Functional WBCs in blood components may be responsible for a number of adverse transfusion effects, including alloimmunization and alloimmune platelet refractoriness. Attempts to reduce these undesired effects have used WBCs reduction filters and γ-irradiation. Previous studies have shown that exposure of platelet concentrates to riboflavin and light (Mirasol PRT treatment) causes irreparable modification of nucleic acids that results in inactivation of a wide range of pathogens as well as inhibition of the immunological responses mediated by the WBCs present in platelet concentrates. This study evaluated the ability of Mirasol PRT treatment to prevent alloimmunization and to modify the immune response to transplanted tissue in rats. Over a 10 week period, test animals (Lewis rats) received 8 transfusions of untreated or Mirasol treated platelet products containing leukocytes from DA rats. A third group of animals received saline injections. Antibody levels (IgG, IgM) in the recipient animals were monitored weekly. Animals were subsequently challenged with heart transplant under cyclosporine treatment to assess the effect of Mirasol PRT treatment on presensitization and transplant rejection. The IgM and IgG response in rats that received Mirasol PRT treated platelets was almost completely abolished compared to animals that received untreated platelets (see Figure below). In preliminary experiments, animals that mounted an IgG response also rejected the subsequent heart transplant. In summary, Mirasol PRT treatment prevented the development of an Ig response in transfused animals. This inhibition of an Ig response, in particular IgG, shows that Mirasol PRT treatment prevents alloimmunization. The inability to reject the heart transplant in the absence of an IgG response indicates that Mirasol PRT treatment may be effective in preventing alloimmune refractoriness to platelets and presensitization to transplants.
Disclosures: Drs Marshner and Goodrich are emplyed by Navigant Biotechnologies that developed Mirasol Pathogen Reduction Technology.; Dr Baldwin consutls with Navigant Biotechnologies that developed Mirasol Pathogen Reduction Technology.; Drs. Asano, Lee and Baldwin receive research funding from Navigant Biotechnologies that developed Mirasol Pathogen Reduction Technology.; Drs. Asano and Baldwin receive travel funding from Navigant Biotechnologies that developed Mirasol Pathogen Reduction Technology.; Dr Goodrich is the chief scientific officer of Navigant Biotechnologies that developed Mirasol Pathogen Reduction Technology.