scholarly journals The induction of CD80 and apoptosis on B cells and CD40L in CD4+ T cells in response to seasonal influenza vaccination distinguishes responders versus non-responders in healthy controls and aviremic ART-treated HIV-infected individuals

Vaccine ◽  
2017 ◽  
Vol 35 (5) ◽  
pp. 831-841 ◽  
Author(s):  
Anna M. Powell ◽  
Zhenwu Luo ◽  
Lisa Martin ◽  
Zhuang Wan ◽  
Lei Ma ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Influenza Vaccination ◽  
Cd4 T Cells ◽  
Seasonal Influenza ◽  
Healthy Controls ◽  
Seasonal Influenza Vaccination

scholarly journals Pre-existing immunity and vaccine history determine hemagglutinin-specific CD4 T cell and IgG response following seasonal influenza vaccination

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Katharina Wild ◽  
Maike Smits ◽  
Saskia Killmer ◽  
Shirin Strohmeier ◽  
Christoph Neumann-Haefelin ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Influenza Vaccination ◽  
Cd4 T Cells ◽  
Seasonal Influenza ◽  
Early Response ◽  
Cd4 T Cell ◽  
Cell Phenotype ◽  
Seasonal Influenza Vaccination ◽  
Hemagglutinin Protein

AbstractEffectiveness of seasonal influenza vaccination varies between individuals and might be affected by vaccination history among other factors. Here we show, by monitoring frequencies of CD4 T cells specific to the conserved hemagglutinin epitope HA118-132 and titres of IgG against the corresponding recombinant hemagglutinin protein, that antigen-specific CD4 T cell and antibody responses are closely linked to pre-existing immunity and vaccine history. Upon immunization, a strong early reaction is observed in all vaccine naïve participants and also in vaccine experienced individuals who have not received the respective seasonal vaccine in the previous year. This response is characterized by HA118-132 specific CD4 T cells with a follicular helper T cell phenotype and by ascending titers of hemagglutinin-specific antibodies from baseline to day 28 following vaccination. This trend was observed in only a proportion of those participants who received the seasonal vaccine the year preceding the study. Regardless of history, levels of pre-existing antibodies and CD127 expression on CD4 T cells at baseline were the strongest predictors of robust early response. Thus, both pre-existing immunity and vaccine history contribute to the response to seasonal influenza vaccines.

scholarly journals Circulating cytokines and lymphocyte subsets in patients who have recovered from COVID-19

2020 ◽  
Author(s):  
Hasi Chaolu ◽  
Xinri Zhang ◽  
Xin Li ◽  
Xin Li ◽  
Dongyan Li
Keyword(s):  
T Cells ◽  
B Cells ◽  
Nk Cells ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Lymphocyte Subsets ◽  
Healthy Controls ◽  
Tnf Α ◽  
Ifn Γ ◽  
Circulating Cytokines

To investigate the immune status of people who previously had COVID-19 infections, we recruited patients 2 weeks post-recovery and analyzed circulating cytokines and lymphocyte subsets. We measured levels of total lymphocytes, CD4+ T cells, CD8+ T cells, CD19+ B cells, CD56+ NK cells, and the serum concentrations of interleukin (IL)-1, IL-4, IL-6, IL-8, IL-10, transforming growth factor beta (TGF-β), tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ) by flow cytometry. We found that in most post-recovery patients, levels of total lymphocytes (66.67%), CD3+ T cells (54.55%), CD4+ T cells (54.55%), CD8 + T cells (81.82%), CD19+ B cells (69.70%), and CD56+ NK cells(51.52%) remained lower than normal, whereas most patients showed normal levels of IL-2 (100%), IL-4 (80.88%), IL-6 (79.41%), IL-10 (98.53%), TNF-α (89.71%), IFN-γ (100%) and IL-17 (97.06%). Compared to healthy controls, 2-week post-recovery patients had significantly lower absolute numbers of total lymphocytes, CD3+ T cells, CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD56+ NK cells, along with significantly higher levels of IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ and IL-17. Among post-recovery patients, T cells, particularly CD4+ T cells, were positively correlated with CD19+ B cell counts. Additionally, CD8+ T cells positively correlated with CD4+ T cells and IL-2 levels, and IL-6 positively correlated with TNF-α and IFN-γ. These correlations were not observed in healthy controls. By ROC curve analysis, post-recovery decreases in lymphocyte subsets and increases in cytokines were identified as independent predictors of rehabilitation efficacy. These findings indicate that the immune system has gradually recovered following COVID-19 infection; however, the sustained hyper-inflammatory response for more than 14 days suggests a need to continue medical observation following discharge from the hospital. Longitudinal studies of a larger cohort of recovered patients are needed to fully understand the consequences of the infection.

B Cell With Regulatory Function Are Enriched Within Transitional and IgM Memory B Cell Subsets In Healthy Donors But Are Reduced and Functionally Impaired In Patients With Chronic Graft-Versus-Host Disease

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4478-4478
Author(s):  
Anushruti Sarvaria ◽  
Ahmad Khoder ◽  
Abdullah Alsuliman ◽  
Claude Chew ◽  
Takuya Sekine ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
B Cell ◽  
Cd4 T Cells ◽  
Memory B Cells ◽  
Regulatory Function ◽  
Healthy Controls ◽  
Transitional B Cells ◽  
B Cell Subsets

The immunosuppressive function of IL10 producing regulatory B cells (Bregs) has been shown in several murine models of inflammation and autoimmune disease. However, there is a paucity of data regarding the existence of an equivalent regulatory B cell subset in healthy individuals and their potential role in the pathogenesis of chronic graft-versus-host disease (cGVHD) remains unknown. Here, we examined the functional regulatory properties of peripheral blood (PB)-derived human B cell subsets from healthy individuals. In addition, we carried out studies to explore their role in cGVHD, using B cells from patients following allogeneic stem cell transplantation (HSCT). We first determined whether human IL-10 producing B cells are enriched within any othe previously described human B cell subsets: CD19+IgM+CD27+ IgM memory, CD19+IgM-CD27+ switched memory, CD19+IgM+CD27- naive, and and transitional CD19+CD24hiCD38hi. Following in vitro stimulation with CD40 ligand, the majority of IL-10 producing B cells were found within the CD24hiCD38hi transitional and CD19+IgM+CD27+B cell subsets. We next assessed the regulatory properties of the PB-derived B cell subsets, by sort-purifying IgM memory (CD19+IgM+CD27+), switched memory (CD19+IgM-CD27+), naïve (CD19+IgM+CD27-) and transitional (CD19+CD24hiCD38hi) B cells from healthy controls, and cultured them 1:1 with autologous magnetic-bead purified CD4+ T cells. CD3/CD28 stimulated CD4+ T cells cultured with either CD19+IgM+CD27- naïve or CD19+IgM-CD27+ switched memory B cells proliferated to the same extent and produced equivalent amounts of IFN-γ to cultures containing CD4+ T cells alone. In contrast, culture of CD4+ T cells with IgM memory and transitional B cells significantly suppressed CD4+ T cell proliferation [median percent proliferating CD4+ T cells 52.5%; (33%-75%)] and 51% (25%-63%)], respectively when compared with CD3/CD28 stimulated CD4+ T cells (positive control) [89.5% (75%-92%], p=0.0001. The inhibitory effect of IgM memory and transitional B cells on CD4+ T cell proliferation was cell dose dependent with the highest suppression observed at a ratio of 1:1. These data suggest that human PB transitional and IgM memory B cells are endowed with regulatory function. We next examined if the in vitro suppressive effect of transitional and IgM memory B cells is mediated by regulatory T cells (Tregs). For this purpose, CD4+ T cells were depleted of CD127lo CD25hi CD4+ T cells by magnetic cell purification. B cell subsets were cultured with CD3/CD28 stimulated CD4+ CD25- T cells at a ratio of 1:1. IgM memory and transitional B cells were able to significantly suppress the proliferation and Th1 cytokine response by CD4+ CD25- T cells compared to cultures containing CD4+ CD25-T cells alone, indicating that the suppressive activity of Bregs is independent of Tregs. To further understand the underlying mechanims though which Bregs exert T-cell suppression, we used antibody blockade experiments and showed that this suppressive effect was mediated partially via the provision of IL-10, but not TGF-ß. Using transwell experiments, we further determined that the suppressive function of Bregs is also partly dependent on direct T cell/B cell contact. We next assessed whether the activity of Breg cells might be altered in patients with cGVHD. B cells from patients with cGVHD were refractory to CD40 stimulation and produced less IL-10 when compared to patients without cGVHD post-SCT and healthy controls, [1.02% (0.22-2.26) vs.1.72% (0.8-5.52) vs. 2.16 (1.3- 5.6), p=0.001]. Likewise, the absolute number of IL-10 producing B cells was significantly lower in cGvHD patients compared to patients without cGVHD and healthy controls (p=0.007), supporting both a qualitative and quantitative defect in IL-10 producing B cells in cGvHD. Our combined studies provide important new data defining the phenotype of B cell populations enriched in regulatory B cells in healthy humans and provide evidence for a defect in the activity of such cells in patients with cGVHD post-SCT. In association with previous reports showing defects in Treg cell activity in GVHD, our results suggest the existence of a broad range of deficiencies in immune regulatory cell function in cGvHD patients. * Both Anushruti Sarvaria and Ahmad K contributed equally. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Circulating Cytokines and Lymphocyte Subsets in Patients Who Have Recovered from COVID-19

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Hasichaolu ◽  
Xinri Zhang ◽  
Xin Li ◽  
Xin Li ◽  
Dongyan Li
Keyword(s):  
T Cells ◽  
B Cells ◽  
Nk Cells ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Lymphocyte Subsets ◽  
Healthy Controls ◽  
Cell Counts ◽  
Tnf Α ◽  
Ifn Γ

To investigate the immune status of people who previously had COVID-19 infections, we recruited two-week postrecovery patients and analyzed circulating cytokine and lymphocyte subsets. We measured levels of total lymphocytes, CD3+ T cells, CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD56+ NK cells and the serum concentrations of interleukin- (IL-) 1, IL-4, IL-6, IL-8, IL-10, transforming growth factor beta (TGF-β), tumor necrosis factor alpha (TNF-α), and interferon gamma (IFN-γ) by flow cytometry. We found that in most postrecovery patients, levels of total lymphocytes (66.67%), CD3+ T cells (54.55%), CD4+ T cells (54.55%), CD8+ T cells (81.82%), CD19+ B cells (69.70%), and CD56+ NK cells (51.52%) remained lower than normal, whereas most patients showed normal levels of IL-2 (100%), IL-4 (80.88%), IL-6 (79.41%), IL-10 (98.53%), TNF-α (89.71%), IFN-γ (100%), and IL-17 (97.06%). Compared to healthy controls, two-week postrecovery patients had significantly lower absolute numbers of total lymphocytes, CD3+ T cells, CD4+ T cells, CD8+ T cells, CD19+ B cells, and CD56+ NK cells, along with significantly higher levels of IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-γ, and IL-17. Among postrecovery patients, T cells, particularly CD4+ T cells, were positively correlated with CD19+ B cell counts. Additionally, CD8+ T cells were positively correlated with CD4+ T cells and IL-2 levels, and IL-6 positively correlated with TNF-α and IFN-γ. These correlations were not observed in healthy controls. By ROC curve analysis, postrecovery decreases in lymphocyte subsets and increases in cytokines were identified as independent predictors of rehabilitation efficacy. These findings indicate that the immune system gradually recovers following COVID-19 infection; however, the sustained hyperinflammatory response for more than 14 days suggests a need to continue medical observation following discharge from the hospital. Longitudinal studies of a larger cohort of recovered patients are needed to fully understand the consequences of the infection.

scholarly journals Further Insights into the Hematological Disorders Observed in Shwachman-Diamond Syndrome: mTOR and STAT3 Hyper-Phosphorylation in CD4+ and CD8+ T Cells and Efficacy of Rapamycin Treatment

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2675-2675
Author(s):  
Valentino Bezzerri ◽  
Antonio Vella ◽  
Ilaria Meneghelli ◽  
Marco Cipolli ◽  
Claudio Sorio
Keyword(s):  
T Cells ◽  
B Cells ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Bone Marrow Failure ◽  
Dependent Manner ◽  
Healthy Controls ◽  
Exact Function ◽  
Increased Risk ◽  
Shwachman Diamond Syndrome

Abstract Shwachman-Diamond syndrome (SDS) is a rare autosomal recessive disease which affects 1/168,000 newborns in Italy with a mean of 3.0 new cases/year. SDS is caused by mutations in the Shwachman-Bodian-Diamond syndrome (SBDS) gene, which encodes for the homonymous protein SBDS, whose exact function is still unknown. SBDS protein has been reported to play a role in eukaryotic ribosome biogenesis. Thus, SDS is considered a ribosomopathy. The pathology is characterized by multiple-organ impairment involving bone marrow failure, exocrine pancreatic insufficiency, skeletal malformations, hepatic and cognitive disorders. Neutropenia and impaired neutrophil chemotaxis, which in turn cause recurrent infections, are reported in young children. Furthermore, 15-20% of SDS patients develop myelodysplastic syndrome (MDS), with increased risk of acute myeloid leukemia (AML) progression, which represent the main cause of mortality. However, the exact pathologic mechanism whereby loss of SDBS function could lead to the specific SDS hematological issues remains unclear. We recently reported, for the first time to the best of our knowledge, that the mammalian Target of Rapamycin (mTOR) and Signal Transducer and Activator of Transcription (STAT)-3 pathways are hyper-activated in B cells, PMNs and, mostly, in monocytes obtained from SDS patients (Bezzerri V et al, Sci Rep 2016, in press). Since mTOR and STAT3 activation are associated with neutrophil development and AML, this finding could at least partially explain the onset of the hematological issues. Here we show a further Phospho flow analysis of mTOR and STAT3 pathways activation in otherlymphocytes subsets,in particular in CD8+/CD4+ T cells and NK cells obtained from five SDS patients. We found that STAT3 S727 is the most phosphorylated site in CD8+ and CD4+ T cells (more than twice than the healthy control cells, each). Furthermore, mTOR (S2448) is hyper-phosphorylated in CD8+ and CD4+ T cells derived from SDS patients. Median fluorescence intensity shifted from 220 ± 25 (healthy controls) to 405 ± 29 (SDS patients) in CD8+ T cells and from 350 ± 132 (healthy controls) to 590 ± 150 (SDS patients) in CD4+ T cells, similarly to results obtained from Monocytes and B cells. NK seems to be less responsive to mTOR/STAT3 activation than B and T cells. Importantly, mTOR inhibitor rapamycin is able to reduce both mTOR and STAT3 activation, with different efficacy, in a cell type-dependent manner. In particular, rapamycin strongly reduces both mTOR and STAT3 S727 phosphorylation in CD8+ and CD4+ T cells. Thus, these results suggest a role of mTOR/STAT3 pathways in both myeloid and lymphoid lineages of SDS blood cells. Since several drugs approved by FDA and EMA targeting the JAK-STAT and mTOR pathways have been currently evaluated for the treatment of different forms of hematological malignancies, this work could open a wider scenario into the current SDS therapeutic approaches. Disclosures No relevant conflicts of interest to declare.

Dysfunctional Tregs with Absence of Cytokine-Secreting CD4+ T-Cell Subsets and Marked Expansion of Th1 Cells Is a Hallmark of Idiopathic Aplastic Anaemia (AA)

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 2233-2233
Author(s):  
Shahram Kordasti ◽  
Judith C. W. Marsh ◽  
Pilar Perez Abellan ◽  
Sufyan Alkhan ◽  
Janet Hayden ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Cd4 T Cells ◽  
Cytokine Secretion ◽  
T Cell Subsets ◽  
Cd4 T Cell ◽  
Th1 Cells ◽  
Healthy Controls ◽  
Ifn Γ

Abstract Abstract 2233 Introduction: Autoimmunity is an important contributor in the aetiology of AA. Although the expansion of oligoclonal CD8+ T-cells and their correlation with response to immunosuppressive therapy (IST) has been reported previously, the role of CD4+ in the pathogenesis is not elucidated. The focus of this study was to investigate the role of different CD4+ T-cell subsets, including regulatory T-cells (Tregs) and T helpers (Th1, Th2 and Th17) in the pathobiology of idiopathic AA. Patients and Methods: The percentage and absolute numbers of CD4+ and CD8+ T-cell subsets, NK & B cells and dendritic cells (DCs) in peripheral blood were assessed in 42 patients with idiopathic AA prior to any IST and 8 healthy age matched controls. T-cells were stimulated first and stained intracellularly for IFN-γ and TNF-a (Th1), IL-4 (Th2) and IL-17 (Th17). Serum levels of 30 cytokines were measured by 30 Plex bead analysis (Luminex). NK cells were defined as CD3– CD56+. B cells were defined as CD3-CD19+. CD3+ CD4+.T-cell subsets were defined as CD45RO–CD27+ naïve, CD45RO+ CD27+ CD62L+ central memory, CD45RO+ CD27+ CD62L– effector memory, CD45RO+CD27– effectors and CD45RO– CD27– terminal effectors. DCs were defined based on their BDCA 1,2, 3 & CD16 expression. CD4 Tregs were defined as CD3+CD4+ CD25high CD27+Foxp3+. Treg subsets were defined as (1) CD45RA+CD25lo resting Tregs, (2) CD45RA-CD25hi activated Tregs, and (3) cytokine-secreting CD45RA-CD25lo non-Tregs1. Treg function was evaluated by cytokine secretion of T effector cells (Te) with and without Tregs. IFN-γ secreting CD4+ T-cells (Th1) were enriched by magnetic beads followed by FACS sorting. The clonality of Th1 cells was evaluated based on the diversity of T-cell receptors by spectratyping as well as sequencing. Transcription factor expression was measured by qPCR. Results: There were no significant differences in the number or percentage of different CD8 T-cells compared to healthy controls. Surprisingly, despite a borderline decrease in the absolute number of naïve (p=0.19) and central memory (p=0.20) CD4+T-cells the number and percentage of Tregs were no different from healthy controls (1.36×107/L v 1.34×107/L, p=0.57). Although the ratio of Tregs to CD4+ T-effectors (Te) was higher than in healthy controls, the difference was not significant (0.49 v 0.12, p=0.86). The absolute numbers and percentages of Th1 cells and TNF-α + CD4+ T-cells were significantly higher in AA patients compared to healthy controls (4.2 × 107/L v 0.9 × 107/L & 2.44 × 108 v 1.26 × 108(p=0.001, p=0.004)). The diversity of T-cell receptor on Th1 cells was significantly lower compared to healthy age matched controls (on average 21 & 52 peaks). Amongst AA patients, the numbers of Th2, Th17, NK and B cells were not significantly different from healthy controls, whereas the absolute numbers of all DCs were reduced(p<0.01). The serum levels of proliferative cytokines, EGF (p=0.01), HGF (p=0.01), VEGF (p=0.01) and pro-inflammatory cytokines IL-13 (p=0.02), IL-8 (p<0.001) were significantly higher in AA patients. The percentage of cytokine secreting CD4+ CD25+ T-cells was markedly decreased in AA patients and the activated Treg subsets were predominantly of CD45RA+ phenotype, which was significantly different from healthy controls. Sorted Tregs from AA patients were unable to suppress cytokine secretion by Te cells in a 1:1 co-culture. However, IL-2, IFN-γ and TNF-α secretion of Te from AA patients was suppressible by allogeneic Tregs from healthy controls (on average 11 time suppression), whereas Tregs from AA patients were unable to suppress healthy Te cells. However, dysfunctional Tregs were not associated with abnormality of transcription factors, as judged by the levels of STAT1, 3, 4, 5 & 6, FoxP3 & T-bet of Tregs that were not significantly different from healthy age matched controls. Conclusion: Our data show that although FoxP3+ Tregs are normal in AA, a subset of these cells is markedly reduced and the activated Tregs aberrantly express CD45RA. Furthermore, unlike normal Tregs, the Tregs from AA patients do not suppress the inflammatory cytokine secretion by Te cells. The absence of DCs in the peripheral blood suggests their immigration to the inflammation site (e.g. bone marrow), which may play a role in the polarisation of T helpers toward a Th1 phenotype. Clonal expansion of Th1 cells may suggest potential antigen specificity that may lead to AA phenotype. 1. Miyara M, et al. Immunity. 2009. Disclosures: No relevant conflicts of interest to declare.

scholarly journals THU0035 OX40L EXPRESSING NEUTROPHILS INDUCE CD4 T FOLLICULAR AND PERIPHERAL HELPER CELL DIFFERENTIATION IN SYSTEMIC LUPUS ERYTHEMATOSUS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 230.2-231
Author(s):  
A. Pappalardo ◽  
E. Wojciechowski ◽  
I. Odriozola ◽  
I. Douchet ◽  
N. Merillon ◽  
...  
Keyword(s):  
Systemic Lupus Erythematosus ◽  
T Cells ◽  
B Cells ◽  
Lupus Erythematosus ◽  
Cd4 T Cells ◽  
Close Contact ◽  
Memory B Cells ◽  
Systemic Lupus ◽  
Research Support

Background:Neutrophils have been described as potent antigen-presenting cells able to activate T cells by MHC/TCR interaction and costimulatory molecules in tumor immunity. However, little is known about the direct interaction between neutrophils and CD4 T cells with respect to systemic lupus erythematosus (SLE). We have previously shown that OX40L expressed by monocytes from SLE patients promote the differentiation of naïve and memory cells into IL21 secreting T cells that are able to help B cells1,2.Objectives:In this study, we investigate OX40L expression on neutrophils from SLE patients and contribution of these OX40L+neutrophils in SLE pathogenesis to modulation of the B cell helper role of CD4 T cells.Methods:Surface expression of co-stimulatory molecules (OX40L, ICOSL, GITRL, 4-1BBL) on neutrophils from SLE patients and healthy donors (HD) was measured by flow cytometry (FC). Neutrophils from HD were stimulated with TLR7 or TLR8 agonists and IFNα after 5 hours of culture, OX40L expression was measured by FC and Western Blotting. CD4 T cells were cultured with the stimulated neutrophils for 3 days. At the end of the co-culture, percentages of IL21-expressing T follicular (Tfh) and peripheral helper (Tph) cells measured by FC. These generated T cells were also cultured in the presence of memory B cells. After 5 days of co-culture, plasmablast generation and Ig levels were assessed by FC and ELISA, respectively. Inhibition of OX40-OX40L interaction in vitro was achieved using ISB 830, a novel anti-OX40 mAb currently used in clinical trials.Results:Among the co-stimulatory molecules tested, percentages of OX40L+neutrophils in SLE (n=54) were increased compared to HD (n=25)(mean + SD: HD = 1,34%±1.62 vs SLE = 4,53%±8.1; p=0.29). OX40L expression positively correlated with SLE disease activity score (SLEDAI) (p = 0,04; r = 0,31) and with anti-DNA antibodies (p= 0,04, r = 0,33). Of note, the percentage of OX40L+neutrophils was higher in anti-sm-RNP+patients (n=16, mean= 9%±9.8), compared to anti-sm-RNP-patients (n=27, mean = 1,4%±2.5; p = 0,02). The percentage of OX40L+neutrophils was higher in patients with class III or IV lupus nephritis, and inflammatory infiltrate within the kidney biopsy disclosed OX40L+neutrophils, in close contact with T cells. Neutrophils from HD express OX40L with TLR8 agonist, or IFNα priming followed by TLR7 agonist. When memory CD4 T cells were cultured in the presence of TLR8-stimulated neutrophils, the proportion of IL21-expressing Tfh (CXCR5+PD1+) and Tph (CXCR5-PD1hi) were increased, compared to culture with unstimulated neutrophils. This process was dependent on OX40-OX40L interactions, since in vitro treatment with the anti-OX40 blocking antibody ISB 830, inhibited the differentiation of memory T cells into Tfh and Tph. Both generated Tfh and Tph were able to promote the differentiation of memory B cells into Ig-secreting plasmablasts.Conclusion:Our results disclose an unprecedented phenomenon where cross-talk between TLR7/8-activated neutrophils and CD4 lymphocytes operates through OX40L-OX40 costimulation, and neutrophils promote the differentiation of pro-inflammatory Tfh and Tph, as well as IL21 production. Therefore, OX40L/OX40 should be considered as a potentially therapeutic axis in SLE patients.References:[1]Jacquemin et al. Immunity 2015;[2]Jacquemin et al. JCI Insight 2018Disclosure of Interests:Angela Pappalardo Grant/research support from: Ichnos Sciences, Elodie Wojciechowski: None declared, Itsaso Odriozola: None declared, Isabelle Douchet: None declared, Nathalie Merillon: None declared, Andrea Boizard-Moracchini: None declared, Pierre Duffau: None declared, Estibaliz Lazaro: None declared, Marie-Agnes Doucey Employee of: Ichnos Sciences, Lamine Mbow Employee of: Ichnos Sciences, Christophe Richez Consultant of: Abbvie, Amgen, Mylan, Pfizer, Sandoz and UCB., Patrick Blanco Grant/research support from: Ichnos Sciences

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