Platelets are required for enhanced activation of the endothelium and fibrinogen in a mouse thrombosis model of APS

Antiphospholipid syndrome (APS) is defined by thrombosis, fetal loss, and the presence of antiphospholipid antibodies, including anti-beta 2-glycoprotein-1 autoantibodies (anti-beta 2GP1) that have a direct role in the pathogenesis of thrombosis in vivo. The cellular targets of the anti-beta 2GP1autoantibody/beta 2GP1complex in vivo were studied using a laser-induced thrombosis model of APS in a live mouse and human anti-beta 2GP1 autoantibodies affinity-purified from APS patients. Cell binding of fluorescently labeled beta 2GP1 and anti-beta 2GP1 autoantibodies revealed their colocalization on the platelet thrombus but not the endothelium. Anti-beta 2GP1 autoantibodies enhanced platelet activation, monitored by calcium mobilization, and endothelial activation, monitored by intercellular adhesion molecule-1 expression. When eptifibatide was infused to block platelet thrombus formation, enhanced fibrin generation and endothelial cell activation were eliminated. Thus, the anti-beta 2GP1 autoantibody/beta 2GP1 complex binds to the thrombus, enhancing platelet activation, and platelet secretion leads to enhanced endothelium activation and fibrin generation. These results lead to a paradigm shift away from the concept that binding of the anti-beta 2GP1 autoantibody/beta 2GP1 complex activates both endothelial cells and platelets toward one in which activation of platelets in response to anti-beta 2GP1 autoantibody/beta 2GP1 complex binding leads to subsequent enhanced endothelium activation and fibrin generation

Lessons learned from bone marrow failure in systemic lupus erythematosus: Case reports and review of the literature

© 2017 Elsevier Inc. Objective: In the present review, four new cases of bone marrow failure are presented and the potential contribution of systemic lupus erythematosus (SLE) is discussed. Furthermore, a comprehensive literature review of cases of autoimmune myelofibrosis (AIMF), aplastic anemia (AA), and paroxysmal nocturnal hemoglobinuria (PNH) with concurrent SLE aims to allow their direct comparison. Based on a clearer characterization of reported cases and our own experience, diagnostic and therapeutic strategies of these disorders in SLE are proposed based on lessons learned from the present and previous cases. Methods: A literature search was done in PubMed, accessed via the National Library of Medicine PubMed interface (http://www.ncbi.nlm.nih.gov/pubmed). Using PubMed, a Boolean search of the literature was performed by crossing the keywords “systemic lupus erythematosus,” AND [“bone marrow fibrosis” or “bone marrow failure” or “myelofibrosis” or “aplastic anemia” or “paroxysmal nocturnal hemoglobinuria”]. Results: After a stringent selection of previous cases with a clear diagnosis of SLE, we summarized in the present review 31 cases of AIMF, 26 cases of AA, and 3 cases of PNH. In addition, four new cases illustrate the problem of attribution of bone marrow failure to SLE. Conclusions: The attribution of SLE to bone marrow failure is challenging due to a lack of biomarkers, which complicates treatment decisions. Autoimmune myelofibrosis is likely underreported, but corticosteroids and intravenous immunoglobulin appear to be effective immediate therapies. In AA attributable to SLE, a serum inhibitor of bone marrow precursors should be tested, since plasma exchange has been universally successful in these cases, and a PNH clone should be tested for in the setting of ongoing hemolysis, as complement inhibition may be effective. Further research is warranted to elucidate pathophysiological mechanisms of bone marrow failure in SLE

Thrombus Formation: Direct Real‐Time Observation and Digital Analysis of Thrombus Assembly in a Living Mouse by Confocal and Widefield Intravital Microscopy

We have developed novel instrumentation using confocal and widefield microscopy to image and analyze thrombus formation in real time in the microcirculation of a living mouse. This system provides high-speed, near-simultaneous acquisition of images of multiple fluorescent probes and a brightfield channel, and supports laser-induced injury through the microscope optics. Although this imaging facility requires interface of multiple hardware components, the primary challenge in vascular imaging is careful experimental design and interpretation. This system has been used to localize tissue factor during thrombus formation, to observe defects in thrombus assembly in genetically altered mice, to study the kinetics of platelet activation and P-selectin expression following vascular injury, to analyze leukocyte rolling on arterial thrombi, to generate three-dimensional models of thrombi, and to analyze the effect of antithrombotic agents in vivo

Establishment of norms in specific areas of the visual field for critical fusion frequency as determined by a modified stroboscope

Establishment of norms in specific areas of the visual field for critical fusion frequency as determined by a modified stroboscop

Acthar Gel (repository corticotropin injection) for persistently active SLE: Study design and baseline characteristics from a multicentre, randomised, double-blind, placebo-controlled trial

© 2020 Author(s). Objective SLE is a chronic inflammatory autoimmune disease characterised by the excessive production of autoantibodies, immune complexes and proinflammatory cytokines. Repository corticotropin injection (RCI) is a naturally sourced complex mixture of adrenocorticotropic hormone analogues and other pituitary peptides. RCI is approved by the US Food and Drug Administration for use during an exacerbation or as maintenance therapy in select cases of SLE. This paper discusses the design and baseline characteristics of a multicentre, double-blind, randomised, placebo-controlled, 24-week clinical trial evaluating the effect of RCI in reducing disease activity for patients with persistently active SLE despite moderate-dose corticosteroid use. Methods Efficacy will be evaluated using the SLE Responder Index-4 (SRI-4), SLE Disease Activity Index-2000 (SLEDAI-2K), British Isles Lupus Assessment Group-2004 (BILAG-2004) and Physician\u27s Global Assessment (PGA). The primary efficacy endpoint will be the proportion of SRI-4 responders at week 16. Secondary and exploratory endpoints will include changes in disease activity scores over time, prednisone dose and biomarkers of inflammation and bone turnover. The safety and tolerability profile of RCI will also be evaluated through adverse event profiles, physical examination, clinical laboratory tests and serum cortisol levels. Results Target enrolment for this global study is 270 patients, and as of 15 November 2019, the modified intent-to-treat population included 169 patients. The study cohort had 91.7% women, had a mean age of 39.7 years, mean SLEDAI-2K total score of 9.9, mean BILAG-2004 total score of 18.1, mean PGA of 59.7 and mean prednisone or equivalent daily dose of 11.1 mg. A total of 79.3% and 64.5% of patients were receiving concomitant antimalarial or immunosuppressive therapy, respectively. Conclusions Data from this study will provide valuable insights into the therapeutic role of RCI in refractory SLE, as well as important information regarding its safety profile

Tubular cell and keratinocyte single-cell transcriptomics applied to lupus nephritis reveal type I IFN and fibrosis relevant pathways

© 2019, The Author(s), under exclusive licence to Springer Nature America, Inc. The molecular and cellular processes that lead to renal damage and to the heterogeneity of lupus nephritis (LN) are not well understood. We applied single-cell RNA sequencing (scRNA-seq) to renal biopsies from patients with LN and evaluated skin biopsies as a potential source of diagnostic and prognostic markers of renal disease. Type I interferon (IFN)-response signatures in tubular cells and keratinocytes distinguished patients with LN from healthy control subjects. Moreover, a high IFN-response signature and fibrotic signature in tubular cells were each associated with failure to respond to treatment. Analysis of tubular cells from patients with proliferative, membranous and mixed LN indicated pathways relevant to inflammation and fibrosis, which offer insight into their histologic differences. In summary, we applied scRNA-seq to LN to deconstruct its heterogeneity and identify novel targets for personalized approaches to therapy

Cell-bound complement activation products associate with lupus severity in SLE.

OBJECTIVES: To evaluate the association between lupus severity and cell-bound complement activation products (CB-CAPs) or low complement proteins C3 and C4. METHODS: All subjects (n=495) fulfilled the American College of Rheumatology (ACR) classification criteria for SLE. Abnormal CB-CAPs (erythrocyte-bound C4d or B-lymphocyte-bound C4d levels \u3e99th percentile of healthy) and complement proteins C3 and C4 were determined using flow cytometry and turbidimetry, respectively. Lupus severity was estimated using the Lupus Severity Index (LSI). Statistical analysis consisted of multivariable linear regression and groups comparisons. RESULTS: Abnormal CB-CAPs were more prevalent than low complement values irrespective of LSI levels (62% vs 38%, respectively, p CONCLUSION: Abnormalities in complement activation as measured by CB-CAPs are associated with increased LSI