Faculty Bibliography

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.

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.

OBJECTIVE: To measure antiphospholipid antibody (aPL) variance during pregnancy; to determine if variation affects outcomes. METHODS: We used data from PROMISSE, a multicenter prospective study of pregnant women with aPL and/or SLE. APL was present if any of the following was positive: anticardiolipin (aCL), anti-beta2glycoprotein I (abeta2GPI) titers >/=40 GPL or MPL units, and/or lupus anticoagulant (LAC). APL were measured every trimester and post-partum. Adverse pregnancy outcomes (APOs) were defined as: fetal/neonatal death, preterm delivery <36 weeks due to preeclampsia or placental insufficiency; or growth restriction. RESULTS: One hundred and fifty-two aPL-positive patients were studied: 57% with clinical APS and 36% with SLE. aPL IgG levels were significantly lower during 2nd and 3rd trimesters compared to screening, but IgG aCL and abeta2GPI remained high-positive through pregnancy in 93% and 85% of patients, respectively. APL IgM titers were negative in the majority of patients and fell modestly during pregnancy. LAC frequency also decreased, but 75% remained positive through the 2nd trimester. Only 4% of patients with aPL at baseline did not have aPL at either 2nd or 3rd trimester. Changes in aPL levels or aPL status were not associated with APOs. LAC was the only aPL associated with APOs. CONCLUSION: APL levels decreased marginally during pregnancy, and changes were not associated with pregnancy outcome. Our findings suggest that measurement of aPL early is sufficient to assess risk . Repeat aPL testing through pregnancy is unnecessary

OBJECTIVES: Extension of disease beyond the atrioventricular (AV) node is associated with increased mortality in cardiac neonatal lupus (NL). Treatment of isolated heart block with fluorinated steroids to prevent disease progression has been considered but published data are limited and discordant regarding efficacy. This study evaluated whether fluorinated steroids given to manage isolated advanced block prevented development of disease beyond the AV node and conferred a survival benefit. METHODS: In this retrospective study of cases enrolled in the Research Registry for NL, inclusion was restricted to anti-SSA/Ro-exposed cases presenting with isolated advanced heart block in utero who either received fluorinated steroids within 1 week of detection (N=71) or no treatment (N=85). Outcomes evaluated were: development of endocardial fibroelastosis, dilated cardiomyopathy and/or hydrops fetalis; mortality and pacemaker implantation. RESULTS: In Cox proportional hazards regression analyses, fluorinated steroids did not significantly prevent development of disease beyond the AV node (adjusted HR=0.90; 95% CI 0.43 to 1.85; p=0.77), reduce mortality (HR=1.63; 95% CI 0.43 to 6.14; p=0.47) or forestall/prevent pacemaker implantation (HR=0.87; 95% CI 0.57 to 1.33; p=0.53). No risk factors for development of disease beyond the AV node were identified. CONCLUSIONS: These data do not provide evidence to support the use of fluorinated steroids to prevent disease progression or death in cases presenting with isolated heart block.

OBJECTIVE: We previously reported that lupus anticoagulant (LAC) is the main predictor of poor pregnancy outcome in antiphospholipid antibody (aPL)-positive patients. We sought to confirm this finding in an independent group of patients who were subsequently recruited into the PROMISSE study. METHODS: The PROMISSE study is a multicentre, prospective, observational study of pregnancy outcomes in women with aPL and/or systemic lupus erythematosus (SLE) that enrolled patients from 2003 to 2015. All consecutive, aPL-positive patients from the PROMISSE study who completed their pregnancy between April 2011 and January 2015 (after the previous PROMISSE report) are included in the current report. Patients were followed monthly until delivery, and aPL was tested at first, second and third trimesters of pregnancy and at 12 weeks post partum. Adverse pregnancy outcomes (APOs) were defined as fetal death after 12 weeks of gestation, neonatal death, delivery prior to 36 weeks of gestation due to pre-eclampsia or placental insufficiency or small-for-gestational age (birth weight <5th percentile). RESULTS: Forty-four aPL-positive patients are included in this paper. Thirteen patients had APOs, which occurred in 80% of cases during the second trimester of pregnancy. LAC was present in 69% of patients with APOs compared with 27% of patients without APOs (p=0.01). No association was found between anticardiolipin antibodies (aCL) or anti-beta2 glycoprotein I antibodies (abeta2GPI) IgG or IgM positivity and APOs. Definite antiphospholipid syndrome (history of thrombosis and/or pregnancy morbidity and aPL) was found in 92% of patients with any APOs compared with 45% of patients without APOs (p=0.004). Conversely, the frequency of SLE was not statistically different between those with and without APOs (30% vs 39%). CONCLUSIONS: Our findings, in an independent group of aPL-positive patients from the PROMISSE study, confirm that LAC, but not aCL and abeta2GPI, is predictive of poor pregnancy outcomes after 12 weeks of pregnancy. TRIAL REGISTRATION NUMBER: NCT00198068.