Cytokines in platelet concentrates prepared from pooled buffy coats

Platelet concentrates (PC) prepared from pooled buffy coat (BC-PC) contain a variable number of leukocytes from different donors. We questioned whether storage of BC-PC can lead to a lymphocyte activation in the sense of a mixed lymphocyte reaction. BC-PC were prepared from four ABO-identical buffy coats and we undertook leukocyte analyses and measurement of different cytokines on days 1, 3 and 5 of PC storage (n = 72). Cytokine content was also determined in freshly prepared plasma (n = 48) and PC prepared by thrombapheresis (SD-PC) (n = 12). As control, we studied lymphoproliferation of pooled peripheral blood mononuclear cells from four individuals in 10 mixed lymphocyte cultures (MLCs) under optimal conditions. In the BC-PC, whole blood count and lymphocyte analysis showed a mean leukocyte contamination of 64 +/- 28 x 10(6) per unit with a proportion of lymphocytes of 66.7 +/- 13%. In the MLC, levels of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were increased on day 3 and 5 of storage (p < 0.001). In a proportion of BC-PC, tumor necrosis factor-alpha (72.2%) and IL-2 (43.1%) were detectable immediately after preparation, whereas IFN-gamma (4.2%), interleukin-1 beta (4.2%) and interleukin-8 (11.1%) were only found in some BC-PC. In all cases, initial values of cytokines did not increase during storage. Cytokine measurement in FFP and SD-PC showed similar results. The study demonstrates that cytokines are detectable in a variety of blood products immediately after preparation.(ABSTRACT TRUNCATED AT 250 WORDS)