Faculty Bibliography

OBJECTIVE:To evaluate seroreactivity and disease flares after COVID-19 vaccination in a multi-ethnic/racial cohort of patients with systemic lupus erythematosus (SLE). METHODS:90 SLE patients and 20 healthy controls receiving a complete COVID-19 vaccine regimen were included. IgG seroreactivity to the SARS-CoV-2 spike receptor-binding domain (RBD) and SARS-CoV-2 microneutralization were used to evaluate B cell responses; IFN-γ production to assess T cell responses was measured by ELISpot. Disease activity was measured by the hybrid SLE disease activity index (SLEDAI) and flares were assigned by the SELENA/SLEDAI flare index. RESULTS:Overall, fully vaccinated SLE patients produced significantly lower IgG antibodies against SARS-CoV-2 spike RBD than controls. Twenty-six SLE patients (28.8%) generated an IgG response below that of the lowest control (<100 units/ml). In logistic regression analyses, the use of any immunosuppressant or prednisone and a normal anti-dsDNA level prior to vaccination associated with decreased vaccine responses. IgG seroreactivity to the SARS-CoV-2 Spike RBD strongly correlated with the SARS-CoV-2 microneutralization titers and antigen-specific IFN-γ production determined by ELISpot. In a subset of patients with poor antibody responses, IFN-γ production was likewise diminished. Pre-/post-vaccination SLEDAI scores were similar. Only 11.4% of patients had a post-vaccination flare; 1.3% were severe. CONCLUSION/CONCLUSIONS:In a multi-ethnic/racial study of SLE patients 29% had a low response to the COVID-19 vaccine which was associated with being on immunosuppression. Reassuringly, disease flares were rare. While minimal protective levels remain unknown, these data suggest protocol development is needed to assess efficacy of booster vaccination.

INTRODUCTION/BACKGROUND:Treatment failures for lupus nephritis (LN) are high with 10%-30% of patients progressing to end-stage renal disease (ESRD) within 10 years. Interstitial fibrosis/tubular atrophy (IFTA) is a predictor of progression to ESRD. Prior studies suggest that tubulointerstitial injury secondary to proteinuria in LN is mediated by complement activation in the tubules, specifically through the membrane attack complex (MAC). This study aimed to investigate the associations between tubular MAC deposition with IFTA and proteinuria. METHODS:In this cross-sectional study, LN kidney biopsies were assessed for MAC deposition by staining for Complement C9, a component of the MAC. Chromogenic immunohistochemistry was performed on paraffin-embedded human renal biopsy sections using unconjugated, murine anti-human Complement C9 (Hycult Biotech, clone X197). Tubular C9 staining intensity was analysed as present versus absent. IFTA was defined as minimal (<10%), mild (10%-24%), moderate (25%-50%) and severe (>50%). RESULTS:Renal biopsies from 30 patients with LN were studied. There were 24 (80%) female sex, mean age (SD) was 33 (12) years old and 23 (77%) had pure/mixed proliferative LN. Tubular C9 staining was present in 7 (23%) biopsies. 27 patients had minimal-to-mild IFTA and 3 patients had moderate IFTA. Among the C9 + patients, 3 (43%) had moderate IFTA as compared with none in the C9- group, p=0.009. C9 + patients had higher median (IQR) proteinuria as compared with C9- patients: 6.2 g (3.3-13.1) vs 2.4 g (1.3-4.6), p=0.001 at the time of biopsy. There was no difference in estimated glomerular filtration rate (eGFR) between the C9 + and C9- groups. CONCLUSION/CONCLUSIONS:This study demonstrated that tubular MAC deposition is associated with higher degree of IFTA and proteinuria, which are predictors of progression to ESRD. These results suggest that tubular MAC deposition may be useful in classification of LN. Understanding the role of complement in tubulointerstitial injury will also identify new avenues for LN treatment.

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

Coronavirus disease 2019 (COVID-19) is associated with a high rate of thrombosis. Prolonged activated partial thromboplastin times (aPTT) and antiphospholipid antibodies (aPL) are reported in COVID-19 patients. The majority of publications have not reported whether patients develop clinically relevant persistent aPL, and the clinical significance of new aPL-positivity in COVID-19 is currently unknown. However, the reports of aPL-positivity in COVID-19 raised the question whether common mechanisms exist in the pathogenesis of COVID-19 and antiphospholipid syndrome (APS). In both conditions, thrombotic microangiopathy resulting in microvascular injury and thrombosis is hypothesized to occur through multiple pathways, including endothelial damage, complement activation, and release of neutrophil extracellular traps (NETosis). APS-ACTION, an international APS research network, created a COVID-19 working group that reviewed common mechanisms, positive aPL tests in COVID-19 patients, and implications of COVID-19 infection for patients with known aPL positivity or APS, with the goals of proposing guidance for clinical management and monitoring of aPL-positive COVID-19 patients. This guidance also serves as a call and focus for clinical and basic scientific research.

BACKGROUND:Antiphospholipid syndrome (APS) is characterized by episodes of thrombosis, obstetric morbidity or both, associated with persistently positive antiphospholipid antibodies (aPL). Studying the profile of a rare disease in an admixed population is important as it can provide new insights for understanding an autoimmune disease. In this sense of miscegenation, Brazil is characterized by one of the most heterogeneous populations in the world, which is the result of five centuries of interethnic crosses of people from three continents. The objective of this study was to compare the clinical and laboratory characteristics of Brazilian vs. non-Brazilian primary antiphospholipid syndrome (PAPS) patients. METHODS:We classified PAPS patients into 2 groups: Brazilian PAPS patients (BPAPS) and PAPS patients from other countries (non-BPAPS). They were compared regarding demographic characteristics, criteria and non-criteria APS manifestations, antiphospholipid antibody (aPL) profile, and the adjusted Global Antiphospholipid Syndrome Score (aGAPSS). RESULTS:We included 415 PAPS patients (88 [21%] BPAPS and 327 [79%] non-BPAPS). Brazilian patients were significantly younger, more frequently female, sedentary, obese, non-white, and had a higher frequency of livedo (25% vs. 10%, p < 0.001), cognitive dysfunction (21% vs. 8%, p = 0.001) and seizures (16% vs. 7%, p = 0.007), and a lower frequency of thrombocytopenia (9% vs. 18%, p = 0.037). Additionally, they were more frequently positive for lupus anticoagulant (87.5% vs. 74.6%, p = 0.01), and less frequently positive to anticardiolipin (46.6% vs. 73.7%, p < 0.001) and anti-ß2-glycoprotein-I (13.6% vs. 62.7%, p < 0.001) antibodies. Triple aPL positivity was also less frequent (8% vs. 41.6%, p < 0.001) in Brazilian patients. Median aGAPSS was lower in the Brazilian group (8 vs. 10, p < 0.0001). In the multivariate analysis, BPAPS patients still presented more frequently with livedo, cognitive dysfunction and sedentary lifestyle, and less frequently with thrombocytopenia and triple positivity to aPL. They were also less often white. CONCLUSIONS:Our study suggests a specific profile of PAPS in Brazil with higher frequency of selected non-criteria manifestations and lupus anticoagulant positivity. Lupus anticoagulant (not triple positivity) was the major aPL predictor of a classification criteria event.

Background/Purpose: The Manhattan Lupus Surveillance Program (MLSP) is a multi-racial/ ethnic population-based registry with the primary goal to determine the prevalence and incidence of Systemic Lupus Erythematosus (SLE). In this study, we compare the three most commonly used classification criteria for SLE (1997 revised ACR, Systemic Lupus International Collaborating Clinics (SLICC) and the recent EULAR/ACR classification criteria) to identify cases that fulfilled only one of the classification criteria and explore each criteria set's unique cases. In addition, we used the EULAR/ACR criteria to determine the incidence and prevalence of SLE in Manhattan.
Method(s): MLSP cases were identified from Manhattan-based hospitals and rheumatologists, and state population databases. For this analysis, SLE cases were defined as fulfilling 1) the 1997 ACR classification criteria, 2) the SLICC criteria or 3) EULAR/ACR classification criteria. We quantified the number of cases that uniquely associated with each classification criteria and the number that fulfilled all three classifications. Prevalence (2007) and incidence rates (2007-2009) using the EULAR/ACR classification criteria and associated 95% confidence intervals (CI) were calculated using denominators obtained from the US Census data (revised 2000-2009 intercensal population files) for Manhattan.
Result(s): Overall 1,568 cases fulfilled at least one of the three classification criteria. Of those, 1008 (64.3%) cases fulfilled all three classification criteria, 166 (10.5%) fulfilled only the SLICC criteria, 50 (3.2%) fulfilled only the 1997 ACR criteria and 36 (2.3%) fulfilled the EULAR/ACR criteria with the remaining cases fulfilling a combination of two classification criteria. Cases that only met one of the classification criteria, and the reasons why they did not meet the other two classification criteria with example cases, are detailed in Tables 1-3. Based on the EULAR/ACR classification criteria, the age-adjusted overall prevalence and incidence rates of SLE in Manhattan were 59.8 (n=1,029, 95%CI:56.1-63.6) and 4.9 (n=245, 95%CI 4.3-5.5) per 100,000 population. Prevalence was 9 times higher and incidence was 6.9 times higher among females compared to males. The age-adjusted prevalence per 100,000 was highest among non-Hispanic Black females (198.9), followed by Hispanic females (133.1), non-Hispanic Asian/Pacific Islander females (97.7) and non-Hispanic White females (59.8). Age-adjusted incidence rates per 100,000 were highest in non-Hispanic Black females (15.8), followed by Hispanic females (7.5), non-Hispanic Asian/Pacific Islander females (7.3) and non-Hispanic White females (6.3). Prevalence and incidence rates for males followed a similar pattern.
Conclusion(s): Applying the three commonly used classification systems to a multi-racial/ ethnic population-based registry allowed for identifying unique cases of SLE who only fulfilled one classification system. The EULAR/ACR classification criteria revealed similar prevalence and incidence estimates and gender and racial/ethnic disparities to the previously published results from the MLSP using the 1997 revised ACR and SLICC classification criteria

Background/Purpose: Data on fluctuation of antibodies against domain 1 (anti-D1) of beta2-glycoprotein I (beta2GPI) are scarce. Patients with antiphospholipid syndrome (APS) and all three criteria tests for antiphospholipid antibodies (aPL) display higher titers of anti-D1, which correlate with abeta2GPI levels. This project aims at evaluating anti-D1 titers over time in a large international cohort of persistently aPL positive patients.
Method(s): AntiPhospholipid Syndrome Alliance For Clinical Trials and InternatiOnal Networking (APS ACTION) Registry was created to study the course of persistently aPL-positive patients with or without autoimmune disorders over at least 10 years. Inclusion criteria are positive aPL by Updated Sapporo Criteria tested within one year prior to enrolment. Patients are followed up every 12+/-3 months with clinical data and blood collection. Patients with available blood samples from at least three time points were included in this analysis. Anti-beta2 GPI and anti-D1 IgG were tested by chemiluminescence (BioFlash, INOVA Diagnostics) at APS ACTION core laboratories. Positive results were defined as >20 CU. Clinical data were retrieved from APS ACTION online database. Anti-D1 titers within the same subject were compared by Friedman's test. The association between categorical and continuous variables was assessed by chi-squared and Spearman's tests.
Result(s): In this longitudinal study, 1942 samples from 515 patients were tested for anti-D1 and abeta2GPI IgG; 230 patients with anti-D1 tested at >=3 time points were included (Table). Patients with thrombotic APS had anti-D1 titers significantly higher than those without thrombosis (p=0.022). Among 135 patients with at least one anti-D1 positive result, anti-D1 titers varied significantly over time (Friedman statistics: 508.5, p< 0.0001; anti-D1 geometric mean [95%CI] at baseline 189.0 [115.9-308.3]; T1 132.3 [81.1-215.8]; T2 113.8 [69.8-185.5]; T3 109.2 [66.9-178.1]. Anti-D1 titers were significantly higher at baseline compared to T3 (p=0.029). Over time, anti-D1 titers significantly decreased in 107 patients, and increased in 28 (p< 0.0001). In 11.3% of patients, anti-D1 results changed from positive to neg-ative (n: 20), or negative to positive (n: 6). (Mc Nemar's chi2=6.5; p=0.011). Anti-beta2GPI titers correlated with anti-D1 titers and significantly reduced at T3 compared to baseline (abeta2GPI at baseline 187.1 [14.5-1586.5]; T1 150.8 [11.1-1379.2]; T2 124.9 [12.2-1304]; T3 117.6 [8.7-1136.6]; Friedman statistics=11.32, p=0.010).
Conclusion(s): Anti-D1 antibodies vary significantly overtime and approximately 10% may become negative during follow up. Our future analysis of the registry will demonstrate the clinical relevance of this variation, and the impact of treatment. (Figure Presented)

Background/Purpose: Damage Index in APS (DIAPS) is a scoring system developed to assess long-term damage in thrombotic primary antiphospholipid syndrome (PAPS), which also correlates with impaired quality of life (EuroQoL) in Latin Americans. DIAPS is not validated in aPL-positive patients without thrombosis. Our primary objective was to quantify damage accrual measured by DIAPS in aPL-positive patients with or without a history of thrombosis in an international cohort. Secondly, we aimed to identify clinical and laboratory characteristics associated with damage in aPL-positive patients.
Method(s): In this cross-sectional study, we analyzed the baseline damage, measured by DIAPS, in APS ACTION Registry patients. The inclusion criteria were positive aPL according to Updated Sapporo Classification Criteria tested within one year prior to enrollment. We excluded patients with other autoimmune diseases. We analyzed the demographic, clinical, and laboratory characteristics of patients based on two subgroups: (1) thrombotic APS patients with high (DIAPS >=3) versus low damage (DIAPS < 3); and (2) non-thrombotic aPL-positive patients with damage (DIAPS >0) versus without damage (DIAPS=0). Chi-square, Fisher's exact test, Mann-Whitney U and Student t test were used when applicable. In the multivariate analysis, our model included age, gender, race and variables with p< 0.10 in the univariate analysis.
Result(s): Of the 826 aPL-positive patients included in the registry as of April 2020, 576 with no other systemic autoimmune diseases were included in the analysis (412 thrombotic and 164 non-thrombotic [108 aPL only and 56 obstetric]). Baseline demographic, clinical and laboratory characteristics are summarized in Table 1. For the thrombotic group, the most frequent domains contributing to damage were peripheral vascular (n=260, 63% -mainly deep vein thrombosis), neuropsychiatric (n=107, 30% -mainly ischemic stroke with sequelae) and cardiovascular (n=57, 14% -mainly heart valve disease). Older age, male gender, hypertension, hyperlipidemia and obesity were associated with high damage (Table 1). In the multivariate analysis, male gender (OR 1.73, 95%CI 1.10-2.71, p=.018) and hypertension (OR 1.90, 95%CI 1.21-2.99, p=.006) were independently correlated with high damage. For the non-thrombotic group, the most frequent domains contributing to damage were neuropsychiatric (n=25, 15% -mainly cognitive impairment) and cardiovascular (n=13, 8% -mainly heart valve disease). Hypertension and hyperlipidemia were independently associated with damage in the multivariate analysis (OR 2.72, 95%CI 1.09-6.80, p=.032 and OR 4.48, 95%CI 1.62-12.29, p=.004, respectively). There was no correlation between aPL profile (triple vs double vs single aPL) and damage in either group.
Conclusion(s): DIAPS was able to discriminate damage in a large multicenter cohort of aPL-positive patients. Traditional cardiovascular risk factors, namely older age, male gender, hypertension, hyperlipidemia and obesity, correlate with higher damage in thrombotic primary APS patients. Hypertension and hyperlipidemia also correlate with damage in aPL-positive patients without a history of thrombosis. (Figure Presented)