Bode A P, Knupp C L, Miller D T
Department of Clinical Pathology and Diagnostic Medicine, East Carolina University School of Medicine, Greenville, NC 27858.
J Lab Clin Med. 1990 Jun;115(6):669-79.
Platelet membrane glycoprotein Ib (GPIb) in stored platelet concentrates was analyzed by flow cytometry with three separate monoclonal antibodies (AN-51, 6D1, and SZ-2), by tritiated glycoprotein radiolabeling, and by ristocetin-induced agglutination. Flow cytometry showed that a population of surface GPIb-negative platelets was evident at 5 days and increased three- to fivefold by the tenth day. Tritium radiolabeling of surface GPIb showed a decrease over 10 days of 37% +/- 17%. The degree of loss of surface GPIb correlated well with other changes during storage: decreased ristocetin-induced agglutination, decreased responsiveness in the hypotonic shock test, lower plasma pH, and increased extracellular lactic dehydrogenase. Immunoblotting of total platelet GPIb with the SZ-2 antibody showed a decrease of 58% +/- 16% during the 10-day storage period. The effect of protease inhibitors or platelet activation inhibitors on the loss of GPIb during storage was studied in platelet concentrates paired with untreated controls. Only the platelet activation inhibitors prostaglandin E1 and theophylline retarded the loss of surface GPIb levels (93% +/- 5% GPIb remaining vs 65% +/- 16%). Total GPIb levels also decreased less in the presence of the activation inhibitors (45% +/- 22% lost vs 70% +/- 14% lost). These findings suggest that platelet activation, rather than plasma enzymatic activity, is responsible for the loss of platelet GPIb during storage of platelet concentrates.
采用三种不同的单克隆抗体（AN-51、6D1和SZ-2），通过流式细胞术、氚标记糖蛋白放射性标记以及瑞斯托菌素诱导的凝集反应，对储存血小板浓缩物中的血小板膜糖蛋白Ib（GPIb）进行分析。流式细胞术显示，在第5天时，一群表面GPIb阴性的血小板明显出现，并在第10天时增加了三到五倍。表面GPIb的氚放射性标记显示，在10天内下降了37%±17%。表面GPIb的丢失程度与储存期间的其他变化密切相关：瑞斯托菌素诱导的凝集反应降低、低渗休克试验中的反应性降低、血浆pH值降低以及细胞外乳酸脱氢酶增加。用SZ-2抗体对总血小板GPIb进行免疫印迹分析显示，在10天的储存期内下降了58%±16%。在与未处理对照配对的血小板浓缩物中，研究了蛋白酶抑制剂或血小板激活抑制剂对储存期间GPIb丢失的影响。只有血小板激活抑制剂前列腺素E1和茶碱能延缓表面GPIb水平的丢失（剩余93%±5%的GPIb，而未处理对照为65%±16%）。在存在激活抑制剂的情况下，总GPIb水平的下降也较少（丢失45%±22%，而未处理对照为70%±14%）。这些发现表明，在血小板浓缩物储存期间，血小板激活而非血浆酶活性是导致血小板GPIb丢失的原因。
