PARE: A framework for removal of confounding effects from any distance-based dimension reduction method.

Dimension reduction tools preserving similarity and graph structure such as t-SNE and UMAP can capture complex biological patterns in high-dimensional data. However, these tools typically are not designed to separate effects of interest from unwanted effects due to confounders. We introduce the partial embedding (PARE) framework, which enables removal of confounders from any distance-based dimension reduction method. We then develop partial t-SNE and partial UMAP and apply these methods to genomic and neuroimaging data. For lower-dimensional visualization, our results show that the PARE framework can remove batch effects in single-cell sequencing data as well as separate clinical and technical variability in neuroimaging measures. We demonstrate that the PARE framework extends dimension reduction methods to highlight biological patterns of interest while effectively removing confounding effects.

Synaptic Protein Loss in Extracellular Vesicles Reflects Brain and Retinal Atrophy in People With Multiple Sclerosis.

OBJECTIVES: To assess whether the rate of change in synaptic proteins isolated from neuronally enriched extracellular vesicles (NEVs) is associated with brain and retinal atrophy in people with multiple sclerosis (MS). METHODS: People with MS were followed with serial blood draws, MRI (MRI), and optical coherence tomography (OCT) scans. NEVs were immunocaptured from plasma, and synaptopodin and synaptophysin proteins were measured using ELISA. Subject-specific rates of change in synaptic proteins, as well as brain and retinal atrophy, were determined and correlated. RESULTS: A total of 50 people with MS were included, 46 of whom had MRI and 45 had OCT serially. The rate of change in NEV synaptopodin was associated with whole brain (rho = 0.31; p = 0.04), cortical gray matter (rho = 0.34; p = 0.03), peripapillary retinal nerve fiber layer (rho = 0.37; p = 0.01), and ganglion cell/inner plexiform layer (rho = 0.41; p = 0.006) atrophy. The rate of change in NEV synaptophysin was also correlated with whole brain (rho = 0.31; p = 0.04) and cortical gray matter (rho = 0.31; p = 0.049) atrophy. DISCUSSION: NEV-derived synaptic proteins likely reflect neurodegeneration and may provide additional circulating biomarkers for disease progression in MS.

Assessment of epidemiology and outcomes of adult patients with kidney-limited thrombotic microangiopathies.

Thrombotic microangiopathies (TMA) are usually associated with hematological features (RH-TMA). The epidemiology of TMA limited to kidneys (RL-TMA) is unclear Therefore, patients with TMA and native kidney biopsies were identified during 2009-2022 in 20 French hospitals and results evaluated. RL-TMA was present in 341/757 (45%) patients and associated with lower creatinine levels (median 184 vs 346 µmol/L) than RH-TMA. RL-TMA resulted from virtually all identified causes, more frequently from anti-VEGF treatment and hematological malignancies but less frequently from shigatoxin-associated hemolytic uremic syndrome (HUS), systemic sclerosis, gemcitabine and bacterial infection, and even less frequently when three or more causes/triggers were combined (RL-TMA: 5%; RH-TMA: 12%). RL-TMA was associated with significantly lower major cardiovascular events (10% vs 20%), kidney replacement therapy (23% vs 43%) and death (12% vs 20%) than RH-TMA during follow-up (median 28 months). Atypical HUS (aHUS) was found in 326 patients (RL-TMA: 43%, RH-TMA: 44%). Among the 69 patients with proven complement-mediated aHUS, eculizumab (anti-C5 therapy) was used in 43 (62%) (RL-TMA: 35%; RH-TMA: 71%). Among the 257 other patients with aHUS, including 51% with RL-TMA, eculizumab was used in 29 but with unclear effects of this treatment. Thus, RL-TMA represents a very high proportion of patients with TMA and results from virtually all known causes of TMA and includes 25% of patients with complement-mediated aHUS. Adverse outcomes of RL-TMA are lower compared to RH-TMA but remain significant. Anti-C5 therapy was rarely used in RL-TMA, even in proven complement-mediated aHUS, and its effects remain to be assessed.

Usefulness and analytical performances of complement multiplex assay for measuring complement biomarkers in plasma.

INTRODUCTION: The complement system is involved in numerous diseases, through diverse mechanisms and degree of activation. With the emergence of complement targeting therapeutic, simple and accessible tools to evaluate the extent of complement activation are strongly needed. METHODS: We evaluated two multiplex panels, measuring complement activation fragments (C4a, C3a, C5a, Bb, Ba, sC5b9) and intact components or regulators (C1q, C2, C3, C4, C5, FD, FP, FH, FI). The specificity of each measurement was assessed by using complement proteins depleted sera and plasma collected from patients with complement deficiencies. Normal values distribution was estimated using 124 plasma samples from healthy donors and complement activation profile was assessed in plasma collected from 31 patients with various complement-mediated disorders. RESULTS: We observed good inter-assay variation. All tested protein deficiencies were accurately detected. We established assay-specific reference values for each analyte. Except for C3, C4 and C4a, the majority of the measurements were in good agreement with references methods or published data. CONCLUSION: Our study substantiates the utility of the Complement Multiplex assay as a tool for measuring complement activation and deficiencies. Quantifying complement cleavage fragments in patients exhibiting classical or alternative pathway activation allowed evaluating the activation state of the whole cascade.

Agreement Between Published Reference Resources for Neurofilament Light Chain Levels in People With Multiple Sclerosis.

OBJECTIVES: To examine the agreement between published reference resources for neurofilament light chain (NfL) applied to a large population of people with multiple sclerosis (MS). METHODS: Six published reference resources were used to classify NfL in participants in the Multiple Sclerosis Partners Advancing Technology and Health Solutions (MS PATHS) network as elevated or normal and to derive age-specific NfL Z-scores. NfL values were classified as elevated if they exceeded the >95th percentile (i.e., Z-score >1.645) of the age-specific reference range. Furthermore, age-specific NfL Z-scores could be derived for 4 of 6 reference resources. RESULTS: NfL measurements were assessed from 12,855 visits of 6,687 people with MS (median 2 samples per individual [range 1-7]). The mean ± SD age was 47.1 ± 11.7 years, 72.1% of participants were female, disease duration was 15.0 ± 10.6 years, body mass index was 28.6 ± 6.9 kg/m2, and serum NfL was 12.87 ± 12.86 pg/mL. Depending on the selection of the reference resource, the proportion of NfL measurements classified as elevated varied from 3.7% to 30.9%. The kappa coefficient across the 6 reference resources used was 0.576 (95% CI 0.571-0.580) indicating moderate agreement. Spearman correlations between Z-scores derived from the various reference resources exceeded 0.90; however, concordance coefficients were lower, ranging from 0.72 to 0.89. DISCUSSION: Interpretation of blood NfL values may vary markedly depending on the selection of the reference resource. Borderline elevated values should be interpreted with caution, and future studies should focus on standardizing NfL measurement and reporting across laboratories/platforms, better characterizing the effects of confounding/influencing factors, and defining the performance of NfL (including as part of multimodal predictive algorithms) for prediction of disease-specific outcomes.

Intersite brain MRI volumetric biases persist even in a harmonized multisubject study of multiple sclerosis.

BACKGROUND AND PURPOSE: Multicenter study designs involving a variety of MRI scanners have become increasingly common. However, these present the issue of biases in image-based measures due to scanner or site differences. To assess these biases, we imaged 11 volunteers with multiple sclerosis (MS) with scan and rescan data at four sites. METHODS: Images were acquired on Siemens or Philips scanners at 3 Tesla. Automated white matter lesion detection and whole-brain, gray and white matter, and thalamic volumetry were performed, as well as expert manual delineations of T1 magnetization-prepared rapid acquisition gradient echo and T2 fluid-attenuated inversion recovery lesions. Random-effect and permutation-based nonparametric modeling was performed to assess differences in estimated volumes within and across sites. RESULTS: Random-effect modeling demonstrated model assumption violations for most comparisons of interest. Nonparametric modeling indicated that site explained >50% of the variation for most estimated volumes. This expanded to >75% when data from both Siemens and Philips scanners were included. Permutation tests revealed significant differences between average inter- and intrasite differences in most estimated brain volumes (P < .05). The automatic activation of spine coil elements during some acquisitions resulted in a shading artifact in these images. Permutation tests revealed significant differences between thalamic volume measurements from acquisitions with and without this artifact. CONCLUSION: Differences in brain volumetry persisted across MR scanners despite protocol harmonization. These differences were not well explained by variance component modeling; however, statistical innovations for mitigating intersite differences show promise in reducing biases in multicenter studies of MS.

CTLA-4 Pathway Is Instrumental in Giant Cell Arteritis.

BACKGROUND: Giant cell arteritis (GCA) causes severe inflammation of the aorta and its branches and is characterized by intense effector T-cell infiltration. The roles that immune checkpoints play in the pathogenesis of GCA are still unclear. Our aim was to study the immune checkpoint interplay in GCA. METHODS: First, we used VigiBase, the World Health Organization international pharmacovigilance database, to evaluate the relationship between GCA occurrence and immune checkpoint inhibitors treatments. We then further dissected the role of immune checkpoint inhibitors in the pathogenesis of GCA, using immunohistochemistry, immunofluorescence, transcriptomics, and flow cytometry on peripheral blood mononuclear cells and aortic tissues of GCA patients and appropriated controls. RESULTS: Using VigiBase, we identified GCA as a significant immune-related adverse event associated with anti-CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) but not anti-PD-1 (anti-programmed death-1) nor anti-PD-L1 (anti-programmed death-ligand 1) treatment. We further dissected a critical role for the CTLA-4 pathway in GCA by identification of the dysregulation of CTLA-4-derived gene pathways and proteins in CD4+ (cluster of differentiation 4) T cells (and specifically regulatory T cells) present in blood and aorta of GCA patients versus controls. While regulatory T cells were less abundant and activated/suppressive in blood and aorta of GCA versus controls, they still specifically upregulated CTLA-4. Activated and proliferating CTLA-4+ Ki-67+ regulatory T cells from GCA were more sensitive to anti-CTLA-4 (ipilimumab)-mediated in vitro depletion versus controls. CONCLUSIONS: We highlighted the instrumental role of CTLA-4 immune checkpoint in GCA, which provides a strong rationale for targeting this pathway.

Effects of Ibudilast on Retinal Atrophy in Progressive Multiple Sclerosis Subtypes: Post Hoc Analyses of the SPRINT-MS Trial.

BACKGROUND AND OBJECTIVES: Ganglion cell + inner plexiform layer (GCIPL) thinning, measured by optical coherence tomography (OCT), reflects global neurodegeneration in multiple sclerosis (MS). Atrophy of the inner (INL) and outer nuclear layer (ONL) may also be prominent in progressive MS (PMS). The phase 2, SPRINT-MS trial found reduced brain atrophy with ibudilast therapy in PMS. In this post hoc analysis of the SPRINT-MS trial, we investigate (1) retinal atrophy (2) differences in response by subtype and (3) associations between OCT and MRI measures of neurodegeneration. METHODS: In the multicenter, double-blind SPRINT-MS trial, participants with secondary progressive MS (SPMS) or primary progressive MS (PPMS) were randomized to ibudilast or placebo. OCT and MRI data were collected every 24 weeks for 96 weeks. Extensive OCT quality control and algorithmic segmentation produced consistent results across Cirrus HD-OCT and Spectralis devices. Primary endpoints were GCIPL, INL, and ONL atrophy, assessed by linear mixed-effects regression. Secondary endpoints were associations of OCT measures, brain parenchymal fraction, and cortical thickness, assessed by partial Pearson correlations. RESULTS: One hundred thirty-four PPMS and 121 SPMS participants were included. GCIPL atrophy was 79% slower in the ibudilast (-0.07 ± 0.23 µm/y) vs placebo group (-0.32 ± 0.20 µm/y, p = 0.003). This effect predominated in the PPMS cohort (ibudilast: -0.08 ± 0.29 µm/y vs placebo: -0.60 ± 0.29 µm/y, a decrease of 87%, p < 0.001) and was not detected in the SPMS cohort (ibudilast: -0.21 ± 0.28 µm/y vs placebo: -0.14 ± 0.27 µm/y, p = 0.55). GCIPL, INL, and ONL atrophy rates correlated with whole brain atrophy rates across the cohort (r = 0.27, r = 0.26, and r = 0.20, respectively; p < 0.001). Power calculations from these data show future trials of similar size and design have ≥80% power to detect GCIPL atrophy effect sizes of approximately 40%. DISCUSSION: Ibudilast treatment decreased GCIPL atrophy in PMS, driven by the PPMS cohort, with no effect seen in SPMS. Modulated atrophy of retinal layers may be detectable in sample sizes smaller than the SPRINT-MS trial and correlate with whole brain atrophy in PMS, further highlighting their utility as outcomes in PMS. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that ibudilast reduces composite ganglion cell + inner plexiform layer atrophy, without reduction of inner or outer nuclear layer atrophy, in patients with primary progressive MS but not those with secondary progressive MS.

The complement system in IgAN: mechanistic context for therapeutic opportunities.

The complement system plays a crucial role in innate immunity, providing essential defense against pathogens. However, uncontrolled or prolonged activation of the complement cascade can significantly contribute to kidney damage, especially in cases of glomerulonephritis. Immunoglobulin A nephropathy (IgAN), the most prevalent form of primary glomerulonephritis, has growing evidence supporting the involvement of complement alternative and lectin pathways. In fact, patients with IgAN experience complement activation within their kidney tissue, which may be involved in the development of glomerular damage and the progression of IgAN. Complement activation has emerged as a significant area of interest in IgAN, with numerous complement-targeting agents currently being explored within this field. Nevertheless, the exact mechanisms of complement activation and their role in IgAN progression require comprehensive elucidation. This review seeks to contextualize the proposed mechanisms of complement activation within the various stages ("hits") of IgAN pathogenesis, while also addressing the clinical implications and anticipated outcomes of complement inhibition in IgAN.

Eculizumab as a therapeutic approach for severe crescentic recurrence of immunoglobulin A nephropathy after kidney transplantation.

Crescentic forms of immunoglobulin A nephropathy (IgAN) are rare but can be associated with rapid kidney failure and a high rate of end-stage renal disease despite immunosuppression therapy. Complement activation has emerged as a key driver of glomerular injury in IgAN. Therefore, complement inhibitors may be a rational treatment option in patients unresponsive to first-line immunosuppressive therapy. Here, we describe the case of a 24-year-old woman presenting with crescentic IgAN recurrence a few months after living kidney transplantation. Considering the dramatic graft failure accompanied by malignant hypertension and thrombotic microangiopathy features worsening after a first-line of high-dose steroids and 3 sessions of plasma exchanges, eculizumab was started as a rescue therapy. For the first time, the clinical response to eculizumab was highly successful, with a complete graft recovery without any relapse after 1 year of treatment. Further clinical studies are strongly needed to specify which patients might benefit from terminal complement blockade.

Reduction of Neutrophil Activation by Phosphodiesterase 4 Blockade in Behçet's Disease.

OBJECTIVE: Behçet's disease (BD) is a systemic vasculitis with inflammatory lesions mediated by cytotoxic T cells and neutrophils. Apremilast, an orally available small-molecule drug that selectively inhibits phosphodiesterase 4 (PDE4), has been recently approved for the treatment of BD. We aimed to investigate the effect of PDE4 inhibition on neutrophil activation in BD. METHODS: We studied surface markers and reactive oxygen species (ROS) production by flow cytometry, and neutrophil extracellular traps (NETs) production and molecular signature of neutrophils by transcriptome analysis before and after PDE4 inhibition. RESULTS: Activation surface markers (CD64, CD66b, CD11b, and CD11c), ROS production, and NETosis were up-regulated in BD patient neutrophils compared to healthy donor neutrophils. Transcriptome analysis revealed 1,021 significantly dysregulated neutrophil genes between BD patients and healthy donors. Among dysregulated genes, we found a substantial enrichment for pathways linked to innate immunity, intracellular signaling, and chemotaxis in BD. Skin lesions of BD patients showed increased infiltration of neutrophils that colocalized with PDE4. Inhibition of PDE4 by apremilast strongly inhibited neutrophil surface activation markers as well as ROS production, NETosis, and genes and pathways related to innate immunity, intracellular signaling, and chemotaxis. CONCLUSION: We highlight key biologic effects of apremilast on neutrophils in BD.

Complement biology for hematologists.

The complement system is part of the innate immunity. An increased activation or a loss of the regulation of this fine-tuned cascade is involved in a variety of hematological diseases. During the last decade, anti-C5 therapies have revolutionized the management and prognosis of paroxysmal nocturnal hemoglobinuria (PNH) and atypical hemolytic and uremic syndrome (aHUS). The availability of a rapidly growing number of innovative complement inhibitors has opened new therapeutic perspectives for several other hematological disorders in which the complement is involved at different degrees. This review focuses on complement biology and its mechanisms of activation in hematological diseases.

Deconfounded Dimension Reduction via Partial Embeddings.

Dimension reduction tools preserving similarity and graph structure such as t-SNE and UMAP can capture complex biological patterns in high-dimensional data. However, these tools typically are not designed to separate effects of interest from unwanted effects due to confounders. We introduce the partial embedding (PARE) framework, which enables removal of confounders from any distance-based dimension reduction method. We then develop partial t-SNE and partial UMAP and apply these methods to genomic and neuroimaging data. Our results show that the PARE framework can remove batch effects in single-cell sequencing data as well as separate clinical and technical variability in neuroimaging measures. We demonstrate that the PARE framework extends dimension reduction methods to highlight biological patterns of interest while effectively removing confounding effects.

Rare germline complement factor H variants in patients with paroxysmal nocturnal hemoglobinuria.

Patients with paroxysmal nocturnal hemoglobinuria (PNH) are susceptible to complement-mediated intravascular hemolysis and thrombosis. Factor H (FH) is the main regulator of the complement alternative pathway, which protects cells from unwanted complement-mediated damage. Although FH is not a glycosylphosphatidylinositol-linked molecule, it may play a role in PNH. We sought to determine if rare germline variants in complement factor H (CFH) affect the PNH course, screening 84 patients with PNH treated with eculizumab for rare variants in CFH, CFI, and C3 genes. We compared the allelic frequencies with populational data and a geographically-matched control group, looking for an association between presence of the variants and treatment response (transfusion independence by 6 months). Sixteen patients presented rare variants, 9 in CFH (10.7%). Germline CFH variants were more frequent among patients with PNH than among controls (P = .02) or public data (P < .001) and were more likely to be transfusion-dependent at 6 months after eculizumab initiation (P = .015). With a median follow-up of 5.8 years, 8 of 9 patients with the CFH variant received transfusions, and 2 developed thromboses. None of the patients with the CFH variant had severe aplastic anemia from eculizumab initiation until 6 months. We demonstrated for the first time that rare CFH variants are over-represented among patients with PNH and that germline genetic background may affect the response to eculizumab.

Effects of Myopia on Rates of Change in Optical Coherence Tomography Measured Retinal Layer Thicknesses in People with Multiple Sclerosis and Healthy Controls.

PURPOSE: To quantify the associations of myopia with longitudinal changes in retinal layer thicknesses in people with multiple sclerosis (PwMS) and healthy controls (HC). METHODS: A cohort of PwMS and HC with recorded refractive error (RE) prospectively scanned on Cirrus HD-OCT at the Johns Hopkins MS Center was assessed for inclusion. Exclusion criteria included OCT follow-up < 6 months, ocular comorbidities, incidental OCT pathologies, and inadequate scan quality. Eyes were classified as having high myopia (HM) (RE≤ -6 diopters), low myopia (LM) (RE> -6 and ≤ -3 diopters), or no myopia (NM) (RE> -3 and ≤ +2.75). Linear mixed-effects regression models were used in analyses. RESULTS: A total of 213 PwMS (eyes: 67 HM, 98 LM, 207 NM) and 80 HC (eyes: 26 HM, 37 LM, 93 NM) were included. Baseline average ganglion cell/inner plexiform (GCIPL) and peri-papillary retinal nerve fiber layer (pRNFL) thicknesses were lower in MS HM compared with MS NM (diff: -3.2 µm, 95% CI: -5.5 to -0.8, p = 0.008 and -5.3 µm, 95% CI: -9.0 to -1.7, p = 0.004, respectively), and similarly in HC HM, as compared with HC NM. Baseline superior, inferior, and nasal pRNFL thicknesses were lower in HM compared with NM, while temporal pRNFL thickness was higher, both in MS and HC (MS: 7.1 µm, 95% CI: 2.7-11.6, p = 0.002; HC: 4.7 µm, 95% CI: -0.3 to 9.7, p = 0.07). No longitudinal differences in rates of GCIPL change were noted between HM and LM vs. NM, either in MS or HC. CONCLUSION: Cross-sectional differences in average GCIPL and pRNFL thicknesses are commonly seen in people with HM as compared to reference normative values from people with NM and can lead to false attribution of pathology if RE is not taken into account. However, our study suggests that longitudinal changes in average GCIPL thickness in PwMS with myopia are similar in magnitude to PwMS with NM, and therefore are appropriate for monitoring disease-related pathology.

Contributors to Serum NfL Levels in People without Neurologic Disease.

OBJECTIVE: To assess the effects of demographics, lifestyle factors, and comorbidities on serum neurofilament light chain (sNfL) levels in people without neurologic disease and establish demographic-specific reference ranges of sNfL. METHODS: The National Health and Nutrition Examination Survey (NHANES) is a representative sample of the US population in which detailed information on demographic, lifestyle, routine laboratory tests, and overall health status are systematically collected. From stored serum samples, we measured sNfL levels using a novel high-throughput immunoassay (Siemens Healthineers). We evaluated the predictive capacity of 52 demographic, lifestyle, comorbidity, anthropometric, or laboratory characteristics in explaining variability in sNfL levels. Predictive performance was assessed using cross-validated R2 (R2 cv ) and forward selection was used to obtain a set of best predictors of sNfL levels. Adjusted reference ranges were derived incorporating characteristics using generalized additive models for location, scale, and shape. RESULTS: We included 1,706 NHANES participants (average age: 43.6 ± 14.8 y; 50.6% male, 35% non-white) without neurological disorders. In univariate models, age explained the most variability in sNfL (R2 cv  = 26.8%). Multivariable prediction models for sNfL contained three covariates (in order of their selection): age, creatinine, and glycosylated hemoglobin (HbA1c) (standardized ß-age: 0.46, 95% confidence interval [CI]: 0.43, 0.50; creatinine: 0.18, 95% CI: 0.13, 0.22; HbA1c: 0.09, 95% CI: 0.06, 0.11). Adjusted centile curves were derived incorporating identified predictors. We provide an interactive R Shiny application to translate our findings and allow other investigators to use the derived centile curves. INTERPRETATION: Results will help to guide interpretation of sNfL levels as they relate to neurologic conditions. ANN NEUROL 2022;92:688-698.

Association of Serum Neurofilament Light Chain With Inner Retinal Layer Thinning in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Serum neurofilament light chain (sNfL) and optical coherence tomography (OCT)-derived retinal measures (including peripapillary retinal nerve fiber layer [pRNFL] and macular ganglion cell layer/inner plexiform layer [GCIPL] thickness) have been proposed as biomarkers of neurodegeneration in multiple sclerosis (MS). However, studies evaluating the associations between sNfL and OCT-derived retinal measures in MS are limited. METHODS: In this retrospective analysis of a longitudinal, observational, single-center cohort study, sNfL levels were measured in people with MS and healthy controls (HCs) using single molecule array. Participants with MS were followed with serial OCT for a median follow-up of 4.5 years. Eyes with optic neuritis (ON) within 6 months of baseline OCT or ON during follow-up were excluded. Age-normative cutoffs of sNfL were derived using the HC data, and MS participants with sNfL greater than the 97.5th percentile for age were classified as having elevated sNfL (sNfL-E). Analyses were performed with mixed-effects linear regression models and adjusted for age, sex, race, and history of ON. RESULTS: A total of 130 HCs (age: 42.4 ± 14.2 years; 62% female) and 403 people with MS (age: 43.1 ± 12.0 years; 78% female) were included. Elevated sNfL levels were present at baseline in 80 participants with MS (19.9%). At baseline, sNfL-E participants had modestly lower pRNFL (-3.03 ± 1.50 µm; p = 0.044) and GCIPL thickness (-2.74 ± 1.02 µm; p = 0.007). As compared with those with sNfL within the reference range, eyes from NfL-E participants exhibited faster longitudinal thinning of the pRNFL (45% faster; -0.74 vs -0.51 µm/y; p = 0.015) and GCIPL (25% faster; -0.35 vs -0.28 µm/y; p = 0.021). Significant differences in rates of pRNFL and GCIPL thinning between sNfL groups were found only in those with relapsing-remitting MS but not progressive MS. DISCUSSION: Elevated baseline sNfL is associated with accelerated rates of retinal neuroaxonal loss in relapsing-remitting MS, independent of overt ON, but may be less reflective of retinal neurodegeneration in progressive MS.

Ex Vivo Test for Measuring Complement Attack on Endothelial Cells: From Research to Bedside.

As part of the innate immune system, the complement system plays a key role in defense against pathogens and in host cell homeostasis. This enzymatic cascade is rapidly triggered in the presence of activating surfaces. Physiologically, it is tightly regulated on host cells to avoid uncontrolled activation and self-damage. In cases of abnormal complement dysregulation/overactivation, the endothelium is one of the primary targets. Complement has gained momentum as a research interest in the last decade because its dysregulation has been implicated in the pathophysiology of many human diseases. Thus, it appears to be a promising candidate for therapeutic intervention. However, detecting abnormal complement activation is challenging. In many pathological conditions, complement activation occurs locally in tissues. Standard routine exploration of the plasma concentration of the complement components shows values in the normal range. The available tests to demonstrate such dysregulation with diagnostic, prognostic, and therapeutic implications are limited. There is a real need to develop tools to demonstrate the implications of complement in diseases and to explore the complex interplay between complement activation and regulation on human cells. The analysis of complement deposits on cultured endothelial cells incubated with pathologic human serum holds promise as a reference assay. This ex vivo assay most closely resembles the physiological context. It has been used to explore complement activation from sera of patients with atypical hemolytic uremic syndrome, malignant hypertension, elevated liver enzymes low platelet syndrome, sickle cell disease, pre-eclampsia, and others. In some cases, it is used to adjust the therapeutic regimen with a complement-blocking drug. Nevertheless, an international standard is lacking, and the mechanism by which complement is activated in this assay is not fully understood. Moreover, primary cell culture remains difficult to perform, which probably explains why no standardized or commercialized assay has been proposed. Here, we review the diseases for which endothelial assays have been applied. We also compare this test with others currently available to explore complement overactivation. Finally, we discuss the unanswered questions and challenges to overcome for validating the assays as a tool in routine clinical practice.

Cloud-Based Influenza Surveillance System in Emergency Departments Using Molecular-Based Testing: Advances and Challenges.

INTRODUCTION: Electronic influenza surveillance systems aid in health surveillance and clinical decision-making within the emergency department (ED). While major advances have been made in integrating clinical decision-making tools within the electronic health record (EHR), tools for sharing surveillance data are often piecemeal, with the need for data downloads and manual uploads to shared servers, delaying time from data acquisition to end-user. Real-time surveillance can help both clinicians and public health professionals recognize circulating influenza earlier in the season and provide ongoing situational awareness. METHODS: We created a prototype, cloud-based, real-time reporting system in two large, academically affiliated EDs that streamed continuous data on a web-based dashboard within hours of specimen collection during the influenza season. Data included influenza test results (positive or negative) coupled with test date, test instrument geolocation, and basic patient demographics. The system provided immediate reporting to frontline clinicians and to local, state, and federal health department partners. RESULTS: We describe the process, infrastructure requirements, and challenges of developing and implementing the prototype system. Key process-related requirements for system development included merging data from the molecular test (GeneXpert) with the hospitals' EHRs, securing data, authorizing/authenticating users, and providing permissions for data access refining visualizations for end-users. CONCLUSION: In this case study, we effectively integrated multiple data systems at four distinct hospital EDs, relaying data in near real time to hospital-based staff and local and national public health entities, to provide laboratory-confirmed influenza test results during the 2014-2015 influenza season. Future innovations need to focus on integrating the dashboard within the EHR and clinical decision tools.