CD62L Expression Research Articles

ApoB-specific CD4+ T cells circulate in human blood and formation of a memory population is driven by coronary artery disease and an elevated cardiovascular risk profile

Abstract Aim Atherosclerosis is a chronic inflammatory disease involving an autoimmune response against Apolioprotein B (ApoB), the core protein of low-density lipoprotein (LDL) cholesterol. Using a translational bench-to-bedside approach, we linked the presence and immuno-phenotype of ApoB-specific CD4+ T cells to clinical risk profiles for cardiovascular disease in humans. Methods Peripheral blood mononuclear cells (PBMCs) from 230 patients that underwent coronary angiography were co-incubated in vitro with a pool of immunodominant peptides from human ApoB for 6h. Reactive ApoB-specific T cells (ApoB+) were defined in flow cytometry by expression of the activation marker CD40L. Partition of ApoBpos into naïve and memory T cells was achieved by extracellular fluorochrome-based staining of CD45RO, CCR7 and CD45RA. Cytokine expression of ApoBpos was determined by intracellular staining. Results We found that a median of 0.69±0.1% of circulating CD4+ T cells were reactive to Apolipoprotein B. We found detectable concentrations of auto reactive ApoB+ T cells in 86,44% of all healthy individuals. However, overall frequencies of ApoB reactive T cells did not correlate with diagnosed coronary artery disease (CAD). Compared to ApoBneg. T cells, we detected a higher fraction of memory T cells in ApoBpos (p<0,0001), suggesting a previously occurred ApoB directed immune response. Accordingly, elevated serum levels of ApoB specific IgG Antibodies associated with high proportions of ApoB specific memory cells. Patients diagnosed with coronary artery disease presented higher percentages of central memory T cells among ApoBpos compared to healthy individuals. Correspondingly, these observations applied to patients with an elevated 10-year risk for cardiovascular events estimated by the ESC-SCORE2. These effects largely grounded on strong associations with the clinical diagnosis of arterial hypertension, elevated levels of Lp(a) and obesity. Interestingly, systolic blood pressure and LDL-serum levels correlated with elevated proportions of memory-status ApoBpos T cells in patients without statin intake, although this was not the case for patients with LDL-lowering medication. Analysis of cytokine expression in ApoBpos CD4+ T cells showed significantly increased expression of anti-inflammatory Il-2 and IL-10 in addition to pro-inflammatory IFNγ. Cytokine secretion was mainly driven by memory-status ApoBpos when compared to naïve ApoBpos T cells. Interestingly, a significant number of patients showed a mixed TH1/Treg phenotype among ApoBpos with simultaneous expression of IL-10 and IFN-γ. Conclusions Our data show for the first time that ApoB-reactive T cells exist even in healthy individuals. Cardiovascular risk factors and clinically relevant atherosclerotic disease drive memory formation and activation of ApoB+ T cells. ApoB+ Memory T cells are prone to secrete pro- and anti-inflammatory cytokines and may modulate systemic inflammation in atherosclerosis.

MyD88 in myeloid cells promotes angiotensin II-induced vascular inflammation and is associated with all-cause mortality and incident heart failure in humans with arterial hypertension

Abstract Background Angiotensin II (AngII) causes hypertension and promotes vascular accumulation of inflammatory cells. We aimed to determine how myeloid factor of differentiation 88 (MyD88) contributes to vascular dysfunction and arterial hypertension in mice and humans. Methods Male C57BL/6 as well as MyD88-/-, LysMCre/wtMyD88LSL/LSL, LysMCre/wt, TLR2-/-, TLR4-/-, TLR7-/- and TLR9-/- were investigated in the AngII-model of hypertension (1 mg/kg/d for 7days). Biodata analyses were performed in the Gutenberg-Health Study (GHS), a population based cohort. In addition, we performed computational analyses of known hypertension-related genes from genome-wide association studies (GWAS) to investigate whether they preferentially interact with MyD88 in the human protein network. Results MyD88 deficiency attenuated AngII-induced blood pressure increase and endothelial dysfunction in conductance and resistance vessels. Vascular mRNA expression levels of vcam-1, nos2, nox2 were decreased in AngII-infused MyD88-/- mice compared to C57BL/6 controls. Flow cytometric analyses revealed that AngII-induced aortic accumulation of CD11b+Ly6Chi inflammatory monocytes was significantly dampened in MyD88-/- mice. AngII increased mRNA expression of cd62L, cd68 and ccl2, which was blocked in MyD88-/- mice, indicating a role of MyD88 for myeloid cell activation and differentiation. Additionally, aortic interferon-g+ NK cells and mRNA levels of interleukin-12 and interleukin-1b were reduced in AngII-treated MyD88-/- mice. Bone marrow transfer experiments demonstrated a vasoprotective effect of MyD88 deficiency in bone marrow-derived cells, and selective expression of MyD88 in LysMCre/wtMyD88LSL/LSL mice restored AngII-induced pathology, revealing that myelomonocytic cells drives vascular dysfunction in a MyD88-dependent manner. Furthermore, data from 1,274 individuals in the GHS indicated, that MyD88 mRNA expression was associated with all cause mortality and incident chronic heart failure after a median follow-up of 11.6 years. Computational analysis of the human protein interaction network demonstrated that MyD88 is significantly connected to proteins encoded by genetic loci associated with blood pressure traits in multiple GWAS. Conclusion We provide evidence, that MyD88 expressed by myelomonocytic cells promotes AngII-induced vascular dysfunction and arterial hypertension. MyD88 might be used as an inflammatory diagnostic marker for the risk of death in hypertensive patients.

Immune modulation via dendritic cells by the effect of Thymosin-alpha-1 on immune synapse in HCMV infection

Tα1 (Thymosin-alpha-1) is a thymus-derived hormone that has been demonstrated to be effective on diverse immune cell subsets. The objective of this study was to determine the in vitro immunomodulatory effect of Tα1 in human cytomegalovirus (HCMV) infection. Dendritic cells (DCs) were isolated from peripheral blood mononuclear cells (PBMCs) by negative selection and cultured in the presence or absence of Tα1. The immunophenotyping of DCs was characterised by multiparametric flow cytometry assessing CD40, CD80, TIM-3 and PDL-1 markers, as well as intracellular TNFα production. Then, autologous CD4+ or CD8+ T-Lymphocytes (TLs) isolated by negative selection from PBMCs were co-cultured with DCs previously treated with Tα1 in the presence or absence of HCMV. Intracellular TNFα, IFNγ, IL-2 production, CD40-L and PD-1 expression were assessed through immunophenotyping, and polyfunctionality in total TLs and memory subsets were evaluated. The results showed that Tα1 increased CD40, CD80, TIM-3 and TNFα intracellular production while decreasing PDL-1 expression, particularly on plasmacytoid dendritic cells (pDCs). Therefore, Tα1 modulated the production of TNFα, IFNγ and IL-2 in both total and memory subsets of CD4+ and CD8+ TLs by upregulating CD40/CD40-L and downregulating PDL-1/PD-1 expression. Our study concludes that Tα1 enhances antigen-presenting capacity of DCs, improves TLs responses to HCMV infection, and enhances the polyfunctionality of CD8+ TLs. Consequently, Tα1 could be an alternative adjuvant for use in therapeutic cell therapy for immunocompromised patients.

Obesity Correlates with Chronic Inflammation of the Innate Immune System in Preeclampsia and HELLP Syndrome during Pregnancy.

HELLP syndrome is characterized by hemolysis, elevated liver enzymes, and a low platelet count and poses an increased risk to the pregnant woman and the unborn child. Individual risk factors such as obesity may alter immunocompetence and influence the course of preeclampsia (PE) or HELLP syndrome. Blood samples were collected from 21 pregnant women (7 healthy, 6 with PE, and 8 with HELLP syndrome) and polymorphonuclear neutrophils (PMNs) were subsequently isolated. Production of radical oxygen species (ROS), cell movement, and NETosis were assessed by live-cell imaging. Surface protein expression and oxidative burst were analyzed by flow cytometry. PE and HELLP patients had significantly higher BMI compared to the healthy control group. Depending on the expression of CD11b, CD62L, and CD66b on PMNs, a surface protein activation sum scale (SPASS) was calculated. PMNs from patients with high SPASS values showed prolonged and more targeted migration with delayed ROS production and NETosis. Obesity is associated with a chronic inflammatory state, which in combination with immunological triggers during pregnancy could modulate PMN functions. Pregnant women with higher BMI tend to have higher SPASS values, indicating activation of the innate immune system that could co-trigger PE or HELLP syndrome.

Regulatory T cells contribute to the immunosuppressive phenotype of neutrophils in a mouse model of chronic lymphocytic leukemia

BackgroundImpaired neutrophil activity is an important issue in chronic lymphocytic leukemia (CLL), as it contributes to a dysfunctional immune response leading to life-threatening infections in patients. Some features typical of CLL neutrophils, e.g., the B-cell-supportive secretion profile, have already been described. However, most of these studies were performed on cells isolated from peripheral blood. It is still unclear which molecular factors and cell types are involved in shaping neutrophil function and phenotype in the CLL microenvironment. Since regulatory T cells (Treg) play an important role in CLL progression and influence the activity of neutrophils, we investigated the crosstalk between Treg and neutrophils in the spleen using a murine model of CLL.MethodsIn this work, we used an Eµ-TCL1 mouse model of human CLL. For our in vivo and ex vivo experiments, we inoculated wild-type mice with TCL1 leukemic cells isolated from Eµ-TCL1 transgenic mice and then monitored disease progression by detecting leukemic cells in peripheral blood. We analyzed both the phenotype and activity of neutrophils isolated from the spleens of TCL1 leukemia-bearing mice. To investigate the interrelation between Treg and neutrophils in the leukemia microenvironment, we performed experiments using TCL1-injected DEREG mice with Treg depletion or RAG2KO mice with adoptively transferred TCL1 cells alone or together with Treg.ResultsThe obtained results underline the plasticity of the neutrophil phenotype, observed under the influence of leukemic cells alone and depending on the presence of Treg. In particular, Treg affect the expression of CD62L and IL-4 receptor in neutrophils, both of which are crucial for the function of these cells. Additionally, we show that Treg depletion and IL-10 neutralization induce changes in the leukemia microenvironment, partially restoring the “healthy” phenotype of neutrophils.ConclusionsAltogether, the results indicate that the crosstalk between Treg and neutrophils in CLL may play an important role in CLL progression by interfering with the immune response.

Bitter Taste Receptor Agonist Denatonium Inhibits Stemness Characteristics in Hematopoietic Stem/Progenitor Cells.

Bone marrow microenvironmental stimuli profoundly impact hematopoietic stem cell fate and biology. As G protein-coupled receptors, the bitter taste receptors (TAS2Rs) are key in transmitting extracellular stimuli into an intracellular response, within the oral cavity but also in extraoral tissues. Their expression in the bone marrow (BM)-derived cells suggests their involvement in sensing the BM microenvironmental fluctuation. In the present study, we demonstrated that umbilical cord blood (UCB)-derived CD34+ cells express fully functional TAS2Rs along with the signal transduction cascade components and their activation by the prototypical agonist, denatonium benzoate, significantly modulated genes involved in stemness maintenance and regulation of cell trafficking. The activation of these specific pathways was confirmed in functional in vitro experiments. Denatonium exposure exerted an antiproliferative effect on UCB-derived CD34+ cells, mainly affecting the most undifferentiated progenitor frequency. It also reduced their clonogenicity and repopulating potential in vitro. In addition, the TAS2R signaling activation impaired the UCB-derived CD34+ cell trafficking, mainly reducing the migration toward the chemoattractant agent CXCL12 and modulating the expression of the adhesion molecules CD62L, CD49d, and CD29. In conclusion, our results in UCB-derived CD34+ cells expand the observation of TAS2R expression in the setting of BM-resident cells and shed light on the role of TAS2Rs in the extrinsic regulation of hematopoietic stem cell functions.

Blood CD62Llow inflammatory eosinophils are related to the severity of asthma and reduced by mepolizumab.

Eosinophils have been divided into different subpopulations with distinct phenotypes based on CD62L expression. No data are available regarding the correlation between eosinophils subphenotypes and clinical severity of asthma, as well as the effect of anti-IL-5 therapy on these cells. The study investigates the correlation between blood CD62Llow inflammatory eosinophils (iEos) and clinical severity of severe eosinophilic asthma (SEA) and evaluates the impact of mepolizumab on iEos. 112 patients were screened and were divided in two groups: biological-naive (n = 51) and biological-treated patients (n = 61). The Biological-naive patients were analyzed before treatment (Group A) and 19 out of 51 patients, were longitudinally analyzed before and after treatment with mepolizumab 100 mg s.c/4 weeks (Group B); 32 patients were excluded because they were being treated with other biological therapies. Blood eosinophils were analyzed by FACS and correlated with clinical scores. In vitro effect of IL-5 and mepolizumab on CD62L expression was assessed. A significant correlation between blood CD62Llow cells and clinical scores of asthma and nasal polyps, as well as the number of asthma exacerbations in the last year was shown in untreated patients. In longitudinally studied patients we observed a marked reduction of CD62Llow cells paralleled by an increase in the proportion of CD62Lbright cells, associated with clinical improvement of asthma control. In vitro, CD62L expression on eosinophils is modulated by IL-5 and anti-IL-5. A positive correlation between CD62Llow iEos and the baseline clinical features of SEA with CRSwNP was shown. Furthermore mepolizumab restores the healthy balance among eosinophils sub-phenotypes in SEA patients.

ACTH impairs the migratory and secretory profile of mononuclear cells during proestrus in cattle

The aim was to evaluate the effect of ACTH on the mechanisms involved in peripheral blood mononuclear cells (PBMCs) infiltration into the ovary during dairy cattle proestrus. Regarding this, proper expression pattern of adhesion molecules must take place both in PBMCs and in endothelial cells. Argentinian Holstein cows (n = 12) were treated with 100 IU of ACTH every 12 h for 4 days before ovulation when ovariectomy was performed (day 18). Blood samples were taken on day 15 (0 h) and immediately before (72 h) and after (74 h) the last ACTH administration. In PBMCs, flow cytometry was performed to analyze CD44, CD11b and CD62-L expression along with gene expression of chemokines' receptors. Interleukin (IL)-4 and tumor necrosis factor-α (TNF-α) production was analyzed by flow cytometry after exposing PBMCs to autologous follicular fluid. In ovarian blood vessels, expression of the vascular endothelium cell adhesion-1 (VCAM-1) and the platelet endothelial cell adhesion molecule-1 was evaluated by immunohistochemistry. In T-lymphocytes, the expression of CD44 and CD11b was lower at 72 h in ACTH-treated cows (P < 0.05). In monocytes, the expression of CD11b and CD62-L was lower at 72 h in ACTH-treated cows (P < 0.05). Also, the percentage of IL-4+ cells was higher in ACTH-treated cows, meanwhile, the percentage TNF-α+ cells was lower in ACTH-treated cows (P < 0.05). Finally, in the vessels associated with the preovulatory follicle VCAM-1 immunoexpression was lower in ACTH-treated cows (P < 0.05). Here, we present novel insights into the effect of stress during the preovulatory period on the inflammatory pathway necessary for ovulation.

Analysis of regulatory T lymphocytes in patients with traumatic brain injury

In recent years, traumatic brain injury (TBI) has been one of the most urgent medical and social problems due to its prevalence, predominantly affecting young people of working age, causing high mortality, disability and economic costs for treatment and subsequent rehabilitation of patients. At present, the role of patients’ immune system in evolving neuroinflammation after traumatic brain injury has been proven. Treg cell populations represent an important factor determining the outcome of the disease due to promoting induction of immunological tolerance, being a significant component of immunoregulation. As a result of our study, we found a decrease in the relative content of Treg within the total lymphocyte pool of peripheral blood, which has the CD3+CD4+CD25bright phenotype in patients of the 3rd and 4th groups, in comparison with the data from control group. Moreover, a decreased relative content of Tregs (CD4+CD25+T cells) was revealed which is due to the degree of brain tissue damage and, as a result, their migration to suppress inflammation due to production of anti-inflammatory cytokines (TGF-â, IL-10). The Treg population is heterogeneous, thus prompting us for analysis of the Treg subpopulations profile based on the expression of CD45R0 and CD62L. When assessing subpopulations of regulatory T lymphocytes within CD45Ro and CD62L, significant changes were found only in patients with brain contusion. The changes were revealed within the pool of “naive” T regulatory lymphocytes with the CD3+CD4+CD25brightCD39+ Treg phenotype, capable of producing a wide range of cytokines specific for Th1, Th2, Th17, in patients with mild, moderate and severe TBI. Meanwhile, the level of highly active CD3+CD4+CD25brightCD73+ Tregs was significantly reduced in patients with moderate and severe TBI. These changes indicate an imbalance in immunoregulatory processes resulting from extensive damage to brain tissues.

Anti-CD1d treatment suppresses immunogenic maturation of lung dendritic cells dependent on lung invariant natural killer T cells in asthmatic mice

Our previous findings show that invariant natural killer T (iNKT)cells can promote immunogenic maturation of lung dendritic cells (LDCs) to enhance Th2 cell responses in asthma. It has been accepted that recognition of glycolipid antigens presented by CD1d molecules by the T cell receptors of iNKT cells leads to iNKT cell activation. Therefore, we examine the immunoregulatory influences of anti-CD1d treatment on Th2 cell response and immunogenic maturation of LDCs and subsequently explored whether these influences were dependent on lung iNKT cells in asthmatic mice. We discoveredthat in wild-type mice sensitized and challenged with house dust mite or ovalbumin (OVA), anti-CD1d treatment inhibited Th2 cell response and immunogenic maturation of LDCs. LDCs from asthmatic mice with anti-CD1d treatment had a markedly decreased influence on Th2 cell responses in vivo and in vitro. Furthermore, anti-CD1d treatment reduced the abundance and activation of lung iNKT cells in asthmatic mice. Moreover, in asthmatic iNKT cell-deficient Jα18-/- mice, anti-CD1d treatment did not influence Th2 cell responses and immunogenic maturation of LDCs. Meanwhile, the quantity of CD40L+ iNKT cells in asthmatic mice was significant decreased by anti-CD1d treatment. Finally, the inhibition of anti-CD1d treatment on LDC immunogenic maturation and Th2 cell responses in asthmatic mice was reversed by anti-CD40 treatment. Our data suggest that anti-CD1d treatment can suppress Th2 cell responses through inhibiting immunogenic maturation of LDCs dependent on lung iNKT cells, which couldbe partially related to the downregulation of CD40L expression on lung iNKT cells in asthmatic mice.

Functional characterization of small and large alveolar macrophages in sarcoidosis and idiopathic pulmonary fibrosis compared with non-fibrosis interstitial lung diseases.

Sarcoidosis is a granulomatous disease that mostly affects the lungs. Advanced tissue injury caused by this disease can progress to pulmonary fibrosis with similar characteristics shared with idiopathic pulmonary fibrosis (IPF). The initial presentations of both sarcoidosis and IPF may be shared with other interstitial lung diseases (ILDs). Two populations of macrophages have been described in the alveolar space: small alveolar macrophages (AMs) and large alveolar macrophages. Despite their protective function, these cells may also play a role in the initiation and maintenance of inflammation leading to fibrosis. The aim of this study was the functional characterization of small and large AM subpopulations in sarcoidosis and IPF as a pathology with respectively mild and advanced tissue injury causing fibrosis, in comparison with non-fibrosis ILDs. Activation and adhesion surface markers as well as functions of small and large AMs isolated from bronchoalveolar lavage (BAL) were assessed by Flow Cytometry within patients with confirmed sarcoidosis (n= 14), IPF (n= 6), and non-fibrosis ILDs (n= 9). Our results showed that small AMs are immunologically more active, which may be important for airway inflammation. They are also proportionally more abundant in IPF, and therefore they may be more involved in a fibrosis process associated with the down-regulation of HLA-DR, LeuCAM, and CD62L expression. In Sarcoidosis, the inflammatory process appears to be associated with up-regulation of CD38 expression and oxidative burst activity. A relevant potential of the activation and adhesion markers as well as oxidative burst activity expressed on small and large AMs, in the perspective of differential diagnosis of sarcoidosis and IPF.

Dengue virus infection in mice induces bone marrow myeloid cell differentiation and generates Ly6Glow immature neutrophils with modulated functions.

While neutrophil activation during dengue virus infection is known, the effect of dengue virus infection on neutrophil biogenesis has not been studied. We demonstrate that dengue virus serotype 2 induces the differentiation of mice progenitor cells ex vivo toward the CD11b+Ly6C+Ly6G+ granulocyte population. We further observed an expansion of CD11b+Ly6CintLy6Glow myeloid cells in the bone marrow of dengue virus serotype 2-infected AG129 mice with low CXCR2 expression, implying an immature population. Additionally, dengue virus serotype 2 alone could induce the differentiation of promyelocyte cell line HL-60 into neutrophil-like cells, as evidenced by increased expression of CD10, CD66b, CD16, CD11b, and CD62L, corroborating the preferential shift toward neutrophil differentiation by dengue virus serotype 2 in the mouse model of dengue infection. The functional analysis showed that dengue virus serotype 2-induced neutrophil-like cells exhibited reduced phagocytic activity and enhanced NETosis, as evidenced by the increased production of myeloperoxidase, citrullinated histones, extracellular DNA, and superoxide. These neutrophil-like cells lose their ability to proliferate irreversibly and undergo arrest in the G0 to G1 phase of the cell cycle. Further studies show that myeloperoxidase-mediated signaling operating through the reactive oxygen species axis may be involved in dengue virus serotype 2-induced proliferation and differentiation of bone marrow cells as ABAH, a myeloperoxidase inhibitor, limits cell proliferation in vitro and ex vivo, affects the cell cycle, and reduces reactive oxygen species production. Additionally, myeloperoxidase inhibitor reduced NETosis and vascular leakage in dengue virus serotype 2-infected AG129 mice. Our study thus provides evidence that dengue virus serotype 2 can accelerate the differentiation of bone marrow progenitor cells into neutrophils through myeloperoxidase and modulate their functions.

Impaired tissue homing by the Ikzf3N159S variant is mediated by interfering with Ikaros function.

AIOLOS, encoded by IKZF3, is a member of the IKZF family of proteins that plays an important role in regulating late B-cell differentiation. Human individuals heterozygous for the AIOLOS p.N160S variant displayed impaired humoral immune responses as well as impaired B and T cell development. We have previously reported that a mouse strain harboring an Ikzf3N159S allele that corresponds to human IKZF3N160S recapitulated immune-deficient phenotypes, such as impaired B cell development and loss of CD23 expression. In this study, we investigated the effect of the Ikzf3N159S variant and found that B1a cell development was impaired in Ikzf3N159S/N159S mice. In addition, CD62L expression was severely decreased in both B and T lymphocytes by the Ikzf3N159S mutation, in a dose-dependent manner. Mixed bone marrow chimera experiments have revealed that most immunodeficient phenotypes, including low CD62L expression, occur in intrinsic cells. Interestingly, while Ikzf3N159S/N159S lymphocytes were still present in the spleen, they were completely outcompeted by control cells in the lymph nodes, suggesting that the capacity for homing or retention in the lymph nodes was lost due to the Ikzf3N159S mutation. The homing assay confirmed severely decreased homing abilities to lymph nodes of Ikzf3N159S/N159S B and T lymphocytes but selective enrichment of CD62L expressing Ikzf3N159S/N159S lymphocytes in lymph nodes. This finding suggests that impaired CD62L expression is the major reason for the impaired homing capacity caused by the Ikzf3N159S mutation. Interestingly, an excess amount of Ikaros, but not Aiolos, restored CD62L expression in Ikzf3N159S/N159S B cells. Together with the loss of CD62L expression due to Ikaros deficiency, the AiolosN159S mutant protein likely interferes with Ikaros function through heterodimerization, at least in activating the Sell gene encoding CD62L expression. Thus, our results revealed that AiolosN159S causes some immunodeficient phenotypes via the pathogenesis referred to as the heterodimeric interference as observed for AiolosG158R variant.

Cytotoxic T cell subsets in peripheral blood and cerebrospinal fluid from patients with multiple sclerosis

Using multicolor flow cytometry, the main cytotoxic T lymphocytes (Tcyt) subsets were identified, based on the expression of CD45RA and CD62L in paired samples of peripheral blood and cerebrospinal fluid from the patients during the relapse (n = 32) and remission (n = 20) of multiple sclerosis (MS), as well as in the peripheral blood samples of healthy volunteers (n = 51). During the relapse of MS, we have observed a decreased relative number of CD3+CD4+ cells and CD4/CD8 ratio in cerebrospinal liquor. In peripheral blood taken from the relapsed MS patients, we have found significant correlations between EDSS score and absolute counts (r = -0,430, p = 0.014), and with relative numbers of CD45RA+CD62L+Tcyt (r = -0,502, p = 0.003). In remission state of MS, the relative numbers of blood CD45RA-CD62L-Tcyt cells exhibited a significant decrease (p = 0.005) to 8.70% (6.51-11.63) against control group with 12.18% (10.38-15.24), although it did not significantly differ (p = 0.114) from the relapsed patients with 11.31% (8.28-13.90). Studies of liquor samples have shown that, during MS relapse, the percentage of CD45RA-CD62L-Tcyt was increased (p = 0.027) up to 8.16% (6.40-11.40), while in remission state these cells comprised only 6.49% (4.51-8.39) from the total CD3+ cell number. During relapse of MS, some positive correlations were revealed between the relative number of nave, CM, EM and TEMRA Tcyt from liquor, and the percentages, as well as contents of similar T cell subsets in peripheral blood samples. The inverse relationship between the level of EM Tcyt from liquor and peripheral blood naive cells showed the close relationship between these two Tcyt subsets and clinical manifestations of MS (i.e., scores of EDSS scale). During the remission period, most of these correlations are disrupted. Further investigations of cytotoxic T cells dynamics in peripheral blood and cerebrospinal fluid will help to approach the understanding of MS pathogenesis by revealing novel markers for the clinical prognosis in this disorder.

Gut Microbiome-Generated Phenylacetylglutamine from Dietary Protein is Associated with Crohn's Disease and Exacerbates Colitis in Mouse Model Possibly via Platelet Activation.

Our aims were to better understand the interplay of diet and gut microbiota in Crohn's disease [CD], taking advantage of a new-onset treatment-naïve CD cohort. We focus on phenylacetylglutamine [PAGln], a diet-derived meta-organismal prothrombotic metabolite. We collected faecal and serum samples from a CD cohort [n = 136] and healthy controls [n = 126] prior to treatment, and quantified serum PAGln using LC-MS/MS. Diet was assessed using food-frequency questionnaires. Mice [C57BL/6] were fed high/low-protein diets and administered dextran sodium sulphate [DSS] to examine plasma PAGly, thrombosis potential, and colitis severity. PAGly or saline was administered to DSS-induced colitis mice, and colitis severity and colonic tissue gene expression were examined. P-selectin and CD40L expression were determined in human platelet-rich plasma [n = 5-6] after exposure to platelet agonists following PAGln priming. Bioinformatic analysis and bacterial culturing identified the main contributor of PAGln in CD. PAGln, a meta-organismal prothrombotic metabolite, is associated with CD. Administration of PAGly exacerbated colitis in a mouse model and upregulated coagulation-related biological processes. Antiplatelet medicine, dipyridamole, attenuated PAGly-enhanced colitis susceptibility. PAGln enhanced platelet activation and CD40L expression in platelet-rich plasma ex vivo. Further study revealed that high dietary protein intake and increased abundance of phenylacetic acid [PAA]-producing Proteobacteria mediated by phenylpyruvate decarboxylase act in concert to cause the elevated PAGln levels in CD patients. Taken together, ppdc-carrying Proteobacteria-generated PAGln from dietary protein is associated with CD and exacerbates colitis possibly via platelet-induced coagulation and inflammation These results suggest that PAGln is a potential early diagnostic marker and therapeutic target of CD.

CD62L expression marks SARS-CoV-2 memory B cell subset with preference for neutralizing epitopes

Severe acute respiratory syndrome coronavirus 2–neutralizing antibodies primarily target the spike receptor binding domain (RBD). However, B cell antigen receptors (BCRs) on RBD-binding memory B (B mem ) cells have variation in the neutralizing activities. Here, by combining single B mem cell profiling with antibody functional assessment, we dissected the phenotype of B mem cell harboring the potently neutralizing antibodies in coronavirus disease 2019 (COVID-19)–convalescent individuals. The neutralizing subset was marked by an elevated CD62L expression and characterized by distinct epitope preference and usage of convergent V H (variable region of immunoglobulin heavy chain) genes, accounting for the neutralizing activities. Concordantly, the correlation was observed between neutralizing antibody titers in blood and CD62L + subset, despite the equivalent RBD binding of CD62L + and CD62L − subset. Furthermore, the kinetics of CD62L + subset differed between the patients who recovered from different COVID-19 severities. Our B mem cell profiling reveals the unique phenotype of B mem cell subset that harbors potently neutralizing BCRs, advancing our understanding of humoral protection.

Blood and Sputum Eosinophils of COPD Patients Are Differently Polarized than in Asthma.

Different eosinophil subpopulations have been identified in asthma and other eosinophilic disorders. However, there is a paucity of data on eosinophil subpopulations in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to compare eosinophil phenotypes in blood and induced sputum in patients with COPD, asthma and controls. Stable patients with mild-to-moderate COPD (n = 15) and asthma (n = 14) with documented blood eosinophilia ≥100 cells/µL in the year prior to the study and the control group (n = 11) were included to the study. The blood and sputum eosinophil phenotypes were analyzed by flow cytometry. IL-5, IL-13, CCL5 and eotaxin-3 levels were measured in the induced sputum. The marker expression on blood eosinophils was similar among control, asthma and COPD groups. The expressions of CD125, CD193, CD14 and CD62L were higher on blood than on sputum eosinophils in all three groups. We found increased levels of CD193+ and CD66b+ sputum eosinophils from COPD patients, and an elevated level of CD11b+ sputum eosinophils in asthma compared to COPD patients. The results of our study suggest that the profile of marker expression on COPD sputum eosinophils differed from other groups, suggesting a distinct phenotype of eosinophils of COPD patients than in asthma or healthy subjects.

Glycopeptide Antibiotics Impair Neutrophil Effector Functions

Introduction: Neutrophilic granulocytes represent the first line of defense against microorganisms. Granulocytes phagocytose microorganisms and specifically synthesize oxygen radicals against them, which eventually kills the invaders. Methods: Neutrophilic granulocytes were isolated from peripheral blood of healthy volunteer donors. Putative interference of new-generation antibiotics with neutrophil function was tested using a collection of granulocyte-stimulating agents and Amplex™ Red-based plate assay and flow cytometry-based respiratory burst assays. In addition, phagocytosis of E. coli, IL-8 production, bactericidal activity, and CD62L expression of granulocytes were evaluated. Results: Of note, we found that the two glycopeptide antibiotics dalbavancin and teicoplanin inhibited ROS production upon granulocyte activation via different signaling pathways in a dose-dependent manner. Dalbavancin also blocked the PMA-induced shedding of CD62L. In contrast, the oxazolidinone antibiotics tedizolid and linezolid had no effect on neutrophil function, while the combination of ceftazidime/avibactam dose dependently inhibited the fMLP/Cytochalasin B-induced granulocyte burst in a dose-dependent manner. Additionally, we showed that dalbavancin and teicoplanin as well as sulfametrole/trimethoprim and ceftazidime/avibactam inhibited baseline and PMA-induced IL-8 production by neutrophilic granulocytes. Moreover, dalbavancin impaired the bactericidal activity of neutrophilic granulocytes. Conclusion: We here identified hitherto unknown inhibitory effects of several classes of antibiotics on the effector functions of neutrophilic granulocytes.

Efficacy of COVID-19 mRNA vaccination in patients with autoimmune disorders: humoral and cellular immune response

BackgroundThe impact of immunosuppressive therapies on the efficacy of vaccines to SARS-CoV-2 is not completely clarified. We analyzed humoral and T cell-mediated response after COVID-19 mRNA vaccine in immunosuppressed patients and patients with common variable immunodeficiency disease (CVID).PatientsWe enrolled 38 patients and 11 healthy sex- and age-matched controls (HC). Four patients were affected by CVID and 34 by chronic rheumatic diseases (RDs). All patients with RDs were treated by corticosteroid therapy and/or immunosuppressive treatment and/or biological drugs: 14 patients were treated with abatacept, 10 with rituximab, and 10 with tocilizumab.MethodsTotal antibody titer to SARS-CoV-2 spike protein was assessed by electrochemiluminescence immunoassay, CD4 and CD4-CD8 T cell-mediated immune response was analyzed by interferon-γ (IFN-γ) release assay, the production of IFN-γ-inducible (CXCL9 and CXCL10) and innate-immunity chemokines (MCP-1, CXCL8, and CCL5) by cytometric bead array after stimulation with different spike peptides. The expression of CD40L, CD137, IL-2, IFN-γ, and IL-17 on CD4 and CD8 T cells, evaluating their activation status, after SARS-CoV-2 spike peptides stimulation, was analyzed by intracellular flow cytometry staining. Cluster analysis identified cluster 1, namely the “high immunosuppression” cluster, and cluster 2, namely the “low immunosuppression” cluster.ResultsAfter the second dose of vaccine, only abatacept-treated patients, compared to HC, showed a reduced anti-spike antibody response (mean: 432 IU/ml ± 562 vs mean: 1479 IU/ml ± 1051: p = 0.0034), and an impaired T cell response, compared with HC. In particular, we found a significantly reduced release of IFN-γ from CD4 and CD4-CD8 stimulated T cells, compared with HC (p = 0.0016 and p = 0.0078, respectively), reduced production of CXCL10 and CXCL9 from stimulated CD4 (p = 0.0048 and p = 0.001) and CD4-CD8 T cells (p = 0.0079 and p = 0.0006). Multivariable General Linear Model analysis confirmed a relationship between abatacept exposure and impaired production of CXCL9, CXCL10, and IFN-γ from stimulated T cells. Cluster analysis confirms that cluster 1 (including abatacept and half of rituximab treated cases) showed a reduced IFN-γ response, as well as reduced monocyte-derived chemokines All groups of patients demonstrated the ability to generate specific CD4 T activated cells after spike proteins stimulation. After the third dose of vaccine, abatacept-treated patients acquired the ability to produce a strong antibody response, showing an anti-S titer significantly higher compared to that obtained after the second dose (p = 0.0047), and comparable with the anti-S titer of the other groups.ConclusionsPatients treated with abatacept showed an impaired humoral immune response to two doses of COVID-19 vaccine. The third vaccine dose has been demonstrated to be useful to induce a more robust antibody response to balance an impaired T cell-mediated one. All patients, exposed to different immunosuppressive drugs, were able to produce specific CD4-activated T cells, after spike proteins stimulation.Trial registrationLocal Ethical Committee NP4187.

T cell CD62L expression following nivolumab therapy is associated with response to rituximab‐nivolumab in treatment naïve follicular lymphoma: the 1st FLOR study

Introduction: Inter-tumoral T cell dysfunction and efficacy of immune checkpoint inhibitors (ICI) in follicular lymphoma (FL) has been well described. However, few studies have examined peripheral blood immunity at diagnosis or the impact of frontline ICI on circulating immunity in FL. We hypothesised that immune dysregulation in peripheral blood would be present in treatment naïve FL and would correlate to response to frontline ICI. Methods: PBMC samples from 34 untreated FL patients receiving rituximab (R) and nivolumab (nivo) in the 1st FLOR trial (Hawkes JCO 2021) were collected at baseline, post 4 cycles of nivo and after 6 months of nivo±R. Immune profile was assessed using a single-tube 29 antibody FACS panel on a spectral flow cytometer and compared to the profile of 12 age matched healthy donors. Results were correlated with centrally determined PET response (Lugano criteria). Results: Compared to healthy donors, FL patients had increased proportions of TRegs (P < 0.0001) with decreased HLA-DR+ (P < 0.01) and increased PD-1+ (P < 0.01) populations. NK cells were increased (P < 0.05) with a 2-fold increase in TIM3 expression (P < 0.01). While total T cells were unchanged, expression of PD-1, TIM3, HLA-DR and 4-1BB were significantly increased in T cells from FL patients. Treatment with nivo significantly increased the populations of TRegs expressing 41BB, LAG-3, TIM3 or PD-L2 (P < 0.05) with a decreased PD-L1 positive population at PET-CT2. Expression of immune checkpoints on T cells was unchanged by therapy. To assess biomarkers of response, patients were stratified into sustained CR (CR achieved by PET-CT4 and maintained for 6 months without evidence of relapse, n = 15) vs. PR/PD (n = 21). At baseline, sustained CR was associated with a trend for increased proportions of Naïve CD4 and CD8 T cells and decreased TRegs and PD-L2 expressing TRegs. Baseline expression of PD-1 on T and NK cells did not correlate with sustained response. Most strikingly, expression of CD62L was significantly downregulated across total CD4 and CD8 T cells and TRegs at PET-CT2 in PR/PD patients (P < 0.05) and maintained at baseline levels in those patients who achieved a sustained CR. At this early timepoint final patient responses had not been established with most patients having either progressive or stable disease, suggesting that dysfunctional downregulation of CD62L in response to nivo may reflect the inability of patient’s T cells to activate and/or migrate to the tumour site and facilitate tumour clearance and long-term treatment responses. Conclusions: Grade 1-3A treatment naïve FL is associated with significant dysregulation of peripheral blood T and NK cells prior to therapy. Early downregulation of CD62L on T cells of patients treated with nivo was associated with the inability to achieve long term complete responses and may indicate aberrant T cell activation and/or function which impacts on long term response to therapy. Encore Abstract - previously submitted to EHA 2023 The research was funded by: Bristol Myers Squibb Keywords: Basic and Translational Science, Diagnostic and Prognostic Biomarkers Conflicts of interests pertinent to the abstract. A. Barraclough Honoraria: Roche, Gilead G. Chong Consultant or advisory role: Bristol Myers Squibb Research funding: Bristol Myers Squibb, Merck Serono, Pharmacyclics, Regeneron, Bayer, Astra Zeneca, Amgen, Hutch Med, Incyte E. A. Hawkes Consultant or advisory role: Roche, Merck Sharpe & Dohme, Astra Zeneca, Gilead, Antigene, Novartis, Regeneron, Janssen, Specialised Therapeutics Research funding: Bristol Myers Squibb, Roche, Merck KgA, Astra Zeneca