title: Evaluation of Plasma Platelet Microparticles in Thrombotic Thrombocytopenic Purpura.
abstract: BACKGROUND
  Platelet microparticles (PMPs) have a procoagulant activity about 50-100 times greater than active platelets due to high expression of negatively charged phospholipids on their surfaces. In this study, we evaluated microparticle immunophenotyping and also plasma PMPs level in patients with Thrombotic Thrombocytopenic Purpura (TTP) in Southern Iran.
  
  
  METHODS
  We had two study groups: 15 TTP patients and 15 healthy control group and PMPs from platelet concentrate (PC) at the 5thday of storage. Microparticles were prepared in two steps, by low and high centrifugation followed by size confirmation via 'Dynamic Light Scattering (DLS)' Zetasizer. Immunophenotyping of PMPs was done via flow cytometry, using a FACS Calibur flow cytometer (BD, USA). PMPs counts were obtained using Partec-cyflow and Polysciences Microbeads (1 micron in diameter). Results were analyzed using FlowJo 7.6 (Treestar, USA) and Partec FlowMax software.
  
  
  RESULTS
  Our results showed that the majority of microparticles in TTP patients and normal individuals were PMPs and also demonstrated that the plasma PMPs level in TTP patients was higher than the normal control group (P-value<0.001).
  
  
  CONCLUSIONS
  It seems that elevated PMPs level in TTP patients could be related to thrombotic events. Nevertheless, more studies are needed to confirm these results.
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Leila
authors.initials: L
authors.lastname: Tahmasbi
authors.affiliation: Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mehran
authors.initials: M
authors.lastname: Karimi
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran dr.amini@gmail.com.
authors.forename: Sedigheh Amini
authors.initials: SA
authors.lastname: Kafiabadi
authors.affiliation: Blood Transfusion Research Center, High Institute for Research and Education in Transfusion Medicine, Tehran, Iran.
authors.forename: Mahin
authors.initials: M
authors.lastname: Nikougoftar
authors.affiliation: Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Sezaneh
authors.initials: S
authors.lastname: Haghpanah
authors.affiliation: Diagnostic Laboratory Sciences and Technology Research Center, School of Paramedical Sciences, Shiraz University of Medical sciences, Shiraz, Iran.
authors.forename: Reza
authors.initials: R
authors.lastname: Ranjbaran
authors.affiliation: Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
authors.forename: Mohamad
authors.initials: M
authors.lastname: Moghadam
mesh_terms: D000328:Adult; D001792:Blood Platelets / Q000378:metabolism*; D055252:Cell-Derived Microparticles / Q000378:metabolism*; D000067493:Dynamic Light Scattering; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D010316:Particle Size; D010976:Platelet Count; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood*
keywords: Cell-derived microparticles; Immunophenotyping; Microangiopathic hemolytic anemia; Thrombotic Thrombocytopenic Purpura