Pathogen Reduction and Alloimmunization

Pathogen reduction is a technology developed to kill undetected pathogens found in blood products using photo-activators and UV light to permanently damage any DNA present in the blood product. This treatment was also shown to impact white blood cells in these products, not only killing them, but also making them less immunogenic in a mixed lymphocyte reaction. We demonstrated this loss of immunogenicity includes not only a failure to stimulate proliferation, but also a failure to stimulate any sign of activation in allogeneic T cells due to a down regulation of key adhesion molecules on the surface of treated cells that prevents productive interaction with allogeneic T cells. We have also been able to show that this treatment prevents alloimmunization from occurring in vivo and may even offer some tolerogenic signals protecting recipients from all responses to subsequent exposures.