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The effect of human platelet alloantigen polymorphisms on the in vitro responsiveness to adrenaline and collagen
Author(s) -
Theodoropoulos Ilias,
Christopoulos Costas,
Metcalfe Paul,
Dimitriadou Ekaterini,
Economopoulos Panagiotis,
Loucopoulos Dimitris
Publication year - 2001
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.2001.02948.x
Subject(s) - platelet , medicine , in vitro , endocrinology , allele , aspirin , thrombogenicity , platelet activation , polymorphism (computer science) , immunology , chemistry , biochemistry , gene
A number of clinical studies have suggested that carriage of the low frequency allele (b) of the human platelet antigen 1 (HPA‐1) system is a risk factor for coronary thrombosis. We have examined the effect of a series of HPA biallelic polymorphisms (systems ‐1, ‐2, ‐3 and ‐5) on the in vitro platelet aggregation in response to adrenaline and collagen in 30 healthy volunteers. There was a significantly higher prevalence (10 out of 18) of carriers of the HPA‐1b polymorphism among subjects showing a > 50% aggregation response to adrenaline (‘responders’) than the prevalence (1/12) in ‘non‐responders’ ( P < 0·05). Platelets heterozygous for the HPA‐1b polymorphism showed a significantly higher rate (slope) and greater extent (%) of adrenaline‐induced aggregation than platelets not carrying the HPA‐1b allele ( P < 0·05). A greater extent of collagen‐induced aggregation was also demonstrated in HPA‐1ab platelets ( P < 0·05). Inhibition of adrenaline‐induced aggregation following incubation with aspirin was greater ( P < 0·01) in HPA‐1ab than in HPA‐1aa platelets. Collagen‐induced aggregation was slower in carriers of the HPA‐5b allele than in HPA‐5aa subjects ( P < 0·05). Polymorphisms of the HPA‐2 and HPA‐3 systems were not associated with different aggregation responses to either adrenaline or collagen. These results support the clinical observation that polymorphism HPA‐1b may predispose to increased platelet thrombogenicity and suggest that the presence of polymorphism HPA‐5b might render the platelet less reactive to collagen.