Faculty Bibliography

OBJECTIVE:Epidemiologic data for mixed connective tissue disease (MCTD) are limited. Leveraging data from the Manhattan Lupus Surveillance Program (MLSP), a racially/ethnically diverse population-based registry of cases with SLE and related diseases including MCTD, we provide estimates of the prevalence and incidence of MCTD. METHODS:MLSP cases were identified from rheumatologists, hospitals, and population databases using a variety of ICD-9 codes. MCTD was defined as one of the following: 1) fulfillment of our modified Alarcon-Segovia and Kahn criteria which required a positive RNP antibody and the presence of synovitis, myositis, and Raynaud's phenomenon, 2) a diagnosis of MCTD and no other diagnosis of another connective tissue disease (CTD), and 3) a diagnosis of MCTD regardless of another CTD diagnosis. RESULTS:Overall, 258 (7.7%) of cases met a definition of MCTD. Using our modified Alarcon-Segovia and Kahn criteria for MCTD, the age-adjusted prevalence was 1.28 (95%CI 0.72-2.09) per 100 000. Using our definition of a diagnosis of MCTD and no other diagnosis of another CTD yielded an age-adjusted prevalence and incidence of MCTD of 2.98 (95%CI 2.10-4.11) per 100 000 and 0.39 (95%CI 0.22-0.64) per 100 000, respectively. The age-adjusted prevalence and incidence were highest using a diagnosis of MCTD regardless of other CTD diagnoses and were 16.22 (95%CI 14.00-18.43) per 100 000 and 1.90 (95%CI 1.49-2.39) per 100 000 respectively. CONCLUSIONS:The MLSP provided estimates for prevalence and incidence of MCTD in a diverse population. The variation in estimates using different case definitions is reflective of the challenge of defining MCTD in epidemiologic studies.

OBJECTIVE:This study aimed to elucidate the presence, antigen specificities, and potential clinical associations of anti-neutrophil extracellular trap (anti-NET) antibodies in a multinational cohort of antiphospholipid (aPL) antibody-positive patients who did not have lupus. METHODS:Anti-NET IgG/IgM levels were measured in serum samples from 389 aPL-positive patients; 308 patients met the classification criteria for antiphospholipid syndrome. Multivariate logistic regression with best variable model selection was used to determine clinical associations. For a subset of the patients (n = 214), we profiled autoantibodies using an autoantigen microarray platform. RESULTS:We found elevated levels of anti-NET IgG and/or IgM in 45% of the aPL-positive patients. High anti-NET antibody levels are associated with more circulating myeloperoxidase (MPO)-DNA complexes, which are a biomarker of NETs. When considering clinical manifestations, positive anti-NET IgG was associated with lesions affecting the white matter of the brain, even after adjusting for demographic variables and aPL profiles. Anti-NET IgM tracked with complement consumption after controlling for aPL profiles; furthermore, patient serum samples containing high levels of anti-NET IgM efficiently deposited complement C3d on NETs. As determined by autoantigen microarray, positive testing for anti-NET IgG was significantly associated with several autoantibodies, including those recognizing citrullinated histones, heparan sulfate proteoglycan, laminin, MPO-DNA complexes, and nucleosomes. Anti-NET IgM positivity was associated with autoantibodies targeting single-stranded DNA, double-stranded DNA, and proliferating cell nuclear antigen. CONCLUSION/CONCLUSIONS:These data reveal high levels of anti-NET antibodies in 45% of aPL-positive patients, where they potentially activate the complement cascade. While anti-NET IgM may especially recognize DNA in NETs, anti-NET IgG species appear to be more likely to target NET-associated protein antigens.

OBJECTIVE:This work aims at evaluating longitudinally titers of antibodies against β2-glycoprotein I (β2GPI) and domain 1 (anti-D1), identifying predictors of the variation of anti-D1 and anti-β2GPI antibody titers and clarifying whether antibody titer fluctuations predict thrombosis in a large international cohort of patients persistently positive for antiphospholipid antibodies (aPL), the "APS ACTION Registry". METHODS:Patients with available blood samples from at least 4 time points were included. Anti-β2GPI and anti-D1 IgG were tested by chemiluminescence (BioFlash, INOVA Diagnostics). RESULTS:In a cohort of 230 patients, anti-D1 and anti-β2GPI titers decreased significantly over time (p<0.0001 and p=0.010, respectively). After adjustment for age, gender, and number of positive aPL tests, the fluctuation of anti-D1 and anti-β2GPI titers was associated with treatment with hydroxychloroquine (HCQ) at each time-point. Treatment with HCQ, but not immunosuppressors, was associated with 1.3-fold and 1.4-fold decrease in anti-D1 and anti-β2GPI titers, respectively. Incident vascular events were associated with 1.9-fold and 2.1-fold increase of anti-D1 and anti-β2GPI titers, respectively. Anti-D1 and anti-β2GPI titers at the time of thrombosis were lower compared to the other time-points: 1.6-fold decrease in anti-D1 titers and 2-fold decrease in anti-β2GPI titers conferred an OR for incident thrombosis of 6.0 (95%CI 0.62-59.3) and 9.4 (95%CI 1.1-80.2), respectively. CONCLUSIONS:Treatment with HCQ and incident vascular events significant predicted anti-D1 and anti-β2GPI titer fluctuation over time. Both anti-D1 and anti-β2GPI titers drop around the time of thrombosis, with potential clinical relevance. This article is protected by copyright. All rights reserved.

Several antiphospholipid antibody (aPL) profiles ("triple" and lupus anticoagulant [LA] positivity) are associated with a higher risk for clinical manifestations of antiphospholipid syndrome (APS). Further risk is correlated with higher levels of anticardiolipin antibody (aCL) and anti-β₂ glycoprotein-I antibody (aβ₂GPI), and with aPL persistence. Given that the 3 aPL tests detect partially overlapping sets of antibodies, the primary goal of this study was to characterize the associations among aPL tests using AntiPhospholipid Syndrome Alliance for Clinical Trials and InternatiOnal Networking (APS ACTION) core laboratory data. The APS ACTION Registry includes annually followed adult patients with positive aPL based on the Revised Sapporo Classification Criteria. We analyzed baseline and prospective core laboratory data of the registry for associations among aPL tests using the Spearman rank correlation with Bonferroni-adjusted significance level for multiple comparisons. An aPL Load was calculated based on 6 tests (aCL IgG/IgM/IgA and aβ₂GPI IgG/IgM/IgA); a receiver operating characteristic curve was used to evaluate the diagnostic performance of the aPL Load in predicting LA positivity. In 351 patients simultaneously tested for LA, aCL, and aβ₂GPI, the frequency of moderate-to-high (≥40 U) titers of aCL and aβ₂GPI IgG/IgM/IgA was higher in patients who were positive for LA vs those who were negative. An aPL Load was calculated for each patient to assess the overall aPL burden. For every 1-point increase in the aPL Load, the possibility of a positive LA test increased by 32% (odds ratio, 1.32; 95% CI, 1.2-1.5; P < .001). Based on core laboratory data from a large international registry, most aPL enzyme-linked immunosorbent assay ≥40 U and a high calculated aPL Load combining 6 aPL enzyme-linked immunosorbent assays were predictive of a positive LA. These data suggest that the combined quantitative burden of aPL may provide a mechanistic explanation of a positive LA.

OBJECTIVE:Using the Manhattan Lupus Surveillance Program (MLSP), a multi-racial/ethnic population-based registry, we compared three commonly used classification criteria for Systemic Lupus Erythematosus (SLE) to identify unique cases and determine the incidence and prevalence of SLE using the EULAR/ACR criteria. METHODS:SLE cases were defined as fulfilling 1997 ACR, SLICC, or EULAR/ACR classification criteria. We quantified the number of cases uniquely associated with each and the number fulfilling all three. Prevalence and incidence using the EULAR/ACR classification criteria and associated 95% confidence intervals (CI) were calculated. RESULTS:1,497 cases fulfilled at least one of the three classification criteria, with 1,008 (67.3%) meeting all three classifications, 138 (9.2%) fulfilling only SLICC criteria, 35 (2.3%) fulfilling only ACR criteria and 34 (2.3%) uniquely fulfilling EULAR/ACR criteria. Patients solely satisfying EULAR/ACR criteria had fewer than four manifestations. The majority classified only by the ACR criteria did not meet any of the defined immunologic criteria. Patients fulfilling only SLICC criteria did so based on the presence of features unique to this system. Using the EULAR/ACR classification criteria, age-adjusted overall prevalence and incidence rates of SLE in Manhattan were 59.6 (95%CI:55.9-63.4) and 4.9 (95%CI 4.3-5.5) per 100,000 population, with age-adjusted prevalence and incidence rates highest among non-Hispanic Black females. CONCLUSION/CONCLUSIONS:Applying the three commonly used classification criteria to a population-based registry identified patients with SLE fulfilling only one validated definition. The most recently developed EULAR/ACR classification criteria revealed similar prevalence and incidence estimates to those previously established for the ACR and SLICC classification schemes.

OBJECTIVE:Platelets are mediators of inflammation with immune effector cell properties, and have been implicated in the pathogenesis of systemic lupus erythematosus (SLE). This study investigated the role of platelet associated lectin galactoside-binding soluble 3 binding protein (LGALS3BP) as a mediator of inflammation in SLE, and a potential biomarker associated with clinical phenotypes. METHODS:We performed RNA sequencing on platelets of patients with SLE (n=54) and age, sex, and race-matched controls (n=18) and measured LGALS3BP in platelet releasate and in circulating serum. We investigated the association between levels of LGALS3BP with the prevalence, disease severity, and clinical phenotpyes of SLE, and studied platelet-mediated effects on myeloid inflammation. RESULTS:). Platelet-released LGALS3BP was highly correlated with circulating LGALS3BP (R = 0.69, p < 0.0001). Circulating LGALS3BP correlated with the SLE disease activity index (R = 0.32, p = 0.0006). Specifically, circulating LGALS3BP was higher in SLE patients with lupus nephritis than those with inactive disease (4.0 μg/mL vs 2.3 μg/mL, P < 0.001). IFN-α induced LGALS3BP transcription and translation in a megakaryoblastic cell line (MEG-01) cells in a dose-dependent manner. Recombinant LGALS3BP and platelet releasates from SLE patients enhanced pro-inflammatory cytokine production by macrophages. CONCLUSIONS:These data support that platelets act as potent effector cells contributing to the pathogenesis of SLE by secreting proinflammatory LGALS3BP, which also represents a novel biomarker of SLE clinical activity.

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.

OBJECTIVES/OBJECTIVE:Hydroxychloroquine is recommended for all patients with systemic lupus erythematous, but reports of cardiac toxicity in SARS CoV-2 patients raised concerns. We aimed to study the relationship between hydroxychloroquine blood levels and QTc intervals. METHODS:Cohort 1 is a retrospective review of 90 SLE patients with data collected regarding demographics, QTc interval and chronic kidney disease (CKD). Cohort 2 is a prospective study of 84 SLE patients with data collected regarding demographics, dose of HCQ, duration of HCQ treatment, presence of echocardiographic abnormalities, and CKD simultaneous with whole blood HCQ levels measured by high performance liquid chromatography. Statistical analysis utilized one way ANOVA, Pearson's correlation coefficient and t test. RESULTS:In the retrospective cohort there was no significant difference in mean QTc based on 75 HCQ-treated (437.91 +/- 20.02) as compared with 15 untreated (434.6 +/- 27.49) patients. In patients with CKD mean QTc in HCQ users (448 +/- 23.37) as compared with non-users (444.5 +/- 24.61) was also with no significant difference. In the prospective cohort HCQ levels did not correlate with QTc interval (r = 0.017) and this applied regardless of dose prescribed (r = 0.113 for 400 mg and r = 0.06 for 200 mg), duration of exposure (p= 0.36 for 0-5, 5-10, or > 10 years), CKD (r = 0.482) or underlying cardiac abnormalities (r = 0.430). CONCLUSION/CONCLUSIONS:This is the first study relying on measured blood levels demonstrating the absence of clinically consequential increase in QTc levels in HCQ treated SLE patients.

OBJECTIVE:Delayed detection of lupus nephritis associates with worse outcomes. There are conflicting recommendations regarding a threshold level of proteinuria at which biopsy will likely yield actionable management. This study addressed the association of urine protein creatinine ratios (UPCR) with clinical characteristics and investigated the incidence of proliferative and membranous histology in patients with a UPCR between 0.5 and 1. METHODS:275 SLE patients (113 first biopsy, 162 repeat) were enrolled in the multicentre multi-ethnic/racial Accelerating Medicines Partnership across 15 U.S. sites at the time of a clinically indicated renal biopsy. Patients were followed for 1 year. RESULTS:At biopsy, 54 patients had UPCR <1 and 221 had UPCR >1. Independent of UPCR or biopsy number, a majority (92%) of patients had class III, IV, V or mixed histology. Moreover, patients with UPCR <1 and class III, IV, V, or mixed had a median activity index of 4.5 and chronicity index of 3, yet 39% of these patients had an inactive sediment. Neither anti-dsDNA nor low complement distinguished class I or II from III, IV, V, or mixed in patients with UPCR <1. Of 29 patients with baseline UPCR <1 and class III, IV, V or mixed, 23 (79%) had a UPCR <0.5 at one year. CONCLUSION/CONCLUSIONS:In this prospective study three quarters of patients with UPCR <1 had histology showing class III, IV, V or mixed with accompanying activity and chronicity despite an inactive sediment or normal serologies. These data support renal biopsy at thresholds lower than a UPCR of 1.

BACKGROUND/PURPOSE/OBJECTIVE:APS ACTION Registry was created to study the outcomes of patients with persistently positive antiphospholipid antibodies (aPL) with or without other systemic autoimmune disease (SAIDx). Given that immunosuppression (IS) is used for certain aPL manifestations, for example, thrombocytopenia (TP), our primary objective was to describe the indications for IS in aPL-positive patients without other SAIDx. Secondly, we report the type of IS used in patients with selected microvascular or non-thrombotic aPL manifestations. METHODS:An online database is used to collect clinical data. The inclusion criteria are positive aPL based on the laboratory section of the APS Classification Criteria, tested at least twice within one year prior to enrollment. Patients are followed every 12 ± 3 months. For this descriptive retrospective and prospective analysis, we included aPL-positive patients without other SAIDx and excluded those with new SAIDx classification during follow-up. For each patient, we retrieved clinical data at baseline and follow-up including selected aPL manifestations (diffuse alveolar hemorrhage [DAH], antiphospholipid-nephropathy [aPL-N], livedoid vasculopathy [LV]-related skin ulcers, TP, autoimmune hemolytic anemia [AIHA], cardiac valve disease [VD]), and IS medications. RESULTS:Of 899 patients enrolled, 537 were included in this analysis (mean age 45 ± 13 years, female 377 [70%], APS Classification in 438 [82%], and at least one selected microvascular or non-thrombotic aPL manifestation in 141 (26%)). Of 537 patients, 76 (14%) were reported to use IS (ever), and 41/76 (54%) received IS primarily for selected aPL manifestation. In six of 8 (75%) DAH patients, 6/19 (32%) aPL-N, 4/28 (14%) LV, 25/88 (28%) TP, 6/11 (55%) AIHA, and 1/43 (2%) VD, the IS (excluding corticosteroids/hydroxychloroquine) indication was specific for selected aPL manifestation. CONCLUSION/CONCLUSIONS:In our international cohort, 14% of aPL-positive patients without other SAIDx were reported to receive IS; the indication was at least one of the selected microvascular and/or non-thrombotic aPL-related manifestations in half. Thrombocytopenia was the most frequent among those selected aPL-related manifestations; however, approximately one-third received IS specifically for that indication. Diffuse alveolar hemorrhage was frequently treated with IS followed by AIHA and aPL-N. Systematic controlled studies are urgently needed to better define the role of IS in APS.