Blood Processor Blocks DNA Replication, Making Platelets Safer

A blood product processing system uses a psoralen molecule for effective pathogen inactivation, thus controlling the safety of platelets and plasma in blood centers and hospital blood banks.

The Intercept blood system offers inactivation for a broad range of viruses (both enveloped and non-enveloped), bacteria, and protozoa (intracellular and extracellular), as well as leukocytes. The system employs the unique properties of a specially developed molecule, amotosalen HCl, to block irreversibly the replication of DNA and RNA, preventing the proliferation of susceptible pathogens. The interaction of amotosalen with DNA and RNA is highly specific and occurs with high frequency even at low concentrations of nucleic acids. Once inside a pathogen, amotosalen docks in between the nucleic acid base pairs; upon illumination with ultraviolet A (UVA) light, an interstrand crosslink is formed, "locking” the DNA or RNA together so that it can no longer replicate; the reaction requires UVA light and will not continue in its absence. The platelets and plasma are not inactivated by the crosslinking process, since they do not require nucleic acids for their therapeutic functions. Prior to transfusion of the stored blood products, a removal process reduces residual amotosalen to trace levels.

The system uses one illumination device for treating both plasma and platelets, with the same process and same active compound; it is designed for high throughput, capable of processing of up to 36 plasma units per hour per UVA illuminator, with a total of less than 10 minutes total hands-on time. Synergy with the platelet treatment further improves efficiency for blood centers performing both processes, allowing over 20 combined units per hour of platelets and plasma from whole blood and apheresis collections. The Intercept blood system is a product of Cerus (Concord, CA, USA).

"We commend the Belgian government on its leadership within the field of transfusion safety, which now includes becoming the first country to require pathogen inactivation of both platelets and plasma for transfusion,” said Dr. Laurence Corash, senior vice president and chief medical officer of Cerus, commenting on a Belgian Royal Decree issued mandating universal use of pathogen inactivation for platelets no later than August 2010. The Intercept blood system has been used in Belgium since 2003 for treatment of platelets, and since 2007 for treatment of plasma.

Amotosalen belongs to a group of photoactive compounds called psoralens, which possess a characteristic three-ring fused structure. Naturally occurring psoralens can be found in a variety of plants and foods such as limes, celery, and parsnips. Reports of the medicinal use of psoralens to treat vitiligo and psoriasis in India date back to about 1400 BC.

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