- Human platelet antigen
Human platelet antigens (HPA) are polymorphisms in
platelet antigens . These can stimulate production ofalloantibodies , (antibodies against other people's antigens) in recipients of transfused platelets from donors with different HPAs. These antibodies causeneonatal alloimmune thrombocytopenia ,post-transfusion purpura and some cases ofrefractoriness to infusion of donor platelets. [cite journal |author=Metcalfe P, Watkins N, Ouwehand W, Kaplan C, Newman P, Kekomaki R, De Haas M, Aster R, Shibata Y, Smith J, Kiefel V, Santoso S |title=Nomenclature of human platelet antigens |journal=Vox Sang |volume=85 |issue=3 |pages=240–5 |year=2003 |pmid=14516468 |doi=10.1046/j.1423-0410.2003.00331.x]Overview
A
nomenclature was devised by International Society of Bone-marrow Transplantation (ISBT), platelet working party to overcome problems generated by many different nomenclatures in use. Since inception of this list, a greater number of antigens have beendescribed and the molecular basis of many has been resolved.To date, 24 platelet-specific alloantigens have been defined by
immune sera , of which 12 are grouped in six biallelic systems (HPA-1, -2, -3, -4, -5, -15). For the remaining 12, alloantibodies against thethetical but not theantithetical antigen have been observed. The molecular basis of 22 of the 24 serologically defined antigens has been resolved. In all but one of the 22, the difference between self and non-self is defined by a single amino acid substitution generally caused by aSingle Nucleotide Polymorphism (SNP).See also
References
Links
* http://www.ebi.ac.uk/ipd/hpa/
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