Blood Platelets ; Humans ; Platelet Membrane Glycoproteins ; Thrombosis

OBJECTIVETo investigate the polymorphisms of platelet membrane glycoprotein genes related to human platelet alloantigen (HPA)-1 to 17w.

METHODSThe DNA segments of platelet membrane glycoprotein genes related to HPA-1 to 17w were amplified using author's designed primers. The amplification products were purified and directly sequenced to identify the HPA genotype and glycoprotein gene polymorphisms.

RESULTSThirteen new single nucleotide polymorphisms (SNPs) and a micro-satellite sequence were found in the glycoprotein genes from the 112 random samples, in which two SNPs (1333G/A and 1960G/A) in ITGB3 gene result in two amino acid change (V419M and E628K) on glycoprotein GPIIIa.

CONCLUSIONNew variants in platelet membrane glycoprotein genes were identified, which may lead to structure change of platelet membrane glycoprotein and affect the accuracy of partial HPA genotyping method.

Antigens, Human Platelet ; genetics ; Humans ; Isoantigens ; genetics ; Platelet Membrane Glycoproteins ; genetics ; Polymorphism, Single Nucleotide

Glanzmann's thrombasthenia (GT) is a rare inherited platelet disorder, which is characterized by a complete lack of platelet aggregation due to a deficiency or abnormality of the membrane glycoprotein IIb/IIIa complex. Anti-GPIIb/IIIa antibodies have also been identified to cause platelet dysfunction in patients with a normal platelet count, but this has only been rarely encountered. The condition is also known as acquired GT. Herein, we describe a patient with acquired GT and a history of Evans' syndrome, who presented with severe bleeding and platelet dysfunction, but with a normal platelet count and GP IIb/IIIa expression.
Antibodies ; Blood Platelets ; Hemorrhage ; Humans ; Membrane Glycoproteins ; Platelet Aggregation ; Platelet Count ; Thrombasthenia*

OBJECTIVE: To analysis the specific protein markers of essential thrombocythemia (ET) based on proteomics technology, to explore and verify the differential protein related to platelet activation. METHODS: Blood samples were obtained from ET patients and healthy people and a certain protein mass spectrometry was detected using label-free quantitative technology. The proteins relative abundance increased or down-regulated by 1.3 times in the disease group compared with the control group, and the protein abundance in the two groups t test P＜0.05 were defined as differential proteins. Bioinformatics analysis of the differential proteins was performed using GO and KEGG. The difference in the average protein abundance between the two groups was analyzed by t test and P＜0.05 was considered statistically significant. Differential proteins were selected for verification by parallel reaction monitoring (PRM) technology. RESULTS: A total of 140 differential proteins were found, of which 72 were up-regulated and 68 were down-regulated. KEGG enrichment showed that the differential protein expression was related to the platelet activation pathway. The differential proteins related to platelet activation were GPV, COL1A2, GP1bα, COL1A1 and GPVI. Among them, the expressions of GPV, GP1bα and GPVI were up-regulated, and the expressions of COL1A2 and COL1A1 were down-regulated. PRM verification of COL1A1, GP1bα, GPVI and GPV was consistent with LFP proteomics testing. CONCLUSION Differential proteins in ET patients are related to platelet activation pathway activation.Differential proteins such as GPV, GPVI, COL1A1 and GP1bα can be used as new targets related to ET platelet activation.
Blood Platelets/metabolism* ; Humans ; Platelet Activation ; Platelet Membrane Glycoproteins/metabolism* ; Technology ; Thrombocythemia, Essential

BACKGROUND: A previous history of transfusion has been known to be associated with production of anti-HLA class I antibodies. However, platelet glycoproteins are the main target of idiopathic thrombocytopenic purpura (ITP). The mechanism of antibody production is known to differ significantly between glycoproteins and anti-HLA class I. The aim of this study was to evaluate the clinical significance of anti-HLA class I antibodies in childhood ITP. METHODS: Enrollment for the normal control group targeted 48 people who visited Gyeongsang National University Hospital from 1990 to 2010, and 48 young children with ITP. Anti-glycoproteins and anti-HLA class I antibodies were tested using the Modified Antigen Capture Enzyme-linked immunosorbent assay (MACE) kit. RESULTS: The positive rate of anti-HLA antibodies was significantly different [36/39 (92.3%) vs 29/46 (63%)] [ITP group vs normal control group] (P=0.002). The mean positive S/C ratio of anti-HLA antibodies was also significantly different (3.55 vs 1.51) [ITP group vs normal control group] (P=0.0000). The positive rate of anti-HLA did not differ significantly between the transfused group and the non-transfused group [12/12 (100%) vs 24/27 (88%)] [transfused ITP vs non-transfused ITP]. The mean positive S/C ratio of anti-HLA antibodies did not differ significantly between the transfused ITP group and the non-transfused ITP group (4.30 vs 3.25) [transfused ITP vs non-transfused ITP]. Consecutive testing showed that positive rate and positive S/C ratio of anti-HLA antibodies did not change significantly between sampling times in both groups [transfused ITP vs non-transfused ITP] (P=1.00 and P=0.15). CONCLUSION: Anti-HLA class I antibodies may be involved in childhood ITP. Transfusion did not affect the course of childhood ITP.
Antibodies* ; Antibody Formation ; Blood Platelets* ; Child* ; Enzyme-Linked Immunosorbent Assay ; Glycoproteins ; Humans ; Platelet Membrane Glycoproteins ; Purpura, Thrombocytopenic, Idiopathic*

Glanzmann's thrombasthenia is a rare autosomal recessive hemorrhagic disorder characterized by prolonged bleeding time, ad deficient or absent clot retraction in the presence of normal platelet count. The major underlying abnormality in this disease is grossly defective first-phase aggregation of platelet, which are unresponsive to ADP or other platelet agonists such as epinephrine, collagen, thrombin in any concentration. This disability is caused by a decrease or absence of the platelet membrans glycoprotein IIb-IIIa complex, a member of the integrin family of adhesive receptors involved in cell-cell and cell-matrix fibronectin, and vitronectin On the development of surface labeling technique, a variety of biochemical techniques such as radioimmunoassay, crossed immunoelectrophoresis and SDS-PAGE have been used to study the structure and the function of platelet membrane glycoproteins, and to detect the platelet functional defect. But all of these techniques demand a relatively large amount of homogeneous paletelet population that requires manipulation through isolation and washing procedures before analysis. In order to eliminaste such an intricate procedure, we have applied method for analyzing platelet surface components in whole blood using monoclonal antibody and flow cytometry to recognize the absence of severe reduction of platelet membrane glycoprotien llb-llla complex. Platelet analysis by flow cytometry is a successful alternative rapid diagnostic technique for Glanzmann's thrombasthenia patients as well as well as for carriers of this disease. Fow cytometry technique provides a sensitive tool for investigating platelet functional defects caused by altered expression or deficiency of platelet surface proteins.
Adenosine Diphosphate ; Adhesives ; Bleeding Time ; Blood Platelets* ; Clot Retraction ; Collagen ; Electrophoresis, Polyacrylamide Gel ; Epinephrine ; Fibronectins ; Flow Cytometry* ; Glycoproteins ; Hemorrhagic Disorders ; Humans ; Immunoelectrophoresis, Two-Dimensional ; Membrane Glycoproteins* ; Membrane Proteins ; Membranes* ; Platelet Count ; Platelet Membrane Glycoproteins ; Radioimmunoassay ; Thrombasthenia* ; Thrombin ; Vitronectin

This study was aimed to investigate the influence of different platelet membrane glycoprotein monoclonal antibodies (McAb) which are common used in laboratories on the monoclonal antibody-specific immobilization of platelet antigens (MAIPA) technique according to the request of 14th International Society of Blood Transfusion Platelet Immunology Workshop. 30 participant laboratories were provided with 10 known human platelet antigen (HPA) antibodies, 1 normal serum, 9 different McAbs (against GPIIb/IIIa, GPIa/IIa, GPIb/IX and GPIV respectively), and the same protocol. Each participant laboratory carried out the test as the protocol to compare the results of different McAbs against the same glycoprotein and submitted the data to organizer. The results indicated that in McAbs against GPIIb/IIIa, AP2, Gi-5 and PL2-73 showed higher mean S/CO than that of others; in GPIa/IIa, MBC202.2 and 143.1 showed higher mean S/CO than that of others; in GPIb/IX, 142.11 and CLB-MB45 (CD42b) showed higher mean S/CO than that of others; as to GPIV, 131.4 showed higher mean S/CO. In conclusion, capture effects of various McAbs are different, so that different products of McAbs exert influences on the sensitivity of MAIPA. To use a panel of McAbs against the same glycoprotein may avoid the false negative results.
Antibodies, Monoclonal ; classification ; Antigens, Human Platelet ; immunology ; Humans ; Indicators and Reagents ; Platelet Glycoprotein GPIIb-IIIa Complex ; immunology ; Platelet Glycoprotein GPIb-IX Complex ; immunology ; Platelet Membrane Glycoproteins ; classification ; immunology

Immune thrombocytopenia (ITP) is an autoimmune hemorrhagic disease. It is considered that production of platelet auto-antibodies was one of the pathogenesis of ITP, first-line therapy including corticosteroid and immunoglobulin could reduce destruction of platelets by inhibiting production of auto-antibodies and blocking Fc-receptor of reticuloendothelial system, but some of the patients were refractory to first-line therapy and have persistent duration of the disease, having worse prognosis and developing into chronic/refractory ITP(C/RITP) . Platelet membrane glycoprotein like GPIIb/IIIa and GPIbα are the most common antigen targets, but first-line therapy was less effective to patients whose anti-GPIbα antibodies are positive. Further studies revealed that the way causing platelet destruction by anti-GPIIb/IIIa antibodies and anti-GPIbα antibodies are different: the former is mainly dependent to Fc-pathway, and the latter mainly cleared platelet by Fc-independent way. Results above indicated that detection of type of platelet auto-antibodies maybe potential to treatment and prognosis of ITP. This article summarizes relationship between platelet specific antibodies and the onset, clinical manifestation, treatment and prognosis of ITP.
Antibodies ; immunology ; Autoimmune Diseases ; Blood Platelets ; immunology ; Humans ; Platelet Membrane Glycoproteins ; Prognosis ; Thrombocytopenia ; immunology ; therapy

Human platelet alloantigens (HPA) are specific antigens carried by platelet glycoproteins, which genes showing single nucleotide polymorphism. HPA can induce alloantibodies bringing about alloimmune response. They play important roles in post-transfusion refractoriness to platelets, post-transfusion thrombocytopenic purpura, fetomaternal alloimmune thrombocytopenia, and graft-versus-host disease. Because of their side effects in clinical blood-transfusion, there were a great deal of studies on HPA during last few decades. This review focuses on the nomenclature of HPA, the polymorphisms of platelet glycoproteins, HPA typing of the serological and molecular technology, as well as the mechanism of alloimmunization to HPA and correlated diseases.
Antigens, Human Platelet ; classification ; immunology ; Humans ; Isoantibodies ; immunology ; Platelet Membrane Glycoproteins ; genetics ; Polymorphism, Single Nucleotide ; Transfusion Reaction

AIMTo study the antagonistic effect of myricetin on platelet activing factor (PAF).

METHODSThe specific binding of [3H] PAF to rabbit platelet receptor was investigated using radio ligand binding assay (RLBA). Platelet adhesion induced by PAF was measured with spectrophotometry. The elevation of inner free calcium concentration in rabbit polymorphonuclear leukocytes (PMNs) induced by PAF was assayed by Fura-2 fluorescent technique.

RESULTSThe specific binding inhibition potency of Myr was found to be concentration-dependent. The IC50 of Myr in [3H] PAF 1, 2 and 4 nmol.L-1 were 34.8, 85.7 and 118.6 mumol.L-1, respectively. The PAF induced reactions of rabbit platelet adhesion and PMNs inner free calcium concentration increase were inhibited by Myr in a dose-dependent manner. The IC50 of Myr to inhibit platelet adhesion was 13.1 mumol.L-1.

CONCLUSIONThe specific receptor binding of PAF can be antagonized by myricetin.

Animals ; Calcium ; metabolism ; Flavonoids ; pharmacology ; Male ; Neutrophils ; metabolism ; Platelet Activating Factor ; antagonists & inhibitors ; metabolism ; Platelet Activation ; drug effects ; Platelet Adhesiveness ; drug effects ; Platelet Aggregation Inhibitors ; pharmacology ; Platelet Membrane Glycoproteins ; metabolism ; Rabbits ; Receptors, G-Protein-Coupled ; metabolism