Bordin J O, Kelton J G, Warner M N, Smith J W, Denomme G A, Warkentin T E, McGrath K, Minchinton R, Hayward C P
Department of Hematology and Transfusion Medicine, Universidade Federal de São Paulo, Escola Paulista de Medicina, Brazil.
Transfusion. 1997 Aug;37(8):823-8. doi: 10.1046/j.1537-2995.1997.37897424405.x.
Immunization to platelet alloantigens can occur during pregnancy or after the transfusion of blood components. Platelet alloantibodies can cause neonatal alloimmune thrombocytopenia and posttransfusion purpura. Transfusion-induced alloimmunization to a novel platelet alloantigen system, Gov, expressed on the 175-kDa glycosyl phosphatidylinositol-anchored platelet glycoprotein, CD109, was previously described. This report describes three unrelated patients who were alloimmunized to Gov(a) or Gov(b) during pregnancy.
Platelets were typed by using radioimmunoprecipitation for HPA-1a, -3a, -5a, -5b, Gov(a), and Gov(b) and by polymerase chain reaction-restriction fragment length polymorphism for HPA-1a, -1b, -3a, and -3b. Maternal sera were screened for platelet antibodies by using radioimmunoprecipitation and the antigen capture assay.
Patients 1 and 2 were investigated after the diagnosis of neonatal alloimmune thrombocytopenia in their children, and alloantibodies specific for Gov(b) and Gov(a), respectively, were detected in maternal serum. Serum from patient 3, who had mild idiopathic thrombocytopenia purpura with no detectable autoantibody, was found to contain alloantibodies to Gov(b) and to HPA-5b, presumably as a result of immunization during pregnancy. Platelet typings confirmed that the patients were at risk for alloimmunization to the respective antigen.
This report of three cases of maternal alloimmunization to antigens in the Gov system indicates that immunization can occur via placental transfer of antigen and that Gov system alloantibodies may be associated with neonatal alloimmune thrombocytopenia.
孕期或输注血液成分后可发生针对血小板同种抗原的免疫反应。血小板同种抗体可导致新生儿同种免疫性血小板减少症和输血后紫癜。此前曾报道过输血诱导的针对一种新型血小板同种抗原系统Gov的同种免疫反应，该抗原系统表达于175 kDa糖基磷脂酰肌醇锚定的血小板糖蛋白CD109上。本报告描述了3例在孕期对Gov(a)或Gov(b)发生同种免疫反应的非相关患者。
采用放射免疫沉淀法对血小板进行HPA-1a、-3a、-5a、-5b、Gov(a)和Gov(b)分型，采用聚合酶链反应-限制性片段长度多态性方法对HPA-1a、-1b、-3a和-3b进行分型。采用放射免疫沉淀法和抗原捕获试验筛查母体血清中的血小板抗体。
患者1和患者2在其子女被诊断为新生儿同种免疫性血小板减少症后接受调查，在母体血清中分别检测到针对Gov(b)和Gov(a)的特异性同种抗体。患者3患有轻度特发性血小板减少性紫癜，未检测到自身抗体，其血清中发现含有针对Gov(b)和HPA-5b的同种抗体，推测是孕期免疫所致。血小板分型证实这些患者有针对相应抗原发生同种免疫反应的风险。
本报告中3例母体对Gov系统抗原发生同种免疫反应的病例表明，免疫反应可通过抗原的胎盘转移发生，且Gov系统同种抗体可能与新生儿同种免疫性血小板减少症有关。
