Lin Marie, Xu Xiuzhang, Lee Hui-Lin, Liang Der-Cheng, Santoso Sentot
Department of Medical Research, Mackay Memorial Hospital, Tamsui, New Taipei City, Taiwan.
Institute for Clinical Immunology and Transfusion Medicine, Justus-Liebig University Giessen, Giessen, Germany.
Transfusion. 2018 Jan;58(1):189-195. doi: 10.1111/trf.14369. Epub 2017 Oct 13.
Isoantibodies against CD36 (platelet glycoprotein 4), developed in Type I CD36-deficient mothers are frequently reported as the cause of fetal/neonatal alloimmune thrombocytopenia in the Asian population. Therefore, further detailed characterization of anti-CD36-mediated fetal/neonatal alloimmune thrombocytopenia is warranted. Here, we report the characterization of a patient with fetal/neonatal alloimmune thrombocytopenia in a Taiwanese family caused by anti-CD36 isoantibodies using a novel antigen-capture method.
Platelets and monocytes were analyzed for CD36 expression by flow cytometry. Sequencing analysis of the CD36 gene was performed to identify the mutation underlying the CD36 deficiency. Stable transfected human embryonic kidney HEK293 cells expressing recombinant CD36 were established. These cells were used for the characterization of anti-CD36 isoantibodies by flow cytometry, immunoprecipitation, and antigen-capture assay.
Flow cytometry analysis revealed a total absence of CD36 on both platelets and monocytes of the mother (Type I CD36-deficient) caused by heterozygous deletions of the CD36 gene (332_333delCA and c.1254 + 6_1254 + 11delTATTTG). Analysis of maternal serum with CD36-transfected HEK293 cells by flow cytometry, immunoprecipitation, and antigen-capture assay demonstrated the presence of anti-CD36 isoantibodies in maternal serum. Interestingly, this antibody could not be detected by the monoclonal antibody immobilization of platelet antigens assay when anti-CD36 monoclonal antibody (clone FA6-152) was used as the capture antibody.
This case reemphasizes the role of anti-CD36 isoantibodies on the pathomechanism of fetal/neonatal alloimmune thrombocytopenia. The fact that the monoclonal antibody immobilization of platelet antigens assay does not seem to be reliable for the identification of all anti-CD36 antibodies indicates that screening of anti-CD36 isoantibodies by a monoclonal antibody-independent method, as presented here, should be considered.
I型CD36缺陷母亲体内产生的抗CD36（血小板糖蛋白4）同种抗体常被报道为亚洲人群中胎儿/新生儿同种免疫性血小板减少症的病因。因此，有必要对抗CD36介导的胎儿/新生儿同种免疫性血小板减少症进行更详细的特征描述。在此，我们报告了一家台湾家庭中一名因抗CD36同种抗体导致胎儿/新生儿同种免疫性血小板减少症患者的特征，采用了一种新型抗原捕获方法。
通过流式细胞术分析血小板和单核细胞的CD36表达。对CD36基因进行测序分析，以确定CD36缺陷的潜在突变。建立稳定转染表达重组CD36的人胚肾HEK293细胞。这些细胞用于通过流式细胞术、免疫沉淀和抗原捕获试验对抗CD36同种抗体进行特征描述。
流式细胞术分析显示，母亲（I型CD36缺陷）的血小板和单核细胞上完全没有CD36，这是由CD36基因的杂合缺失（332_333delCA和c.1254 +6_1254 +11delTATTTG）引起的。通过流式细胞术、免疫沉淀和抗原捕获试验对转染CD36的HEK293细胞进行母亲血清分析，结果表明母亲血清中存在抗CD36同种抗体。有趣的是，当使用抗CD36单克隆抗体（克隆FA6-152）作为捕获抗体时，血小板抗原单克隆抗体固定试验无法检测到这种抗体。
该病例再次强调了抗CD36同种抗体在胎儿/新生儿同种免疫性血小板减少症发病机制中的作用。血小板抗原单克隆抗体固定试验似乎不能可靠地识别所有抗CD36抗体，这一事实表明，应考虑采用本文介绍的不依赖单克隆抗体的方法对抗CD36同种抗体进行筛查。
