LEUKOCYTE PROTEINASE RELEASE DURING STORAGE OF RED-CELL CONCENTRATES

The release of polymorphonuclear leukocyte proteinases in buffy-coat-d epleted red cell concentrates was examined during a storage period of 35 days. Collagenase, gelatinase and elastase predominantly induce bre akdown of connective tissue. However, when released by cell disintegra tion during red cell concentrate storage, the considerable proteolytic activities of these enzymes might influence the quality of the stored blood. During the observation period a considerable decrease in the p olymorphonuclear leukocyte count was observed, accompanied by increase s in the levels of collagenase, gelatinase and elastase. Compared with the enzyme levels on the day of red cell concentrate preparation, col lagenase increased 20-fold, gelatinase 6-fold and elastase 100-fold du ring the storage period. When cells were treated with the chemoattract ant hexapeptide, N-formyl-nle-leu-phe-nle-tyr-leu, and the degranulati on promoting cytochalasin B, gelatinase exhibited the highest secreted concentration in the freshly prepared red cell concentrate, exceeding the maximum of spontaneously released elastase by 4- to 6-fold. Howev er, these compounds stimulated enzyme release only during the first da y after red cell concentrate preparation. Thereafter, no differences b etween stimulated and non-stimulated samples were observed. The data i ndicate that polymorphonuclear leukocytes contain a large storage pool of proteolytic enzymes. These enzymes together with other polymorphon uclear leukocyte enzymes, e.g. hydrolases and oxidoreductases, might a lter the erythrocyte membrane surface and thus influence the storage q uality of the prepared red cell concentrate.