Alloimmunization against the platelet-specific Zwa antigen, resulting in neonatal alloimmune thrombocytopenia or posttransfusion purpura, is associated with the supertypic DRw52 antigen including DR3 and DRw6.
The strong association between HLA-DR3 and Zwa alloimmunization in Zwa-negative mothers, resulting in the production of anti-Zwa antibodies and ultimately in neonatal alloimmune thrombocytopenic purpura (NAITP) in the newborn, could be confirmed. In addition, we have shown an equally strong association between HLA-DR3 and Zwa alloimmunization in Zwa-negative recipients of blood transfusions, resulting in posttransfusion purpura (PTP). However, the strongest association both in mothers of NAITP patients and in PTP patients was observed with the supertypic DRw52 antigen. In fact, all individuals carried this antigen. Normally, DRw52 includes DR3, DR5, DRw6, and DRw8 almost completely. However, in our material, DRw52 included only DR3 and DRw6 with one exception. Another interesting observation is that all PTP patients were women with previous pregnancies without any clinical signs of a bleeding disorder in their children. This indicates that alloimmunization against Zwa during pregnancy is DR3- and/or DRw52-positive women does not always lead to the development of NAITP, but these women may be at risk for the development of PTP after blood transfusion.
D000917:Antibody Formation; D016824:Antigens, Human Platelet; D001327:Autoimmune Diseases / Q000276:immunology*; D001792:Blood Platelets / Q000276:immunology*; D005260:Female; D006684:HLA-DR Antigens; D015803:HLA-DR3 Antigen; D015808:HLA-DR6 Antigen; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D007231:Infant, Newborn; D039661:Integrin beta3; D007518:Isoantibodies / Q000276:immunology*; D007519:Isoantigens / Q000276:immunology*; D011247:Pregnancy; D011693:Purpura / Q000209:etiology / Q000276:immunology*; D011696:Purpura, Thrombocytopenic / Q000276:immunology*; D065227:Transfusion Reaction
D016824:Antigens, Human Platelet; D006684:HLA-DR Antigens; D015803:HLA-DR3 Antigen; D015808:HLA-DR6 Antigen; D000949:Histocompatibility Antigens Class II; C061248:ITGB3 protein, human; D039661:Integrin beta3; D007518:Isoantibodies; D007519:Isoantigens