TY - JOUR
T1 - Thrombotic thrombocytopenic purpura plasma enhances platelet-leucocyte interaction in vitro
AU - Valant, Peter A.
AU - Jy, Wenche
AU - Horstman, Lawrence L.
AU - Mao, Wei Wei
AU - Ahn, Yeon S.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1998
Y1 - 1998
N2 - In thrombotic thrombocytopenic purpura (TTP), intravascular platelet aggregation and formation of platelet-rich thrombi impair the microcirculation. TIP plasma has been shown to induce aggregation of normal platelets in vitro. The present study investigates the formation of activated platelet aggregates (aPAg) induced by TTP plasma, with particular attention to their binding to leucocytes (LPAg). Results were compared with the effects of plasmas from normal controls (CTL) and from patients with immune thrombocytopenic purpura (ITP) or thrombosis (THR). Following addition of test plasma to normal whole blood (WB), aPAg and LPAg were assayed by flow cytometry using mAbs against CD41 (platelet marker), CD62p (platelet activation marker) and CD45 (pan-leucocyte marker). Compared to control plasma, TIP plasma was more potent than ITP or THR plasma in increasing aPAg; only TIP plasma significantly promoted leucocyte binding to give increased LPAg. Prior removal of neutrophils (PMN) from WB by beads coated with anti- CD15 mAb largely prevented formation of aPAg and LPAg. However, TTP plasma added to normal platelet-rich plasma significantly increased aPAg, which suggested possible hindrance of aPAg formation by erythrocytes and other leucocytes in PMN-depleted blood. We concluded that TIP plasma was most potent in the induction of aPAg and unique in promoting LPAg formation in WB. Neutrophils, and not other leucocytes, appear to be essential for LPAg formation. Enhanced PMN-platelet interaction in the microcirculation may facilitate platelet adhesion to vessel walls and promote the formation of platelet-rich microthrombi in TTP.
AB - In thrombotic thrombocytopenic purpura (TTP), intravascular platelet aggregation and formation of platelet-rich thrombi impair the microcirculation. TIP plasma has been shown to induce aggregation of normal platelets in vitro. The present study investigates the formation of activated platelet aggregates (aPAg) induced by TTP plasma, with particular attention to their binding to leucocytes (LPAg). Results were compared with the effects of plasmas from normal controls (CTL) and from patients with immune thrombocytopenic purpura (ITP) or thrombosis (THR). Following addition of test plasma to normal whole blood (WB), aPAg and LPAg were assayed by flow cytometry using mAbs against CD41 (platelet marker), CD62p (platelet activation marker) and CD45 (pan-leucocyte marker). Compared to control plasma, TIP plasma was more potent than ITP or THR plasma in increasing aPAg; only TIP plasma significantly promoted leucocyte binding to give increased LPAg. Prior removal of neutrophils (PMN) from WB by beads coated with anti- CD15 mAb largely prevented formation of aPAg and LPAg. However, TTP plasma added to normal platelet-rich plasma significantly increased aPAg, which suggested possible hindrance of aPAg formation by erythrocytes and other leucocytes in PMN-depleted blood. We concluded that TIP plasma was most potent in the induction of aPAg and unique in promoting LPAg formation in WB. Neutrophils, and not other leucocytes, appear to be essential for LPAg formation. Enhanced PMN-platelet interaction in the microcirculation may facilitate platelet adhesion to vessel walls and promote the formation of platelet-rich microthrombi in TTP.
KW - Activated platelet aggregates
KW - Platelet activation
KW - Platelet-neutrophil interaction
KW - TTP
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U2 - 10.1046/j.1365-2141.1998.00526.x
DO - 10.1046/j.1365-2141.1998.00526.x
M3 - Article
C2 - 9450786
AN - SCOPUS:0031962093
VL - 100
SP - 24
EP - 32
JO - British Journal of Haematology
JF - British Journal of Haematology
SN - 0007-1048
IS - 1
ER -