Faculty Bibliography

Background/Purpose: Apolipoprotein L1 (APOL1) risk variants (RV), G1 and G2, associate with CKD in African Americans (AA) and are evolutionarily preserved due to improved infectious resistance. Interferons (IFN) in SLE, have been shown to increase APOL1 expression and RV toxicity in endothelial cells and podocytes. Though RV homozygotes with SLE nephritis demonstrate advanced renal progression, associations with renal histopathologies have not been validated in SLE.
Method(s): Herein, this cohort study tested the hypothesis that RV homozygosity (RV/RV) associates with specific clinical and biopsy features compared to reference allele (G0) homozygosity (G0/G0) or RV heterozygosity (RV/G0). Whole blood DNA for genotyping, kidney biopsy slides, and clinical reports from 77 AA SLE patients with biopsy-proven nephritis reviewed for: biopsy class, activity index (AI), chronicity index (CI) and clinical features across APOL1 genotype. RVattributed mitochondrial morphology, was assessed on electron microscopy (EM) images. Analysis was confirmed by two blinded pathologists. As proof of concept, primary endothelial cells across genotype were given IFN to over-express APOL1, and features on EM were compared.
Result(s): The G0/G0, RV/G0, and RV/RV groups comprised 35%, 52%, and 12% of the cohort. There were no genotype differences in SLE history or demographics. Compared to G0/G0, and RV/G0 groups, the RV/RV had higher urine protein to creatinine ratios (uPCR) and creatinine (Cr) at biopsy (mean uPCR: 2.5; 2.7; 4.3 mg/L p=0.06 and Cr: 1.3; 1.03; 2.3 mg/dL p=0.01 respectively). Adjusting for dsDNA, AI, CI, and percent sclerotic glomeruli, the RVs independently associated with proteinuria at biopsy (OR=2.1, p=0.05). Paradoxically, the G0/G0 and RV/G0 vs the RV/RV group displayed higher AI and CI with a trend toward higher dsDNAs at biopsy (G0/G0 or RV/G0: AI: 5.3/24; CI: 2.6/12 dsDNA: 447 vs RV/RV: AI: 1.2/24; CI: 1.3/12; dsDNA: 69, p=AI: 0.004; CI: 0.01; dsDNA: 0.1). In 30% of the RV/RV cases, the reading pathologist commented that clinical severity was out of proportion to the biopsy lesion. The RVassociated with ESRD in 7.9%, 3.9%, and 20% of the G0/ G0, RV/G0, and RV/RV cases (OR: 5.7; p=0.03). On EM, RVs associated with mitochondrial condensation (mitochondrial area: G0/G0: 0.17; RV/G0: 0.09; RV/RV: 0.06 mum²; p<0.01); this result was recapitulated in our cell culture model. IFNtreated endothelial cells increased APOL1 expression 18 fold across genotypes (p<0.01). Compared to G0/G0 and RV/G0 cells, RV/RV cells had mitochondrial areas: G0/G0: 0.08; RV/G0: 0.07; RV/RV: 0.04 mum²; (p<0.01).
Conclusion(s): In this SLE cohort, APOL1 RVs associated with poorer prognosticators, initial proteinuria and creatinine, and ultimately progressive nephritis. These features were paradoxically out of proportion to the SLE lesion on biopsy. The literature supports RV-conferred podocyte and endothelial cell mitochondrial defects owing to a mitophagy deficiency. As evidenced by EM images from both SLE patient biopsies and primary cell cultures, these genes may conferrer intrinsic renal pathology. Consequently, traditional scoring of histopathologic severity may underestimate injury that associates with RValleles

Objective The objective of this study was to determine the efficacy of hydroxychloroquine (HCQ) in the primary thrombosis prevention of antiphospholipid antibody (aPL)-positive patients with no other systemic autoimmune diseases. Methods Under the auspices of Antiphospholipid Syndrome Alliance for Clinical Trials and International Networking, a multicenter, international, randomized controlled trial (RCT) was initiated, in which persistently aPL-positive but thrombosis-free patients without systemic autoimmune diseases were randomized to receive HCQ or no treatment in addition to their standard regimen. The primary objective was the efficacy of HCQ in preventing the first thrombosis. The secondary objectives were the thrombosis incidence rate, and the effects of HCQ on aPL profile and mortality rate. Patients were risk-stratified based on antiplatelet agent use. The goal was to follow patients every 6 months for 5 years. Results We recruited 20 persistently aPL-positive patients (female: 19, mean age: 46.6 +/- 9.9 years, and baseline antiplatelet medication: 14); 9/20 were randomized to HCQ. During the mean follow-up of 1.7 years, no patients developed thrombosis or a serious adverse event. The study was terminated early due to the low recruitment rate, exacerbated by the prolonged manufacturing shortage and significant price increase of HCQ in the United States. Conclusion Given that a small number of patients with a relatively short follow-up were enrolled in our RCT, and no patients developed thrombosis, we cannot accurately assess the effectiveness of HCQ for primary thrombosis prevention in persistently aPL-positive patients with no other systemic autoimmune diseases. Our experience suggests that conducting an international RCT, especially without pharmaceutical support, is an extremely challenging undertaking.

Objectives/UNASSIGNED:The study aimed to determine if serum albumin at 12 months predicts long-term renal outcome at 48 months. Data from the NYU SAMPLE (Specimen and Matched Phenotype Linked Evaluation) Lupus Registry were used to compare the performance of albumin, anti-double-stranded DNA, C3/C4, proteinuria and haematuria. Methods/UNASSIGNED:82 patients with SLE with data at time of renal biopsy, at 12 months and at a second visit, and up to 48 months were included. The significance of each biomarker as a predictor of an adverse renal outcome (ARO), defined as doubling of serum creatinine, as creatinine >4 mg/dL if initial >2.5 mg/dL or ESRD, was evaluated in univariate and exploratory multivariable Cox proportional hazards models. Hazard ratios (HRs) for ARO with 95% CIs were generated. The receiver operating characteristic (ROC) curves at 48 months were used to identify the optimal cut-off point for albumin and proteinuria to predict ARO. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for albumin and proteinuria. Results/UNASSIGNED:Serum albumin and proteinuria had statistically significant HRs for ARO (0.140 and 1.459, respectively). The model with both albumin and proteinuria indicated no additional independent contribution of proteinuria to albumin alone. The ROC curves identified cut-offs of 3.7 g/dL for albumin and 0.964 urine protein to creatinine ratio for proteinuria. Albumin had a sensitivity of 94%, specificity of 87%, PPV of 64% and NPV of 98%. Conclusions/UNASSIGNED:This study demonstrates serum albumin >3.7 g/dL is a predictor of a favourable long-term renal outcome. These results support the inclusion of albumin as an outcome in lupus nephritis trials and treat-to-target guidelines.

OBJECTIVE: The Manhattan Lupus Surveillance Program (MLSP) is a population-based registry designed to determine the prevalence of systemic lupus erythematosus (SLE) in 2007 and the incidence from 2007 to 2009 among residents of New York County (Manhattan), New York, and to characterize cases by race/ethnicity, including Asians and Hispanics, for whom data are lacking. METHODS: We identified possible SLE cases from hospital records, rheumatologist records, and administrative databases. Cases were defined according to the American College of Rheumatology (ACR) classification criteria, the Systemic Lupus International Collaborating Clinics (SLICC) classification criteria, or the treating rheumatologist's diagnosis. Rates among Manhattan residents were age-standardized, and capture-recapture analyses were conducted to assess case underascertainment. RESULTS: By the ACR definition, the age-standardized prevalence and incidence rates of SLE were 62.2 and 4.6 per 100,000 person-years, respectively. Rates were approximately 9 times higher in women than in men for prevalence (107.4 versus 12.5) and incidence (7.9 versus 1.0). Compared with non-Hispanic white women (64.3), prevalence was higher among non-Hispanic black (210.9), Hispanic (138.3), and non-Hispanic Asian (91.2) women. Incidence rates were higher among non-Hispanic black women (15.7) compared with non-Hispanic Asian (6.6), Hispanic (6.5), and non-Hispanic white (6.5) women. Capture-recapture adjustment increased the prevalence and incidence rates (75.9 and 6.0, respectively). Alternate SLE definitions without capture-recapture adjustment revealed higher age-standardized prevalence and incidence rates (73.8 and 6.2, respectively, by the SLICC definition and 72.6 and 5.0 by the rheumatologist definition) than the ACR definition, with similar patterns by sex and race/ethnicity. CONCLUSION: The MLSP confirms findings from other registries on disparities by sex and race/ethnicity, provides new estimates among Asians and Hispanics, and provides estimates using the SLICC criteria.

Lupus nephritis is a leading cause of mortality among systemic lupus erythematosus (SLE) patients, and its heterogeneous nature poses a significant challenge to the development of effective diagnostics and treatments. Single cell RNA sequencing (scRNA-seq) offers a potential solution to dissect the heterogeneity of the disease and enables the study of similar cell types distant from the site of renal injury to identify novel biomarkers. We applied scRNA-seq to human renal and skin biopsy tissues and demonstrated that scRNA-seq can be performed on samples obtained during routine care. Chronicity index, IgG deposition, and quantity of proteinuria correlated with a transcriptomic-based score composed of IFN-inducible genes in renal tubular cells. Furthermore, analysis of cumulative expression profiles of single cell keratinocytes dissociated from nonlesional, non-sun-exposed skin of patients with lupus nephritis also revealed upregulation of IFN-inducible genes compared with keratinocytes isolated from healthy controls. This indicates the possible use of scRNA-seq analysis of skin biopsies as a biomarker of renal disease. These data support the potential utility of scRNA-seq to provide new insights into the pathogenesis of lupus nephritis and pave the way for exploiting a readily accessible tissue to reflect injury in the kidney.