title: Flow cytometric evaluation of platelet activation in chronic autoimmune thrombocytopenia.
abstract: Platelets from 42 patients (platelet counts median 42x10(9)/L, range 3-223x10(9)/L) with chronic idiopathic autoimmune thrombocytopenia (cAITP) were investigated for P-Selectin expression and PAC-1 binding. The results showed that the levels of P-Selectin positive platelets (n=20) were higher in cAITP than in controls (P<0.0001), and correlated with platelet counts (P=0.04). PAC-1 binding was increased in only six patients, and not correlated with platelet counts. There was no correlation of P-Selectin or PAC-1 with detectable platelet antibodies. Thus, platelets are activated in cAITP, but platelets, characterized by PAC-1 binding, are rare. These are either needed to maintain vascular integrity, or underwent premature sequestration.
authors.affiliation: Clinic for Blood Group Serology, Department of Internal Medicine, Medical University of Vienna, Vienna, Austria. simon.panzer@meduniwien.ac.at
authors.forename: Simon
authors.initials: S
authors.lastname: Panzer
authors.forename: Lisa
authors.initials: L
authors.lastname: Höcker
authors.forename: Rainer
authors.initials: R
authors.lastname: Vormittag
authors.forename: Miriam
authors.initials: M
authors.lastname: Rieger
authors.forename: Daniela
authors.initials: D
authors.lastname: Koren
authors.forename: Daniela
authors.initials: D
authors.lastname: Dunkler
authors.forename: Ingrid
authors.initials: I
authors.lastname: Pabinger
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D054641:Dual Specificity Phosphatase 2; D005434:Flow Cytometry / Q000379:methods; D006801:Humans; D008875:Middle Aged; D019007:P-Selectin / Q000096:biosynthesis; D015539:Platelet Activation / Q000276:immunology*; D010976:Platelet Count; D054648:Protein Phosphatase 2; D017027:Protein Tyrosine Phosphatases / Q000276:immunology; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000175:diagnosis* / Q000276:immunology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D019007:P-Selectin; D054648:Protein Phosphatase 2; C517032:DUSP2 protein, human; D054641:Dual Specificity Phosphatase 2; D017027:Protein Tyrosine Phosphatases