Current position on preparation and quality of leucodepleted platelet concentrates for clinical use.

Double dose leucodepleted PC without filtration is considered to be the most cost-effective way of preparing leucodepleted PC in a reasonable time. The procedure lends itself to a multicomponent system and production of hyperconcentrate and dry platelets, with < 10-15 ml plasma in final product and viral inactivation without considerable loss of in vitro platelet functions. Platelet concentrates obtained by various procedures are highly heterogeneous, even if a standard protocol is used for the preparation. Therefore, standard/standardisation in both production and testing procedures remain a challenging area in order to obtain comparative results. Attention needs to be focused on growing and complex technical features of preparation and on the use of new filter material in terms of biocompatibility and the related effects of activated factors on function of platelets and leucocytes. Both the production process and storage containers appear to contribute to various cellular lesion and generation of some biological response modifiers such as complements, cytokines and microparticles. In this respect it is relevant to adopt a multiparameter analysis for the validation of platelet quality as some markers of platelet storage lesion have different affinity to various surfaces, leading to false under estimation. Further development work is still needed in preparation and usage of dry platelet, platelet alternative and bacterially safe products. The underlying conditions of the transfused patients is also an important issue in this respect, it is interesting to note that patients with high IL8 levels have a substantially lower platelet recovery.