Benjamin Stephanie, Vi Lisa, Chatterjee Diptendu, Jaeggi Edgar T, Ruffatti Amelia, Hiraki Linda T, Sepiashvili Lusia, Laskin Carl A, Fatah Meena, Tonello Marta, Dominguez Daniela, Ng Lawrence, Lohbihler Michelle, Luchessi Andre D, Hogarth Kaley, Daoud Abdelkader, Maynes Jason T, Protze Stephanie, Hamilton Robert M
Department of Pediatrics, University of Toronto, Toronto, ON, Canada; Department of Pediatrics, Hospital for Sick Children, Toronto, ON, Canada.
Department of Pediatrics, Hospital for Sick Children, Toronto, ON, Canada.
Lancet Rheumatol. 2025 Aug;7(8):e554-e564. doi: 10.1016/S2665-9913(25)00092-X. Epub 2025 May 21.
Fetal autoimmune congenital heart block is a rare but life-threatening condition that is difficult to predict. This study sought to identify a serological biomarker predictive of autoimmune congenital heart block in pregnancies at risk due to maternal systemic lupus erythematosus, Sjögren's disease, undifferentiated connective tissue disease, or a history of congenital heart block offspring.
This case-control study analysed maternal blood samples from pregnancies affected and unaffected by autoimmune congenital heart block from two centres (The Hospital for Sick Children, Canada, and The University of Padua, Italy). Serum samples collected across varying gestational ages were used for biomarker discovery, verification, and validation. The key inclusion criterion was a positive clinical test for maternal anti-Sjögren's syndrome-related antigen A/Ro autoantibodies, and the key exclusion criterion was structural congenital heart disease associated with heart block. Cases were pregnancies that resulted in fetal or neonatal congenital heart block and controls were pregnancies that resulted in offspring with a normal heart rhythm. Two-dimensional western blotting was used to identify maternal autoantibodies targeting fetal cardiac proteins, using fetal heart tissue and stem-cell-derived cardiomyocytes. Findings were validated using commercial proteins. Sensitivity and specificity for predicting fetal heart block outcomes were assessed using receiver-operating characteristic curves. The primary study outcomes were the presence and specificity of anti-cardiac autoantibodies in autoimmune congenital heart block cases versus controls, the association between specific autoantibodies and congenital heart block development, and the predictive accuracy of identified autoantibodies. This study did not involve individuals with lived experience in the study design or implementation.
Serum samples were collected between Jan 1, 2010, and Dec 31, 2020, in the discovery cohort (The Hospital for Sick Children), between Aug 1, 1999, and Dec 31, 2019 in the verification cohort (University Hospital of Padua), and between June 1, 2018, and Aug 31, 2023, in the validation cohort (The Hospital for Sick Children). Mean maternal age was 34·2 years (SD 5·2) in the discovery cohort, 33·5 years (4·6) in the verification cohort, and 32·8 years (4·3) in the validation cohort. Maternal serum samples from pregnancies affected by fetal autoimmune congenital heart block (cases; n=46) showed an expanded repertoire of anti-cardiac autoantibodies compared with unaffected pregnancies (controls; n=65). Mass spectrometry identified 11 potential cardiac protein targets for maternal autoantibodies and the presence of seven autoantibodies were confirmed in serum samples from affected pregnancies. Four targets were identified before the onset of congenital heart block (ANXA1, BIP, MYPC3, and AT1A1). Maternal autoantibodies against the Na and K ATPase α1 isoform (AT1A1) were detected as early as 7 weeks gestation and were present in all affected pregnancies of mothers with and without previous fetal heart block history (six [100%] of six in the discovery cohort, 22 [100%] of 22 in the verification cohort, and 16 [100%] of 16 in the validation cohort). Anti-AT1A1 autoantibodies were absent in all unaffected pregnancies in pregnant women with no fetal heart block history (54/65 [83%]).
This study identifies a novel maternal autoantibody targeting the fetal AT1A1 cardiac protein as a potential biomarker for the early and accurate detection of fetal autoimmune congenital heart block in pregnant women who had not previously had an affected pregnancy. This advancement might improve the maternal-fetal management of at-risk pregnancies through enhanced surveillance and timely and informed therapeutic interventions.
Heart and Stroke Foundation of Canada and Canadian Institutes of Health Research.
胎儿自身免疫性先天性心脏传导阻滞是一种罕见但危及生命的疾病，难以预测。本研究旨在确定一种血清生物标志物，用于预测因母亲患系统性红斑狼疮、干燥综合征、未分化结缔组织病或有先天性心脏传导阻滞后代病史而处于风险中的妊娠中的自身免疫性先天性心脏传导阻滞。
本病例对照研究分析了来自两个中心（加拿大多伦多病童医院和意大利帕多瓦大学）受自身免疫性先天性心脏传导阻滞影响和未受影响的妊娠的母亲血液样本。收集的不同孕周的血清样本用于生物标志物的发现、验证和确认。关键纳入标准是母亲抗干燥综合征相关抗原A/ Ro自身抗体的临床检测呈阳性，关键排除标准是与心脏传导阻滞相关的结构性先天性心脏病。病例为导致胎儿或新生儿先天性心脏传导阻滞的妊娠，对照为导致后代心律正常的妊娠。使用胎儿心脏组织和干细胞衍生的心肌细胞，通过二维蛋白质印迹法鉴定靶向胎儿心脏蛋白的母亲自身抗体。使用商业蛋白质验证研究结果。使用受试者工作特征曲线评估预测胎儿心脏传导阻滞结局的敏感性和特异性。主要研究结果是自身免疫性先天性心脏传导阻滞病例与对照中抗心脏自身抗体的存在和特异性、特定自身抗体与先天性心脏传导阻滞发展之间的关联，以及所鉴定自身抗体的预测准确性。本研究在研究设计或实施过程中未涉及有实际经验的个体。
在发现队列（加拿大多伦多病童医院）中，于2010年1月1日至2020年12月31日期间收集血清样本；在验证队列（帕多瓦大学医院）中于1999年8月1日至2019年12月31日期间收集；在确认队列（加拿大多伦多病童医院）中于2018年6月1日至2023年8月31日期间收集。发现队列中母亲的平均年龄为34.2岁（标准差5.2），验证队列中为33.5岁（4.6），确认队列中为32.8岁（4.3）。与未受影响的妊娠（对照；n = 65）相比，受胎儿自身免疫性先天性心脏传导阻滞影响的妊娠（病例；n = 46）的母亲血清样本显示抗心脏自身抗体谱有所扩大。质谱分析确定了11种母亲自身抗体的潜在心脏蛋白靶点，并在受影响妊娠的血清样本中确认了7种自身抗体的存在。在先天性心脏传导阻滞发作前确定了4个靶点（膜联蛋白A1、结合免疫球蛋白蛋白、肌球蛋白结合蛋白C3和α1亚基钠钾ATP酶）。针对α1亚基钠钾ATP酶（AT1A1）的母亲自身抗体早在妊娠7周时就被检测到，并且在有和没有先前胎儿心脏传导阻滞病史的母亲的所有受影响妊娠中均存在（发现队列中的6例中有6例[100%]，验证队列中的22例中有22例[100%]，确认队列中的16例中有16例[100%]）。在没有胎儿心脏传导阻滞病史的孕妇的所有未受影响妊娠中均未检测到抗AT1A1自身抗体（54/65 [83%]）。
本研究确定了一种靶向胎儿AT1A1心脏蛋白的新型母亲自身抗体，作为在先前未发生过受影响妊娠的孕妇中早期准确检测胎儿自身免疫性先天性心脏传导阻滞的潜在生物标志物。这一进展可能通过加强监测以及及时和明智的治疗干预，改善高危妊娠的母胎管理。
加拿大心脏与中风基金会和加拿大卫生研究院。
