INFLUENCE OF A 12-HOUR, 22-DEGREES-C HOLDING PERIOD FOR BUFFY COATS ON THE PREPARATION OF PLATELET CONCENTRATES STORED IN PLASMA

Background: The preparation of platelet concentrates (PCs) from buffy coats (BCs) stored at room temperature is controversial, because of th e strong metabolic activity of cells in BCs and the possible detriment al effect of neutrophil enzymes on platelets when the holding time bef ore separation is prolonged. Despite good in vitro and in vivo behavio r of BC-PCs stored in synthetic solution, little is known of the quali ty of BC-PCs stored in plasma. Study Design and Methods: Comparison wa s made of PCs prepared from BCs held at 22 degrees C for 3 hours (3-ho ur BC-PCs) or overnight (12-hour BC PCs) and stored in plasma. Platele t and white cell counts, pH, response to osmotic shock, and morphologi c scores were determined on 20 PCs of each type. The decrease in dense granule and alpha granule content, a marker of platelet activation, w ere estimated by mepacrine counting and beta-thromboglobulin measureme nt, respectively (n = 8-10). Platelet function was studied in terms of aggregation and thromboxane production in response to various concent rations of collagen and thrombin (n = 8-17). PCs prepared from unstore d BCs (n = 15) and from BCs held for 90 minutes (n = 15) were used as controls. Results: Platelet yield was increased from 53 +/- 10 percent of donated platelets to 73 +/- 4 percent by increasing the BC holding time from 0 to 90 minutes to 3 hours (p<0.001). Similar yields (7.8 /- 1.8 vs. 7.9 +/- 2 x 10(10) platelets) and white cell contamination (0.9 +/- 0.8 vs. 1.0 +/- 0.9 x 10(7)) were obtained with 3-hour and 12 -hour BC-PCs. At the end of the storage period (Day 5), all variables known to correlate with platelet survival in vivo were well maintained in both 3-hour and 12-hour BC-PCs: pH greater than or equal to 6.9, r esponse to osmotic shock greater than or equal to 70 percent, and morp hology Scores always greater than or equal to 240. During storage, the dense granule content decreased moderately (30% after 5 days), whatev er the conditions. By contrast, the total platelet beta-thromboglobuli n content was better preserved in 12-hour BC-PCs than in 3-hour BC-PCs (p<0.04). No significant differences were observed in collagen-induce d aggregation and thromboxane production in the two PC preparations. H owever, aggregation responses to thrombin were higher in 12-hour BC-PC s on Day 5 of storage (p<0.01). Conclusion: BCs can be held at 22 degr ees C for up to 12 hours, with no detrimental effect on the quality of PCs stored for up to 5 days in plasma. Such a holding time might help overcome logistic problems in blood banks.