Specificity and effector mechanisms of autoantibodies in congenital heart block

Subclinical maternal autoimmune disease leading to congenital high degree atrioventricular block: Case report and review of the literature

Maternal autoimmune disease is the most common cause of congenital heart block (CHB), a rare illness characterized by fibrosis and calcification of the fetal atrioventricular (AV) node due to maternal autoantibodies anti-SSA/Ro and anti-SSB/La. We report the full autopsy and clinical information on a female neonate with high degree AV block and calcification in the AV node, atrial approaches to the AV node, and both right and left bundle branches, born to a 27-year-old female with subclinical autoimmune disease.

Autoimmune Congenital Complete Heart Block: How Late Can It Occur?

Objective  Maternal anti-Ro (SSA) and/or anti-La (SSB) antibodies are a risk factor for congenital complete heart block (CHB). Because detailed analysis of the incidence of CHB after 24 weeks of gestational age (GA) is lacking, we aimed to ascertain the risk of "later-onset" CHB among offspring of SSA/SSB-positive mothers in the published literature. Study Design  Using search terms "neonatal lupus heart block" and "autoimmune congenital heart block" on PubMed and Ovid, we gathered prospective studies of SSA/SSB-positive mothers with fetal echo surveillance starting from before CHB diagnosis and retrospective cases of fetal CHB diagnosis after 24 weeks of GA (if there was prior normal heart rate) or after birth. Results  Ten prospective studies included 1,248 SSA/SSB-positive pregnancies with 24 cases of CHB diagnosed during pregnancy (1.9%). Among these, three (12.5%) were after 24 weeks-at weeks 25, 26, and 28. Our retrospective studies revealed 50 patients with CHB diagnosis in late fetal life and neonatal period and 34 in the nonneonatal childhood period. An additional four cases were diagnosed after age 18 years. Conclusion  Later-onset autoimmune CHB in offspring of SSA/SSB-positive mothers does occur. Our analysis suggests that prenatal surveillance should continue beyond 24 weeks of GA but is limited by inconsistent published surveillance data.

An Overview of Neonatal Lupus with Anti-Ro Characteristics

Neonatal lupus erythematosus (NLE) is a syndrome of clinical symptoms observed in neonates born to mothers with antibodies to soluble antigens of the cell nucleus. The main factors contributing to the pathogenesis of this disease are anti-Sjögren Syndrome A (anti-SS-A) antibodies, known as anti-Ro, and anti-Sjögren Syndrome B (anti-SS-B) antibodies, known as anti-La. Recent publications have also shown the significant role of anti-ribonucleoprotein antibodies (anti-RNP). Seropositive mothers may have a diagnosed rheumatic disease or they can be asymptomatic without diagnosis at the time of childbirth. These antibodies, after crossing the placenta, may trigger a cascade of inflammatory reactions. The symptoms of NLE can be divided into reversible symptoms, which concern skin, hematological, and hepatological changes, but 2% of children develop irreversible symptoms, which include disturbances of the cardiac stimulatory and conduction system. Preconceptive care and pharmacological prophylaxis of NLE in the case of mothers from the risk group are important, as well as the monitoring of the clinical condition of the mother and fetus throughout pregnancy and the neonatal period. The aim of this manuscript is to summarize the previous literature and current state of knowledge about neonatal lupus and to discuss the role of anti-Ro in the inflammatory process.

Maternal Systemic Lupus Erythematosus (SLE) High Risk for Preterm Delivery and Not for Long-Term Neurological Morbidity of the Offspring

Objective: Pregnancies of women with systemic lupus erythematosus (SLE) are associated with preterm delivery. As preterm delivery is associated with long-term neurological morbidity, we opted to evaluate the long-term neurologic outcomes of offspring born to mothers with SLE regardless of gestational age. Methods: Perinatal outcomes and long-term neurological disease of children of women with and without SLE during pregnancy were evaluated. Children of women with and without SLE were followed until 18 years of age for neurological diseases. Generalized estimating equation (GEE) models were used to assess perinatal outcomes. To compare cumulative neurological morbidity incidence a Kaplan–Meier survival curve was used, and a Cox proportional hazards model was used to control for confounders. Result: A total of 243,682 deliveries were included, of which 100 (0.041%) were of women with SLE. Using a GEE model, maternal SLE was noted as an independent risk factor for preterm delivery. The cumulative incidence of long-term neurological disease was not found to be significantly higher when using the Kaplan Meier survival curves and maternal SLE was not found to be associated with long-term neurological disease of the offspring when a Cox model was used. Conclusion: Despite the association of SLE with preterm delivery, no difference in long-term neurological disease was found among children of women with or without SLE.

Case Report: Prenatal Diagnosis and Treatment of Fetal Autoimmune-Associated First-Degree Atrioventricular Block: First Report From China

Background: The rapid progression from fetal first-degree atrioventricular block (AVB) to third-degree AVB had been reported. However, how to define fetal first-degree AVB with proper technique and the necessity of the treatment in utero for fetal autoimmune-associated first-degree AVB are still controversial.

Purpose: To explore the diagnosis and the effect of treatment for fetal first-degree AVB.

Cases Presentation: Four pregnant women with positive autoantibodies anti-SSA/Ro were admitted into our hospital with complaints of rapid prolonged atrioventricular (AV) intervals of their fetuses. Fetal AV intervals were re-measured by tissue Doppler imaging (TDI) from the onset of atrial contraction to ventricular systole (Aa-Sa), which were 170 ms (case 1-twin A), 160 ms (case 1-twin B), 163 ms (case 2) and 172 ms (case 3) and 170 ms (case 4), respectively. The histories of medication usage or infection during gestation were denied. Amniotic fluid genetic screenings and virological tests were negative in all cases. No structural cardiac disorders were found and the cardiovascular profile scores were 10 for each fetus. Oral dexamethasone (initial dose of 4.5 mg daily) and hydroxychloroquine (200 mg bid) plus weekly follow-up surveillance were suggested. The dosage of dexamethasone was adjusted according to the changes of the AV intervals and fetal development of biparietal diameters (BPD) and femur lengths (FL). All fetal AV intervals were controlled well. Maternal and fetal adverse effects were noted as diabetes in 1 mother and growth retardation in all fetuses. All fetuses were delivered via cesarean section at 35⁺⁴, 37, 38, and 37⁺¹ gestational weeks, with 10 scores of Apgar score. Postnatally, positive anti-SSA/Ro was found in all neonates. However, there were no clinical or laboratory evidence of neonatal lupus syndrome. No abnormal signs were found on postnatal electrocardiogram and echocardiography for all neonates. With a follow-up of 8–53 months, there was no progression of disease and all infants demonstrated normal physical, mental, and motor development.

Conclusion: Prenatal treatment for fetal autoimmune-associated first-degree AVB could be an alternative. Strict surveillance and timely adjustment of the treatment according to the conditions of the mother and the fetus are indicated. Further studies are necessary to prove our concept.

Type I IFN system activation in newborns exposed to Ro/SSA and La/SSB autoantibodies in utero

OBJECTIVE

In utero exposure of the fetus to Ro/La autoantibodies may lead to congenital heart block (CHB). In the mother, these autoantibodies are associated with activation of the type I interferon (IFN)-system. As maternal autoantibodies are transferred to the fetus during pregnancy, we investigated whether the type I IFN-system is activated also in newborns of anti-Ro/La positive mothers, and whether fetal IFN activation is affected by maternal immunomodulatory treatment.

METHODS

Blood drawn at birth from anti-Ro/La positive mothers, their newborns and healthy control pairs was separated into plasma and peripheral blood mononuclear cells (PBMC). PBMC were analysed directly or cultured. mRNA expression was analysed by microarrays, cell surface markers by flow cytometry, and IFNα levels by immunoassays.

RESULTS

We observed increased expression of IFN-regulated genes and elevated plasma IFNα levels not only in anti-Ro/La positive women, but also in their newborns. CD14⁺ monocytes of both anti-Ro/La positive mothers and their neonates showed increased expression of Sialic acid-binding Ig-like lectin-1, indicating cellular activation. Notably, the IFN score of neonates born to mothers receiving immunomodulatory treatment was similar to that of controls, despite persistent IFN activation in the mothers. In both maternal and neonatal PBMC, IFNα production was induced when cells were cultured with anti-Ro/La positive plasma.

CONCLUSIONS

Ro/La autoantibody-exposed neonates at risk of CHB have signs of an activated immune system with an IFN signature. This study further demonstrates that neonatal cells can produce IFNα when exposed to autoantibody-containing plasma, and that maternal immunomodulatory treatment may diminish the expression of IFN-regulated genes in the fetus.

Interferons and innate immune activation in autoimmune congenital heart block

Autoimmune congenital heart block (CHB) may develop in foetuses of women carrying anti-Ro/SSA and La/SSB autoantibodies and is characterized by disruption of signal conduction at the atrioventricular (AV) node, resulting in partial or complete AV block. If not fatal in utero, complete CHB typically requires lifelong cardiac pacing. No treatment has so far been unequivocally demonstrated to prevent or treat autoimmune CHB, and the relatively low incidence (1%-5%) and recurrence (12%-16%) rates of second/third-degree AV block add to the complexity of managing pregnancies in women with anti-Ro/La antibodies. Altogether, a better understanding of events leading to development of autoimmune CHB is needed to improve surveillance and treatment strategies. In the past decade, studies have started to look beyond the role of maternal autoantibodies in disease pathogenesis to assess other contributing factors such as foetal genetics and, more recently, immune responses in foetuses and neonates of anti-Ro/La antibody-positive women. In this review, we provide an update on the epidemiology, clinical presentation and current treatment approaches of autoimmune CHB, summarize the previously proposed pathogenic mechanisms implicating maternal autoantibodies, and discuss the recent findings of type I interferon (IFN) and innate immune activation in foetuses with autoimmune CHB and in neonates of anti-Ro/La antibody-positive mothers, and how these may contribute to autoimmune CHB pathogenesis.

Comorbidity and long-term outcome in patients with congenital heart block and their siblings exposed to Ro/SSA autoantibodies in utero

Objective

Congenital heart block (CHB) may develop in fetuses of Ro/SSA autoantibody-positive women. Given the rarity of CHB, information on comorbidity and complications later in life is difficult to systematically collect for large groups of patients. We therefore used nation-wide healthcare registers to investigate comorbidity and outcomes in patients with CHB and their siblings.

Methods

Data from patients with CHB (n= 119) and their siblings (n= 128), all born to anti-Ro/SSA-positive mothers, and from matched healthy controls (n= 1,190) and their siblings (n= 1,071), were retrieved from the Swedish National Patient Register. Analyses were performed by Cox proportional hazard modelling.

Results

Individuals with CHB had a significantly increased risk of cardiovascular comorbidity, with cardiomyopathy and/or heart failure observed in 20 (16.8%) patients versus 3 (0.3%) controls, yielding a HR of 70.0 (95% CI 20.8 to 235.4), and with a HR for cerebral infarction of 39.9 (95% CI 4.5 to 357.3). Patients with CHB also had a higher risk of infections. Pacemaker treatment was associated with a decreased risk of cerebral infarction but increased risks of cardiomyopathy/heart failure and infection. The risk of systemic connective tissue disorder was also increased in patients with CHB (HR 11.8, 95% CI 4.0 to 11.8), and both patients with CHB and their siblings had an increased risk to develop any of 15 common autoimmune conditions (HR 5.7, 95% CI 2.83 to 11.69 and 3.6, 95% CI 1.7 to 8.0, respectively).

Conclusions

The data indicate an increased risk of several cardiovascular, infectious and autoimmune diseases in patients with CHB, with the latter risk shared by their siblings.

Hemodynamics in fetal arrhythmia

Fetal arrhythmias are among the few conditions that can be managed in utero. However, accurate diagnosis is essential for appropriate management. Ultrasound-based imaging methods can be used to study fetal heart structure and function noninvasively and help to understand fetal cardiovascular pathophysiology, and they remain the mainstay of evaluating fetuses with arrhythmias in clinical settings. Hemodynamic evaluation using Doppler echocardiography allows the elucidation of the electrophysiological mechanism and helps to make an accurate diagnosis. It can also be used as a tool to understand fetal cardiac pathophysiology, for assessing fetal condition and monitoring the effect of antiarrhythmic treatment. This narrative review describes Doppler techniques that are useful for evaluating fetal cardiac rhythms to refine diagnosis and provides an overview of hemodynamic changes observed in different types of fetal arrhythmia.

Doppler echocardiographic isovolumetric time intervals in diagnosis of fetal blocked atrial bigeminy and 2:1 atrioventricular block

OBJECTIVE

To distinguish between blocked atrial bigeminy (BB) and incomplete atrioventricular block with 2:1 conduction (2:1 AVB) can be very difficult, especially in the mid-term fetus. Making a correct diagnosis has important clinical implications, as their prognosis and management differ markedly. Our objective was to investigate whether analysis of isovolumetric time intervals could improve Doppler echocardiography in differentiating these conditions.

METHODS

Sixteen fetuses with sustained BB or isolated 2:1 AVB, diagnosed at our tertiary center from 2002 to 2012, were reviewed retrospectively. Doppler recordings of left ventricular in- and outflow, including mitral and aortic valve movements, were used to measure isovolumetric contraction (ICT) and relaxation (IRT) time intervals. ICT reference values obtained from 104 normal pregnancies were used for comparison.

RESULTS

Ten fetuses had BB and six 2:1 AVB. Five of the AVB cases were anti-Ro antibody positive and one had long QT syndrome (LQTS). ICT was systematically shorter in BB than in antibody-mediated 2:1 AVB. Nine of 10 cases with BB had an ICT below -2 SD and the five with antibody-mediated 2:1 AVB had values at or above +2 SD. All 15 fetuses with either BB or antibody-mediated AVB had an IRT of < 70 ms, as opposed to a markedly prolonged IRT (105 ms) in the LQTS case.

CONCLUSION

Measurement of ICT can improve the differential diagnosis between BB and antibody-mediated 2:1 AVB. Fetuses with BB or antibody-mediated AVB are unlikely to have IRT measurements exceeding 70 ms and, when this is observed, LQTS should be considered a more likely diagnosis.

Gender differences in autoimmune disease

Autoimmune diseases are a range of diseases in which the immune response to self-antigens results in damage or dysfunction of tissues. Autoimmune diseases can be systemic or can affect specific organs or body systems. For most autoimmune diseases there is a clear sex difference in prevalence, whereby females are generally more frequently affected than males. In this review, we consider gender differences in systemic and organ-specific autoimmune diseases, and we summarize human data that outlines the prevalence of common autoimmune diseases specific to adult males and females in countries commonly surveyed. We discuss possible mechanisms for sex specific differences including gender differences in immune response and organ vulnerability, reproductive capacity including pregnancy, sex hormones, genetic predisposition, parental inheritance, and epigenetics. Evidence demonstrates that gender has a significant influence on the development of autoimmune disease. Thus, considerations of gender should be at the forefront of all studies that attempt to define mechanisms that underpin autoimmune disease.

Late development of complete atrioventricular block may be immune mediated and congenital in origin

AIM

To investigate the correlation between maternal autoantibodies and age at diagnosis of isolated complete atrioventricular (AV) block (CAVB) and to study signs of late progression of foetal immune-mediated insults in cases of postnatally diagnosed CAVB.

METHODS

Patients with CAVB (n = 190) identified in a population-based manner were included. Maternal autoantibody profile was correlated with age at CAVB diagnosis. A structured review of medical records was performed if a late CAVB diagnosis (>27 days post-partum) was associated with a sero-positive mother.

RESULTS

Maternal Ro/La autoantibodies were observed in 88% of cases with a congenital diagnosis. Thirteen cases with a sero-positive mother and late CAVB diagnosis were found (age-range: 4 months-43 years). In two cases, CAVB was diagnosed in conjunction with infections, one case had a family history of cardiomyopathy and two cases had nontypical clinical presentations, indicating alternative pathogenetic mechanisms. In the remaining eight cases, no likely factors inducing CAVB, other than maternal autoantibodies, could be identified.

CONCLUSION

Our observations support the hypothesis that late progression to CAVB can be the result of an immune-mediated pathogenetic mechanism during foetal life. An autoantibody-associated diagnosis after the neonatal period is therefore possible, and testing of maternal serology at the time of diagnosis is recommended.

Non benign neonatal arrhythmias observed in a tertiary neonatal intensive care unit

OBJECTIVE

To analyze non benign neonatal arrhythmias (NA) observed in a tertiary neonatal intensive care unit (NICU).

METHODS

From June 2006 through July 2011, newborns admitted to the NICU for NA or diagnosed as NA after hospitalization were evaluated retrospectively. The newborns with non benign NA were included in the study.

RESULTS

During the study period, the incidence of non-benign NA was 0.7 % (n = 55/7880). The mean age at diagnosis was 16.7 ± 1.8 d ranging from 1 d to 90 d. The most common type was supraventricular arrhythmia (SVT) with an incidence of 0.3 %. Univariate analyses showed that there were significant differences between the survived and died infants according types of congenital heart disease (CHD), electrolyte imbalance, and arrhythmias. The mortality rates were higher among infants with obstructive type left-to right shunt and common mixing type CHD. The most dangerous type of electrolyte imbalance was hyperkalemia.

CONCLUSIONS

Many arrhythmias could not be noticed at neonatal period even in NICU, implying that it is increasingly important for the physician to be aware of the etiology, development, and natural history of these arrhythmias.

Neurodevelopment in children with and without congenital heart block born to anti-Ro/SSA-positive mothers

OBJECTIVE

To define factors influencing neurodevelopment in children with and without complete congenital heart block (CHB) born to mothers with Ro/SSA autoantibodies.

PATIENTS AND METHODS

Medical records of a population-based cohort of siblings with (n = 60) and without (n = 54) CHB born 1974-2009 to anti-Ro/SSA-positive mothers were retrieved from children primary healthcare centres and school health services and used to extract data on neurodevelopment.

RESULTS

Impaired neurodevelopment was reported in 16% of the children (18/114) during the follow-up time of 13.0 (8.2-17.5) years, median (quartiles). Reported problems included speech (9%), motor (8%) and learning (8%) impairment, attention deficit (5%) and behavioural impairment (4%). Impairment in motor skill development was more common in boys (p < 0.001) if the child was born preterm (p < 0.001). Learning impairment was significantly influenced by maternal SLE (p < 0.005), while attention deficits was influenced by both maternal SLE (p < 0.05) and CHB in the child (p < 0.05).

CONCLUSIONS

Our data indicate that in addition to well-established factors such as male sex and being born preterm, both maternal SLE and CHB may influence neurodevelopment. Follow-up of neurodevelopment should therefore be considered for children with CHB, especially if the mother is diagnosed with SLE.

Atrioventricular conduction delay in fetuses exposed to anti-SSA/Ro and anti-SSB/La antibodies: a magnetocardiography study

Background. The presence of anti-SSA/Ro and anti-SSB/La antibodies during pregnancy is associated with fetal congenital heart block (CHB), which is primarily diagnosed through fetal echocardiography. Conclusive information about the complete electrophysiology of the fetal cardiac conducting system is still lacking. In addition to echocardiography, fetal magnetocardiography (fMCG) can be used. fMCG is the magnetic analogue of the fetal electrocardiogram (ECG). Patients and Methods. Forty-eight pregnant women were enrolled in an observational study; 16 of them tested positive for anti-SSA/Ro and anti-SSB/La antibodies. In addition to routine fetal echocardiography, fMCG was used. Fetal cardiac time intervals (fCTIs) were extracted from the magnetic recordings by predefined procedures. ECGs in the neonates of the study group were performed within the first month after delivery. Results. The PQ segment of the fCTI was significantly prolonged in the study group (P = 0.007), representing a delay of the electrical impulse in the atrioventricular (AV) node. Other fCTIs were within normal range. None of the anti-SSA/Ro and/or anti-SSB/La fetuses progressed to a more advanced heart block during pregnancy or after birth. Conclusion. The study identified a low-risk population within antibody positive mothers, where PQ segment prolongation is associated with a lack of progression of the disease.

The predictive value of anti-SS-A antibodies titration in pregnant women with fetal congenital heart block

OBJECTIVE

Fetal congenital complete heart block (CHB) is irreversible and is associated with significant mortality and morbidity. Anti-SS-A antibodies in the maternal sera are involved in its pathogenesis; however, the predictive value of the antibody titer and its role in prediction of this complication are controversial. The aim of this study was to determine the predictive value of maternal anti-SS-A antibodies on the development of fetal CHB.

METHODS

A retrospective chart review was performed for 189 cases of positive anti-SS-A antibodies determined by the double immunodiffusion (DID) method, and included 17 patients that developed fetal CHB. The relationship between the appearance of CHB and the anti-SS-A antibodies titer was examined.

RESULTS

An anti-SS-A antibodies titer of 1:32 or higher was identified by analyzing the receiver-operating characteristics (area under curve 0.72) curve. An anti-SS-A antibodies titer of 32 or more times greater than the upper limit by DID was a risk factor for fetal CHB (odds ratio 27.77, 95% confidence interval (CI) 1.91-21.02, P < 0.05) in the multivariate analysis. Among 107 cases of anti-SS-A antibodies titers of 1:32 or higher, 65 patients (60.7%) were treated with oral steroids. Of these, four patients had CHB (6.2%). This rate of CHB was significantly lower (P < 0.01) than the rate in patients not treated with steroids.

CONCLUSION

An anti-SS-A antibodies titer of 1:32 or higher in the maternal sera by DID was an independent risk factor for fetal CHB. In these patients, either antenatally administered prednisolone or betamethasone, was associated with a lower risk of fetal CHB.

Cardiac manifestations of neonatal lupus: a review of autoantibody-associated congenital heart block and its impact in an adult population

Within the last decade the prevalence of adult patients living with congenital heart disease equals that seen in children. This expanding population poses a challenge to clinical cardiologists who will be caring for patients with the clinical manifestations of this condition. Neonatal lupus is a model of passively acquired autoimmunity and is responsible for the majority of clinical cases of congenital heart block (CHB). This review will focus on the presentation, pathophysiology, and the long-term follow-up of CHB associated with neonatal lupus, and discuss important diagnostic tests, familial implications, and pacemaker issues associated with the care of an adult with CHB.

Neonatal autoimmune diseases: a critical review

Neonatal autoimmune diseases are distinctly rare. Most neonatal autoimmune diseases result from the transplacental transfer of maternal antibodies directed against fetal or neonatal antigens in various tissues. In neonatal lupus, the heart seems to be particularly susceptible. Primary autoimmunity in newborns, with the exception of familial autoinflammatory diseases, is virtually non-existent. The pathophysiologic basis for the development of neonatal autoimmunity is not entirely clear, but differences in the neonatal immune system compared with the adult immune system, as well as unique characteristics of target antigens in the newborn period may be important factors. Neonatal lupus is the most common presentation of autoimmunity in the newborn. But the characteristics defining neonatal lupus are not well defined and the presentation of neonatal lupus differs from that of classical lupus. Other neonatal autoimmune diseases involving the interaction between maternal antibodies and fetal/neonatal antigens include neonatal anti-phospholipid syndrome, Behcet's disease, neonatal autoimmune thyroid disease, neonatal polymyositis and dermatomyositis, neonatal scleroderma and neonatal type I diabetes mellitus. While autoantibodies have been detected in patients with neonatal autoimmune disease, the pathogenic role of autoantibodies has not been well defined. Other mechanisms may play a role in the development of neonatal autoimmunity, including fetal/maternal microchimerism and aberrant apoptosis of fetal cells. The autoinflammatory syndromes are a completely different category, but are also included in discussion of neonatal autoimmune diseases. The autoinflammatory syndromes include the cryopyrin associated periodic syndromes (CAPS) - familial cold autoinflammatory syndrome (FCAS), neonatal onset multisystem inflammatory disease (NOMID) and Muckle-Wells syndrome, which all share a common pathophysiologic mechanism.

The developing immune system - from foetus to toddler

During foetal development, neonatal period and childhood, the immune system is constantly maturing. In the foetus, infection responsiveness is low and associates with spontaneous abortion. During the neonatal period, the infection response shifts towards a more pro-inflammatory response. The immune system of the newborn acquires adaptive features as a result of exposure to microbes.

CONCLUSION

The development of the human immune system is a continuous process where both accelerated and retarded development is deleterious.

A population-based investigation of the autoantibody profile in mothers of children with atrioventricular block

The objective of the study was to investigate the antigen specificity and occurrence of individual autoantibodies in mothers of children diagnosed with atrioventricular (AV) block in a nation-wide setting. Patients with AV block detected before 15 years of age were identified using national quality registries as well as a network of pediatric and adult cardiologists and rheumatologists at the six university hospitals in Sweden. Patients with gross heart malformations, surgically or infectiously induced blocks were excluded. Blood samples were obtained from the mothers and maternal autoantibody profile, including the occurrence of antibodies against Ro52, Ro60, La, SmB, SmD, RNP-70k, RNP-A, RNP-C, CENP-C, Scl-70, Jo-1, ribosomal RNP and histones was investigated in 193 mothers of children with AV block by immunoblotting and ELISA. Autoantibody reactivity was detected in 48% (93/193) of the mothers of children with AV block. In autoantibody-positive mothers, the vast majority, 95% (88/93), had antibodies against Ro52, while 63% (59/93) had autoantibodies to Ro60 and 58% (54/93) had autoantibodies to La. In addition, 13% (12/93) of the autoantibody-positive mothers had antibodies to other investigated antigens besides Ro52, Ro60 and La, and of these anti-histone antibodies were most commonly represented, detected in 8% (7/93) of the mothers. In conclusion, this Swedish population-based study confirms that maternal autoantibodies may associate with heart block in the child. Further, our data demonstrate a dominant role of Ro52 antibodies in association with AV block.

Fetal echocardiographic assessment of endocardial fibroelastosis in maternal anti-SSA antibody-associated complete heart block

BACKGROUND

There are few reports describing the features of maternal anti-SSA antibody-associated congenital complete heart block (CCHB) patients developing endocardial fibroelastosis (EFE). The aim of this study was to describe the clinical features and the outcome of patients with CCHB, with or without EFE.

METHODS AND RESULTS

Over a 20-year period, 12 consecutive patients diagnosed with maternal anti-SSA antibody-associated CCHB were identified. The maternal anti-SSA antibody levels were measured and fetal echocardiographic findings were reviewed. The ratios of the thickness of the endocardium to that of the whole wall of the left ventricle (LE/W) and right ventricle (RE/W) were measured to investigate the degree of endocardial thickening. A total of 7 patients survived (living group) and were not diagnosed as having EFE. The remaining 5 patients died and were diagnosed with EFE during autopsy (dead group). Fetal echocardiography of the patients showed differences in the thickening and hyperintensity of the endocardium. The RE/W value was significantly higher in the dead group than in the living group. The titers of both maternal anti-52-kDa and anti-60-kDa SSA antibodies were high, but showed no significant differences between the 2 patient groups.

CONCLUSIONS

EFE was the major negative prognostic factor for CCHB. Myocardial damage, predominantly in the right ventricle, was related to the outcome of CCHB associated with EFE.

Serum and organ-associated anti-hemoglobin humoral autoreactivity: association with anti-Sm responses and inflammation

The release of hemoglobin (Hb) occurs in some infectious and autoimmune diseases characterized by inflammation. As levels of haptoglobin (Hp) fall, free Hb can cause pathology. Humoral autoreactivity to human Hb was demonstrated in the sera of systemic lupus erythematosus (SLE), leishmania and malaria patients. Serum anti-murine Hb antibody levels in lupus-prone mice also exhibited an age-dependent increase, with progressive organ sequestration; significant isotypic correlation was observed with anti-dsDNA antibodies. A suggestive link between anti-Hb and anti-Sm responses was observed: Human lupus sera expressing anti-Sm antibody reactivity preferentially contained heightened levels of anti-Hb autoantibodies, and immunization of lupus-prone mice with Sm led to enhanced anti-murine Hb reactivity. Human and murine anti-Hb monoclonal antibodies were generated, some of which were preferentially reactive toward disease-associated methemoglobin. Epitope-mapping studies revealed evidence of intra-molecular cross-reactivity. One such autoantibody synergized with Hb to enhance the secretion of pro-inflammatory cytokines while eliciting the increased production of monocyte migratory signals from endothelial cells. Preferential usage of specific variable region gene segments was not observed, although somatic mutations were documented. These studies reveal that, while the etiology, specificity and sequences of anti-Hb autoreactive antibodies can vary, they occur quite frequently and can have inflammatory consequences.

The experiences of pregnancy in women with SSA/Ro52 autoantibodies

OBJECTIVE

 Congenital heart block may develop in the foetus during pregnancy in SSA/Ro52 autoantibody-positive women. The aim of this study was to investigate how women with SSA/Ro52 autoantibodies experience their pregnancy in terms of the risk of developing foetal heart block, and in undergoing serial ultrasound Doppler echocardiography to detect early signs of congenital heart block.

METHODS

 Data were collected through individual semi-structured interviews with SSA/Ro52-positive women post-pregnancy (n = 14). The interviews were audio-taped, transcribed verbatim and analysed according to qualitative content analysis.

RESULTS

 Three categories emerged from the responses: information, emotional response and support. The information received prior to and during early pregnancy was focused on the need for attending a specialized antenatal clinic, and information on the risk for congenital heart block was scarce or missing. During gestational weeks 18-24, when the ultrasound/Doppler examinations were performed, all women described increased stress. However, the interaction with the caregivers made the women feel more safe and secure. Several women also said that they did not emotionally acknowledge the pregnancy until after gestational week 24. None had been offered psychological support.

CONCLUSION

 There is a need for structured information and organized programmes for the surveillance of women who are SSA/Ro52 positive during their pregnancy. Further, offering psychological support to the women and their families to manage the stress and to facilitate the early attachment to the child should be considered.

Spectrum of cardiac involvement in neonatal lupus

'Neonatal' lupus erythematosus (NLE) describes a clinical spectrum of cardiac and non-cardiac abnormalities observed in neonates and foetuses whose mothers have the auto-antibodies anti-SSA/Ro (anti-Ro) and anti-SSB/La (anti-La). Of the cardiac abnormalities, congenital AVB is the most common cardiovascular abnormality found in affected foetuses and infants. Many other cardiovascular manifestations of NLE have been more recently recognized including atrial and ventricular arrhythmias and other conduction abnormalities, myocarditis, cardiomyopathy often with endocardiofibroelastosis and structural heart disease, particularly valvar lesions. In this report, the spectrum of cardiovascular manifestations observed in foetuses and infants with NLE are reviewed and the pathogenesis, diagnosis and clinical outcomes are briefly discussed.

Anti-Ro/SSA antibodies and cardiac arrhythmias in the adult: facts and hypotheses

It is well established that the passive trans-placental passage of anti-Ro/SSA antibodies from mother to foetus is associated with the risk to develop an uncommon syndrome named neonatal lupus (NLE), where the congenital heart block represents the most severe clinical feature. Recent evidence demonstrated that also adult heart, classically considered invulnerable to the anti-Ro/SSA antibodies, may represent a target of the arrhythmogenicity of these autoantibodies. In particular, the prolongation of the QTc interval appears the most frequent abnormality observed in adults with circulating anti-Ro/SSA antibodies, with some data suggesting an association with an increased risk of ventricular arrhythmias, also life threatening. Moreover, even though the association between anti-Ro/SSA antibodies and conduction disturbances is undoubtedly less evident in adults than in infants, from the accurate dissection of the literature data the possibility arises that sometimes also the adult cardiac conduction tissue may be affected by such antibodies. The exact arrhythmogenic mechanisms involved in foetus/newborns and adults, respectively, have not been completely clarified as yet. However, increasing evidence suggests that anti-Ro/SSA antibodies may trigger rhythm disturbances through an inhibiting cross-reaction with several cardiac ionic channels, particularly the calcium channels (L-type and T-type), but also the potassium channel hERG, whose different expression and involvement in the cardiac electrophysiology during lifespan might account for the occurrence of age-related differences.

Autoantibodies associated with congenital heart block

Congenital heart block is the most severe manifestation of neonatal lupus syndrome. It is a passively acquired disease where transplacental passage of maternal autoantibodies is associated with irreversible damage of the foetal cardiac conduction system. It is well established that the condition, in the absence of structural abnormalities, is strongly associated with maternal autoantibodies to the Ro/La antigens. More specifically the disease has been closely linked to antibodies to the Ro52 component of the antigen complex. Congenital heart block constitutes a unique model where specific autoantibodies target and mediate organ-specific disease. A wide panel of maternal antibodies has been discussed in literature in association with the disease and are described in this review.

Maternal MHC regulates generation of pathogenic antibodies and fetal MHC-encoded genes determine susceptibility in congenital heart block

Congenital heart block develops in fetuses of anti-Ro52 Ab-positive women. A recurrence rate of 20%, despite the persistence of maternal autoantibodies, indicates that there are additional, yet unidentified, factors critical for development of congenital heart block. In this study, we demonstrate that besides the maternal MHC controlling Ab specificity, fetal MHC-encoded genes influence fetal susceptibility to congenital heart block. Using MHC congenic rat strains, we show that heart block develops in rat pups of three strains carrying MHC haplotype RT1(av1) (DA, PVG.AV1, and LEW.AV1) after maternal Ro52 immunization, but not in LEW rats (RT1(l)). Different anti-Ro52 Ab fine specificities were generated in RT1(av1) versus RT1(l) animals. Maternal and fetal influence was determined in an F(2) cross between LEW.AV1 and LEW strains, which revealed higher susceptibility in RT1(l) than RT1(av1) pups once pathogenic Ro52 Abs were present. This was further confirmed in that RT1(l) pups more frequently developed heart block than RT1(av1) pups after passive transfer of RT1(av1) anti-Ro52 sera. Our findings show that generation of pathogenic Ro52 Abs is restricted by maternal MHC, whereas the fetal MHC locus regulates susceptibility and determines the fetal disease outcome in anti-Ro52-positive pregnancies.

Ultrasonographic diagnosis of delayed atrioventricular conduction during fetal life: a reliability study

OBJECTIVE

The objective of the study was to evaluate the reliability of the 2 most commonly used ultrasonographic approaches for monitoring fetal atrioventricular conduction time (AVCT): (1) superior vena cava/ascending aorta (SVC/AA), and (2) left ventricular inflow/outflow tract (LVI/O) Doppler recordings.

STUDY DESIGN

Echographic studies from fetuses followed up for first-degree atrioventricular block (AVB-1) between 1998 and 2008 were reviewed. The ability to identify atrial contractions in the same fetuses by the SVC/AA and LVI/O approaches was analyzed.

RESULTS

Sixty-six studies of 13 fetuses with AVB-1 were available. Atrial contractions were visible in all SVC/AA studies. With the LVI/O approach, atrial contractions could not be identified in 26 studies (39%). AVCT delay was significantly greater in the nonidentifiable compared with the identifiable atrial contraction group (P < .001). Differences in heart rate and gestational age were not significant.

CONCLUSION

The LVI/O is unsuitable for prenatal screening of conduction system anomalies.

Controversies in the therapy of isolated congenital complete heart block

Controversies in the therapy of congenital complete heart block are reviewed in terms of the timing of pacemaker implantation, the type and complications of pacing and its role in the presence of myocardial dysfunction. Drug treatment may be useful in selected cases in the presence of pleural effusions, ascites and hydrops of the fetus, but have no effect on complete heart block. Administration of fluorinated steroids in anti-Ro antibody-positive mothers with the aim of preventing complete heart block has given controversial results. Because of the variety of the clinical presentations, especially in regard to pacing therapy, it is mandatory to refer patients with congenital complete heart block to specialized centers with adequate resources and experienced personnel.

Congenital heart block: identification of autoantibody binding site on the extracellular loop (domain I, S5-S6) of alpha(1D) L-type Ca channel

Congenital heart block (CHB) is an autoimmune disease associated with autoantibodies against intracellular ribonucleoproteins SSB/La and SSA/Ro. The hallmark of CHB is complete atrioventricular block. We have recently established that anti-SSA/Ro -SSB/La autoantibodies inhibit alpha(1D) L-type Ca current, I(Ca-L), and cross-react with the alpha(1D) Ca channel protein. This study aims at identifying the possible binding sites on alpha(1D) protein for autoantibodies from sera of mothers with CHB children. GST fusion proteins of the extracellular regions between the transmembrane segments (S5-S6) of each of the four alpha(1D) Ca channel protein domains I-IV were prepared and tested for reactivity with sera from mothers with CHB children and controls using ELISA. Sera containing anti-Ro/La autoantibodies from 118 mothers with CHB children and from 15 mothers with anti-Ro/La autoantibodies but have healthy children, and from 28 healthy mothers without anti-Ro/La autoantibodies and healthy children were evaluated. Seventeen of 118 (14.4%) sera from mothers with CHB children reacted with the extracellular loop of domain I S5-S6 region (E1). In contrast, only 2 of 28 (7%) of sera from healthy mothers (-anti-Ro/La) and healthy children reacted with E1 loop and none (0 of 15) of sera from healthy mothers (+anti-Ro/La) and healthy children reacted with the E1 loop. Preincubation of E1 loop with the positive sera decreased the O.D reading establishing the specificity of the response. Electrophysiological characterization of the ELISA positive sera and purified IgG showed inhibition (44.1% and 49.8%, respectively) of the alpha(1D) I(Ca-L) expressed in tsA201 cells. The inhibition was abolished when the sera were pre-incubated with E1 fusion protein. The results identified the extracellular loop of domain I S5-S6 of L-type Ca channel alpha(1D) subunit as a target for autoantibodies from a subset of mothers with CHB children. This novel finding provides insights into the potential development of therapeutic peptides that could bind to the pathogenic antibodies and prevent CHB.

Nucleic acid-associated autoantigens: pathogenic involvement and therapeutic potential

Autoimmunity to ubiquitously expressed macromolecular nucleic acid-protein complexes such as the nucleosome or the spliceosome is a characteristic feature of systemic autoimmune diseases. Disease-specificity and/or association with clinical features of some of these autoimmune responses suggest pathogenic involvement which, however, has been proven in only a few cases so far. Although the mechanisms leading to autoimmunity against nucleic acid-containing complexes are still far from being fully understood, there is increasing experimental evidence that the nucleic acid component may act as a co-stimulator or adjuvans via activation of nucleic acid-binding receptor systems such as Toll-like receptors in antigen-presenting cells. Dysregulated apoptosis and inappropriate stimulation of nucleic acid-sensing receptors may lead to loss of tolerance against the protein components of such complexes, activation of autoreactive T cells and formation of autoantibodies. This has been demonstrated to occur in systemic lupus erythematosus and seems to represent a general mechanism that may be crucial for the development of systemic autoimmune diseases. This review provides a comprehensive overview of the most thoroughly-characterized nucleic acid-associated autoantigens, describing their structure and biological function, as well as the nature and pathogenic importance of the reactivities directed against them. Furthermore, recent advances in immunotherapy such as antigen-specific approaches targeted at nucleic acid-binding antigens are discussed.

Serologic follow-up of children born to mothers with Ro/SSA autoantibodies

Neonatal lupus erythematosus (NLE) develops in foetuses of mothers with Ro/SSA and La/SSB antibodies and may include foetal atrioventricular block and dermatologic manifestations. In this study, we investigated postnatal Ro and La IgG, IgA and IgM antibody levels up to 1 year of age in 32 children born to Ro/SSA positive mothers. Antibody levels were correlated with NLE manifestations, and the role of breast feeding in transfer of autoantibodies from mother to child was evaluated. Ro52, Ro60 and La IgG antibodies all transferred from the mothers to their foetus in utero and were present in the infant at birth as detected by enzyme-linked immunosorbent assay using recombinant antigens and a synthetic peptide. A significant decrease in Ro52, Ro60 and La IgG autoantibody levels of the infants was observed from birth to 4-5 weeks of age (P < 0.05, P < 0.05 and P < 0.01). Ro- and La-specific IgA and IgM antibodies were detected in the serum from a subset of mothers. However, Ro- and La-specific IgA and IgM antibody levels were low or non-detectable in children raised both with and without breastfeeding. Furthermore, NLE skin lesions developed independently of breastfeeding. Our findings support a role for placental materno-foetal transfer of IgG autoantibodies in the pathogenesis of NLE and indicate that refraining from breastfeeding does not protect from NLE skin involvement.

Clinical significance of anti-Ro/SSA-52 kDa antibodies: a retrospective monocentric study

OBJECTIVES

Two types of anti-Ro/SSA antibodies have been described, anti-SSA-52 kDa (aSSA52) and anti-SSA-60 kDa (aSSA60), each specific to different antigens. However, conflicting data exist concerning the involvement of the aSSA52 in autoimmune diseases (ADs). We therefore determined the clinical significance of these antibodies in patients displaying aSSA52, but not aSSA60.

METHODS

The 2005-08 retrospective monocentric study: all patients positive for aSSA60 and/or aSSA52 antibodies were investigated.

RESULTS

Among 297 patients, 82 were aSSA52 positive and aSSA60 negative. There were 21 males and 61 females. Forty-eight (58.5%) patients met our criteria for an AD. Two groups were distinguished according to the association (Group 1) or not (Group 2) of the aSSA52 with other autoantibodies. In Group 1, 33 out of 34 patients suffered from an AD. The two most common being SLE and SSc. The prevalence of AD was lower in Group 2 (15 out of 48, 31.3%, P = 0.001). aSSA52 levels were similar in patients with or without AD.

CONCLUSIONS

The existence of aSSA52 in association with other antibodies did not predict the presence of AD. There was no evidence to suggest that aSSA52 antibodies were associated with a specific clinical form of SLE or SSc. In the absence of other autoantibodies, aSSA52 was less associated with the presence of an AD. A positive aSSA52 test is of low diagnostic value for AD. Nevertheless, a longitudinal prospective follow-up study would determine whether or not persistence of these autoantibodies was of use in diagnosing AD.

A neonate with the rupture of mitral chordae tendinae associated with maternal-derived anti-SSA antibody

Acute mitral insufficiency due to the rupture of chordae tendinae from papillary muscles is a rare but sometimes fatal condition in neonates and infants. Here, we report a 21-day-old neonate with sudden onset of mitral insufficiency due to rupture of the chordae tendinae. The baby was successfully rescued by appropriate diagnosis and emergency surgical operation with reconstruction of the ruptured chordae using autologous pericardium-reinforced mattress suture. Intraoperative findings revealed fibrous scar formation at the distal end of the posterior papillary muscle, indicating a remnant of a certain inflammatory reaction. Transplacental passage of maternal anti-SSA antibody could account for the fetal inflammation at the ruptured chordae and the papillary muscle.

Overview of fetal arrhythmias

PURPOSE OF REVIEW

Though fetal arrhythmias account for a small proportion of referrals to a fetal cardiologist, they may be associated with significant morbidity and mortality. The present review outlines the current literature with regard to the diagnosis and, in brief, some management strategies in fetal arrhythmias.

RECENT FINDINGS

Advances in echocardiography have resulted in significant improvements in our ability to elucidate the mechanism of arrhythmia at the bedside. At the same time, magnetocardiography is broadening our understanding of mechanisms of arrhythmia especially as it pertains to ventricular arrhythmias and congenital heart block. It provides a unique window to study electrical properties of the fetal heart, unlike what has been available to date. Recent reports of bedside use of fetal ECG make it a promising new technology. Fetal magnetocardiography is also developing. The underlying mechanisms resulting in immune-mediated complete heart block in a small subset of 'at-risk' fetuses is under investigation.

SUMMARY

There have been great strides in noninvasive diagnosis of fetal arrhythmias. However, we still need to improve our knowledge of the electromechanical properties of the fetal heart as well as the mechanisms of arrhythmia to further improve outcomes. Multiinstitutional collaborative studies are needed to help answer some of the questions regarding patient, drug selection and management algorithms.

Antibodies to amino acid 200-239 (p200) of Ro52 as serological markers for the risk of developing congenital heart block

Maternal autoantibodies to the p200-epitope of Ro52 have been suggested to correlate with development of congenital heart block. The aim of the present study was to evaluate the clinical relevance and predictive value of p200-antibodies in high-risk pregnancies. Sera from 515 Finnish, Swedish and American women were included in the study. Sera originated from 202 mothers with an infant affected by second- or third-degree atrioventricular block (AVB), 177 mothers with rheumatic disease having infants with normal heart rate and female blood donors (n = 136). A novel serological assay for Ro52 p200-antibodies with intra- and inter-assay variability of 3% and 3.8% respectively was developed. Mothers of children affected by AVB II-III had significantly higher p200-antibody levels than mothers with rheumatic disease having children with normal heart rate (P < 0.001). In the Swedish cohort, a distinction between foetuses with normal conduction, AVB I, AVB II and III was possible. A significant difference in anti-p200 levels between AVB I and AVB II-III groups compared with foetuses with normal conduction (P < 0.05 and P < 0.01) was observed. Using p200-antibodies as a second step analysis in Ro52-positive pregnancies increased the positive predictive value for foetal cardiac involvement (AVB I, II or III) from 0.39 (0.27-0.51) to 0.53 (0.37-0.68). In conclusion, Ro52 p200-antibodies may occur in women with unaffected children, but levels are significantly higher in mothers of children with congenital heart block and are suggested as a relevant marker in evaluating the risk for foetal AV block.

Different temporal expression of immunodominant Ro60/60 kDa-SSA and La/SSB apotopes

Opsonization of apoptotic cardiocytes by maternal anti-Ro/SSA and anti-La/SSB antibodies contributes to tissue injury in the neonatal lupus syndrome. The objective of the current study was to quantify the surface membrane expression of Ro/La components during different phases of apoptosis and map the Ro/La apotopes (epitopes expressed on apoptotic cells) bound by cognate antibodies. Multi-parameter flow cytometry was used to define early and late apoptotic populations and their respective binding by monospecific anti-Ro and anti-La IgGs. Anti-Ro60 bound specifically to early apoptotic Jurkat cells and remained accessible on the cell surface throughout early and late apoptosis. In contrast, anti-La bound exclusively to late apoptotic cells in experiments controlled for non-specific membrane leakage of IgG. Ro52 was not accessible for antibody binding on either apoptotic population. The immunodominant NH2-terminal and RNA recognition motif (RRM) epitopes of La were expressed as apotopes on late apoptotic cells, confirming recent in vivo findings. An immunodominant internal epitope of Ro60 that contains the RRM, and is recognized by a majority of sera from mothers of children with congenital heart block (CHB) and patients with primary Sjögren's syndrome, was also accessible as an apotope on early apoptotic cells. The distinct temporal expression of the immunodominant Ro60 and La apotopes indicates that these intracellular autoantigens translocate independently to the cell surface, and supports a model in which maternal antibody populations against both Ro60 and La apotopes act in an additive fashion to increase the risk of tissue damage in CHB.