An optimized multiplex flow cytometry protocol for the analysis of intracellular signaling in peripheral blood mononuclear cells

AbstractPhosphoflow cytometry is increasingly being used as a tool for the discovery of biomarkers used in the treatment and monitoring of disease and therapy. The ability to measure numerous phospho-protein targets simultaneously at a single cell level accurately and rapidly provides significant advantages over other methods. We here discuss important considerations required to successfully implement these methods. Three different blood collection tubes (lithium-heparin tubes, CPT with sodium citrate and CPT with sodium heparin) were evaluated, with PBMC isolated through lithium-heparin tubes/lymphoprep displaying reduced basal and increased stimulation induced phosphorylation compared to the other two methods. Further, we provide a protocol outlining an 8 color assay developed for the study of intracellular signaling in peripheral blood mononuclear cells. The assay allows for the quantitative measurement of the phospho-proteins ERK1/2, NF-κB p65, Stat1 (Y701), Stat1 (S727), Stat3 (Y705), Stat3 (S727), Stat4 (Y693), p38 and Stat5 (Y694), as well as the identification of T cells, B cells, natural killer cells and monocytes. The assay additionally incorporates fluorescent cell barcoding, reducing assay costs and increasing throughput while increasing data robustness. Inter-assay precision was assessed over a month long period for all experimental variables (phospho-protein measured, cell type and stimulant). Coefficient of variations (CVs) calculated from process triplicates of normalized median fluorescence intensity (MFI) of the phospho-proteins displayed median CVs under 10% when grouped according to cell type, stimulation agent and phospho-protein measured, while the CV for each triplicate did not exceed 20%

Biomarker profiles in serum and saliva of experimental Sjögren's syndrome: associations with specific autoimmune manifestations

Introduction Sjögren's syndrome (SS) is a systemic autoimmune disease that mainly targets the exocrine glands. The aim of this study was to investigate the involvement of 87 proteins measured in serum and 75 proteins analyzed in saliva in spontaneous experimental SS. In addition, we intended to compute a model of the immunological situation representing the overt disease stage of SS. Methods Nondiabetic, nonobese diabetic (NOD) mice aged 21 weeks were evaluated for salivary gland function, salivary gland inflammation and extraglandular disease manifestations. The analytes, comprising chemokines, cytokines, growth factors, autoantibodies and other biomarkers, were quantified using multi-analyte profile technology and fluorescence-activated cell sorting. Age-matched and sex-matched Balb/c mice served as a reference. Results We found NOD mice to exhibit impaired salivary flow, glandular inflammation and increased secretory SSB (anti-La) levels. Thirty-eight biomarkers in serum and 34 in saliva obtained from NOD mice were significantly different from those in Balb/c mice. Eighteen biomarkers in serum and three chemokines measured in saliva could predict strain membership with 80% to 100% accuracy. Factor analyses identified principal components mostly correlating with one clinical aspect of SS and having distinct associations with components extracted from other families of proteins. Conclusion Autoimmune manifestations of SS are greatly independent and associated with various immunological processes. However, CD40, CD40 ligand, IL-18, granulocyte chemotactic protein-2 and anti-muscarinic M3 receptor IgG3 may connect the different aspects of SS. Processes related to the adaptive immune system appear to promote SS with a strong involvement of T-helper-2 related proteins in hyposalivation. This approach further established saliva as an attractive biofluid for biomarker analyses in SS and provides a basis for the comparison and selection of potential drug targets and diagnostic markers

Inflammatory Stratification in Primary Sjögren’s Syndrome Reveals Novel Immune Cell Alterations in Patients’ Minor Salivary Glands

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Lymphoid organisation in labial salivary gland biopsies is a possible predictor for the development of malignant lymphoma in primary Sjögren's syndrome

Objective The development of non-Hodgkin's lymphoma (NHL) confers a high risk of mortality in primary Sjogren's syndrome (pSS) patients, but the sensitivity and specificity of proposed lymphoma predictors are insufficient for practical use. The performance of lymphoid organisation in the form of germinal centre (GC)-like lesions was evaluated in labial salivary gland biopsies taken at pSS diagnosis as a potential lymphoma-predicting biomarker. Methods Labial salivary gland tissue biopsies available from two Swedish pSS research cohorts (n = 175) were re-evaluated by light microscopy in a blind study in order to identify GC-like structures as a sign of ectopic lymphoid tissue formation and organisation. A linkage study was performed with the Swedish Cancer Registry for lymphoma identification. The risk of developing NHL in GC-positive patients in comparison with GC-negative patients was evaluated using Kaplan-Meier statistics and log-rank test. Associations between GC-like structures and clinical and/or laboratory disease markers were also determined using. 2 or Fisher's exact tests. Results At diagnosis, 25% of pSS patients had GC-like structures in their salivary glands. Seven of the 175 patients studied (14% GC+ and 0.8% GC-) developed NHL during 1855 patient-years at risk, with a median onset of 7 years following the initial diagnostic salivary gland biopsy. Six of the seven patients had GC-like structures at diagnosis; the remaining patient was GC negative at the time of diagnosis (p=0.001). Conclusions The detection of GC-like structures by light microscopy in pSS diagnostic salivary biopsies is proposed as a highly predictive and easy-to-obtain marker for NHL development. This allows for risk stratification of patients and the possibility to initiate preventive B-cell-directed therapy

Maturation of monocyte derived dendritic cells with OK432 boosts IL-12p70 secretion and conveys strong T-cell responses

Background: Design of tumour specific immunotherapies using the patients’ own dendritic cells (DC) is a fast advancing scientific field. The functional qualities of the DC generated in vitro are critical, and today’s gold standard for maturation is a cytokine cocktail consisting of IL-1b, IL-6, TNF-a and PGE2 generating cells lacking IL- 12p70 production. OK432 is an immunotherapeutic agent derived from killed Streptococcus pyogenes that has been used clinically to treat malignant and benign neoplasms for decades. Methods: In this study, we analysed the effects of OK432 on DC maturation, DC migration, cytokine and chemokine secretion as well as T-cell stimulatory capacity, and compared it to the cytokine cocktail alone and combinations of OK432 with the cytokine cocktail. Results: OK432 induced a marked up-regulation of CD40 on the cell surface as well as a strong inflammatory response from the DC with significantly more secretion of 19 different cytokines and chemokines compared to the cytokine cocktail. Interestingly, secretion of IL-15 and IL-12p70 was detected at high concentrations after maturation of DC with OK432. However, the OK432 treated DC did not migrate as well as DC treated with cytokine cocktail in a transwell migration assay. During allogeneic T-cell stimulation OK432 treated DC induced proliferation of over 50 percent of CD4 and 30 percent of CD8 T-cells for more than two cell divisions, whereas cytokine cocktail treated DC induced proliferation of 12 and 11 percent of CD4 and CD8 T-cells, respectively. Conclusions: The clinically approved compound OK432 has interesting properties that warrants its use in DC immunotherapy and should be considered as a potential immunomodulating agent in cancer immunotherapy

A five-year prospective study of fatigue in primary Sjögren's syndrome

Introduction: Fatigue is prevalent in primary Sjögren’s syndrome (pSS), and contributes to the considerably reduced health related quality of life in this disease. The symptom is included in proposed disease activity and outcome measures for pSS. Several studies indicate that there is an inflammatory component of fatigue in pSS and other chronic inflammatory rheumatic diseases. The purpose of this study was to investigate fatigue change in pSS in a longitudinal study, and explore whether any clinical or laboratory variables at baseline, including serum cytokines, were associated with a change in fatigue scores over time. Methods: A clinical and laboratory investigation of 141 patients fulfilling the American-European consensus criteria of pSS was undertaken in the period May 2004 to April 2005. Median time since diagnosis was 5.5 years. Examinations included the fatigue questionnaires: fatigue severity scale (FSS), fatigue visual analogue scale (VAS), functional assessment of chronic illness therapy - fatigue (FACIT-F) and medical outcome study short form-36 (SF- 36) vitality, which were repeated in a follow-up investigation in January and February 2010. Results: A total of 122 patients (87%) responded at both time-points. Thirty-five percent of patients experienced a clinically significant FSS increase. On the group level, fatigue measures did not change except that there was a slight deterioration in SF-36 vitality score. High serum anti-Sjögren’s syndrome A antigen (anti-SSA) showed weak associations with high baseline fatigue, and patients with increasing fatigue had lower baseline unstimulated whole salivary volume. Weak associations between increasing fatigue and serum immunoglobulin G (IgG), and the pro-inflammatory cytokine interleukin-17 (IL-17), were observed. Baseline sicca symptoms correlated with higher fatigue both at baseline and with increasing fatigue over time. Linear regression analysis did not identify any predictive ability of clinical or laboratory measures on fatigue change over time. Conclusions: Fatigue remained mainly unchanged over time. Using multivariate models did not reveal any clinical or laboratory predictors of fatigue change over time

Impaired activation of STAT5 upon IL-2 stimulation in Tregs and elevated sIL-2R in Sjögren’s syndrome

Background Interleukin-2 (IL-2) and the high-affinity IL-2 receptor (IL-2R) are essential for the survival of regulatory T cells (Tregs) which are the main players in immune tolerance and prevention of autoimmune diseases. Sjögren’s syndrome (SS) is a chronic autoimmune disease predominantly affecting women and is characterised by sicca symptoms including oral and ocular dryness. The aim of this study was to investigate an association between IL-2R and Treg function in patients with SS of different severity defined by the salivary flow rate. Methods In a cross-sectional study, we determined plasma soluble IL-2R (sIL-2R) levels in women with SS (n=97) and healthy females (n=50) using ELISA. A subset of those (n=51) was screened for Treg function measured by the STAT5 signalling response to IL-2 using phospho-flow cytometry. Results We found that elevated plasma levels of sIL-2R were positively associated with the severity of SS reflected by a pathologically low salivary flow. Phospho-flow analysis revealed that patients with SS have a significantly lower frequency of pSTAT5+ Tregs upon IL-2 stimulation compared with healthy individuals, while the frequency of Tregs and pSTAT5 in conventional T cells remained unchanged. In addition, we observed more pSTAT5+ Tregs at baseline in patients with SS, which is significantly associated with seropositivity and elevated sIL-2R. Conclusions Our data indicates that Tregs have a weakened immunosuppressive function in patients with SS due to impaired IL-2/IL-2R signalling capacity. This could mediate lymphocytic infiltration into salivary glands inducing sicca symptoms. We believe that sIL-2R could act as a useful indicator for SS and disease severity.publishedVersio

Framgångsrik Förändring – ett nationellt kommunforskningsprogram om hantering av förändrade ekonomiska förutsättningar och besvärliga situationer

Programmets innehåll har vuxit fram i samtal mellan forskare från de fem forskningsmiljöerna och företrädare för de kommuner som har uttalat intresse för att delta i programmet. Intresset har kommit till uttryck i samtal med kommunföreträdare som har berättat om erfarenheter från besvärliga situationer, erfarenheter som behöver analyseras och ställas i relation till andra kommuners erfarenheter och på så sätt rusta organisationen för framtiden. Intresse för att utveckla kunskap har också uttryckts i form av utmaningar som behöver hanteras. Det kan handla om utmaningar i form av att kunna skapa bra förutsättningar för stora och växande industriföretag i kommunen, om utmaningar relaterade till hög ungdomsarbetslöshet och de påfrestningar detta innebär på välfärden, om utmaningar relaterade till befolkningsutveckling eller utmaningar som har att göra med infrastruktursatsningar och svårigheter att få till stånd sådana. Sammantaget innebär programmet en mångsidig, djuplodande, problematiserande och lösningsorienterad fokusering på kommuners handlande i besvärliga situationer som kan uppkomma till följd av förändrade förutsättningar . Inom ramen för programmet söks förklaringar till hur anpassning sker till förändrade villkor och varför vissa organisationer lyckas bättre än andra att framgångsrikt förändra verksamhet och organisation. Erfarenheter av besvärliga situationer kommer att beskrivas och tolkas till grund för utveckling av resonemang kring hur förändrade förutsättningar kan bemästras

Single cell based phosphorylation profiling identifies alterations in toll-like receptor 7 and 9 signaling in patients with primary Sjögren's syndrome

Primary Sjögren's syndrome (pSS) is associated with polymorphisms and mRNA expression profiles that are indicative of an exaggerated innate and type I IFN immune response. Excessive activation potential of signaling pathways may play a role in this profile, but the intracellular signaling profile of the disease is not well characterized. To gain insights into potentially dysfunctional intracellular signaling profiles of pSS patients we conducted an exploratory analysis of MAPK/ERK and JAK/STAT signaling networks in peripheral blood mononuclear cells (PBMC) from 25 female pSS patients and 25 female age-matched healthy donors using phospho-specific flow cytometry. We analyzed unstimulated samples, as well as samples during a 4 h time period following activation of Toll-like receptor (TLR) 7 and 9. Expression levels of MxA, IFI44, OAS1, GBP1, and GBP2 in PBMC were analyzed by real-time PCR. Cytokine levels in plasma were determined using a 25-plex Luminex-assay. Principal component analysis (PCA) showed that basal phosphorylation profiles could be used to differentiate pSS patients from healthy donor samples by stronger intracellular signaling pathway activation in NK and T cells relative to B cells. Stimulation of PBMC with TLR7 and −9 ligands showed significant differences in the phosphorylation profiles between samples from pSS patients and healthy donors. Including clinical parameters such as extraglandular manifestations (EGM), we observed stronger responses of NF-κB and STAT3 S727 in B cells from EGM-negative patients compared to EGM-positive patients and healthy controls. Plasma cytokine levels were correlated to the basal phosphorylation levels in these patients. In addition, 70% of the patients had a positive IFN score. These patients differed from the IFN score negative patients regarding their phosphorylation profiles and their plasma cytokine levels. In conclusion, we here report increased signaling potentials in peripheral B cells of pSS patients in response to TLR7 and −9 stimulation through STAT3 S727 and NF-κB that correlate with a type I IFN signature. Induction of these pathways could contribute to the generation of a type I IFN signature in pSS. Patients displaying elevated potentiation of STAT3 S727 and NF-κB signaling could therefore benefit from therapies targeting these pathways.publishedVersio