Faculty Bibliography

Background/Purpose: Lupus nephritis (LN) is characterized by considerable variability in its clinical manifestations and histopathological findings. Understanding the cellular and molecular mechanisms underlying this heterogeneity is key for the development of personalized treatments for LN.
Method(s): Droplet-based single-cell RNA-sequencing was applied to the analysis of dissociated kidney samples, collected from 155 LN patients with active kidney disease and 30 living donor controls as part of a large-scale, multi-center study. 73,440 immune cells passing quality control were identified, spanning 134 cell subsets, representing various populations of tissue-resident and infiltrating leukocytes, as well as the activation states these cells assume as part of their diseaserelated activation and differentiation (Fig. 1). Principal component analysis (PCA) was used to characterize the variability in cell subset frequencies across the LN patients. Relationships between the resulting principal components (PCs) and the demographic, clinical and histopathological features of the patients were then assessed. Figure 1. Single-cell RNA-sequencing was used to profile immune cells isolated from the kidneys of LN patients and healthy controls. Five main lineages of cells were identified, as shown in a Uniform Manifold Approximation and Projection (UMAP) plot: myeloid cells, T/NK cells, B cells, plasma cells and dividing cells. The cells of each lineage were further split into finer subsets of cells (color-coded).
Result(s): The first PC (PC1), explaining 33% of the total variability in cell subset frequencies, reflected the balance between lymphocytes and monocytes/macrophages. The second PC (PC2), explaining an additional 21% of the total variability, represented the degree of macrophage differentiation to an alternatively activated phagocytic profile. The third and fourth PCs, bringing the total explained variability to 74%, were related to the balance between cell-mediated and humoral immune responses. PC1 was significantly correlated with the Chronicity index, such that patients with a higher percentage of lymphocytes compared to monocytes/macrophages had a higher Chronicity score (rho =-0.439, p-value < 0.001; Fig. 2A). A high degree of macrophage differentiation, as represented by PC2, was associated with a high Activity score (rho =-0.495, p-value < 0.001; Fig. 2B), and, in addition, with proliferative or mixed histology class, compared to pure membranous nephritis (p-value = 0.001, Kruskal-Wallis test). We further identified a significant correlation of these PCs with age; specifically, older patients had a higher relative frequency of lymphocytes compared to monocytes/macrophages, a lesser degree of macrophage differentiation, and a higher representation of cells putatively involved in a humoral immune response compared to a cell-mediated one.
Conclusion(s): These results identify distinct leukocyte populations active in different LN patients and, possibly, different stages of disease, and suggest potential therapeutic targets, that must be validated in mechanistic studies. This approach may pave the way to personalized treatment of LN

Background Lupus nephritis can occur as an isolated component of disease activity or be accompanied by diverse extrarenal symptoms that can adversely affect a patient's quality of life (QOL). Whether renal disease absent other activity is sufficient to decrease QOL is unknown. A lack of reported QOL impairment may place patients at risk for delayed diagnosis of nephritis or medication noncompliance yet nephritis trials have largely neglected QOL. As such, this study leveraged the multi-center multi-racial Accelerating Medicines Partnership (AMP) lupus nephritis cohort to assess QOL measured by PROMIS-29. Methods Patients (n=182) fulfilling ACR or SLICC criteria for SLE with a uPCR >= .5 and biopsy Class III, IV, V, or mixed were consecutively enrolled in AMP at the time of renal biopsy and clinical history, PROMIS-29, and disease activity as assessed by the hybrid SELENA-SLEDAI were recorded. Patients were determined to have extrarenal clinical activity if, after excluding all laboratory parameters from the SLEDAI, the score remained >= 1. Raw PROMIS-29 scores were transformed to t-scores with the mean of 50 +/- 10 representing the US population and a difference of 5 points considered clinically meaningful. PROMIS-29 physical and mental health summary scores were calculated according to published formulas. Results Forty-three percent of patients (n=78) had extrarenal clinical manifestations including vasculitis (4%), arthritis (39%), rash (45%), alopecia (42%), mucosal ulcers (13%), pleurisy (12%), pericarditis (8%), and fever (4%). Patients with isolated renal disease (n=104, 57%) did not have PROMIS-29 scores that differed clinically from the US population whereas patients with extrarenal disease reported deficits in physical functioning, fatigue, social functioning, and pain (table 1). Patients with extrarenal disease had significantly lower physical health summary scores compared to patients with isolated disease (median [IQR]: 40.31 [35.79, 47.02] p<0.001 vs. 48.6 [40.14, 57.08]) and significantly lower mental health summary scores (44.12 [38.63, 51.39], p=0.024 vs. 48.67 [40.51, 55.07]). Female and African American patients and those with nephrotic range proteinuria or undergoing first biopsy had significantly lower physical health summary scores, but mental health summary scores did not differ by these variables. Patients on greater than 20 mg of prednisone had both significantly lower physical and mental health summary scores compared to those on lower doses. PROMIS-29 scores did not differ by low complements, anti-dsDNA, or anti-Ro antibodies. Stepwise multivariable linear regression analysis demonstrated that the association between extrarenal disease and lower PROMIS-29 summary scores was primarily driven by arthritis and independent of potential confounders (tables 2 and 3). Conclusion The majority of patients had isolated renal disease and report a QOL similar to that of the general population. In contrast, those with extrarenal manifestations report significantly worse QOL outcomes. These results reinforce the critical importance of routine laboratory surveillance and medication compliance for nephritis even in patients with seemingly quiescent clinical disease since lupus nephritis is often asymptomatic

Introduction Fetal cardiac disease is strongly associated with maternal anti-SSA/Ro antibodies, but gaps in our knowledge include the influence of antibody specificity and titer, maternal diagnosis, overall non-cardiac adverse pregnancy outcomes (APOs), optimal surveillance protocols, and efficacy of rapid treatment. Methods The multi-center Surveillance and Treatment To Prevent Fetal AV Block Likely to Occur Quickly (STOP BLOQ) study recruited pregnant women with commercially positive anti-Ro antibodies and stratified them into high and low titers of anti-Ro60 and Ro52 based on a research ELISA, using a cutoff defined by that obtained for 50 mothers with previous AVB offspring. Mothers with anti-Ro60 and/or 52 antibodies at or above 1,000 I.U. were trained to perform FHRM. From 17-25 weeks of gestation, FHRM was completed 3x/day in addition to weekly or biweekly fetal echocardiograms (echo). Mothers texted all audio sounds to the coordinating center. Texts deemed abnormal by mothers were immediately sent to an on call pediatric cardiologist who either reassured if FHRM was normal or referred for emergency fetal echo in < 6 hours if abnormal. Results 250 anti-Ro pregnant women (22% Hispanic, 50% white, 12% Black, 12% Asian, 4% other) have been consented, including 28 whose previous child had AVB. Of mothers tested to date, 153 were provided home monitors given high titer anti-Ro60 and/or 52 antibodies (26 high titer anti-Ro60 alone, 21 high titer anti-Ro52 alone,105 high titer antibodies to both antigens). The 83 patients with low titers were surveilled with echos per local standard of care. Regarding maternal diagnosis, of 161 assessed to date, 39% were asym/UAS, 11% RA, 31% SS, 19% SLE. Antibody titers did not significantly differ by ethnicity, race or diagnosis (table 1). Non-AVB APOs occurred in 18% and were not predicted by Ro60 or 52 titers but rather SLE diagnosis (table 2). In total, 24,759 FHRM audiotexts were received from 131 patients (90 of whom have delivered) during the monitoring period. Of these, 22 were evaluated by the on-call pediatric cardiologist, who prompted an emergency echo (all completed in < 6 hrs). In 11 cases, the emergency echo was normal. In 9, there were premature atrial contractions, confirming the mother's perception. In 2 with 2degree block on urgent echo (both treated per protocol with IVIG and dexamethasone), 1 reverted to normal sinus rhythm and the other progressed to 3degree block. In 2 others, the mother did not perceive abnormal FHRM for > 24 hrs, echo identified 3degree block, and retrospective cardiology review of FHRM audio captures identified an abnormality prior to obtaining the echo. All 4 AVB developed in fetuses of mothers with high titer antibodies to both Ro60 and 52 (mean 32,451 and 34,991 respectively). Of the 18 mothers with a previous AVB child who followed the 400mg hydroxychloroquine PATCH protocol, 1 developed AVB in accord with the results of Step 1 in that study. Conclusion These data support that APOs in this clinically diverse group of mothers are not influenced by anti-Ro titer or specificity, but rather SLE diagnosis. All conduction defects were initially identified by FHRM and in mothers with high titer anti-Ro60 and 52. Hydroxychloroquine continues to show efficacy in reducing the AVB recurrence rate with rapid intervention of emergent block being promising

Background/Purpose: Patients with SLE may be at increased risk for developing a venous thromboembolism (VTE), particularly in the postpartum period. The Royal College of Obstetricians and Gynaecologists (RCOG) guideline for postpartum VTE prophylaxis is unique in its inclusion of "active" SLE as an actionable risk factor. In this guideline, a score >= 3 drives a formal recommendation for a 6-week prophylactic treatment course with enoxaparin. Although not defined, "active" SLE alone scores 3 points. The inclusion of SLE raises concerns regarding appropriate attribution and subsequent management decisions. The current study applied the RCOG model to a cohort of postpartum SLE patients to determine whether these patients a) qualify as having "active" SLE b) have other risk factors for VTE c) received the recommended prophylaxis and d) had a postpartum VTE.
Method(s): The retrospective study comprised 55 pregnancies in 49 patients fulfilling criteria for classification of SLE based on ACR, SLICC or EULAR/ACR definitions consecutively seen over the last 5 years. Disease activity at delivery was assessed by the SLEPDAI using SELENA and Hybrid SELENA definitions for scoring proteinuria. Remission was assigned by applying the DORIS (Definitions of Remission in SLE) criteria. Patients not in remission were considered to have "active" SLE, even if a low level with only one clinical domain scored. RCOG scoring was calculated for each patient prior to and after delivery.
Result(s): The median age was 32 years (IQR 29-36 years) and the median BMI was 26.6 kg/m2 (IQR 23.0-30.9 kg/m2), with 49.1% African-American, 16.4% Asian, 29.1% White, 5.5% Other and 32.7% of Hispanic ethnicity. The median SELENA and Hybrid SELENA SLEPDAI scores were 2.0 (IQR 0-6) and 2.0 (IQR 0-5) respectively. The components of the RCOG model with each of its elements scored for the cohort (Table 1). 34 pregnancies (61.8%) were in DORIS remission throughout pregnancy. 21 (38.2%) were not in DORIS remission at delivery and received 3 points on the RCOG model, since by not achieving remission their SLE could be considered at least mildly active. Of these pregnancies, only 19% were recommended for VTE prophylaxis despite RCOG score >= 3. Only 35.7% of pregnancies in DORIS remission, but with 3 points for non-SLE related VTE risk factors, were recommended for VTE prophylaxis (Table 2). Of the 20 pregnancies in remission with an RCOG score < 3 after assessing all risk factors, 15% were nevertheless recommended for VTE prophylaxis. In contrast, of the 14 inactive pregnancies with RCOG score >= 3 for non-SLE activity factors, only 35.7% were recommended for VTE prophylaxis. No patients had a postpartum VTE regardless of therapy.
Conclusion(s): These data reveal that even for SLE patients in remission at the time of delivery, points for SLE alone should not automatically be assigned on the RCOG model. However, those who are in remission may still warrant VTE prophylaxis if other non-SLE related risk factors are present. Although no patient had a postpartum VTE, prophylactic anticoagulation should be instituted only when clinically appropriate. The healthcare team should carefully consider disease activity before applying 3 points for the diagnosis of SLE

Background Nearly 20% of pregnancies in patients with Systemic lupus erythematosus (SLE) result in an adverse pregnancy outcome (APO); early identification of women with SLE who are at high risk of APO is vital. We previously examined several regression and machine learning (ML) predictive models for APO using data from the PROMISSE Study, a large multi-center, multi-ethnic/racial study of APO in women with mild/moderate SLE and/or aPL. Penalized logistic regression (LASSO), as well as several black box ML algorithms (Random Forest, Support Vector Machine, and Super Learner) each achieved good internal cross-validated performance, with area under the receiver operating curve (AUC) of 0.77-0.78. The goal of this study was to externally validate the performance of these promising APO risk models using three independent, external cohorts. Methods The PROMISSE data set used to develop the initial APO prediction models consisted of N=385 pregnancies, 71 APO events (18.4%), and 32 known or potential APO risk factors that are routinely measured in clinical practice early in pregnancy. APO was defined as preterm delivery due to placental insufficiency or preeclampsia, fetal or neonatal death, or fetal growth restriction. Three independent prospective cohorts were provided by a team of international investigators with expertise in SLE pregnancy (Bronx, NY: N=96; NYC, NY: N=62; Pisa, Italy: N=152). Patient demographics were summarized for each cohort and missing data handled using multiple imputation with chained equations. Using the APO risk models developed with the PROMISSE data, we computed for each cohort: 1) the standard deviation (SD) of predicted risk scores to summarize the degree of heterogeneity in patient characteristics and 2) the area under the receiver operating curve (AUC) to summarize the ability of each model to discriminate patients with and without APO. Results The three external cohorts and the PROMISSE development cohort showed distributional differences in previously identified APO risk factors (table 1). Non-Hispanic White comprised 49.3% of the PROMISSE, compared to 98.7% in Pisa, 27.4% in NYC, and 0% in the Bronx. LAC positivity varied from 8.1% in PROMISSE to 22.6% in the NYC cohort, while PGA > 1 varied from 10.6% in the development cohort to 4.4% in the Bronx, NY cohort. Current antihypertensive use was 8.6% in PROMISSE, higher in the Bronx cohort (12.6%), and lower in the NYC (4.8%) and Pisa (5.3%) cohorts. APO rates were the same in PROMISSE and Pisa (18.4%) and higher in the Bronx (24%) and NYC cohorts (25.8%). Prediction risk score SD indicated similar levels of heterogeneity within each external cohort compared to the PROMISSE cohort. Model performance in external validation cohorts varied depending on the algorithm used. As expected, AUCs in the external cohorts were generally lower than cross-validated internal estimates, but still indicated satisfactory performance of the different models with the independent data sets (table 2). Super Learner, the highest performing algorithm in PROMISSE, performed well across all three external cohorts, with a minimum AUC of 0.63 in the NYC cohort and a maximum of 0.71 in the Pisa cohort (table 2). LASSO also maintained consistent external performance with minimum AUC of 0.60 and maximum of 0.66. Overall, performance was highest using data from the Pisa cohort, which was the largest and most complete of the three external validation data sets. Conclusions Penalized regression and ML approaches using variables obtained early in pregnancy show potential in discriminating pregnancies with high APO risk from those pregnancies with lower risk. This study provides confirmation of the geographic transportability of the best performing algorithms developed with PROMISSE. While Super Learner showed the most satisfactory performance across external cohorts, LASSO also performed well and yielded a parsimonious model that may be easier and more efficient to use as a risk assessment tool in practice. Data from additional external cohorts from the US and abroad will be obtained in the future for further validation and refinement of our APO prediction models

Objectives We previously reported in a single centre prevalent SLE cohort that antibodies against the cytokinesis-associated protein M-Phase Phosphoprotein 1 (anti-MPP-1) were associated with SLE-related cranial neuropathy (CN), a rare manifestation of neuropsychiatric SLE (NPSLE). The purpose of this study was to assess whether anti-MPP-1 is a biomarker for CN or other NPSLE manifestations using an international SLE inception cohort. Methods SLE patients fulfilling the updated 1997 ACR classification criteria for SLE were included. Anti-MPP-1 antibody testing was performed on baseline samples (within 15 months of diagnosis) or first annual assessment using an addressable laser bead immunoassay (ALBIA) with purified recombinant human protein with results expressed as median florescence units (MFU). Based on healthy controls, a dilution of >=1:500 MFU was considered positive. NPSLE manifestations occurring over the first 5 years of follow up were documented annually based on ACR case definitions using published NPSLE attribution rules1). The frequency of anti-MPP-1 positivity between patients with versus without each of the 19 NPSLE manifestations was compared using univariate logistic regression. For any NPSLE manifestations where anti-MPP-1 positivity differed between patients with versus without the manifestation, baseline demographic and clinical characteristics were compared using t-tests and twosample tests of proportions. For NPSLE manifestations associated with anti-MPP-1 positivity in the univariate analysis, multivariable logistic regression analysis using penalized maximum likelihood estimates was then performed to assess the relationship between anti-MPP-1 and the NPSLE manifestation, adjusting for age at anti-MPP-1 testing, female, White race/ethnicity, and significantly different baseline clinical characteristics. Results Seven hundred and ninety-five SLE patients were assessed; 29.8% were anti-MPP-1 positive, 88.7% female, and 52.1% White. The frequency of anti-MPP-1 positivity differed only for those with versus without CN (70.0% vs. 29.3%; odds ratio [OR] 5.16, 95%CI 1.44, 18.54) (table 1). Compared to patients without CN (n=785), patients with CN (n=10) were more likely to fulfill the ACR hematologic (difference: 23.9%, 95%CI 5.0%, 42.8%) and antinuclear antibody criteria (difference: 4.3%, 95%CI 2.9%, 5.8%) (table 2). (Table Presanted)In the multivariate analysis, anti-MPP-1 remained associated with CN (OR 5.24, 95%CI 1.44, 19.09) after adjusting for age at anti-MPP-1 testing, female, White race/ethnicity, hematologic disorder, and antinuclear antibody (table 3). Conclusion Anti-MPP-1 is a potential biomarker for CN. Although anti-MPP-1 is differentially expressed in a variety of neurological cells and tissues, the link to a pathogenic role requires further study

Background/Purpose: Fractures in patients with systemic lupus erythematosus (SLE) are more common than age and sex matched controls. Fracture risk is traditionally assessed by dual-energy X-ray absorptiometry (DEXA) measured BMD and refined using the Fracture Risk Assessment Tool (FRAX). Several studies have demonstrated fractures in SLE patients despite normal DEXA BMD. We hypothesize that changes in bone microarchitecture may explain fracture vulnerability in SLE. This study was initiated to characterize bone quality by evaluating measures of microarchitecture at the proximal femur via 3T MRI in patients with SLE and compare these measurements with a control group of patients with known low bone density (LBD) and osteoporosis (OP).
Method(s): 50 SLE patients and 177 controls with known LBD or OP underwent DEXA and 3T MRI of the non-dominant hip. DEXA measured BMD of the total hip, femoral neck, and spine. LBD was defined as Z score <=-2.0 in premenopausal women and men younger than fifty, and T score <=-1.0 in others. OP was defined as the presence of LBD and history of fragility fracture in premenopausal women and men younger than fifty, and T score <=-2.5 in others. MRI measured favorable microarchitectural characteristics trabecular plate width (PW), trabecular plate-to-rod ratio (PRR), plate volume fraction (PVF), trabecular bone thickness (Tb.Th), and trabecular network area (NA), as well as unfavorable characteristics rod volume fraction (RVF) and trabecular spacing (Tb.Sp). Demographics, medication use and inflammatory markers at the time of the study visit were recorded. Statistical analysis was performed using Pearson correlations, t-scores, and multivariable linear regressions as appropriate.
Result(s): 50 SLE patients and 177 patients with LBD or OP completed all imaging studies. The SLE cohort was younger, and a higher percent of black patients compared to controls (Table 1). SLE patients had lower MRI PW and PRR and higher Tb. Sp as compared to controls, while having higher DEXA BMDs at all sites after adjustment for confounders (Figure 1). SLE patients had an inverse relationship between ESR and PW, PRR, Tb.Th, and NA (Figure 2, A-D). Similar results were found with CRP, which had an inverse relationship with PW, PRR, and NA. Body mass index (BMI) in SLE patients had an inverse relationship between PW, PVF, Tb.Th, and NA (Figure 2, E-H), and a positive relationship between all measured BMDs. In the control group, similar relationships were found between BMI and BMD, but only Tb.Th was inversely associated with BMI. Age, current steroid use, and history of lupus nephritis were not associated with MRI measures of bone microarchitecture.
Conclusion(s): Compared to controls, SLE patients had decreased bone quality as measured by MRI bone microarchitecture, despite having higher DEXA BMD. Elevated inflammatory markers inversely associated with bone quality. Elevated BMI, despite its association with higher BMD, was also associated with lower measures of bone microarchitectural strength, unlike controls. Further connection of bone microarchitecture to fracture risk and change over time in patients with SLE are needed to determine clinical significance of these findings and to guide additional monitoring and potential treatments. A-C: multivariate linear regression adjusting for significant microarchitectural confounders of BMI and gender. D-F: multivariate linear regression adjusting for significant BMD confounders of age, BMI, race, and gender

Background/Purpose: Patients with systemic lupus erythematosus (SLE) are at high risk for severe disease from COVID-19 and decreased vaccine efficacy, due to inherent immune perturbations and frequent immunosuppressant use. The impact of vaccine responses was "pressure" tested in New York City (NYC) from December 2021-February 2022, due to the highly infectious omicron BA.1 variant which resulted in a significant increase in COVID-19 cases and hospitalizations. This study was performed to assess clinical efficacy and seroreactivity in SLE patients with and without an additional vaccination dose after initial vaccine series, particularly during the omicron BA.1 surge in NYC.
Method(s): COVID-19 infections after vaccination were evaluated during patient encounters and chart review in subjects from the NYU Lupus Cohort who received an initial SARS-CoV-2 vaccine series with follow-up for at least 6 months or until breakthrough infection. Clinical follow-up was required after February 4, 2022 (when NYC COVID-19 cases returned to their preomicron BA.1 baseline), with last patient follow-up recorded April 24, 2022. Positive PCR or antigen-based testing was required, performed at the clinical site or self-reported. Fifty-seven patients receiving additional vaccine doses were evaluated longitudinally for recombinant SARS-CoV-2 spike receptor binding domain antibodies (#BT10500; R&D Systems). Low post-vaccine antibody response was defined as <=100 units/ml.
Result(s): Among the 163 subjects evaluated, 125 (76.7%) received an additional COVID-19 vaccination after the initial series. Demographics and medication usage were similar in patients who did and did not receive the additional vaccination dose, with 50% on at least one immunosuppressant and 16% on more than one at the time of the initial vaccine. Twentyeight (63.6%) of the 44 patients with a breakthrough infection had received an additional vaccination compared to 97 (81.5%) of the 119 without breakthrough infection (p=0.022) (Table 1). Of the 44 COVID-19 cases, only 2 occurred prior to the omicron wave, both in patients who did not receive the additional dose. There were no COVID-19 related deaths and two patients were hospitalized. Among the 57 patients with serologic evaluation, the median antibody level after initial vaccination series was 397 u/mL (IQR 57-753), and 1036 (IQR 517-1338.5) after the additional dose. After initial vaccination, 21 (37%) had low ELISA responses, but only 4 (7%) continued to have low responses after the additional dose. There was no association between the level of antibody after the additional dose and COVID-19 breakthrough.
Conclusion(s): SLE patients from a cohort of patients in NYC who received an additional SARS-CoV-2 vaccine dose were significantly less likely to have a subsequent COVID-19 infection compared to those who only completed their initial vaccine series. SLE patients demonstrated an improvement in serologic response after an additional dose of SARS-CoV-2 vaccine. The mild disease in all vaccinated patients is reassuring given the risks inherent and frequent immunosuppressant use in this patient population

Background/Purpose: SLE is characterized by autoantibody production. The most common lupus-specific serology is the anti-dsDNA antibody (anti-DNA). Traditionally, anti-DNA is measured by an enzyme immunoassay or equivalent such as multiplex flow immunoassay (EIA), which is considered sensitive. In contrast, the crithidia luciliae immunofluorescence test (CLIFT) is considered more specific. Serial measurement of anti-DNA is often used to monitor lupus disease activity. With NYU's extensive multi-race/ethnic lupus registry, we studied the relationship between these two methods, their association with lupus nephritis (LN), and their ability to predict subsequent flares.
Method(s): Using the NYU Lupus Registry of patients who meet ACR, SLICC, or EULAR criteria, we identified patients who had one or more simultaneous anti-DNA results by multiplex EIA and CLIFT. We report on their concordance (e.g., always, never, or fluctuating), association with LN, and ability to predict flare within 90 days using the SELENA-SLEDAI Flare Index. To account for degree of positivity, we defined tertiles for EIA and CLIFT as low positive [11-50 and 1:10-1:40], mild positive [51-200 and 1:80-1:320], and high positive [> 200 and > 1:640]. Table 1. 586 total visits with paired EIA and CLIFT. H = high positive M = mild positive L = low positive defined in Methods section Table 2. Relationship between EIA, CLIFT and hypocomplementemia with lupus nephritis. Chi-square test comparing significance between 60/100 v 72/100 (EIA/CLIFT) p = 0.07 Table 3. Relationship between EIA, CLIFT, hypocomplementemia and flare within 90 days Results: 207 patients had one or more paired anti-DNA results generating 586 paired results (Table 1). Cohort demographics: 92% Female, 22% Hispanic ethnicity, 24% Black, 16% Asian, 49% White, 10% Other. Overall, 377 pairs were always concordant, and 209 were never concordant. 236 pairs demonstrated titer concordance and 350 with titer discordance. Of the 207 patients, 64 patients had only one and 143 patients had two or more paired tests. Of the 64 patients, 46 were always concordant: 18 had positive EIA/CLIFT and 28 had negative EIA/CLIFT. The remaining 18 patients were never concordant: 8 had +EIA/-CLIFT and 10 had-EIA/+CLIFT. The concordance of the 143 patients with multiple paired results: 73 always, 23 never, and 47 fluctuating. Whether by one or multiple paired tests, 41/207 patients were never concordant. 100 of the 207 patients had LN associated with +EIA in 60 and +CLIFT in 72 (Table 2). Hypocomplementemia was present in 88% of +EIA and 89% of +CLIFT patients with LN. 51 visits in 42 patients had paired anti-DNA results and a SELENA-SLEDAI Flare Index assessment within 90 days. 7 patients had mild flares with +EIA in 4 and +CLIFT in 3. 4 patients had severe flares with +EIA and +CLIFT in 3 (Table 3). Low C3 and or C4 occurred in 1 of 7 (14%) mild flares and in 4 of 4 (100%) severe flares.
Conclusion(s): Our data demonstrate that discordance of positivity between two assays for anti-DNA occurred in 41/207 (20%) patients, in 207/586 (36%) visits and in 350/586 (60%) visits magnitude of positivity nonconcordant. EIA positivity is associated with LN less often than CLIFT positivity. Flares were infrequent and associated with either EIA or CLIFT positivity, with severe flares more likely if accompanied by hypocomplementemia. We recommend the utility of more than one anti-DNA assay in routine monitoring for lupus disease activity

Background Lupus nephritis (LN) is characterized by considerable variability in its clinical manifestations and histopathological findings. Understanding the cellular and molecular mechanisms underlying this heterogeneity is key for the development of personalized treatments for LN. Methods Droplet-based single-cell RNA-sequencing was applied to the analysis of dissociated kidney samples, collected from 155 LN patients with active kidney disease and 30 living donor controls as part of the Accelerating Medicines Partnership (AMP) in SLE consortium -a large-scale, multi-center study. 73,440 immune cells passing quality control were identified, spanning 134 cell subsets, representing various populations of tissue-resident and infiltrating leukocytes, as well as the activation states these cells assume as part of their diseaserelated activation and differentiation (figure 1). Principal component analysis (PCA) was used to characterize the variability in cell subset frequencies across the LN patients. Relationships between the resulting principal components (PCs) and the demographic, clinical and histopathological features of the patients were then assessed. Results The main source of variability in immune cell subset frequencies, as represented by the first PC (PC1), reflected the balance between lymphocytes and monocytes/macrophages. Subsequent PCs represented the balance between B cells and T cells (PC2); the levels of cytotoxic T lymphocytes and NK cells, as compared to plasma cells (PC3); and the degree of macrophage differentiation to an alternatively activated phagocytic profile (PC4). PC1 was significantly correlated with the Chronicity index, such that patients with a higher percentage of lymphocytes compared to monocytes/macrophages had a higher Chronicity score (rho = -0.422, p-value < 0.001; figure 2A). A high degree of macrophage differentiation, as represented by PC4, was associated with a high Activity score (rho = 0.387, p-value < 0.001; figure 2B), and, in addition, with proliferative or mixed histology class, compared to pure membranous nephritis (p-value = 0.001, Kruskal-Wallis test). The ratio of B cells to T cells, as represented by PC2, demonstrated a positive correlation with the Activity index (rho = 0.311, p-value < 0.001). We further identified a significant correlation of PC1 with age; specifically, older patients had a higher relative frequency of lymphocytes compared to monocytes/macrophages (rho = -0.239, p-value = 0.003). Our analysis indicated that these relations are not driven by demographic, clinical and technical sources of variation in our data, including race, ethnicity, the mixture of different nephritic classes, and the inclusion of both first and later biopsies. Conclusion Our work identifies distinct leukocyte populations active in different LN patients and, possibly, different stages of disease, and points to potential therapeutic targets, that must be validated in mechanistic studies. This approach may pave the way to personalized treatment of LN