Author Correction: Tubular cell and keratinocyte single-cell transcriptomics applied to lupus nephritis reveal type I IFN and fibrosis relevant pathways.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Tubular cell and keratinocyte single-cell transcriptomics applied to lupus nephritis reveal type I IFN and fibrosis relevant pathways.

The molecular and cellular processes that lead to renal damage and to the heterogeneity of lupus nephritis (LN) are not well understood. We applied single-cell RNA sequencing (scRNA-seq) to renal biopsies from patients with LN and evaluated skin biopsies as a potential source of diagnostic and prognostic markers of renal disease. Type I interferon (IFN)-response signatures in tubular cells and keratinocytes distinguished patients with LN from healthy control subjects. Moreover, a high IFN-response signature and fibrotic signature in tubular cells were each associated with failure to respond to treatment. Analysis of tubular cells from patients with proliferative, membranous and mixed LN indicated pathways relevant to inflammation and fibrosis, which offer insight into their histologic differences. In summary, we applied scRNA-seq to LN to deconstruct its heterogeneity and identify novel targets for personalized approaches to therapy.

Digestion of Chromatin in Apoptotic Cell Microparticles Prevents Autoimmunity.

Antibodies to DNA and chromatin drive autoimmunity in systemic lupus erythematosus (SLE). Null mutations and hypomorphic variants of the secreted deoxyribonuclease DNASE1L3 are linked to familial and sporadic SLE, respectively. We report that DNASE1L3-deficient mice rapidly develop autoantibodies to DNA and chromatin, followed by an SLE-like disease. Circulating DNASE1L3 is produced by dendritic cells and macrophages, and its levels inversely correlate with anti-DNA antibody response. DNASE1L3 is uniquely capable of digesting chromatin in microparticles released from apoptotic cells. Accordingly, DNASE1L3-deficient mice and human patients have elevated DNA levels in plasma, particularly in circulating microparticles. Murine and human autoantibody clones and serum antibodies from human SLE patients bind to DNASE1L3-sensitive chromatin on the surface of microparticles. Thus, extracellular microparticle-associated chromatin is a potential self-antigen normally digested by circulating DNASE1L3. The loss of this tolerance mechanism can contribute to SLE, and its restoration may represent a therapeutic opportunity in the disease.

Store-Operated Ca(2+) Entry in Follicular T Cells Controls Humoral Immune Responses and Autoimmunity.

T follicular helper (Tfh) cells promote affinity maturation of B cells in germinal centers (GCs), whereas T follicular regulatory (Tfr) cells limit the GC reaction. Store-operated Ca(2+) entry (SOCE) through Ca(2+) release-activated Ca(2+) (CRAC) channels mediated by STIM and ORAI proteins is a fundamental signaling pathway in T lymphocytes. Conditional deletion of Stim1 and Stim2 genes in T cells abolished SOCE and strongly reduced antibody-mediated immune responses following viral infection caused by impaired differentiation and function of Tfh cells. Conversely, aging Stim1Stim2-deficient mice developed humoral autoimmunity with spontaneous autoantibody production due to abolished Tfr cell differentiation in the presence of residual Tfh cells. Mechanistically, SOCE controlled Tfr and Tfh cell differentiation through NFAT-mediated IRF4, BATF, and Bcl-6 transcription-factor expression. SOCE had a dual role in controlling the GC reaction by regulating both Tfh and Tfr cell differentiation, thus enabling protective B cell responses and preventing humoral autoimmunity.

Modeling of clinical phenotypes in systemic lupus erythematosus based on the platelet transcriptome and FCGR2a genotype.

BACKGROUND: The clinical heterogeneity of SLE with its complex pathogenesis remains challenging as we strive to provide optimal management. The contribution of platelets to endovascular homeostasis, inflammation and immune regulation highlights their potential importance in SLE. Prior work from our group showed that the Fcγ receptor type IIa (FcγRIIa)-R/H131 biallelic polymorphism is associated with increased platelet activity and cardiovascular risk in SLE. The study was initiated to investigate the platelet transcriptome in patients with SLE and evaluate its association across FcγRIIa genotypes and distinct clinical features. METHODS: Fifty-one patients fulfilling established criteria for SLE (mean age = 41.1 ± 12.3, 100% female, 45% Hispanic, 24% black, 22% Asian, 51% white, mean SLEDAI = 4.4 ± 4.2 at baseline) were enrolled and compared with 18 demographically matched control samples. The FCGR2a receptor was genotyped for each sample, and RNA-seq was performed on isolated, leukocyte-depleted platelets. Transcriptomic data were used to create a modular landscape to explore the differences between SLE patients and controls and various clinical parameters in the context of FCGR2a genotypes. RESULTS: There were 2290 differentially expressed genes enriched for pathways involved in interferon signaling, immune activation, and coagulation when comparing SLE samples vs controls. When analyzing patients with proteinuria, modules associated with oxidative phosphorylation and platelet activity were unexpectedly decreased. Furthermore, genes that were increased in SLE and in patients with proteinuria were enriched for immune effector processes, while genes increased in SLE but decreased in proteinuria were enriched for coagulation and cell adhesion. A low-binding FCG2Ra allele (R131) was associated with decreases in FCR activation, which further correlated with increases in platelet and immune activation pathways. Finally, we were able to create a transcriptomic signature of clinically active disease that performed significantly well in discerning SLE patients with active clinical disease form those with inactive clinical disease. CONCLUSIONS: In aggregate, these data demonstrate the platelet transcriptome provides insight into lupus pathogenesis and disease activity, and shows potential use as means of assessing this complex disease using a liquid biopsy.

Reducing the burden of surveillance in pregnant women with no history of fetal atrioventricular block using the negative predictive value of anti-Ro/SSA antibody titers.

BACKGROUND: The risk of fetal atrioventricular block in anti-Ro/SSA antibody-exposed pregnancies with no previous affected offspring is approximately 2%. A high antibody titer is necessary but not sufficient for atrioventricular block, and specific antibody titers do not predict risk. However, there are no data on the negative predictive value of antibody titer to identify pregnancies at low risk of fetal atrioventricular block, and may not require surveillance. OBJECTIVE: This study aimed to define anti-Ro52 and anti-Ro60 antibody thresholds for the identification of fetuses unlikely to develop atrioventricular block using clinically validated and research laboratory tests. STUDY DESIGN: This study performed a multicenter review of pregnant subjects who tested positive in their local commercial laboratories for anti-Ro/SSA antibodies at the University of Colorado Children's Hospital (2014-2021) and Phoenix Children's Hospital (2014-2021) and enrolled in the Research Registry for Neonatal Lupus (RRNL) at New York University Langone Medical Center (2002-2021). The subjects were referred on the basis of rheumatologic symptoms or history of atrioventricular block in a previous pregnancy and were retrospectively grouped on the basis of pregnancy outcome. Group 1 indicated no fetal atrioventricular block in current or past pregnancies; group 2 indicated fetal atrioventricular block in the current pregnancy; and group 3 indicated normal current pregnancy but with fetal atrioventricular block in a previous pregnancy. Maternal sera were analyzed for anti-Ro52 and anti-Ro60 antibodies using a clinically validated multiplex bead assay (Associated Regional and University Pathologists Laboratories, Salt Lake City, UT) and a research enzyme-linked immunosorbent immunoassay (New York University). This study calculated the negative predictive value separately for anti-Ro52 and anti-Ro60 antibodies and for the 2 combined using a logistic regression model and a parallel testing strategy. RESULTS: This study recruited 270 subjects (141 in group 1, 66 in group 2, and 63 in group 3). Of note, 89 subjects in group 1 had data on hydroxychloroquine treatment: anti-Ro/SSA antibody titers were no different between those treated (n=46) and untreated (n=43). Mean anti-Ro52 and anti-Ro60 titers were the lowest in group 1 and not different between groups 2 and 3. No case of fetal atrioventricular block developed among subjects with anti-Ro52 and anti-Ro60 titers of <110 arbitrary units per milliliter using the multiplex bead assay of the Associated Regional and University Pathologists Laboratories (n=141). No case of fetal atrioventricular block developed among subjects with research laboratory anti-Ro52 titers of <650 and anti-Ro60 of <4060 enzyme-linked immunosorbent immunoassay units (n=94). Using these 100% negative predictive value thresholds, more than 50% of the anti-Ro/SSA antibody pregnancies that ultimately had no fetal atrioventricular block could be excluded from surveillance based on clinical and research titers, respectively. CONCLUSION: Study data suggested that there is a clinical immunoassay level of maternal anti-Ro/SSA antibodies below which the pregnancy is at low risk of fetal atrioventricular block. This study speculated that prospectively applying these data may avert the costly serial echocardiograms currently recommended for all anti-Ro/SSA-antibody positive pregnancies and guide future management.

Siglec-1 Macrophages and the Contribution of IFN to the Development of Autoimmune Congenital Heart Block.

Given that diseases associated with anti-SSA/Ro autoantibodies, such as systemic lupus erythematosus and Sjögren syndrome, are linked with an upregulation of IFN and type I IFN-stimulated genes, including sialic acid-binding Ig-like lectin 1 (Siglec-1), a receptor on monocytes/macrophages, recent attention has focused on a potential role for IFN and IFN-stimulated genes in the pathogenesis of congenital heart block (CHB). Accordingly, three approaches were leveraged to address the association of IFN, IFN-stimulated genes, and the phenotype of macrophages in affected fetal cardiac tissue: 1) cultured healthy human macrophages transfected with hY3, an anti-SSA/Ro-associated ssRNA, 2) RNA isolated from freshly sorted human leukocytes/macrophages after Langendorff perfusion of three fetal hearts dying with CHB and three healthy gestational age-matched hearts, and 3) autopsy tissue from three additional human CHB hearts and one healthy heart. TLR ligation of macrophages with hY3 led to the upregulation of a panel of IFN transcripts, including SIGLEC1, a result corroborated using quantitative PCR. Using independent and agnostic bioinformatics approaches, CD45+CD11c+ and CD45+CD11c- human leukocytes flow sorted from the CHB hearts highly expressed type I IFN response genes inclusive of SIGLEC1. Furthermore, Siglec-1 expression was identified in the septal region of several affected fetal hearts. These data now provide a link between IFN, IFN-stimulated genes, and the inflammatory and possibly fibrosing components of CHB, positioning Siglec-1-positive macrophages as integral to the process.

High prevalence of Crohn disease and ulcerative colitis among older people in Sydney.

OBJECTIVES: To determine the age-standardised prevalence of inflammatory bowel disease (IBD) in a metropolitan area of Sydney, with a focus on its prevalence among older people. DESIGN, SETTING: Population-based epidemiological study of people with IBD in the City of Canada Bay, a local government area in the inner west of Sydney, during 1 March 2016 - 10 November 2016. PARTICIPANTS: Patients diagnosed with confirmed IBD according to the Copenhagen or revised Porto criteria. MAIN OUTCOME MEASURES: Crude prevalence of IBD, including Crohn disease and ulcerative colitis; age-standardised prevalence of IBD, based on the World Health Organization standard population; prevalence rates among people aged 65 years or more. RESULTS: The median age of 364 people with IBD was 47 years (IQR, 34-62 years); 185 were women (50.8%). The crude IBD prevalence rate was 414 cases (95% CI, 371-456 cases) per 100 000 population; the age-standardised rate was 348 cases (95% CI, 312-385 cases) per 100 000 population. The age-standardised rate for Crohn disease was 166 cases (95% CI, 141-192 cases) per 100 000 population; for ulcerative colitis, 148 cases (95% CI, 124-171 cases) per 100 000 population. The IBD prevalence rate in people aged 65 years or more was 612 cases (95% CI, 564-660 cases) per 100 000, and for those aged 85 years or more, 891 cases (95% CI, 833-949 cases) per 100 000; for people under 65, the rate was 380 cases (95% CI, 342-418 cases) per 100 000. CONCLUSIONS: We found that the prevalence of confirmed IBD in a metropolitan sample was highest among older people. Challenges for managing older patients with IBD include higher rates of comorbid conditions, polypharmacy, and cognitive decline, and the immunosuppressive nature of standard therapies for IBD.

Clinical and economic impact of "triple therapy" for Helicobacter pylori eradication on peptic ulcer disease in Australia.

BACKGROUND: Helicobacter pylori infection has had a major impact on the global health of billions of people. Triple therapy was extensively used in Australia by 1986 for H pylori eradication after its discovery in 1984 and was critical in reducing the morbidity and mortality associated with this infection. AIMS: This study analyzed hospital admission, mortality, and therapeutic data to determine the economic and clinical impact that antibiotic triple therapy had on peptic ulcer disease (PUD) in Australia. METHODS: An analysis of indirect and direct cost-savings in Australia between 1990 and 2015 associated with triple therapy and the impact on PUD mortality and hospital admissions. RESULTS: The direct and indirect impacts of PUD treated by triple therapy between 1990 and 2015 suggest that triple therapy is likely to have prevented 18 665 deaths, and saved 258 887 life years and 33 776 productive life years. The total savings, over the 26-year period, including direct and indirect costs, are calculated to be $10.03 billion, equating to an average annual saving of $393.419 million. CONCLUSIONS: This study highlights the enormous benefits to Australia's health care of the discovery of triple therapy, a relatively low-cost antibiotic regimen which brought considerable savings via the reduction in morbidity (hospital admissions) and mortality related to PUD. It is likely that benefits of similar scale occurred internationally.

Endosomal Toll-like receptors in clinically overt and silent autoimmunity.

Toll-like receptors (TLRs), first identified as pattern recognition receptors, are now recognized to serve as a key interface between innate and adaptive immunity. Systemic lupus erythematosus (SLE) is characterized by both continuous and cyclic stimulation of the innate and adaptive immune system by endogenous nucleic acids released from apoptotic or necrotic cells. TLR7 and TLR9 function as innate sensors of viral infection as their ligands are ssRNA and dsDNA, respectively. Recognition of self nucleic acids by endosomal TLRs in B cells and pDCs is thought to be an important step in the pathogenesis of SLE, generating anti-nuclear antibodies and producing type I IFN. In this review, we take a specific look at how TLR7, non-coding RNA, and SSA/Ro60 can contribute to clinical autoimmunity and organ damage in the context of neonatal lupus (NL). Although 15 times less common than SLE, NL provides a unique opportunity to study two different aspects of autoimmunity: passively acquired tissue injury in a developing fetus and clinical progression of disease in an asymptomatic mother found to have anti-Ro60 autoantibodies only after identification of heart block/rash in a child. Finally, we discuss hydroxychloroquine (HCQ) use by asymptomatic subjects which may forestall the clinical expression of autoimmunity.

Hearing Loss after Cardiac Surgery in Infancy: An Unintended Consequence of Life-Saving Care.

OBJECTIVES: To investigate the prevalence of hearing loss after cardiac surgery in infancy, patient and operative factors associated with hearing loss, and the relationship of hearing loss to neurodevelopmental outcomes. STUDY DESIGN: Audiologic and neurodevelopmental evaluations were conducted on 348 children who underwent repair of congenital heart disease at the Children's Hospital of Philadelphia as part of a prospective study evaluating neurodevelopmental outcomes at 4 years of age. A prevalence estimate was calculated based on presence and type of hearing loss. Potential risk factors and the impact of hearing loss on neurodevelopmental outcomes were evaluated. RESULTS: The prevalence of hearing loss was 21.6% (95% CI, 17.2-25.9). The prevalence of conductive hearing loss, sensorineural hearing loss, and indeterminate hearing loss were 12.4% (95% CI, 8.8-16.0), 6.9% (95% CI, 4.1-9.7), and 2.3% (95% CI, 0.6-4.0), respectively. Only 18 of 348 subjects (5.2%) had screened positive for hearing loss before this study and 10 used a hearing aid. After adjusting for patient and operative covariates, younger gestational age, longer postoperative duration of stay, and a confirmed genetic anomaly were associated with hearing loss (all P < .01). The presence of hearing loss was associated with worse language, cognition and attention (P <.01). CONCLUSIONS: These findings suggest that the prevalence of hearing loss in preschool children after heart surgery in infancy may be 20-fold higher than in the 1% prevalence seen in the general population. Younger gestational age, presence of a genetic anomaly, and longer postoperative duration of stay were associated with hearing loss. Hearing loss was associated with worse neurodevelopmental outcomes.

Nontypeable Haemophilus influenzae and chronic obstructive pulmonary disease: a review for clinicians.

Chronic Obstructive Pulmonary Disease (COPD) is a leading cause of morbidity and mortality worldwide. In the lower airways of COPD patients, bacterial infection is a common phenomenon and Haemophilus influenzae is the most commonly identified bacteria. Haemophilus influenzae is divided into typeable and nontypeable (NTHi) strains based on the presence or absence of a polysaccharide capsule. While NTHi is a common commensal in the human nasopharynx, it is associated with considerable inflammation when it is present in the lower airways of COPD patients, resulting in morbidity due to worsening symptoms and increased frequency of COPD exacerbations. Treatment of lower airway NTHi infection with antibiotics, though successful in the short term, does not offer long-term protection against reinfection, nor does it change the course of the disease. Hence, there has been much interest in the development of an effective NTHi vaccine. This review will summarize the current literature concerning the role of NTHi infections in COPD patients and the consequences of using prophylactic antibiotics in patients with COPD. There is particular focus on the rationale, findings of clinical studies and possible future directions of NTHi vaccines in patients with COPD.

Activated Platelets Induce Endothelial Cell Activation via an Interleukin-1ß Pathway in Systemic Lupus Erythematosus.

OBJECTIVE: Systemic lupus erythematosus (SLE) is associated with the premature development of cardiovascular disease. The platelet-endothelium interaction is important in the pathogenesis of cardiovascular disease. In this study, we investigated the platelet phenotype from patients with SLE and matched controls, and their effect on endothelial cells. APPROACH AND RESULTS: Platelet aggregability was measured in 54 SLE subjects off antiplatelet therapy (mean age 40.1±12.8 years; 82% female; 37% white) with age- and sex-matched controls. Platelets were coincubated with human umbilical vein endothelial cells (HUVECs) and changes to gene expression assessed by an RNA array and quantitative reverse transcription polymerase chain reaction. SLE disease activity index ranged from 0 to 22 (mean 5.1±3.9). Compared with controls, patients with SLE had significantly increased monocyte and leukocyte-platelet aggregation and platelet aggregation in response to submaximal agonist stimulation. An agnostic microarray of HUVECs cocultured with SLE platelets found a platelet-mediated effect on endothelial gene pathways involved in cell activation. Sera from SLE versus control subjects significantly increased (1) activation of control platelets; (2) platelet adhesion to HUVECs; (3) platelet-induced HUVEC gene expression of interleukin-8, and intercellular adhesion molecule 1; and (4) proinflammatory gene expression in HUVECs, mediated by interleukin-1ß-dependent pathway. Incubation of SLE-activated platelets with an interleukin-1ß-neutralizing antibody or HUVECs pretreated with interleukin-1 receptor antibodies attenuated the platelet-mediated activation of endothelial cells. CONCLUSIONS: Platelet activity measurements and subsequent interleukin-1ß-dependent activation of the endothelium are increased in subjects with SLE. Platelet-endothelial interactions may play a role in the pathogenesis of cardiovascular disease in patients with SLE.

Systemic lupus erythematosus and the risk of perioperative major adverse cardiovascular events.

Systemic lupus erythematosus (SLE) is a significant risk factor for cardiovascular disease. The relationship between SLE and perioperative cardiovascular risks following non-cardiac surgery is uncertain. We investigated associations between a diagnosis of SLE and outcomes following major non-cardiac surgery in a large national database from the United States. Patients age ≥ 18 years requiring major non-cardiac surgery were identified from Healthcare Cost and Utilization Project's National Inpatient Sample data from 2004 to 2014. Systemic lupus erythematosus and perioperative major adverse cardiovascular events (MACE; myocardial infarction, ischemic stroke or death) were defined by ICD-9 diagnosis codes. Perioperative MACE were reported for SLE patients stratified by age and sex. From 2004 to 2014, a total of 17,853,194 hospitalizations for major non-cardiac surgery met study inclusion criteria. SLE was identified in 70,578 (0.4%) hospitalizations. Overall, the frequency of perioperative MACE was higher in patients with vs. without SLE [2.4 vs. 2.0%, p < 0.001; adjusted OR (aOR) 1.25; 95% CI 1.18-1.31]. Perioperative MACE associated with SLE was largely driven by increased death (aOR 1.58 95% CI 1.40-1.77) and myocardial infarction (aOR 1.32; 95% CI 1.05-1.66) in younger patients with SLE. The increased risk of perioperative MACE associated with SLE in younger patients was attenuated with increasing age. A diagnosis of SLE is associated with increased risk of perioperative MACE, particularly among younger patients. Efforts to improve the perioperative management and outcomes of patients with SLE are needed.

Cardiac fibroblast transcriptome analyses support a role for interferogenic, profibrotic, and inflammatory genes in anti-SSA/Ro-associated congenital heart block.

The signature lesion of SSA/Ro autoantibody-associated congenital heart block (CHB) is fibrosis and a macrophage infiltrate, supporting an experimental focus on cues influencing the fibroblast component. The transcriptomes of human fetal cardiac fibroblasts were analyzed using two complementary approaches. Cardiac injury conditions were simulated in vitro by incubating human fetal cardiac fibroblasts with supernatants from macrophages transfected with the SSA/Ro-associated noncoding Y ssRNA. The top 10 upregulated transcripts in the stimulated fibroblasts reflected a type I interferon (IFN) response [e.g., IFN-induced protein 44-like (IFI44L), of MX dynamin-like GTPase (MX)1, MX2, and radical S-adenosyl methionine domain containing 2 (Rsad2)]. Within the fibrotic pathway, transcript levels of endothelin-1 (EDN1), phosphodiesterase (PDE)4D, chemokine (C-X-C motif) ligand (CXCL)2, and CXCL3 were upregulated, while others, including adenomedullin, RAP guanine nucleotide exchange factor 3 (RAPGEF3), tissue inhibitor of metalloproteinase (TIMP)1, TIMP3, and dual specificity phosphatase 1, were downregulated. Agnostic Database for Annotation, Visualization and Integrated Discovery analysis revealed a significant increase in inflammatory genes, including complement C3A receptor 1 (C3AR1), F2R-like thrombin/trypsin receptor 3, and neutrophil cytosolic factor 2. In addition, stimulated fibroblasts expressed high levels of phospho-MADS box transcription enhancer factor 2 [a substrate of MAPK5 (ERK5)], which was inhibited by BIX-02189, a specific inhibitor of ERK5. Translation to human disease leveraged an unprecedented opportunity to interrogate the transcriptome of fibroblasts freshly isolated and cell sorted without stimulation from a fetal heart with CHB and a matched healthy heart. Consistent with the in vitro data, five IFN response genes were among the top 10 most highly expressed transcripts in CHB fibroblasts. In addition, the expression of matrix-related genes reflected fibrosis. These data support the novel finding that cardiac injury in CHB may occur secondary to abnormal remodeling due in part to upregulation of type 1 IFN response genes.NEW & NOTEWORTHY Congenital heart block is a rare disease of the fetal heart associated with maternal anti-Ro autoantibodies which can result in death and for survivors, lifelong pacing. This study provides in vivo and in vitro transcriptome-support that injury may be mediated by an effect of Type I Interferon on fetal fibroblasts.

Ro52 autoantibodies arise from self-reactive progenitors in a mother of a child with neonatal lupus.

The detection of cardiac conduction defects in an 18-24 week old foetus in the absence of structural abnormalities predicts with near certainty the presence of autoantibodies against 60kD and 52kD SSA/Ro in the mother regardless of her health status. Previous studies have emphasized these autoantibodies as key mediators of tissue injury. The aim of this study was to focus on the anti-Ro52 response to determine whether these autoantibodies originate from progenitors that are inherently self-reactive or from B-cells that acquire self-reactivity during an immune response. We traced the evolution of two anti-Ro52 autoantibodies isolated from circulating IgG1-switched B-cells from an asymptomatic mother of a child with third degree congenital heart block. The autoantibodies were expressed as their immune form and as pre-immune ancestors by reverting somatic mutations to germline sequence. The reactivity of pre-immune and immune antibodies for Ro52, Ro60, La and DNA was measured. Both anti-Ro52 autoantibodies exhibited a low frequency of somatic mutations (3-4%) and utilised the same heavy and light chain genes but represented distinct clones based on differing complementarity determining region sequences. Pre- and post-immune antibodies showed specific binding to Ro52 with no measurable reactivity for other autoantigens. Ro52 binding was higher for immune antibodies compared to pre-immune counterparts demonstrating that autoreactivity was enhanced by affinity maturation. These data indicate that Ro52 reactivity is an intrinsic property of the germline antibody repertoire in a mother with a pathogenic antibody defined by cardiac injury in her offspring, and implies defects in both central and peripheral tolerance mechanisms.

No histologic evidence of foetal cardiotoxicity following exposure to maternal hydroxychloroquine.

It is currently recommended that hydroxychloroquine (HCQ) be maintained during pregnancy in patients with systemic lupus erythematosus. Recent data suggest that this Toll-like receptor inhibitor may also reduce the recurrence rate of anti-SSA/Ro associated congenital heart block (CHB). This case report describes a unique situation in which a CHB-afflicted, HCQ-exposed pregnancy was electively terminated. The heart did not reveal any characteristic features of cardiotoxicity, providing further evidence supporting the safety of foetal exposure to HCQ.

ApoL1 and the Immune Response of Patients with Systemic Lupus Erythematosus.

PURPOSE OF REVIEW: Systemic lupus erythematosus (SLE) confers up to a 50-fold increased risk of cardiovascular disease (CVD), and African Americans with SLE experience accelerated damage accrual and doubled cardiovascular risk when compared to their European American counterparts. RECENT FINDINGS: Genome-wide association studies have identified a substantial signal at 22q13, now assigned to variation at apolipoprotein L1 (APOL1), which has associated with progressive nondiabetic nephropathy, cardiovascular disease, and many immune-associated renal diseases, including lupus nephritis. We contend that alterations in crucial APOL1 intracellular pathways may underpin associated disease states based on structure-functional differences between variant and ancestral forms. While ancestral APOL1 may be a key driver of autophagy, nonconserved primary structure changes result in a toxic gain of function with attenuation of autophagy and an unsupervised pore-forming feature. Thus, the divergent intracellular biological pathways of ancestral and variant APOL1 may explain a worsened prognosis as demonstrated in SLE.

Targeting downstream transcription factors and epigenetic modifications following Toll-like receptor 7/8 ligation to forestall tissue injury in anti-Ro60 associated heart block.

Based on the consistent demonstration of fibrosis of the atrioventricular node surrounded by macrophages and multinucleated giant cells in anti-Ro antibody exposed fetuses dying with heart block, this study focuses on macrophage signaling stimulated by ssRNA associated with the Ro60 protein and the impact of antagonizing innate cell drivers such as TLR7/8. Transcriptome and epigenetic modifications which affect transcription factors, NF-κB and STAT1, were selected to evaluate the phenotype of macrophages in which TLR7/8 was ligated following treatment with either anti-Ro60/Ro60/hY3 RNA immune complexes or transfection with hY3. Based on microarray, TNF and IL6 were among the most highly upregulated genes in both stimulated conditions, each of which was significantly inhibited by preincubation with hydroxychloroquine (HCQ). In contrast, following stimulation of macrophages with either TNF-α or IFN-α, which do not signal through TLR, the resultant gene expression was refractory to HCQ. Ligation of TLR7/8 resulted in increased histone methylation as measured by increased H3K4me2, a requirement for binding of NF-κB at certain promoters, specifically the kB1 region in the TNF promoter (ChIP-qPCR), which was significantly decreased by HCQ. In summary, these results support that the HCQ-sensitive phenotype of hY3 stimulated macrophages reflects the bifurcation of TLR downstream signals involving NF-κB and STAT 1 pathways and for the former dimethylation of H3K4. Accordingly, HCQ may act more as a preventive measure in downregulating the initial production of IFN-α or TNF-α and not affect the resultant autocoid stimulation reflected in TNF-α and IFN-α responsive genes. The beneficial scope of antimalarials in the prevention of organ damage, inclusive of heart block in an anti-Ro offspring or more broadly SLE, may include in part, a mechanism targeting TLR-dependent epigenetic modification.

Modulation of natural IgM autoantibodies to oxidative stress-related neo-epitopes on apoptotic cells in newborns of mothers with anti-Ro autoimmunity.

At birth, the human immune system already contains substantial levels of polymeric IgM, that include autoantibodies to neo-epitopes on apoptotic cells (ACs) that are proposed to play homeostatic and anti-inflammatory roles. Yet the biologic origins and developmental regulation of these naturally arising antibodies remain poorly understood. Herein, we report that levels of IgM-antibodies to malondialdehyde (MDA) protein adducts, a common type of in vivo generated oxidative stress-related neoepitope, directly correlate with the relative binding of neonatal-IgM to ACs. Levels of IgM to phosphorylcholine (PC), a natural antibody prevalent in adults, were relatively scant in cord blood, while there was significantly greater relative representation of IgM anti-MDA antibodies in newborns compared to adults. To investigate the potential interrelationships between neonatal IgM with pathogenic IgG-autoantibodies, we studied 103 newborns born to autoimmune mothers with IgG anti-Ro (i.e., 70 with neonatal lupus and 33 without neonatal lupus). In these subjects the mean levels of IgM anti-Ro60 were significantly higher than in the newborns from non-autoimmune mothers. In contrast, levels of IgM anti-MDA in IgG anti-Ro exposed neonates were significantly lower than in neonates from non-autoimmune mothers. The presence or absence of neonatal lupus did not appear to influence the total levels of IgM in the anti-Ro exposed newborns. Taken together, our studies provide evidence that the immune development of the natural IgM-repertoire may be affected, and become imprinted by, the transfer of maternal IgG into the fetus.