THE STORAGE LESION OF SINGLE-DONOR PLATELETS - INSIGHTS FROM FLOW CYTOMETRIC ANALYSIS AND TRANSMISSION ELECTRON-MICROSCOPY

Background: During storage, platelets undergo morphological and immuno logical alterations. This study was performed to investigate the influ ence of storage on platelet antigens by flow cytometry and on morpholo gy by electron microscopy. Materials and Methods: Platelet concentrate s (n=24 were prepared by continuous-flow centrifugation plateletpheres is. Afterwards, they were stored in polyvinylchloride (PVC) containers for 7 days. Aliquots were taken daily to examine platelet glycoprotei ns CD41a, CD42b, CD62p, and CD63 by flow cytometry. Every second day, aliquots were drawn for electron microscopic analyses. Results: During storage, the expression of CD62p (P-selectin) and CD63 (gp53) progres sively increased. Mean channel fluorescence intensity (MCFI) for CD62p increased from day 1 to day 7 from 21.3 to 43.4 (p < 0.05), MCFI of C D63 from 19.5 to 29.5 MCFI (p < 0.05). MCFI of CD41a decreased from 1, 165.2 to 1,119.0 and subsequently returned to baseline levels (p < 0.0 5). MCFI of CD42b continuously decreased from 301.6 to 279.7 from day 0 to 7 (p < 0.05). Transmission electron microscopy (TEM) revealed pro gressive platelet activation and destruction. Over the storage period external and internal reorganization became clearly apparent. Conclusi on: During storage of platelet concentrates, antigens and morphology o f platelets are altered. Flow cytometry and TEM provide insights into the storage lesion and are suitable techniques for quality control of platelet concentrates and evaluation of biocompatibility. However, due to the more objective, faster and more sensitive analysis, only now c ytometry may also be suitable for routine applications in quality cont rol.