Pergamon PlI: S095S-3886(96)00045-8 TranMus. Sc/.,Vol. 17, No. 4, pp. 489-492, 1996 © 1997 ElsevierScience Ltd. All rights reserved Printed in Great Britain 0955-3886]96 $15.00* 0.00 Modification of Activation- dependent Platelet Antigens CD62p and CD63 During Haemodialysis K. Gutensohn, MD*~: A. Sputtek, MD* A. Voss, MDt R. A. K. Stahl, PhDt P. Kuehnl, PhD* • In particular, activated platelets are thought to be involved in the patho- physiology of thrombotic occlusions of vessels. In this study, we evaluated acti- vation-dependent changes in platelet antigens during extracorporeal haemo- dialysis treatment. Flow cytometry was used in combination with monoclonal antibodies that bind to platelet glyco- proteins CD62p (GMP-140) and CD63 (GP53). Maximum peaks of mean chan- nel fluorescence intensity (MCFI) were reached after 60 min in 20/25 proce- dures in CD62p (p<0.005) and in 15/25 treatments in CD63 (p<0.002), respec- tively. An initial peak of CD62p and CD63 fluorescence expression could be detected in 21/25 and 23/25 treatments, respectively (CD62p within 15, CD63 within 30 min), indicating the early onset of activation. The structural anti- gen CD41a MCFI slightly decreased over time in all treatments, while CD42b expression did not change. From these results we conclude that haemodialysis contributes to platelet activation and secondary hypercoagulability. Analysis of platelet glycoproteins by flow cytome- try may provide clinical information on patients at a higher risk for thrombosis "Department of Transfusion Medicine/Transplantation Immunology, University Hospital Eppendorf, University of Hamburg, Martinistrasse 52, 20246 Hamburg, Germany. tDepartment of Nephrology, University Hospital Eppendorf, University of Hamburg, Martinistrasse 52, 20246 Hamburg, Germany. ~tAuthor for correspondence. and may help in further improvement of haemodialysis equipment. © 1997 Elsevier Science Ltd. • 489 INTRODUCTION In patients with end-stage renal disease (ESRD) haemostatic disorders are pre- sent.l Bleeding tendencies and hyperco- agulable states may occur and both seem to be related to the underlying dis- ease and the severity of the illness. Before the development of a thrombotic event, numerous studies have postu- lated that a hypercoagulable state exists for a period of time. 2 Platelets play a key role in bleeding disorders and thrombo- sis of arterial and venous vessels. '~When stimulated, platelets become highly reactive and may promote this pre- thrombotic potential. 4 Fluid shear stress and contact of blood with artificial surfaces influence human cells, particularly blood platelets. 4 As during haemodialysis blood passes through the extracorporeal circuit, haemo- static abnormalities may be triggered. With flow cytometry, the analysis of large numbers of cells has become possi- ble at a single-event level. '~ In combina- tion with monoclonal antibodies this method provides insight into antigenic changes of platelet surface glycoproteins. We therefore examined the influence of