32 research outputs found
Cytotoxic T-Lymphocyte-Associated Protein 4 Haploinsufficiency-Associated Inflammation Can Occur Independently of T-Cell Hyperproliferation
Located contiguously on the long arm of the second chromosome are gene paralogs encoding the immunoglobulin-family co-activation receptors CD28 and cytotoxic T-lymphocyte-associated protein 4 (CTLA4). CD28 and CTLA4 share the same B7 ligands yet each provides opposing proliferative signals to T cells. Herein, we describe for the first time two unrelated subjects with coexisting CD28 and CTLA4 haploinsufficiency due to heterozygous microdeletions of chromosome 2q. Although their clinical phenotype, multi-organ inflammatory disease, is superficially similar to that of CTLA4 haploinsufficient autoimmune lymphoproliferative syndrome type V (ALPS5) patients, we demonstrate our subjectsâ underlying immunopathology to be distinct. Unlike ALPS5 T cells which hyperproliferate to T-cell receptor-mediated activation and infiltrate organs, T cells from our subjects are hypoproliferative and do not. Instead of T cell infiltrates, biopsies of affected subject tissues demonstrated infiltrates of lineage negative lymphoid cells. This histologic feature correlated with significant increases in circulating type 3 innate lymphoid cells (ILC3s) and ILC3 cytokines, interleukin 22, and interleukin-17A. CTLA4-Ig monotherapy, which we trialed in one subject, was remarkably effective in controlling inflammatory diseases, normalizing ILC3 frequencies, and reducing ILC3 cytokine concentrations
What contribution for molecular and cellular germinal center components during lupus development?
Le lupus Ă©rythĂ©mateux dissĂ©minĂ© est une maladie auto-immune systĂ©mique trĂšs invalidante dont les atteintes sont multiples, les plus frĂ©quentes Ă©tant cutanĂ©es, articulaires et rĂ©nales. Dans ce type de maladie, le systĂšme immunitaire, hyperactif, ne se limite pas Ă lutter contre des agents extĂ©rieurs mais s'attaque Ă ses propres cellules, entre autres par le biais d'auto-anticorps. Ces anticorps dĂ©lĂ©tĂšres sont produits par des plasmocytes, cellules issus de la diffĂ©renciation des lymphocytes B. Ce processus se dĂ©roule principalement au sein des centres germinatifs (GC) dans les organes lymphoĂŻdes secondaires, et fait intervenir de nombreux acteurs molĂ©culaires et cellulaires. Mon projet de thĂšse a portĂ© sur l'Ă©tude de la contribution du GC et de ses constituants, tels que les cellules auxiliaires folliculaires (Tfh) et l'IL-21, au cours du lupus. Au cours de ce travail, nous avons mis en Ă©vidence une altĂ©ration Ă la fois quantitative et qualitative des cellules Tfh chez des patients lupiques et dans un modĂšle murin, altĂ©ration entre autres responsable de taux anormalement Ă©levĂ©s d'IL-21. Nous avons Ă©galement observĂ© une sensibilitĂ© accrue des cellules B de souris lupiques Ă cette cytokine, dont la cause est une surexpression de molĂ©cules clĂ©s telles que STAT3, et dont la consĂ©quence est un surcroit de diffĂ©renciation plasmocytaire. Tous les Ă©lĂ©ments sont donc prĂ©sents pour favoriser l'interaction "Tfh-B" et la rĂ©action du GC, et amplifier la rĂ©ponse autoimmune. Enfin, la dĂ©couverte de l'existence de GC ectopiques fonctionnels dans les reins de souris lupiques permet d'envisager l'existence de rĂ©ponses locales au sein mĂȘme des organes cibles. Les donnĂ©es obtenues, fondamentales, sont prometteuses et laissent entrevoir de nouvelles perspectives de biothĂ©rapies, plus ciblĂ©es, pour le traitement de la maladie lupique.Systemic lupus erythematosus is a disabling chronic autoimmune disease characterized by B cell hyperactivity leading to the production of autoantibodies, some of which exerting pathogenic effects. Autoantibodies are produced by plasma cells, which originate from the differentiation of B cells through a process that mainly takes place in germinal centers (GC) in secondary lymphoĂŻd organs and involves many molecular and cellular parameters. The aim of my PhD project was to analyze the individual contribution of GC components, such as follicular helper T cells (Tfh) and IL-21, to lupus development. During this work, we have shown both a quantitative and qualitative impairment of Tfh cells in lupus patients and in a mouse model, leading, among other things, to high IL-21 levels. We also observed that B cells from lupus mice display a specific intrinsic sensitivity to this cytokine, due to over-expression of key molecules such as STAT3, which results in increased plasma cell differentiation. Thus, all elements are gathered that favor "Tfh-B" cell interactions and the GC reaction, and therefore the autoimmune response. Finally, the discovery of functional ectopic GC in the kidneys of lupus mice allows envisaging that local responses occur within the target organs and likely participate to kidney injury. The fundamental data we obtained are promising and anticipate new and better targeted biotherapies for lupus treatment
Biological, physiological, immunological and nutritional assessment of farm-reared Litopenaeus stylirostris shrimp affected or unaffected by vibriosis
Shrimp aquaculture in New Caledonia is subject to seasonal mortalities during grow-out due to highly virulent Vibrio nigripulchritudo (Vn). To understand the mechanisms affecting shrimp resistance and leading to significant mortality, a shrimp ecophysiology and immunology survey was conducted on two farms, the first considered as a "control" farm (HC), the second affected by the disease (DF). Mortality observed during the survey at DF started 50 days after stocking and was typical of this disease. The main observations regarding shrimp were: (a) growth was not affected by the disease and was faster in the DF than in the HC pond; (b) disease did not affect one sex more than the other, or a specific part of the population in terms of weight; (c) the physical condition of shrimp did not specifically allow us to foresee disease outbreak; (d) shrimp at late premolt stage D-2 and early postmolt stage A appeared to be at some points of the mortalities - but not continuously - the most sensitive to disease; (e) physiological, immunological and nutritional parameters of uninfected shrimp in the DF pond were altered, suggesting that environmental stress occurred just before the first mortalities; (f) data suggest that Vn-infected shrimp are more stressed than the presumed healthy shrimp. Combined with pathological and environmental knowledge gained in parallel during this survey, a conceptual model is proposed. Results suggest that an unstable environment induced conditions (i) stressful for the shrimp, increasing their susceptibility to bacterial infections and (ii) favoring the proliferation of the pathogen in the pond. The combination of these two processes could lead to significant mortality
Early Differentiated CD138<sup>high</sup>MHCII<sup>+</sup>IgG<sup>+</sup> Plasma Cells Express CXCR3 and Localize into Inflamed Kidneys of Lupus Mice
<div><p>Humoral responses are central to the development of chronic autoimmune diseases such as systemic lupus erythematosus. Indeed, autoantibody deposition is responsible for tissue damage, the kidneys being one of the main target organs. As the source of pathogenic antibodies, plasma cells are therefore critical players in this harmful scenario, both at systemic and local levels. The aim of the present study was to analyze plasma cells in NZB/W lupus mice and to get a better understanding of the mechanisms underlying their involvement in the renal inflammation process. Using various techniques (i.e. flow cytometry, quantitative PCR, ELISpot), we identified and extensively characterized three plasma cell intermediates, according to their B220/CD138/MHCII expression levels. Each of these cell subsets displays specific proliferation and antibody secretion capacities. Moreover, we evidenced that the inflammation-related CXCR3 chemokine receptor is uniquely expressed by CD138<sup>high</sup>MHCII<sup>+</sup> plasma cells, which encompass both short- and long-lived cells and mostly produce IgG (auto)antibodies. Expression of CXCR3 allows efficient chemotactic responsiveness of these cells to cognate chemokines, which production is up-regulated in the kidneys of diseased NZB/W mice. Finally, using fluorescence and electron microscopy, we demonstrated the presence of CD138<sup>+</sup>CXCR3<sup>+</sup>IgG<sup>+</sup> cells in inflammatory areas in the kidneys, where they are very likely involved in the injury process. Thus, early differentiated CD138<sup>high</sup>MHCII<sup>+</sup> rather than terminally differentiated CD138<sup>high</sup>MHCII<sup>low</sup> plasma cells may be involved in the renal inflammatory injury in lupus, due to CXCR3 expression and IgG secretion.</p> </div
Continuous deep sedation until death of children at the end of life: French physiciansâ opinions
B cell/plasma cell subsets in diseased lupus NZB/W mice.
<p>A) Percentage of CD138-expressing cells among living cells in the blood and spleen of 32â36 week-old NZB/W mice and BALB/c mice (10 and 4 mice per group respectively) as determined by flow cytometry analysis. Results are expressed as mean % +/â SEM. B) Representative FACS figures showing four main populations of cells in the spleen of a sick NZB/W mouse according to surface expression of key B cell and plasma cell markers: (a) B220<sup>+</sup>CD138<b><sup>â</sup></b>Ly6C<b><sup>â</sup></b>CD79b<sup>+</sup> cells, (b) B220<sup>+</sup>CD138<sup>int</sup>Ly6C<sup>int</sup>CD79b<sup>int</sup> cells, (c) CD138<sup>high</sup>MHCII<sup>+</sup>Ly6C<sup>+</sup>CD79b<b><sup>â</sup></b> cells and (d) CD138<sup>high</sup>MHCII<sup>low</sup>Ly6C<sup>+</sup>CD79b<b><sup>â</sup></b> cells. This phenotypic analysis was performed in eleven 32â36 week-old proteinuria-positive NZB/W mice with similar results.</p
Des formations différenciées pour des réussites plurielles : le cas d'écri+ (ANR-17-NCUN-00015)
International audienceDes formations différenciées pour des réussites plurielles : le cas d'écri+ (ANR-17-NCUN-00015
Characteristic ultrastructural morphology and transcription factor expression in cell subsets identified according to B220/CD138/MHCII expression.
<p>A) The four spleen cell subsets (a to d, as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058140#pone-0058140-g001" target="_blank">Figure 1</a>) were sorted by flow cytometry from the spleen of diseased NZB/W mice. Cells were then embedded for electron microscopy observation. Images show one representative cell (out of 20 observed) in each panel. A representative experiment out of two is shown. Scale barsâ=â500 nm. B) Total RNA was isolated from each FACS-sorted cell subset and the expression of <i>prdm1</i> (Blimp-1; grey bars), <i>xbp1</i> (dark grey bars) and <i>pax5</i> (hatched bars) transcripts was evaluated by quantitative real-time PCR. Results are expressed as the fold induction of gene transcription as compared to the cell subset expressing the lowest transcript amount (B220<sup>+</sup> cells as for <i>prdm1</i> and <i>xbp1</i>, and CD138<sup>high</sup>MHCII<sup>+</sup> cells as for <i>pax5)</i>. All differences between raised values in each subset are statistically significant except for <i>pax5</i> when comparing the two B220<sup>+</sup> subsets and the two CD138<sup>high</sup> subsets to each other, respectively. Data of one representative experiment out of three are shown.</p
Circulating T<sub>FH</sub> Subset Distribution Is Strongly Affected in Lupus Patients with an Active Disease
<div><p>Follicular helper T cells (T<sub>FH</sub>) represent a distinct subset of CD4<sup>+</sup> T cells specialized in providing help to B lymphocytes, which may play a central role in autoimmune diseases having a major B cell component such as systemic lupus erythematosus. Recently, T<sub>FH</sub> subsets that share common phenotypic and functional characteristics with T<sub>FH</sub> cells from germinal centers, have been described in the peripheral blood from healthy individuals. The aim of this study was to analyze the distribution of such populations in lupus patients. Circulating T<sub>FH</sub> cell subsets were defined by multicolor flow cytometry as T<sub>FH</sub>17 (CXCR3<sup>-</sup>CCR6<sup>+</sup>), T<sub>FH</sub>1 (CXCR3 <sup>+</sup> CCR6<sup>-</sup>) or T<sub>FH</sub>2 (CXCR3<sup>-</sup>CCR6<sup>-</sup>) cells among CXCR5 <sup>+</sup> CD45RA<sup>-</sup>CD4<sup>+</sup> T cells in the peripheral blood of 23 SLE patients and 23 sex and age-matched healthy controls. IL-21 receptor expression by B cells was analyzed by flow cytometry and the serum levels of IL-21 and Igs were determined by ELISA tests. We found that the T<sub>FH</sub>2 cell subset frequency is strongly and significantly increased in lupus patients with an active disease (SLEDAI score>8), while the T<sub>FH</sub>1 cell subset percentage is greatly decreased. The T<sub>FH</sub>2 and T<sub>FH</sub>1 cell subset frequency alteration is associated with the presence of high Ig levels and autoantibodies in patientâs sera. Moreover, the T<sub>FH</sub>2 cell subset enhancement correlates with an increased frequency of double negative memory B cells (CD27<sup>-</sup>IgD<sup>-</sup>CD19<sup>+</sup> cells) expressing the IL-21R. Finally, we found that IgE levels in lupus patientsâ sera correlate with disease activity and seem to be associated with high T<sub>FH</sub>2 cell subset frequency. In conclusion, our study describes for the first time the distribution of circulating T<sub>FH</sub> cell subsets in lupus patients. Interestingly, we found an increased frequency of T<sub>FH</sub>2 cells, which correlates with disease activity. Our results suggest that this subset might play a key role in lupus pathogenesis.</p> </div