Laboratory of Blood Genetics, Department of Clinical Immunology, Rigshospitalet, Copenhagen, Denmark.
Department of Technology, Faculty of Health and Technology, University College Copenhagen, Copenhagen, Denmark.
PLoS One. 2023 Oct 20;18(10):e0286432. doi: 10.1371/journal.pone.0286432. eCollection 2023.
The prevailing concept is that gestational alloimmune liver disease (GALD) is caused by maternal antibodies targeting a currently unknown antigen on the liver of the fetus. This leads to deposition of complement on the fetal hepatocytes and death of the fetal hepatocytes and extensive liver injury. In many cases, the newborn dies. In subsequent pregnancies early treatment of the woman with intravenous immunoglobulin can be instituted, and the prognosis for the fetus will be excellent. Without treatment the prognosis can be severe. Crucial improvements of diagnosis require identification of the target antigen. For this identification, this work was based on two hypotheses: 1. The GALD antigen is exclusively expressed in the fetal liver during normal fetal life in all pregnancies; 2. The GALD antigen is an alloantigen expressed in the fetal liver with the woman being homozygous for the minor allele and the father being, most frequently, homozygous for the major allele. We used three different experimental approaches to identify the liver target antigen of maternal antibodies from women who had given birth to a baby with the clinical GALD diagnosis: 1. Immunoprecipitation of antigens from either a human liver cell line or human fetal livers by immunoprecipitation with maternal antibodies followed by mass spectrometry analysis of captured antigens; 2. Construction of a cDNA expression library from human fetal liver mRNA and screening about 1.3 million recombinants in Escherichia coli using antibodies from mothers of babies diagnosed with GALD; 3. Exome/genome sequencing of DNA from 26 presumably unrelated women who had previously given birth to a child with GALD with husband controls and supplementary HLA typing. In conclusion, using the three experimental approaches we did not identify the GALD target antigen and the exome/genome sequencing results did not support the hypothesis that the GALD antigen is an alloantigen, but the results do not yield basis for excluding that the antigen is exclusively expressed during fetal life., which is the hypothesis we favor.
目前的观点认为，妊娠同种免疫性肝疾病（GALD）是由针对胎儿肝脏上目前未知抗原的母体抗体引起的。这导致补体在胎儿肝细胞上沉积，导致胎儿肝细胞死亡和广泛的肝损伤。在许多情况下，新生儿会死亡。在随后的妊娠中，可以对女性进行早期静脉注射免疫球蛋白治疗，胎儿的预后将非常好。如果不治疗，预后可能会很严重。为了改善诊断，关键是要确定靶抗原。为此，这项工作基于两个假设：1. 在所有妊娠中，GALD 抗原在正常胎儿期仅在胎儿肝脏中表达；2. GALD 抗原是一种在胎儿肝脏中表达的同种抗原，女性为杂合子，而父亲通常为纯合子。我们使用了三种不同的实验方法来鉴定来自已分娩出具有临床 GALD 诊断的婴儿的女性的母体抗体的肝脏靶抗原：1. 通过用母体抗体进行免疫沉淀，从人肝细胞系或人胎肝中免疫沉淀，然后对捕获的抗原进行质谱分析；2. 从人胎肝 mRNA 构建 cDNA 表达文库，并用诊断为 GALD 的婴儿的母亲的抗体在大肠杆菌中筛选约 130 万个重组体；3. 对 26 名先前分娩过 GALD 患儿的女性及其丈夫对照的 DNA 进行外显子/基因组测序，并进行补充 HLA 分型。总之，使用这三种实验方法，我们没有鉴定出 GALD 靶抗原，外显子/基因组测序结果也不支持 GALD 抗原是同种抗原的假设，但结果也没有依据排除抗原仅在胎儿期表达的假设，这是我们倾向的假设。
