Novel modification of Luminex assay for characterization of extracellular vesicle populations in biofluids.

Most approaches to extracellular vesicle (EV) characterization focus on EV size or density. However, such approaches provide few clues regarding EV origin, molecular composition, and function. New methods to characterize the EV surface proteins may aid our understanding of their origin, physiological roles, and biomarker potential. Recently developed immunoassays for intact EVs based on ELISA, NanoView, SIMOA and MesoScale platforms are highly sensitive, but have limited multiplexing capabilities, whereas MACSPlex FACS enables the detection of multiple EV surface proteins, but requires significant quantities of purified EVs, which limits its adoption. Here, we describe a novel Luminex-based immunoassay, which combines multiplexing capabilities with high sensitivity and, importantly, bypasses the enrichment and purification steps that require larger sample volumes. We demonstrate the method specificity for detecting EV surface proteins using multiple EV depletion techniques, EVs of specific cellular origin isolated from culture media, and by co-localization with established EV surface markers. Using this novel approach, we elucidate differences in the tetraspanin profiles of the EVs carrying erythrocyte and neuron markers. Using size exclusion chromatography, we show that plasma EVs of putative neuronal and tissue macrophage origin are eluted in fractions distinct from those derived from erythrocytes, or from their respective cultured cells. In conclusion, our novel multiplexed assay differentiates between EVs from erythrocytes, macrophages, and neurons, and offers a new means for capture, classification, and profiling of EVs from diverse sources.

Fpr2/CXCL1/2 Controls Rapid Neutrophil Infiltration to Inhibit Streptococcus agalactiae Infection

Streptococcus agalactiae, also known as group B streptococcus (GBS), can cause pneumonia, meningitis, and bacteremia, making it a pathogen that can increase the risk of death in newborns and immunodeficient individuals. Neutrophils are the first barrier to a host’s innate immune defense against these infections. Fpr2(Formyl peptide receptor 2) is an important chemotactic receptor of neutrophils, though its activation would cause pro- and anti-inflammatory effects. In this study, we found that mice without Fpr2 receptor were highly susceptible to GBS infections. These mice demonstrated decreased chemotaxis to neutrophils, decreased bactericidal ability of neutrophils, and high mortality. RNA-seq and Luminex assay indicated that Fpr2 activates key signal molecules downstream and produces chemokines CXCL1/2 to chemotaxis neutrophils. Like Fpr2-/-, CXCL1/2 or neutrophil depletion impairs host’s ability to defend against GBS infection. Altogether, these data indicate that Fpr2 contributes to a host’s ability to control GBS infection and that a lack of Fpr2 was associated with selective impairment during the production of chemokines CXCL1 and CXCL2 as well as neutrophil recruitment. Here, We clarified that Fpr2, as a chemotactic receptor, could not only directly chemotactic neutrophils, but also regulate the production of chemokines to control infection by chemotactic neutrophils.

Naturally acquired antibody kinetics against Plasmodium vivax antigens in people from a low malaria transmission region in western Thailand

Plasmodium vivax is the dominant Plasmodium spp. causing the disease malaria in low-transmission regions outside of Africa. These regions often feature high proportions of asymptomatic patients with sub-microscopic parasitaemia and relapses. Naturally acquired antibody responses are induced after Plasmodium infection, providing partial protection against high parasitaemia and clinical episodes. However, previous work has failed to address the presence and maintenance of such antibody responses to P. vivax particularly in low-transmission regions. We followed 34 patients in western Thailand after symptomatic P. vivax infections to monitor antibody kinetics over 9 months, during which no recurrent infections occurred. We assessed total IgG, IgG subclass and IgM levels to up to 52 P. vivax proteins every 2-4 weeks using a multiplexed Luminex assay, and identified protein-specific variation in antibody longevity. Generally, an increase in antibody level was observed within 1-week post symptomatic infection, followed by an exponential decay of different rates. We observed mostly IgG1 dominance and IgG3 sub-dominance in this population. IgM responses followed similar kinetic patterns to IgG, with some proteins unexpectedly inducing long-lived IgM responses. We also monitored antibody responses against 27 IgG-immunogenic antigens in 30 asymptomatic individuals from a similar region. Our results demonstrate that most antigens induced robust and long-lived total IgG responses following asymptomatic infections in the absence of (detected) boosting infections. Our work provides new insights into the development and maintenance of naturally acquired immunity to P. vivax and will guide the potential use of serology to indicate immune status and/or identify populations at risk.

Specific Cytokine Profiles Predict the Severity of Influenza A Pneumonia: A Prospectively Multicenter Pilot Study

Purpose. Studying the cytokine profiles in influenza A pneumonia could be helpful to better understand the pathogenesis of the disease and predict its prognosis. Patients and Methods. Patients with influenza A pneumonia (including 2009H1N1, H1N1, H3N1, and H7N1) hospitalized in six hospitals from January 2017 to October 2018 were enrolled (ClinicalTrials.gov ID, NCT03093220). Sputum samples were collected within 24 hours after admission and subsequently analyzed for cytokine profiles using a Luminex assay. Results. A total of 35 patients with influenza A pneumonia were included in the study. The levels of IL-6, IFN-γ, and IL-2 were increased in patients with severe influenza A pneumonia (n =10) ( P = 0.002 , 0.009, and 0.008, respectively), while those of IL-5, IL-25, IL-17A, and IL-22 were decreased compared to patients with nonsevere pneumonia ( P = 0.0001 , 0.009, 0.0001, and 0.006, respectively). The levels of IL-2 and IL-6 in the nonsurvivors ( n = 5 ) were significantly higher than those in the survivors ( P = 0.043 and 0.0001, respectively), while the levels of IL-5, IL-17A, and IL-22 were significantly lower ( P = 0.001 , 0.012, and 0.043, respectively). The IL-4/IL-17A ratio has the potential to be a good predictor ( AUC = 0.94 , P < 0.05 , sensitivity = 88.89 % , specificity = 92.31 % ) and an independent risk factor (OR, 95% CI: 3.772, 1.188-11.975; P < 0.05 ) for intermittent positive pressure ventilation (n = 9). Conclusion. Significant dysregulation of cytokine profiles can be observed in patients with severe influenza A pneumonia.

Diminished seroconversion following a single SARS-COV-2 vaccine in ocrelizumab-treated relapsing-remitting multiple sclerosis patients

Background: Despite impressive efficacy in immunocompetent individuals, the immunogenicity of a single dose of COVID-19 vaccine in B-cell-deplete patients remains unknown. Objectives: We aimed to quantify real-world vaccine immunogenicity in ocrelizumab recipients. Methods: We measured post-vaccination SARS-COV-2 immunoglobulin G (IgG) in ocrelizumab recipients using a highly sensitive Luminex assay. Results: 44.1% of patients had detectable SARS-COV-2-IgG 21+ days after one vaccine dose, regardless of vaccine type (AZD1222 vs BNT162b2, odds ratio (OR) = 0.62, 95% confidence interval (CI) = 0.157–2.32, p = 0.72). B-cell count strongly predicted seroconversion (β1 = 12.38, 95% CI = 4.59–20.16, p = 0.0029), but undetectable B-cells did not preclude it. The second vaccine seroconverted 53% of the patients who had not already responded to dose 1. Conclusion: Humoral response after one COVID-19 vaccine dose is lower than expected in CD20-deplete patients.

Urinary Cytokines Reflect Renal Inflammation in Acute Tubulointerstitial Nephritis: A Multiplex Bead-Based Assay Assessment

Background: Acute tubulointerstitial nephritis (ATIN) diagnosis lays on histological assessment through a kidney biopsy, given the absence of accurate non-invasive biomarkers. The aim of this study was to evaluate the accuracy of different urinary inflammation-related cytokines for the diagnostic of ATIN and its distinction from acute tubular necrosis (ATN). Methods: We included 33 patients (ATIN (n = 21), ATN (n = 12)), and 6 healthy controls (HC). We determined the urinary levels of 10 inflammation-related cytokines using a multiplex bead-based Luminex assay at the time of biopsy and after therapy, and registered main clinical, analytical and histological data. Results: At the time of biopsy, urinary levels of I-TAC/CXCL11, CXCL10, IL-6, TNFα and MCP-1 were significantly higher in ATIN compared to HC. A positive correlation between the extent of the tubulointerstitial cellular infiltrates in kidney biopsies and the urinary concentration of I-TAC/CXCL11, MIG/CXCL9, CXCL10, IL17, IFNα, MCP1 and EGF was observed. Notably, I-TAC/CXCL11, IL-6 and MCP-1 were significantly higher in ATIN than in ATN, with I-TAC/CXCL11 as the best discriminative classifier AUC (0.77, 95% CI 0.57–0.95, p = 0.02). A combinatory model of these three urinary cytokines increased the accuracy in the distinction of ATIN/ATN compared to the individual biomarkers. The best model resulted when combining the three cytokines with blood eosinophil and urinary leukocyte counts (LR = 9.76). Follow-up samples from 11ATIN patients showed a significant decrease in I-TAC/CXCL11, MIG/CXCL9 and CXCL10 levels. Conclusions: Urinary I-TAC/CXCL11, CXCL10, IL6 and MCP-1 levels accurately distinguish patients developing ATIN from ATN and healthy individuals and may serve as novel non-invasive biomarkers in this disease.

Plasma Inflammatory Cytokines and Depressed Patients With Comorbid Pain: Improvement by Ketamine

Background: Depression and pain frequently coexist clinically. Ketamine has analgesic and antidepressant effects, but few studies have evaluated individual differences in antidepressant outcomes to repeated ketamine in depressed patients with comorbid pain. Our aims were to determine the difference in ketamine’s antidepressant effects in depressed patients with or without pain and then to examine whether inflammatory cytokines might contribute to ketamine’s effect. Methods: Seventy-eight patients with major depressive disorder received six infusions of ketamine. Plasma levels of 19 inflammatory cytokines were assessed at baseline and post-infusion (day 13 and day 26) using the Luminex assay. Plasma inflammatory cytokines of sixty healthy controls (HCs) were also examined. Results: At baseline, the levels of GM-CSF, IL-1β and IL-6 were higher in pain group than in non-pain and HC groups. Pain group had better antidepressant outcomes than non-pain group. Pain group showed a greater decrease in IL-6 at day 13 and a greater decrease in IL-10, MIP-3α, IL-1β, IL-5 and IL-6 at day 26 than non-pain group. In the pain group, the changes in IL-6 levels were associated with improvement in pain intensity (β=0.347, t=2.159, P=0.038) and depressive symptoms (β=0.590, t=4.201, P<0.001) at day 13. The Sobel test showed indirect effects between decreases in IL-6 levels and improvement in depressive symptoms (Z=2.026, P=0.043).Conclusion: This study suggested that an elevated inflammatory response plays a key role in individual differences in depressed patients with or without pain. Ketamine showed great antidepressant and analgesic effects in depressed patients with pain, which may be related to its anti-inflammatory effect.

Altered levels of interleukins and neurotrophic growth factors in mood disorders and suicidality: an analysis from periphery to central nervous system

Interleukins and neurotrophins levels are altered in the periphery of patients with major depression and suicidal behavior, however it is not clear if similar abnormalities occur in the central nervous system. Our objective was to examine the association of IL-6, IL-1β, BDNF, and GDNF levels between postmortem plasma, cerebrospinal fluid (CSF), and brain tissue in a heterogeneous diagnostic subject groups including normal controls, mood disorders only, mood disorders with AUD/SUD (alcohol abuse disorder, substance abuse disorder), and AUD/SUD without mood disorders. To address these questions we collected postmortem plasma (n = 29), CSF (n = 28), and brain (BA10) (n = 57) samples from individuals with mood disorder, mood disorder with AUD/SUD, AUD/SUD and normal controls. These samples were analyzed using a multiplex based luminex assay with a customized 4-plex cytokine/interleukins- IL-6, IL-1β, BDNF, and GDNF human acute phase based on xMAP technology platform. Protein levels were determined using a Luminex 200 instrument equipped with Xponent-analyzing software. We observed IL-6 (p = 2.1e-07), and GDNF (p = 0.046) were significantly correlated between brain and CSF. In addition, IL-6 (p = 0.031), were significantly correlated between brain and plasma. Overall diagnostic group analysis showed a significant difference with brain GDNF, p = 0.0106. Pairwise comparisons showed that GDNF level is—39.9 ± 12 pg/ml, p = 0.0106, was significantly higher than in the brains derived from mood disorders compared to normal controls, —23.8 ± 5.5 pg/ml, p = 0.034. Brain BDNF was higher in suicide (p = 0.0023), males compared to females (p = 0.017), and psychiatric medication treated vs. non-treated (p = 0.005) individuals. Overall, we demonstrate that blood IL-6, GDNF and BDNF could be informative peripheral biomarkers of brain biology associated with mood disorders, substance disorders, and suicide.

Microvesicles and Exosomes Released by Amnion Epithelial Cells Under Oxidative Stress Cause Inflammatory Changes in Uterine Cells

Extracellular vesicles (EVs) play a crucial role in feto-maternal communication and provide an important paracrine signaling mechanism in pregnancy. We hypothesize that fetal cells-derived exosomes and microvesicles (MVs) under oxidative stress carry unique cargo and traffic through feto-maternal interface, which cause inflammation in uterine cells associated with parturition. Exosomes and MVs, from primary amnion epithelial cell (AEC) culture media under normal or oxidative stress (OS)-induced conditions, were isolated by optimized differential centrifugation method followed by characterization for size (nanoparticle tracking analyzer), shape (transmission electron microscopy), and protein markers (western blot and immunofluorescence). Cargo and canonical pathways were identified by mass spectroscopy and Ingenuity Pathway Analysis. Myometrial, decidual, and cervical cells were treated with 1x107 control/OS-derived exosomes/MVs. Pro-inflammatory cytokines were measured using a Luminex assay. Statistical significance was determined by paired T-test (p &lt; 0.05). AEC produced cup-shaped exosomes of 90–150 nm and circular MVs of 160–400 nm. CD9, HSP-70, and Nanog were detected in exosomes while OCT-4, HLA-G, and calnexin were found in MVs. MVs, but not exosomes, were stained for phosphatidylserine. The protein profiles for control versus OS-derived exosomes and MVs were significantly different. Several inflammatory pathways related to OS were upregulated that were distinct between exosomes and MVs. Both OS-derived exosomes and MVs significantly increased pro-inflammatory cytokines (GMCSF, IL-6, and IL-8) in maternal cells compared to control (p &lt; 0.05). Our findings suggest that fetal-derived exosomes and MVs under OS exhibited distinct characteristics and a synergistic inflammatory role in uterine cells associated with the initiation of parturition.

MO335URINARY CYTOKINES REFLECT THE ONGOING RENAL INFLAMMATION IN THE DIAGNOSTIC OF ACUTE TUBULOINTERSTITIAL NEPHRITIS: RESULTS OF A MULTIPLEX BEAD-BASED ASSAY ASSESSMENT

Background and Aims Acute tubulointerstitial nephritis (ATIN) diagnostic lays on the kidney biopsy given the absence of non-invasive biomarkers for disease demonstration and follow-up. The aim of this study was to evaluate the accuracy of ten urinary inflammatory-related cytokines in the diagnostic of ATIN and its clinical distinction from acute tubular necrosis (ATN). Method Observational prospective study including 21 ATIN and 12 ATN patients, and 6 healthy controls. We determined the urinary levels of 10 inflammation-related cytokines using a multiplex bead-based Luminex assay. We registered clinical, analytical and histological data from the medical records. Results Urinary levels of I-TAC/CXCL11, CXCL10, IL-6, TNFα and MCP-1 were higher in ATIN compared to healthy controls. In contrast, healthy controls exhibited higher EGF urinary levels compared to ATIN patients. Follow-up samples available from 11/21 ATIN patients showed a significant decrease in I-TAC/CXCL11, MIG/CXCL9 and CXCL10 levels. Urinary levels of I-TAC/CXCL11, IL-6 and MCP-1 were significantly higher in ATIN compared to ATN patients, with I-TAC/CXCL11 as the best discriminatory biomarker based on its higher AUC in the ROC curve and likelihood ratio. The combinatory model of the three cytokines increased the sensitivity of the individual biomarkers in the distinction of ATIN/ATN but the best results were obtained when blood eosinophil count and leukocyturia were added to the model. We found a positive correlation of the extent of the tubulointerstitial infiltrate in kidney biopsies with the urinary concentration of I-TAC/CXCL11, MIG/CXCL9, CXCL10, IL17, IFNα, MCP1 and EGF, indicating the potential renal source of the cytokines Conclusion the higher cytokine levels in ATIN compared to ATN patients and healthy controls, the significant decline after treatment and the positive correlation of the cytokines with the grade of the inflammatory infiltrate allows us to propose I-TAC/CXCL11, CXCL10, IL6 and MCP-1 as candidate biomarkers in this disease.