor that he or she has an invariably fatal disease. Regardless, there are no available diagnostic tests sensitive enough to identify asymptomatic vCJD infected people.
Measures to Safeguard the Blood Supply
Since vCJD emerged, the UK has taken steps to reduce the risk of food-borne infections from consumption of contaminated bovine produc ts. In 1999, the UK also instituted universal leukocyte reduction of blood to prevent the transmission of cell-associated vCJD prions. The UK also defers donors who have previously received a blood transfusion. Unfortunately, transfusion recipients are often the people most motivated to donate blood.
Other nations around the globe have implemented safeguards similar to those enacted in the UK including leukocyte reduction and donor deferral. Many nations ban blood donations from people who lived or visited countries where BSE infected cattle have been found.
These donor deferral measures have put increased pressures on the availability of adequate supply of blood for transfusion. As the donor population becomes even more limited with each additional residency deferral, it further reduces the potential number of people giving blood and can result in serious blood shortages.
Despite all these safeguards, the risk of vCJD transmission via blood transfusion has not been eliminated. There is no cure for vCJD and treatment is palliative to reduce patient suffering.
Janet Gibbs, Chair of the Human BSE Foundation whose daughter died from vCJD says, "Knowing the devastating effect that vCJD can have, the Human BSE Foundation fully supports any innovations that could potentially save anyone from the suffering we had to endure." She also notes that although we should hope for the best, we must prepare for the worst and take every measure available today to safeguard the blood supply.
Pall Corporation developed the Leukotrap Affinity Prion filter to help blood authorities around the world stop the transmission of prions as part of the Company's mission to ensure the safety of the global blood supply. The adoption of the new prion reduction filter has the potential to support the global need for adequate supplies of safe blood for the benefit of the public health. Pall is continuing its prion research and development program to apply its t echnologies to meet the specific requirements of each nation throughout Europe, followed by Canada and the US. The Company is also developing an ante mortem test to detect infectious prions in cattle prior to entering the food supply.