Ultraviolet irradiation of platelet concentrates: In Vitro and In Vivo preclinical evaluation

Ultraviolet B (UV-B) irradiation abolishes lymphocyte function in mixed lymphocyte culture (MLC) and could theoretically prevent alloimmunization against HLA class I antigens. We describe a system available in transfusion practice for such a treatment of platelet concentrates (PC). PC obtained from the Haemonetics V50 cell separator or by cytapheresis (Cobe 2997) were evaluated using two irradiators and three different bags: Stericell^TM from DuPont and two bags from Macopharma (PVC MP and EVA MP). The Stericell bag and the EVA MP bags allow a complete abolition of lymphocyte activity without platelet function impairment (as measured by aggregation tests) and without reduction of survival of transfused platelets (autologous or allogeneic). The temperature increase during irradiation is negligible. The time of irradiation is very short (less than 3 min). These results show that the necessary conditions for clinical evaluation of UV-B irradiated patelet concentrates in preventing HLA alloimmunization are obtained.