Capillary leak leading to shock in Kawasaki disease without myocardial dysfunction.

Kawasaki disease is an acute vasculitis of childhood. Its clinical presentation is well known, and coronary artery aneurysms are classical complications. Shock and pleural or pericardiac effusion are rare presentations of the disease. In intensive care units, the disease may be mistaken for septic shock or toxic shock syndrome. Owing to the fact that immunoglobulin therapy improves the course of the disease, especially if given early, and thus the diagnosis should not be delayed.

Notch1 expression on T cells is not required for CD4+ T helper differentiation.

Notch1 proteins are involved in binary cell fate decisions. To determine the role of Notch1 in the differentiation of CD4(+) Th1 versus Th2 cells, we have compared T helper polarization in vitro in naive CD4(+) T cells isolated from mice in which the N1 gene is specifically inactivated in all mature T cells. Following activation, Notch1-deficient CD4(+) T cells transcribed and secreted IFN-gamma under Th1 conditions and IL-4 under Th2 conditions at levels similar to that of control CD4(+) T cells. These results show that Notch1 is dispensable for the development of Th1 and Th2 phenotypes in vitro. The requirement for Notch1 in Th1 differentiation in vivo was analyzed following inoculation of Leishmania major in mice with a T cell-specific inactivation of the Notch1 gene. Following infection, these mice controlled parasite growth at the site of infection and healed their lesions. The mice developed a protective Th1 immune response characterized by high levels of IFN-gamma mRNA and protein and low levels of IL-4 mRNA with no IL-4 protein in their lymph node cells. Taken together, these results indicate that Notch1 is not critically involved in CD4(+) T helper 1 differentiation and in resolution of lesions following infection with L. major.

Induction of the alternative NF-κB pathway by lymphotoxin αβ (LTαβ) relies on internalization of LTβ receptor.

Several tumor necrosis factor receptor (TNFR) family members activate both the classical and the alternative NF-κB pathways. However, how a single receptor engages these two distinct pathways is still poorly understood. Using lymphotoxin β receptor (LTβR) as a prototype, we showed that activation of the alternative, but not the classical, NF-κB pathway relied on internalization of the receptor. Further molecular analyses revealed a specific cytosolic region of LTβR essential for its internalization, TRAF3 recruitment, and p100 processing. Interestingly, we found that dynamin-dependent, but clathrin-independent, internalization of LTβR appeared to be required for the activation of the alternative, but not the classical, NF-κB pathway. In vivo, ligand-induced internalization of LTβR in mesenteric lymph node stromal cells correlated with induction of alternative NF-κB target genes. Thus, our data shed light on LTβR cellular trafficking as a process required for specific biological functions of NF-κB.

Generation and function of mouse central memory and effector memory T cells

1. SUMMARY Based on functional and homing properties, two subsets of memory T lymphocytes have been defined both in humans and in mice. Central memory T cells (TCM cells) express the lymph node homing receptors CD62L and CCR7, have poor effector function and proliferate efficiently upon antigenic stimulation. Effector memory T cells (TEM cells) do not express CCR7, are mostly CD62L negative and therefore are excluded from lymph nodes, but are able to migrate to sites of inflammation where they exert immediate effector function by producing inflammatory cytokines and cytotoxic mediators. In the present work we have addressed two questions that emerged since the definition of TCM and TEM cells. Firstly, what are the priming conditions for generation of TCM and TEM and, secondly, what is the migratory capacity of TCM and TEM cells in inflammatory conditions. By using naive TCR-transgenic OT-I CD8+ T cells and OT-II CD4+ T cells and ovalbumin pulsed-mature dendritic cells (DCs) we set up an in vitro system in which the strength of T cell stimulation is controlled by varying the ratio of T cells and DCs and the duration of DC-T cell interaction. Using this system we found that precursors of TCM and TEM cells are generated at different strength of stimulation and that T cells capable of persisting in vivo in the absence of antigen and of mounting recall responses is optimally induced by intermediate stimulatory strength. In addition, we found that lymph nodes draining sites of mature DC or adjuvant inoculation recruit CD8+ CD62L- CCR7- effector and TEM cells. CD8+ T cell recruitment in reactive lymph nodes requires CXCR3 expression on T cells and occurs through high endothelial venules (HEVs) in concert with HEV lurninal expression of the CXCR3 ligand CXCL9. In reactive lymph nodes, recruited T cells establish stable interactions with and kill antigen-bearing DCs, limiting the ability of these DCs to activate CD4+ and CD8+ T cells. Taken togther these data define conditions for the generation of TCM and TEM cells and define an inflammatory pathway of effector T cell migration in lymph nodes. The inducible recruitment of blood-borne effector and TEM CD8+ cells to lymph nodes may represent a mechanism for terminating primary and limiting secondary immune responses.

An unusual uterine tumour with signet ring cell features

Objective: Lymphomas with signet ring cell features are rare, as is uterine dissemination of lymphomas. We report an exceptional case of a uterine tumor combining these two characteristics. Method: A 61-year-old female was diagnosed in 2004 with localized nodal grade 2 follicular lymphoma (stage IA). She received local radiation therapy, experienced total remission, and did well until 2009 when a systematic CT scan evidenced a pelvic anterior-lateral mass. Total enlarged hysterectomy was performed. Results: The anterior uterine wall contained a 4.8-cm fish flesh well-delineated mass corresponding to a mostly diffuse and focally nodular proliferation of medium to large cells with extensive signet ring cell changes. Tumor cells were CD20-, CD10-, Bcl2-, and Bcl6-positive with a low proliferation rate (<10-15%); CD21 underlined a focal follicular architecture. The vacuoles were PAS-negative and did not stain for immunoglobulin; ultrastructural analysis revealed nonspecific degenerative vacuoles. No lymph nodes were identified isolated from the surgical specimen. The tumor was considered as a secondary localization of the systemic follicular lymphoma, though no signet ring cells were evidenced in the cervical lymph node biopsy (reviewed). Follow-up showed retroperitoneal tissue infiltration (PET-CT) and normal medullar biopsy. She recently started R-CHOP chemotherapy. Conclusion: This case illustrates both an unusual site of dissemination and challenging cytological characteristics in a follicular lymphoma. The signet ring cell changes challenged the adequate classification of this lymphoma as either a large B cell or a follicular B cell lymphoma.

Inflammation And Autoimmune Responses Are Independent Of Peripheral Mhc Class Ii Expression Driven By Ciita Piv In Collagen Induced Arthritis

Background In rheumatoid arthritis (RA), non-professional antigen presenting cells (APCs) such as fi broblast-like synoviocytes (FLS) can express MHC class II (MHCII) molecules and function as non-professional APCs in vitro.Objective To examine the regulation of MHCII expression in FLS and to investigate the role of FLS as non-professional APCs in collagen-induced arthritis (CIA). Methods Expression of MHCII, CIITA and Ciita isoforms pI, pIII and pIV was examined by RT-qPCR, immunohistochemistry and fl ow cytometry in human synovial tissues, arthritic mouse joints and human as well as mouse FLS. CIA was induced in mice knockout for the isoform IV of Ciita (pIV-/-), in pIV-/- mice transgenic for CIITA in the thymus (pIV-/- K14 CIITA) and in control littermates in the DBA/1 background by immunising with bovine collagen type II (CII) in complete Freund's adjuvant.Results HLA-DRA, total CIITA and CIITA pIII mRNA levels were signifi cantly increased in the synovial tissues from RA compared to osteoarthritis patients. Human FLS expressed surface MHCII via CIITA pIII and pIV, while MHCII expression in murine FLS was entirely mediated by pIV. pIV-/- mice lacked both inducible MHCII expression on non-professional APCs including FLS, and in the thymic cortex. The thymic defect in pIV-/- mice impaired CD4+ positive selection, thus protecting pIV-/- mice from CIA by preventing CD4+ T cells immune responses against CII and blocking the release of IFN-γ and IL-17 in ex vivo stimulated lymph node cells. The production of T dependent, arthritogenic anti-CII antibodies was also impaired in pIV-/- mice. A normal thymic expression of MHCII and CD4+ T cell repertoire was obtained in pIV-/- K14 CIITA Tg mice. Immune responses against CII were restored in pIV-/- K14 CIITA Tg mice, as well as the arthritis incidence and clinical severity despite the lack of MHCII expression by mouse FLS. At histology, infl ammation andneutrophils infi ltration scores were not reduced in pIV-/- K14 CIITA Tg mice, while the bone erosion score was signifi cantly lower than in controls.Conclusion Over expression of MHCII is tightly correlated with CIITA pIII in the arthritic human synovium. MHCII is induced via CIITA pIII and pIV in human FLS. In the mouse, MHCII expression in the thymic cortex and in FLS is strictly dependent upon Ciita pIV. The lack of Ciita pIV in the periphery of pIV-/- K14 CIITA Tg mice lowered the bone erosion score but did not signifi cantly protect from infl ammation and autoimmune responses in CIA.

Simultaneous renal oncocytoma and lymphoma: interest of lymphadenectomy

Kidney lesions may be difficult to diagnose only by radiological exams, often requiring proof by tissue biopsy. Moreover, if enlarged regional lymph nodes are also present, the spectrum of differential diagnoses is even greater. The role of regional lymph node dissection in this setting is not clearly established. We show the case of a patient with a kidney mass associated with a conglomerate of para-aortic and iliac lymphadenopathies corresponding to an oncocytoma and a nodular lymphocyte predominant Hodgkin' lymphoma, respectively. Diagnosis of these two lesions was performed by morphology and immunohistochemistry. This case reflects how imaging can mislead to diagnosis and how histological confirmation helps decide treatment management.

Lymphocyte specificity to protein antigens. III. Capacity of low responder mice to beef cytochrome c to respond to a peptide fragment of the molecule.

Lymph node cells derived from A.TH or A.TL mice primed with beef cytochrome c show striking patterns of reactivity when assayed in vitro for antigen-induced T cell proliferation. Whereas cells from A.TH mice respond specifically to beef cytochrome c or peptides composed of amino acids 1-65 and 81-104, cells from A.TL mice respond neither to beef cytochrome c nor to peptide 1-65, but proliferate following exposure to either peptide 81-104 or to a cytochrome c hybrid molecule in which the N-terminal peptide of beef (1-65) was substituted by a similar peptide obtained from rabbit cytochrome c. Thus, T cells from mice phenotypically unresponsive to beef cytochrome may, in fact, contain populations of lymphocytes capable of responding to a unique peptide, the response to which is totally inhibited when the same fragment is presented in the sequence of the intact protein.

New formulation of vasoactive intestinal peptide using liposomes in hyaluronic acid gel for uveitis.

We evaluated the benefits of a novel formulation of vasoactive intestinal peptide (VIP) based on the incorporation of VIP-loaded rhodamine-conjugated liposomes (VIP-Rh-Lip) within hyaluronic acid (HA) gel (Gel-VIP-Rh-Lip) for the treatment of endotoxin-induced uveitis (EIU) in comparison with VIP-Rh-Lip alone. In vitro release study and rheological analysis showed that interactions between HA chains and liposomes resulted in increased viscosity and reinforced elasticity of the gel. In vivo a single intravitreal injection of Gel-VIP-Rh-Lip was performed in rats 7 days prior to uveitis induction by subcutaneous lipopolysaccharide injection. The maximal ocular inflammation occurs within 16-24 h in controls (VIP-Rh-Lip, unloaded-Rh-Lip). Whereas intraocular injection of VIP-Rh-Lip had no effect on EIU severity compared with controls, Gel-VIP-Rh-Lip reduced significantly the clinical score and number of inflammatory cells infiltrating the eye. The fate of liposomes, VIP and HA in the eyes, regional and inguinal lymph nodes and spleen was analyzed by immunostaining and fluorescence microscopy. Retention of liposomes by HA gel was observed in vitro and in vivo. Inflammation severity seemed to impact on system stability resulting in the delayed release of VIP. Thus, HA gel containing VIP-Rh-Lip is an efficient strategy to obtain a sustained delivery of VIP in ocular and lymph node tissues.

Feasibility of radiotherapy or chemoradiotherapy after taxane-based induction chemotherapy for nonoperated locally advanced head and neck squamous cell carcinomas.

To assess the use of radiotherapy (RT) or concurrent chemoradiotherapy (CRT) following taxane-based induction chemotherapy (T-ICT) in locally advanced head and neck squamous cell carcinoma (LAHNSCC) and to evaluate the tolerability of CRT after T-ICT. From 01/2006 to 08/2012, 173 LAHNSCC patients treated as a curative intent by T-ICT, followed by definitive RT/CRT were included in this analysis. There was an 86% objective response (OR) after ICT among 154 evaluable patients. Forty-four patients received less than three cycles (25%) and 20 received only one cycle of T-ICT. The 3-year actuarial overall survival (OS) was 49% and there was no OS difference according to the type of ICT (regimen or number of cycle) or the addition of concurrent CT (cisplatin, carboplatin, or cetuximab) to RT. In multivariate analysis (MVA), clinically involved lymph node (cN+), age more than 60 years, the absence of OR after ICT, and performance status of at least 1 predicted for a decreased OS, with hazard ratios (HR) of 2.8, 2.2, 2.1, and 2, respectively. The 3-year actuarial locoregional control (LRC) and distant control (DC) rates were 52 and 73%, respectively. In MVA, the absence of OR after ICT (HR: 3.2), cN+ (HR: 3), and age more than 60 years (HR: 1.7) were prognostic for a lower LRC whereas cN+ (HR: 4.2) and carboplatin-based T-ICT (HR: 2.9) were prognostic for a lower DC. The number of cycles (≤ 2) received during ICT was borderline significant for DC in the MVA (P=0.08). Among patients receiving less than or equal to three cycles of ICT, higher outcomes were observed in patients who received cisplatin-based T-ICT (vs. carboplatin-based T-ICT) or subsequent CRT (vs. RT). T-ICT in our experience, followed by RT or CRT, raises several questions on the role and type of induction, and the efficacy of CRT over RT. The role of RT or CRT following induction, although feasible in these advanced patients, awaits answers from randomized trials.

Blocking Junctional Adhesion Molecule C Enhances Dendritic Cell Migration and Boosts the Immune Responses against Leishmania major.

The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C) on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs) from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1) response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2) response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response.

NLRP3 inflammasome is required in murine asthma in the absence of aluminum adjuvant.

Background: Inflammasome activation with the production of IL-1 beta received substantial attention recently in inflammatory diseases. However, the role of inflammasome in the pathogenesis of asthma is not clear. Using an adjuvant-free model of allergic lung inflammation induced by ovalbumin (OVA), we investigated the role of NLRP3 inflammasome and related it to IL-1R1 signaling pathway.Methods: Allergic lung inflammation induced by OVA was evaluated in vivo in mice deficient in NLRP3 inflammasome, IL-1R1, IL-1 beta or IL-1 alpha. Eosinophil recruitment, Th2 cytokine, and chemokine levels were determined in bronchoalveolar lavage fluid, lung homogenates, and mediastinal lymph node cells ex vivo.Results: Allergic airway inflammation depends on NLRP3 inflammasome activation. Dendritic cell recruitment into lymph nodes, Th2 lymphocyte activation in the lung and secretion of Th2 cytokines and chemokines are reduced in the absence of NLRP3. Absence of NLRP3 and IL-1 beta is associated with reduced expression of other proinflammatory cytokines such as IL-5, IL-13, IL-33, and thymic stromal lymphopoietin. Furthermore, the critical role of IL-1R1 signaling in allergic inflammation is confirmed in IL-1R1-, IL-1 beta-, and IL-1 alpha-deficient mice.Conclusion: NLRP3 inflammasome activation leading to IL-1 production is critical for the induction of a Th2 inflammatory allergic response.

Inflammatory role of ASC in antigen-induced arthritis is independent of caspase-1, NALP-3, and IPAF.

Because IL-1beta plays an important role in inflammation in human and murine arthritis, we investigated the contribution of the inflammasome components ASC, NALP-3, IPAF, and caspase-1 to inflammatory arthritis. We first studied the phenotype of ASC-deficient and wild-type mice during Ag-induced arthritis (AIA). ASC(-/-) mice showed reduced severity of AIA, decreased levels of synovial IL-1beta, and diminished serum amyloid A levels. In contrast, mice deficient in NALP-3, IPAF, or caspase-1 did not show any alteration of joint inflammation, thus indicating that ASC associated effects on AIA are independent of the classical NALP-3 or IPAF inflammasomes. Because ASC is a ubiquitous cytoplasmic protein that has been implicated in multiple cellular processes, we explored other pathways through which ASC may modulate inflammation. Ag-specific proliferation of lymph node and spleen cells from ASC-deficient mice was significantly decreased in vitro, as was the production of IFN-gamma, whereas IL-10 production was enhanced. TCR ligation by anti-CD3 Abs in the presence or absence of anti-CD28 Abs induced a reduction in T cell proliferation in ASC(-/-) T cells compared with wild-type ones. In vivo lymph node cell proliferation was also significantly decreased in ASC(-/-) mice, but no effects on apoptosis were observed either in vitro or in vivo in these mice. In conclusion, these results strongly suggest that ASC modulates joint inflammation in AIA through its effects on cell-mediated immune responses but not via its implication in inflammasome formation.

Specific fibroblastic niches in secondary lymphoid organs orchestrate distinct Notch-regulated immune responses.

Fibroblast-like cells of secondary lymphoid organs (SLO) are important for tissue architecture. In addition, they regulate lymphocyte compartmentalization through the secretion of chemokines, and participate in the orchestration of appropriate cell-cell interactions required for adaptive immunity. Here, we provide data demonstrating the functional importance of SLO fibroblasts during Notch-mediated lineage specification and immune response. Genetic ablation of the Notch ligand Delta-like (DL)1 identified splenic fibroblasts rather than hematopoietic or endothelial cells as niche cells, allowing Notch 2-driven differentiation of marginal zone B cells and of Esam(+) dendritic cells. Moreover, conditional inactivation of DL4 in lymph node fibroblasts resulted in impaired follicular helper T cell differentiation and, consequently, in reduced numbers of germinal center B cells and absence of high-affinity antibodies. Our data demonstrate previously unknown roles for DL ligand-expressing fibroblasts in SLO niches as drivers of multiple Notch-mediated immune differentiation processes.

Bacterial translocation in cirrhotic rats. Its role in the development of spontaneous bacterial peritonitis

Bacterial translocation occurs in ascitic cirrhotic rats, but its association with ascites infection is unknown. The aim of this study was to assess the relation between bacterial translocation and ascites infection in cirrhotic rats. Male Sprague-Dawley rats were induced to cirrhosis with intragastric CCl4. Ascitic fluid, portal and peripheral blood, mesenteric lymph nodes, liver and spleen samples were cultured before death in those cirrhotic rats with less (group A) or more (group B) than 250 polymorphonuclear neutrophils/mm3 in ascitic fluid, as well as in healthy control rats. Histological examination of jejunum, ileum, and caecum was also performed. Bacterial translocation occurred in 45% of ascitic rats (without differences between groups A and B), but in 0% controls (p = 0.01). Bacterial translocation was associated with positive ascitic fluid culture in 60% of the cases. In all of them the same bacterial species was isolated in both mesenteric lymph node and ascitic fluid. Submucosal caecal oedema (100%), ileal lymphangiectasia (41%), and caecal inflammatory infiltrate (41%) occurred in ascitic rats, the last being associated with ascitic fluid positive culture (p = 0.04). These results suggests that bacterial translocation occurs frequently in ascitic cirrhotic rats, and may play a permissive, but not unique, part in a number of ascites infections. Whether histological changes seen in cirrhotic ascitic rats favour bacterial translocation remains to be elucidated.