LEUKOCYTE DEPLETION AND STORAGE OF SINGLE-DONOR PLATELET CONCENTRATES

Background and objectives: Because of widespread use of leukocyte redu ction in platelet concentrates (PCs) and the need to store such concen trates, we investigated the effects of leukocyte depletion on the qual ity of stored PCs. Materials and methods: Ten double-sized PCs were di vided into 2 equal units which were tested simultaneously. One half wa s stored for 5 days after filtration through a polyester filter, the o ther one was stored unfiltered. Results: The volume of the 10 'oversiz ed' PCs was 483+/-40 ml (mean+/-standard deviation) and they contained 5.9+/-1.5x10(11) platelets and 80+/-23x10(6) leukocytes. Filtration s ignificantly reduced the leukocyte concentration (168+/-56/mu l before , 6+/-4/mu l after filtration) and leukocyte count (39.9+/-11.3x10(6) vs. 1.3+/-0.9x10(6) p<0.0005). Filtration caused a platelet loss of 16 %, the platelet count decreasing not significantly from 2.91+/-0.75x10 (11) to 2.40+/-0.94x10(11) (p=0.26). After 5 days of storage all param eters of platelet function (platelet aggregation to several stimuli, h ypotonic shock reaction [HSR] and platelet retraction), mean platelet volume, and pH and pCO(2) showed no advantage for PCs filtered prior t o storage compared to PCs stored unfiltered. Moreover, platelet aggreg ation on day 5 using 4 agonists at 10 concentrations shelved worse res ults in 4 assaps in prestorage filtered PCs (collagen [4 mu g/ml: p<0. 05, ADP [0.2 mM]: p<0.05, ADP [0.3 mM]: p<0.05, thrombin [0.6 E/ml]: p <0.05). But there is no convincing trend in all aggregation tests, and HSR, presumably the most useful parameter, was not different on day 5 . Conclusions: There is so advantage in terms of improved duality for prestorage leukodepletion of PCs. Taking into account the obvious disa dvantages of filtration, such as platelet loss and increasing costs pe r transfusion, we conclude that pre- or post-storage filtration of sin gle-donor PCs should be done only for patients who have a clear indica tion for the transfusion of leukocyte-poor blood products.