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Thrombocytopenic Patients (thrombocytopenic + patient)
Selected AbstractsAutoimmune thrombocytopenia: flow cytometric determination of platelet-associated autoantibodies against platelet-specific receptorsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 1 2005A. TOMER Summary., Immune thrombocytopenic purpura (ITP) is an autoimmune disorder characterized by antibody-induced platelet destruction. Despite its clinical importance, the diagnosis of ITP is one of exclusion, thus, inevitably associated with potential difficulties. We here describe a feasible diagnostic method using the commonly available technique of flow cytometry. An antigen-specific assay for platelet-associated antibody was developed and tested in 62 adult patients with chronic ITP, 14 patients with thrombocytopenia of decreased production and 60 healthy controls. The method is based on flow cytometric (FCM) detection of autoantibodies reacting with specific platelet receptors immobilized on microbeads. The average fluorescence level in the ITP group calculated as a ratio to normal was 4.07 (range 0.8,31.0), in the non-ITP thrombocytopenic patients 0.9 (range 0.7,1.2), and in the healthy controls 1.0 (range 0.7,1.3). The average assay coefficient of variation was 0.218 [95% confidence interval (CI) 0.213, 0.221]. The difference between the ITP patients and both groups was highly significant (P < 0.001), using a stringent non-parametric analysis. A comparison of the FCM assay with the radioactive immunobead assay previously reported on the same cohort of patients showed significant correlation (R2 = 0.71, 95% CI 0.39, 0.53). The overall performance of the FCM assay in discriminating between ITP patients and normals was estimated by the receiver operating characteristic (ROC) plot, showing an area under the curve of 0.96 (maximal value 1.0), with standard error of 0.033. We conclude that the present FCM assay is clinically useful for routine diagnosis and follow-up of ITP. [source] Substitutes and alternatives to platelet transfusions in thrombocytopenic patientsJOURNAL OF THROMBOSIS AND HAEMOSTASIS, Issue 7 2003M. A. Blajchman Summary., Over the past decade, there have been many improvements in both the safety profile and quality of liquid-stored allogeneic platelet concentrates. However, significant problems with the clinical use of such products remain. Efforts to overcome some of these have resulted in the development of an array of novel therapeutic strategies for the manufacture of platelet products and platelet substitutes, as well as other approaches using alternatives to platelet concentrates. These various products or procedures are at various stages of clinical development. This review summarizes some recent advancements in the preparation of liquid and frozen stored platelets, as well as approaches used for the pathogen inactivation of platelets. Thus, the status of lyophilized platelets, infusible platelet membranes, red blood cells (RBCs) bearing RGD ligands, fibrinogen-coated albumin microcapsules, and liposome-based agents are discussed. Pre-clinical studies and phase 1,3 clinical trials have been encouraging for several of these; however, to date, very few have been licensed for clinical use. Potential alternatives to allogeneic platelet transfusions including correction of anemia by RBC transfusions, recombinant activated factor VII and HLA-reduced platelets are also reviewed. With the ongoing technical and scientific development of such diverse products, those properties that may be necessary for such agents to have hemostatic efficacy will become apparent. However, safety and efficacy must be demonstrable in preclinical studies and clinical trials, before novel platelet concentrates, platelet substitutes and alternatives to platelets can be used in patients with thrombocytopenia. [source] Recurrent idiopathic thrombocytopenic purpura in childhoodPEDIATRIC BLOOD & CANCER, Issue 2 2008Maria Vranou MD Abstract Background Idiopathic thrombocytopenic purpura (ITP) is a common haematological disease during childhood, that usually has a benign course; however, literature on the recurrent form of the disease (rITP) is limited. Procedure rITP was characterized by intermittent episodes of thrombocytopenia (TP) followed by periods of recovery, unrelated to therapeutic intervention. We retrospectively reviewed features of patients with rITP, diagnosed and systematically followed up at our center, during the period 1975,2004. Results Forty-eight of 795 children with ITP (6.0 %) presented with rITP. The majority of patients (68.8%) had only one recurrence, whereas only one patient had four. A time interval between two episodes longer than 3 months (up to 96) was identified in 2/3 of episodes and <3 months in 1/3. The initial episode and the first recurrence mostly shared features of acute ITP; however, 22.9% of the episodes appeared with a chronic self-limited course. Bleeding manifestations were rare (18.6% of episodes) and mild, and they tended to occur in severely thrombocytopenic patients, mainly at the onset of the initial episode; intracranial hemorrhage (ICH) occurred in a toddler with short duration thrombocytopenia. Intravenous , globulin (IVIG) or corticosteroids were administered in 24.5% of episodes. None of the patients needed splenectomy. Conclusion: rITP is a rare, mild, self-limited type of ITP, although ICH may occur in a profoundly TP child. Recurrence may occur close or far apart to a previous isolated TP episode. The duration of episodes varies considerably from patient to patient and from episode to episode in the same patient. The pathogenesis of rITP still remains unclear. Pediatr Blood Cancer 2008;51:261,264. © 2008 Wiley-Liss, Inc. [source] Association between particular polymorphic residues on apical membrane antigen 1 (AMA-1) and platelet levels in patients with vivax malariaCLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2007P. Grynberg Abstract Apical membrane antigen 1 (AMA-1) is an immunogenic type 1 integral membrane protein, present in all Plasmodium spp., that probably has a role in the initiation of the invasion process of the erythrocyte. The DNA sequence of variable domain I of the Plasmodium vivax ama1 gene was sequenced in Brazilian isolates obtained from thrombocytopenic patients (n = 32) and patients with normal platelet counts (n = 22). There was a significant negative correlation between parasite density and platelet counts. It was concluded that there is an additional effect of sequence on platelet counts. The presence of amino-acid residues Y193 and S210 was associated significantly with normal platelet counts in P. vivax malaria, independent of the level of parasitaemia (p <0.0001). These data have implications for AMA-1-based vaccine design and suggest the possible use of this molecule as a marker of morbidity. [source] | ||||||||||