Three cases of platelet alloimmunisation associated with the presence of a novel platelet-specific antibody.
OBJECTIVE
In three cases of platelet alloimmunisation, a platelet-specific alloantibody was detected which could not be classified within the known human platelet alloantigen or HLA systems. The first case was of a family in which two siblings suffered neonatal alloimmune thrombocytopenia at birth. In the second case, the newborn was suffering from phocomelia with hypoplastic thrombocytopenia. The third case was a male who became refractory to transfusions of HLA-matched platelets after a related bone marrow transplantation.


METHODS
The serum samples were investigated by: enzyme-linked immunosorbent assay, platelet suspension immunofluorescence test (PSIFT), monoclonal antibody immobilisation of platelet antigens assay (MAIPA), and by the lymphocytotoxicity test.


RESULTS
The antibody gave positive reactions with 26% of normal donor platelets. Surprisingly, no platelet-specific antibody was detected by PSIFT or by MAIPA and there was no evidence found to support classifying the antibody within the HLA system.


CONCLUSIONS
The reactivity pattern of the antibody detected and the clinical presentation of the three cases described, strongly suggest the presence of an additional platelet-specific alloantigen system.
Masters
R
R
National Blood Service, Brentwood Centre, Brentwood, UK.
Taaning
E
E
D016824:Antigens, Human Platelet / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology*; D016026:Bone Marrow Transplantation / Q000276:immunology; D004480:Ectromelia / Q000150:complications; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007112:Immunity, Maternally-Acquired; D007114:Immunization; D007231:Infant, Newborn; D039661:Integrin beta3; D007518:Isoantibodies / Q000096:biosynthesis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011247:Pregnancy; D013921:Thrombocytopenia / Q000150:complications / Q000151:congenital* / Q000276:immunology; D014184:Transplantation, Homologous / Q000276:immunology
C071221:2b alloantigen, human; D016824:Antigens, Human Platelet; D006680:HLA Antigens; C061248:ITGB3 protein, human; D039661:Integrin beta3; D007518:Isoantibodies; C083451:human platelet antigen 1b