Creutzfeldt-Jakob disease is the most well-known of a group of rare, degenerative brain disorders called transmissible spongiform encephalopathies. TSEs, also referred to as prion diseases, are characterized by the presence and long incubation period of an infectious agent that attacks the brain, causing affected areas to take on a sponge-like appearance. Approximately one case of CJD is reported globally per million people each year.
There are three main types of CJD — sporadic, familial and infectious. Sporadic CJD accounts for approximately 85 percent of cases, and in the majority of these cases, the mode of infection is unknown. Ten to 15 percent of cases are familial, while infectious — or acquired — CJD accounts for less than 1 percent of CJD cases and is transmitted by exposure to infected brain or nervous system tissue. Although no case of transmission of CJD through blood transfusion or blood derivative has been documented, there remains a theoretical possibility that it could occur based on experimental studies in animals. As a precaution, FDA prohibits blood donation by individuals who may be at risk for CJD.
A similar disease, variant CJD, is commonly known as the human form of "mad cow" disease because it has been linked to the consumption of beef products from cattle infected with bovine spongiform encephalopathy. Most cases of vCJD have appeared in the United Kingdom, where a small number of transfusion-transmitted cases also have been reported. The risk of vCJD posed by plasma-derived blood products also is most likely to be extremely small, based on results of a risk assessment conducted by the U.S. Public Health Service and the fact that no cases of vCJD have been reported despite decades of use by patients with hemophilia and von Willebrand disease. In a single case in the U.K., plasma derivatives might have been implicated.
While a number of manufacturers are working on assays that could be used to diagnose and screen for TSEs, no FDA-approved screening test currently exists for CJD or vCJD. One alternative to testing that is being explored is filtration technology to remove the prions from blood components.
On behalf of the transfusion medicine and cellular therapies community, AABB works directly with the FDA and through government advisory committees as part of an ongoing, collaborative effort to protect against the transmission of CJD and vCJD through the blood supply and human cells, tissue, and cellular- and tissue-based products. Please refer to the Blood Donor History Questionnaire webpage for flowcharts and the vCJD countries of risk that provide assistance in establishing donor eligibility.
FDA released a final guidance, “Revised Preventive Measures to Reduce the Possible Risk of Transmission of Creutzfeldt-Jakob Disease and Variant Creutzfeldt-Jakob Disease by Blood and Blood Products,” for implementation. It amends the 2010 guidance (the previous guidance for blood products) and finalizes the 2012 draft guidance (relevant to plasma derivatives) by providing revised labeling recommendations for plasma-derived products, including albumin and products containing plasma-derived albumin.