Human platelet antigen-1a antibodies induce the release of the chemokine RANTES from human platelets.
OBJECTIVE
Binding of human platelet antigen-1a (HPA-1a)-specific antibodies to target platelets can trigger platelet activation and mediator release. Here we tested the effect of HPA-1a antibody-containing sera on platelet release of the chemokine RANTES (regulated on activation, normal, T-cell expressed, and presumably secreted) in vitro.


METHODS
HPA-1a-containing sera obtained from 11 mothers delivered of an infant with neonatal alloimmune thrombocytopenia (NAIT) and from six patients with post-transfusion purpura (PTP) were incubated with HPA-1a/a target platelets. Antibody-induced release of soluble RANTES was determined by enzyme-linked immunosorbent assay (ELISA).


RESULTS
A significant release of soluble RANTES was induced by four out of the 17 sera. Two out of the four reactive sera were obtained from mothers who were delivered of a baby with NAIT and the remaining two sera were from patients with PTP. Chemokine release was specific for binding of anti-HPA-1a to the platelet membrane, as none of the reactive sera induced the release of soluble RANTES when incubated with HPA-1b/b platelets. The blockade of platelet-expressed Fc gamma receptor type II (FcgammaRII) inhibited anti-HPA-1a-mediated RANTES release when incubated with the reactive sera of patients with NAIT, but not when platelets were incubated with sera of patients with PTP.


CONCLUSIONS
Our findings suggest that anti-HPA-1a antibody-induced release of platelet-derived RANTES can play a role in adverse reactions in alloimmunized patients.
Dettke
M
M
Department for Blood Group Serology and Transfusion Medicine, AKH Wien, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria. markus.dettke@univie.ac.at
Dreer
M
M
Höcker
P
P
Panzer
S
S
D000328:Adult; D016824:Antigens, Human Platelet / Q000276:immunology*; D001792:Blood Platelets / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D018929:Cell Culture Techniques; D018946:Chemokine CCL5 / Q000378:metabolism*; D005260:Female; D015395:Histocompatibility Antigens Class I; D006801:Humans; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000097:blood / Q000276:immunology; D039661:Integrin beta3; D007518:Isoantibodies / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D011693:Purpura / Q000097:blood / Q000209:etiology / Q000276:immunology; D017452:Receptors, IgG / Q000276:immunology; D013921:Thrombocytopenia / Q000097:blood / Q000276:immunology; D065227:Transfusion Reaction
D016824:Antigens, Human Platelet; D018946:Chemokine CCL5; D015395:Histocompatibility Antigens Class I; C061248:ITGB3 protein, human; D039661:Integrin beta3; D007518:Isoantibodies; D017452:Receptors, IgG