Human platelets carry membrane glycoproteins that control platelet aggregation and activation. A number of clinical studies have suggested that certain polymorphisms of genes encoding these proteins increase the risk for cardiovascular disease. The frequency of gene polymorphisms for the four most common platelet glycoproteins (HPA 1, 2, 3 and 5) was examined and correlated with the primary cau...

Objective—Glycoprotein (GP) Iba is the functionally dominant subunit of the platelet GPIb-IX-V receptor complex. The N-terminal domain of the GPIba chain contains binding sites for a-thrombin and von Willebrand factor (VWF). The human platelet alloantigen (HPA)-2 polymorphism of the GPIba gene is associated with a C/T transition at nucleotide 1018, resulting in a Thr/Met dimorphism at residue 1...

The human platelet alloantigen 1 system (HPA-1) is determined by a polymorphism at position 33 in the N-terminus of human glycoprotein IIIa (GPIIIa). This naturally occurring substitution creates a conformation in the HPA-1a allelic form that can be antigenic when presented to an individual expressing the HPA-1b form. Anti-HPA-1a antibodies generated by this immune response can lead to the dest...

Aims: The frequencies of alloantibodies to platelet glycoproteins and HLA class 1 have not been reported in this part of the world. To determine the prevalence of these antibodies in Nigeria. Methods: The sera of 100 multiparous women were tested for antibodies to HPA and HLA class 1 antigens using GTI PakPlus solid phase ELISA Kit in a cross sectional study. Results: The prevalence of platelet...

In our study we investigated the presence of anti-human platelet antigen (HPA) alloantibodies in a series of 10 beta-thalassemia major patients submitted for more than 10 years to periodic blood transfusions (every 2-3 weeks). We found that 2 out of the 10 patients developed anti-HPA2a + HPA1b and anti-HPA2b antibodies. Our results highlight that HPA alloimmunization in multitransfused patients...

Two heparin-neutralizing proteins secreted by thrombin-stimulated platelets were purified to homogeneity by means of heparin-agarose affinity chromatography. These proteins, termed porcine platelet basic protein (PBP) and porcine platelet factor 4 (PF4), were eluted from a heparin-agarose column at 0.6-0.9 M NaCl and at 1-1.4 M NaCl, respectively. The molecular weight of porcine platelet basic ...

We describe a patient who developed transient and moderately severe thrombocytopenia (platelet count nadir 35 x 10(9)/L) after the transfusion of plasma. Using the technique of direct radioimmunoprecipitation, we showed that during the thrombocytopenia episode, the patient's platelets had IgG specifically bound to the glycoprotein (GP) Ia/IIa complex. Indirect radioimmunoprecipitation using ser...

OBJECTIVES To assess neonatal platelet counts by comparing alloimmunised pregnancies from a Norwegian screening and intervention study with subsequent pregnancies from the same women. DESIGN Prospective observational follow-up study. SETTING A university hospital. POPULATION HPA-1a immunised women from a large Norwegian screening study that gave birth to one or more children after the scr...