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OBJECTIVE Our aim was to compare transcriptome and phenotype profiles of CD4+ T cells and CD19+ B cells in patients with Takayasu arteritis (TAK), patients with giant cell arteritis (GCA), and healthy donors. METHODS Gene expression analyses, flow cytometry immunophenotyping, T cell receptor (TCR) gene sequencing, and functional assessments of cells from peripheral blood and arterial lesions from TAK patients, GCA patients, and healthy donors were performed. RESULTS Among the most significantly dysregulated genes in CD4+ T cells of TAK patients compared to GCA patients (n = 720 genes) and in CD4+ T cells of TAK patients compared to healthy donors (n = 1,447 genes), we identified a follicular helper T (Tfh) cell signature, which included CXCR5, CCR6, and CCL20 genes, that was transcriptionally up-regulated in TAK patients. Phenotypically, there was an increase in CD4+CXCR5+CCR6+CXCR3- Tfh17 cells in TAK patients that was associated with a significant enrichment of CD19+ B cell activation. Functionally, Tfh cells helped B cells to proliferate, differentiate into memory cells, and secrete IgG antibodies. Maturation of B cells was inhibited by JAK inhibitors. Locally, in areas of arterial inflammation, we found a higher proportion of tertiary lymphoid structures comprised CD4+, CXCR5+, programmed death 1+, and CD20+ cells in TAK patients compared to GCA patients. CD4+CXCR5+ T cells in the aortas of TAK patients had an oligoclonal α/β TCR repertoire. CONCLUSION We established the presence of a specific Tfh cell signature in both circulating and aorta-infiltrating CD4+ T cells from TAK patients. The cooperation of Tfh cells and B cells might be critical in the occurrence of vascular inflammation in patients with TAK.

International audience; Background: Takayasu arteritis (TAK) is a large vessel vasculitis resulting in artery wall remodeling with segmental stenosis and/or aneurysm formation. Mast cells (MCs) are instrumental in bridging cell injury and inflammatory response.Objectives: This study sought to investigate the contribution of MCs on vessel permeability, angiogenesis, and fibrosis in patients with TAK. Methods: MC activation and their tissue expression were assessed in sera and in aorta from patients with TAK and from healthy donors (HDs). In vivo permeability was assessed using a modified Miles assay. Subconfluent cultured human umbilic vein endothelial cells and fibroblasts were used in vitro to investigate the effects of MC mediators on angiogenesis and fibrogenesis.Results: This study found increased levels of MC activation markers (histamine and indoleamine 2,3-dioxygenase) in sera of patients with TAK compared with in sera of HDs. Marked expression of MCs was shown in aortic lesions of patients with TAK compared with in those of noninflammatory aorta controls. Using Miles assay, this study showed that sera of patients with TAK significantly increased vascular permeability in vivo as compared with that of HDs. Vessel permeability was abrogated in MC-deficient mice. MCs stimulated by sera of patients with TAK supported neoangiogenesis (increased human umbilic vein endothelial cell proliferation and branches) and fibrosis by inducing increased production of fibronectin, type 1 collagen, and a-smooth muscle actin by fibroblasts as compared to MCs stimulated by sera of HD.Conclusions: MCs are a key regulator of vascular lesions in patients with TAK and may represent a new therapeutic target in large vessel vasculitis.

ObjectiveTakayasu’s arteritis (TAK) is a large vessel vasculitis with important infiltration of proinflammatory T cells in the aorta and its main branches, but its aetiology is still unknown. Our work aims to explore the involvement of Janus Kinase/Signal Transducers and Activators of Transcription (JAK/STAT) signalling pathway in proinflammatory T cells differentiation and disease activity of TAK.MethodsWe analysed transcriptome and interferons gene signatures of fluorescence-activated cell sorting (FACS-sorted) CD4+ and CD8+ T cells from healthy donors (HD) and in 25 TAK (median age of 37.6 years including 21 active TAK with National Institutes of Health (NIH) score >1). Then we tested, in vitro and in vivo, the effects of JAK inhibitors (JAKinibs) in TAK.ResultsTranscriptome analysis showed 248 and 432 significantly dysregulated genes for CD4+ and CD8+ samples between HD and TAK, respectively. Among dysregulated genes, we highlighted a great enrichment for pathways linked to type I and type II interferons, JAK/STAT and cytokines/chemokines-related signalling in TAK. We confirmed by Real Time Reverse Transcription Polymerase Chain Reaction (RT-qPCR) the upregulation of type I interferons gene signature in TAK as compared with HD. JAKinibs induced both in vitro and in vivo a significant reduction of CD25 expression by CD4+ and CD8+ T cells, a significant decrease of type 1 helper T cells (Th1) and Th17 cells and an increase of Tregs cells in TAK. JAKinibs also decreased C reactive protein level, NIH score and corticosteroid dose in TAK patients.ConclusionsJAK/STAT signalling pathway is critical in the pathogenesis of TAK and JAKinibs may be a promising therapy.

The mechanisms regulating inflammation in large vessels vasculitis (LVV) are poorly understood. Interleukin 33 (IL-33) has been shown to license innate and adaptive immunity by enhancing Th2 cytokines production. We aimed to examine the role of IL-33 in the immunomodulation of T cell activation in LVV. T cell homeostasis and cytokines production were determined in peripheral blood from 52 patients with giant cell arteritis (GCA) and 50 healthy donors (HD), using Luminex assay, flow cytometry, quantitative RT-PCR and by immunofluorescence analysis in inflammatory aorta lesions. We found increased level of IL-33 and its receptor ST2/IL-1R4 in the serum of patient with LVV. Endothelial cells were the main source of IL-33, whereas Th2 cells, Tregs and mast cells (MC) express ST2 in LVV vessels. IL-33 had a direct immunomodulatory impact by increasing Th2 and Tregs. IL-33 and MC further enhanced Th2 and regulatory responses by inducing a 6.1 fold increased proportion of Tregs (p = 0.008). Stimulation of MC by IL-33 increased indoleamine 2 3-dioxygenase (IDO) activity and IL-2 secretion. IL-33 mRNA expression was significantly correlated with the expression of IL-10 and TGF-β within aorta inflammatory lesions. To conclude, our findings suggest that IL-33 may exert a critical immunoregulatory role in promoting Tregs and Th2 cells in LVV.

Molecular mechanisms underlying large-vessel involvement in giant cell arteritis (LV-GCA) are largely unknown. Herein, we explore the critical involvement of pro-inflammatory signaling pathways in both aorta and T cells from patients with LV-GCA.We analyzed transcriptome and interferon gene signature in inflamed aortas from LV-GCA patients and compared them to non-inflammatory control aorta. Differential transcriptomic analyses of circulating CD4Transcriptomic analyses revealed 1042, 1479 and 2075 significantly dysregulated genes for aortas, CD4LV-GCA presents a clear type I interferon signature in aortas, which paves the way for tailored therapeutical targeting.

Introduction La maladie de Behcet (MB) est une affection inflammatoire et systemique chronique evoluant par poussees. Elle est caracterisee par l’atteinte de plusieurs organes dont les muqueuses (aphtes) et la peau (pseudo-folliculites). La physiopathologie de la MB est en grande partie inconnue. Le role de l’immunite innee semble preponderant avec notamment une activation des polynucleaires neutrophiles. La voie NF-κB, engagee des le contact d’un ligand sur le recepteur 1 du facteur de necrose tumorale (TNFR1), joue un role critique dans l’engagement du processus inflammatoire car elle produit des cytokines majeures comme l’interleukine 1 (IL-1), l’IL-6 et le facteur de necrose tumorale α (TNF- α). Sa regulation negative est essentielle a l’arret du processus inflammatoire et depend du niveau d’ubiquitination des proteines associees au TNFR1 et d’autres composes intermediaires. A20 et OTULINE sont des proteines qui modifient cette ubiquitination et leur defaut resulte en une activation de la voie NF-κB avec production excessive de cytokines proinflammatoires. L’haploinsuffisance de A20 partage avec la maladie de Behcet l’aphtose bipolaire et l’uveite, mais elle s’en distingue par sa transmission dominante, un debut des symptomes plus precoce, et une atteinte digestive severe au premier plan. Des lymphocytes T CD8+ (LT CD8 + ) secretant de l’interferon-γ (IFN-γ) et du TNF-α. ainsi que des mediateurs de cytotoxicite ont ete retrouve dans le sang peripherique et l’humeur aqueuse des patients atteints de MB, indiquant qu’ils pourraient ainsi participer a la physiopathologie de la MB. La phosphodiesterase 4 (PDE4) une enzyme du systeme immunitaire qui, en degradant l’adenosine monophosphate cyclique (AMPc), augmente la secretion de mediateurs de l’inflammation. Sachant que l’AMPc induit l’inhibition de la voie NF-κB, sa degradation entraine une augmentation de cette importante voie de l’inflammation. L’Apremilast est une molecule administree oralement qui inhibe la PDE4. Bien que ses mecanismes d’action precis ne soient pas connus dans la MB, l’Apremilast s’est revele efficace dans le traitement des manifestations cutaneo-articulaires de la MB. Resultats Methodes et resultats: Trente-cinq patients atteints de MB et 34 temoins apparies sur l’âge et le sexe ont ete inclus. L’analyse du transcriptome des LT CD8+ a permis de montrer qu’il existait un enrichissement des voies de signalisation NF-κB, de l’immunite innee et de l’inflammation dans les LT CD8+ de patients compares aux temoins. Nous avons confirme par cytometrie en flux la surexpression de pNF-κB dans les LT CD8+ de patients (4,4 ± 0,9 vs. 1,8 ± 0,2 en MFI, p = 0,001). L’analyse transcriptomique de LT CD8+ a egalement montre un enrichissement des isoformes de PDE4 (A, B, C et D) chez les patients atteints de MB par rapport aux temoins. L’analyse en immunohistochimique a confirme cette surexpression de PDE4 dans les lesions cutanees de patients. Nous avons ensuite evalue l’effet in vitro par cytometrie en flux du Roflumilast (un inhibiteur de PDE4) sur les LT CD8+ de patients et de temoins. Les LT CD8+ de patients exprimaient davantage de marqueurs d’activation de surface (CD11c, CD11b, CD25 et CD69), intracellulaires (IFN-γ et TNF-α), de cytotoxicite (Perforine et Granzyme B) et de proliferation par rapport aux LT CD8+ de temoins. Le traitement par Roflumilast abrogeait specifiquement l’expression de ces differents marqueurs d’activation et de fonctionnalite. Enfin nous avons confirme ces resultats in vivo. Les LT CD8+ de 10 patients traites par Apremilast (30 mg 2 fois par jour) ont ete analyse avant et apres 12 semaines de traitement. Les marqueurs d’activation de surface (CD11c, CD11b, CD25 et CD69), intracellulaires (IFN-γ, TNF-a), de cytotoxicite (Perforine et Granzyme B) et de proliferation diminuaient significativement apres 12 semaines de traitement. Conclusion Nous avons mis en evidence in vitro et in vivo l’implication de la voie NF-κB dans l’activation des LT CD8+ de patients atteints de MB. Nous avons egalement pu montrer qu’elle etait, au moins en partie, mediee par PDE4 et qu’elle etait pharmacologiquement reversible.

Background: Takayasu’s arteritis (TA) and giant cell arteritis (GCA), the two most common types of large vessel vasculitis (LVV), are characterized by an arterial inflammatory granulomatous infiltrate mainly located in the media and the adventitia. However, distinct histological features of the immune response are poorly known. Objectives: To investigate distinct pathological mechanisms of the immune response in patients with GCA and TA. Methods: We performed comparative immunohistochemistry analysis of aorta of GCA and TA patients. We performed microarray gene analysis of purified CD4+ T cells of TA and GCA patients. Reverse transcriptase PCR, flow cytometry analysis and cell culture were used to investigate T and B cells subpopulations in 54 patients with TA, 52 with GCA and 60 controls. Results: We found higher proportion of tertiary lymphoid structures composed of CXCR5+, CD4+, PD-1+ and CD-20+ cells in inflammatory aortic lesions in TA as compared to GCA. We demonstrated increased proportion of aortic B cells in TA. We next evaluated differentiation of circulating CD4+ T cells in both diseases. Among sixty-seven genes differentially expressed in CD4+ T cells of TA compared to GCA patients, we identified a specific “T follicular helper” (Tfh) signature in TA patients. We also found a specific Tfh 17 signature in TA patients. Flow cytometry analysis confirmed increased circulating Tfh, defined as CXCR5+ CD4+ T cells, in TA patients as compared to GCA and healthy donors (HD) [median of 15.4 (10;30.8)% versus 5.3 (1.4; 12.2)% and 9.7 (5.6; 12.5)% (p Functionally, CXCR5+ CD4+ T cells of TA patients helped B cells to differentiate into memory cells, to proliferate and to secrete type G immunoglobulins. We sequenced the TCR repertoire α/β in CD3+CD4+CXCR5- and CD3+CD4+CXCR5+ cells, in aortic and blood samples from 2 patients. In both patients, we identified oligoclonal profile of TCR repertoire only for aortic CXCR5+ cells, suggesting antigenic selection of CXCR5+ CD4+ T cells. Conclusion: We provide evidence of the presence of tertiary lymphoid structures composed of Tfh and B cells in TA aorta. We identified a specific Tfh signature in circulating CD4+ T cells that distinguishes TA and GCA patients. The key cooperation of Tfh and B cells in TA and the oligoclonal repertoire of CXCR5+ CD4+ T cells strongly suggest the role of antigenic trigger. Disclosure of Interests: Anne-Claire DESBOIS Speakers bureau: SOBI en 2015, Anna Maciejewski-Duval: None declared, Paul Regnier: None declared, Valentin QUINIOU: None declared, Cloe Comarmond: None declared, Helene Vallet: None declared, Patrick Bruneval: None declared, Pierre Fouret: None declared, Michele Rosenzwajg: None declared, David Klatzmann: None declared, Fabien Koskas: None declared, Marlene Garrido: None declared, Guillaume Darrasse-Jeze: None declared, Patrice cacoub Consultant for: d’Abbvie, Astra Zeneca, Bayer, Boehringer Ingelheim, Gilead, Glaxo Smith Kline, Janssen, Merck Sharp Dohme, Pfizer, Roche, Servier, and Vifor., Speakers bureau: d’Abbvie, Astra Zeneca, Bayer, Boehringer Ingelheim, Gilead, Glaxo Smith Kline, Janssen, Merck Sharp Dohme, Pfizer, Roche, Servier, and Vifor., David Saadoun Grant/research support from: Roche, Abbvie, Consultant for: Janssen, Celgene, Abbvie, Roche

Introduction Les vascularites des gros vaisseaux dont la maladie de Takayasu sont des pathologies inflammatoires responsables d’un remodelage de la paroi arterielle conduisant a la formation de stenose ou d’anevrysmes. Les mecanismes physiopathologiques impliques dans ce remodelage ne sont pas connus. Les mastocytes sont des cellules cles dans le remodelage vasculaire comme cela a ete montre dans diverses pathologies telles que l’anevrysme de l’aorte abdominale, l’infarctus du myocarde et l’atherosclerose. L’objectif de cette etude etait d’etudier le role des mastocytes dans la remodelage vasculaire des patients atteints de maladie de Takayasu. Resultats Methodes et Resultats Trente patients atteints de maladie de Takayasu et 20 temoins apparies sur l’âge et le sexe ont ete inclus. Nous avons tout d’abord montre que les patients avaient des taux d’histamines seriques plus eleves que les temoins [11,23 ± 1,3 vs 7,15 ± 0,5 nM, p = 0,008] et que le serum des patients activait de facon plus importante des mastocytes humains (lignees cellulaire ROSAKIT WT) [11,19 ± 7,5 vs 3,2 μM ± 0,2, p Conclusion Nos resultats montrent que les mastocytes jouent un role essentiel dans la regulation de la permeabilite vasculaire, de l’angiogenese et de la fibrogenese dans la maladie de Takayasu. Des therapeutiques ciblant les mastocytes pourraient ainsi favorablement modifier le remodelage vasculaire dans cette vascularite.

Background:Takayasu’s arteritis (TAK) is a large vessel vasculitis (LVV) in which the aorta and its main branches are greatly inflamed, leading to wall thickening, fibrosis, stenosis and to artery occlusion(1). The disease is more common in women mostly between 20 and 30 years old. TAK has a high morbidity rate: 50% of patients will relapse within 10 years after diagnosis(2, 3). This inflammation is essentially mediated by infiltration with macrophages and pro-inflammatory Th1/Th17 effector subsets(4–8). But the mechanisms behind these phenomena are essentially unknown. TAK is mainly treated with non-specific steroids(1) which are associated with potential side effects when used for a long-time course.Objectives:Our work aims to explore the involvement of JAK/STAT signaling pathway and its downstream biological cascades in pro-inflammatory T cells differentiation and disease activity of TAK. Plus, our work allows to consider targeting the JAK/STAT pathway in TAK using JAK inhibitors (JAKinibs).Methods:We analyzed transcriptome of FACS-sorted CD4+ and CD8+ T cells from healthy donors (HD) and TAK, using differential gene, pathway and network analysis. Then, we assessed in vitro and in vivo effects of JAKinibs in TAK by flow cytometry (FC).Results:Transcriptome analysis showed hundreds of significantly dysregulated genes/pathways for CD4+ and CD8+ samples between HD and TAK. Among these, we noticed in TAK a great enrichment for pathways linked to type I and II interferons (IFN), JAK/STAT and cytokines/chemokines-related signaling. We confirmed by RT-qPCR the upregulation of a type I IFN-specific gene signature in TAK T cells as compared to HD. Using genes coming from the previous pathways, we constructed networks connecting them according to their respective protein interactions. This representation showed for both CD4+ and CD8+ T cells that JAK and STAT genes were densely connected, thus representing core genes/proteins in the TAK physiopathology.We then performed in vitro cell cultures of PBMCs from HD or TAK supplemented with Ruxolitinib (JAK1/2 inhibitor) or PBS. We observed by FC that JAKinibs significantly induced in TAK CD4+ and CD8+ T cells reduction of CD25 expression, decrease of Th1/Th17 pro-inflammatory cells and increase of Tregs.Next, we followed by FC 3 TAK (refractory to conventional treatments) treated with JAKinibs. We also observed in their PBMCs a reduction of CD25 expression by CD4+ T cells, a decrease of Th1 and Th17 cells and an increase of Tregs, accompanied by an increase of the Tregs/Teffs ratio. JAKinibs also decreased C-Reactive Protein level, NIH score and co-administered steroids doses (present before JAKinibs introduction) in these 3 in vivo-treated TAK.Conclusion:JAK/STAT signaling pathway is critical in the pathogenesis of TAK and JAKinibs may be promising in its treatment.References:[1]F. Numano, M. Okawara, H. Inomata, Y. Kobayashi, The Lancet. 356, 1023–1025 (2000).[2]C. Comarmond et al., Circulation. 136, 1114–1122 (2017).[3]A. Mirouse et al., J. Autoimmun. 96, 35–39 (2019).[4]C. M. Weyand, J. J. Goronzy, Nat. Rev. Rheumatol. 9, 731–740 (2013).[5]C. M. Weyand et al., Clin. Immunol. 206, 33–41 (2019).[6]D. Saadoun et al., Arthritis Rheumatol. 67, 1353–1360 (2015).[7]T. Mirault, H. Guillet, E. Messas, Presse Médicale. 46, e189–e196 (2017).[8]D. P. Misra, S. Chaurasia, R. Misra, Autoimmune Dis. 2016, 1–8 (2016).Disclosure of Interests:Paul Régnier: None declared, Alexandre Le Joncour: None declared, Anna Maciejewski-Duval: None declared, Anne-Claire DESBOIS: None declared, Cloé Comarmond: None declared, Michelle Rosenzwajg: None declared, David Klatzmann Consultant of: ILTOO Pharma, Patrice cacoub: None declared, David Saadoun: None declared

International audience; Background & aims: Hepatitis C virus (HCV) infection contributes to the development of autoimmune disorders such as cryoglobulinaemia vasculitis (CV). However, it remains unclear why only some individuals with HCV develop HCV-associated CV (HCV-CV). HCV-CV is characterized by the expansion of anergic CD19+CD27+CD21low/- atypical memory B cells (AtMs). Herein, we report the mechanisms by which AtMs participate in HCV-associated autoimmunity.Methods: The phenotype and function of peripheral AtMs were studied by multicolour flow cytometry and co-culture assays with effector T cells and regulatory T cells in 20 patients with HCV-CV, 10 chronicallyHCV-infected patients without CV and 8 healthy donors. We performed gene expression profile analysis of AtMs stimulated or not by TLR9. Immunoglobulin gene repertoire and antibody reactivity profiles of AtM-expressing IgM antibodies were analysed following single B cell FACS sorting and expression-cloning of monoclonal antibodies.Results: The Tbet+CD11c+CD27+CD21- AtM population is expanded in patients with HCV-CV compared to HCV controls without CV. TLR9 activation of AtMs induces a specific transcriptional signature centred on TNFα overexpression, and an enhanced secretion of TNFα and rheumatoid factor-type IgMs in patients with HCV-CV. AtMs stimulated through TLR9 promote type 1 effector T cell activation and reduce the proliferation of CD4+CD25hiCD127-/lowFoxP3+ regulatory T cells. AtM expansions display intraclonal diversity with immunoglobulin features of antigen-driven maturation. AtM-derived IgM monoclonal antibodies do not react against ubiquitous autoantigens or HCV antigens including NS3 and E2 proteins. Rather, AtM-derived antibodies possess rheumatoid factor activity and target unique epitopes on the human IgG-Fc region.Conclusion: Our data strongly suggest a central role for TLR9 activation of AtMs in driving HCV-CV autoimmunity through rheumatoid factor production and type 1 T cell responses.Lay summary: B cells are best known for their capacity to produce antibodies, which often play a deleterious role in the development of autoimmune diseases. During chronic hepatitis C, self-reactive B cells proliferate and can be responsible for autoimmune symptoms (arthritis, purpura, neuropathy, renal disease) and/or lymphoma. Direct-acting antiviral therapy clears the hepatitis C virus and eliminates deleterious B cells.

Background Mammalian target of rapamycin complex 1 (mTORC 1) drives the proinflammatory expansion of T helper (TH) type 1, TH17 cells and controls fibroblast proliferation, typical features of large vessel vasculitis (LVV) pathogenesis. Molecular pathways involved in arterial lesions of LVV are unknown. Objectives To analyse mTOR pathway activation in LVV (giant cell arteritis and Takayasu arteritis). Methods We evaluate pathway activation in the mTORC and the nature of cell proliferation in blood and vessels of patients with LVV compared non-inflammatory aorta by using double immunostaining, western blot and flow cytometry. Finally, using flow cytometry, we study the effect of rapamycin on T cells homeostasis in LVV compared to HD. Results Proliferation of both endothelial cells and vascular smooth-muscle cells was shown in vascular lesions in LVV. The vascular endothelium of proliferating aorta vessels from patients with LVV showed indications of activation of the mTORC1 pathway en endothelial cells (S6RP phosphorylation) compared to non-inflammatory aorta (45%24;48 versus 10.4% [9.7;14.9] positive S6RP endothelial cells, p=0.03). In cultured vascular endothelial cells, sera from patients with LVV stimulated mTORC1 through the phosphorylation of S6RP. Activation of mTORC1 was also found in Th1 and Th17 cells both systemically and in the blood vessels. Patients with LVV exhibited a diminished S6RP phosphorylation in Tregs. Inhibition of mTORC1 pathway with rapamycin, increase Tregs and decrease effector CD4+IFNγ+, CD4+IL17+ and CD4+IL21+ T cells in patients with LVV. Conclusions Our results suggest that the mTORC1 pathway is involved in the vascular lesions of LVV. Targeting mTORC pathway may represent a new therapeutic option in patients with LVV. Disclosure of Interest None declared

The goal of this study was to evaluate for the first time the expression of the androgen receptors (AR) in Harderian glands (HG) of the male Meriones lybicus in relation to the reproductive cycle. Six male Harderian glands of the resting period and 6 of the breeding period were collected. The animals were trapped in the desert of Beni Abbes (Algeria). The morphology of the Harderian glands was studied by light microscopy and morphometry, whereas the expression of the androgen receptors was assessed and quantified based on immunohistochemistry techniques. We have shown that the Harderian glands of Meriones libycus are tubuloalveolar glands with wide lumen. The glandular epithelium is composed of two types of cells (types I and II) in the resting season and three types of cells (types I, II and III) in the breeding season. These three types of cells differ in size and shape. Type-I cells have a prismatic shape, an acidophilic cytoplasm, and small lipidic vacuoles, whereas type-II ones are pyramidal in shape, with basophilic cytoplasm. Type-III cells resemble those of type I, and so they are prismatic in shape and have an acidophilic cytoplasm with larger lipidic vacuoles. The immunoreactivity of type-I and type-III cells was mainly cytoplasmic and the intensity of the immunostaining was significantly higher during the breeding season. Among other functions, the Harderian gland seems to be involved in the production of pheromones under the effect of androgens.

International audience; Background:Mammalian target of rapamycin complex 1 (mTORC 1) drives the proinflammatory expansion of T helper (TH) type 1, TH17 cells and controls fibroblast proliferation, typical features of large vessel vasculitis (LVV) pathogenesis. Molecular pathways involved in arterial lesions of LVV are unknown.Methods: We evaluate mTORC pathway activation in vascular aorta lesions and in T cell homeostasis of patients with LVV.Results: Proliferation of both endothelial cells and vascular smooth-muscle cells was shown in vascular lesions in LVV. The vascular endothelium of proliferating aorta vessels from patients with LVV showed indications of activation of the mTORC1 pathway (S6RP phosphorylation). In cultured vascular endothelial cells, sera from patients with LVV stimulated mTORC1 through the phosphorylation of S6RP. mTORC1 activation was found also in Th1 and Th17 cells both systemically and in inflamed vessels. Patients with LVV exhibited a diminished S6RP phosphorylation in Tregs. Inhibition of mTORC1 pathway with rapamycin, increase Tregs and decrease effector CD4+IFNγ+, CD4+IL17+ and CD4+IL21+ T cells in patients with LVV.Conclusions: We provided evidence that mTORC1 pathway has a central role in driving T cell inflammation and vascular lesions in LVV. Targeting mTORC pathway may represent a new therapeutic option in patients with LVV.

GATA2 deficiency—formerly described as MonoMAC syndrome; dendritic cells, monocytes, B cells, and natural killer cell deficiency; familial myelodysplastic syndrome/acute myeloid leukemia; or Emberger syndrome—encompasses a range of hematologic and nonhematologic anomalies, mainly characterized by monocytopenia, B lymphopenia, natural killer cell cytopenia, neutropenia, immunodeficiency, and a high risk of developing acute myeloid leukemia. Herein, we present 7 patients with GATA2 deficiency recruited into the French Severe Chronic Neutropenia Registry, which enrolls patients with all kinds of congenital neutropenia. We performed extended immunophenotyping of their whole blood lymphocyte populations, together with the analysis of their chemotactic responses. Lymphopenia was recorded for B and CD4+ T cells in 6 patients. Although only 3 patients displayed natural killer cell cytopenia, the CD56bright natural killer subpopulation was nearly absent in all 7 patients. Natural killer cells from 6 patients showed decreased CXCL12/CXCR4-dependent chemotaxis, whereas other lymphocytes, and most significantly B lymphocytes, displayed enhanced CXCL12-induced chemotaxis compared with healthy volunteers. Surface expression of CXCR4 was significantly diminished in the patients’ natural killer cells, although the total expression of the receptor was found to be equivalent to that of natural killer cells from healthy individual controls. Together, these data reveal that GATA2 deficiency is associated with impaired membrane expression and chemotactic dysfunctions of CXCR4. These dysfunctions may contribute to the physiopathology of this deficiency by affecting the normal distribution of lymphocytes and thus potentially affecting the susceptibility of patients to associated infections.

Basonuclin 1 and the recently discovered basonuclin 2 are vertebrate proteins with multiple paired C(2)H(2) zinc fingers. It has long been known that the zinc fingers of basonuclin 1 closely resembled those of the Drosophila disconnected and discorelated proteins, two proteins essential for head development, but the relation between the basonuclins and the disco proteins has remained unclear because the putative function of basonuclin 1 in the control of keratinocyte growth potential appeared unrelated to that of disco and there was no resemblance between basonuclin 1 and Drosophila disco outside of the zinc fingers. The recent generation of a basonuclin-2 knockout has demonstrated that basonuclin 2 shares with disco a function in head development and the availability of new arthropod genome sequences has shown that the basonuclins are the vertebrate orthologs of the insect disco proteins. All these proteins are thought to be transcription factors, and it will have to be determined to what extent they share similar targets.

Basonuclin 2 is a recently discovered zinc finger protein of unknown function. Its paralog, basonuclin 1, is associated with the ability of keratinocytes to multiply. The basonuclin zinc fingers are closely related to those of the Drosophila proteins disco and discorelated, but the relation between disco proteins and basonuclins has remained elusive because the function of the disco proteins in larval head development seems to have no relation to that of basonuclin 1 and because the amino acid sequence of disco, apart from the zinc fingers, also has no similarity to that of the basonuclins. We have generated mice lacking basonuclin 2. These mice die within 24 h of birth with a cleft palate and abnormalities of craniofacial bones and tongue. In the embryonic head, expression of the basonuclin 2 gene is restricted to mesenchymal cells in the palate, at the periphery of the tongue, and in the mesenchymal sheaths that surround the brain and the osteocartilagineous structures. In late embryos, the rate of multiplication of these mesenchymal cells is greatly diminished. Therefore, basonuclin 2 is essential for the multiplication of craniofacial mesenchymal cells during embryogenesis. Non- Drosophila insect databases available since 2008 reveal that the basonuclins and the disco proteins share much more extensive sequence and gene structure similarity than noted when only Drosophila sequences were examined. We conclude that basonuclin 2 is both structurally and functionally the vertebrate ortholog of the disco proteins. We also note the possibility that some human craniofacial abnormalities are due to a lack of basonuclin 2.