Hepatotoxicity Associated with the Use of Anti-TNF-α Agents

Medications to inhibit the actions of tumour necrosis factor alpha have revolutionized the treatment of several pro-inflammatory autoimmune conditions. Despite their many benefits, several serious side effects exist and adverse reactions do occur from these medications. While many of the medications' potential adverse effects were anticipated and recognized in clinical trials prior to drug approval, several more rare adverse reactions were recorded in the literature as the popularity, availability and distribution of these medications grew. Of these potential adverse reactions, liver injury, although uncommon, has been observed in some patients. As case reports accrued over time and ultimately case series developed, the link became better established between this family of medicines and various patterns of liver injury. Interestingly, it appears that the majority of cases exhibit an autoimmune hepatitis profile both in serological markers of autoimmune liver disease and in classic autoimmune features seen on hepatic histopathology. Despite the growing evidence of this relationship, the pathogenesis of this reaction remains incompletely understood, but it appears to depend on characteristics of the medications and the genetic composition of the patients; it is likely more complicated than a simple medication class effect. Because of this still incomplete understanding and the infrequency of the occurrence, treatments have also been limited, although it is clear that most patients improve with cessation of the offending agent and, in certain cases, glucocorticoid use. However, more needs to be done in the future to unveil the underlying mechanisms of this adverse reaction

Profiles of miRNAs in serum in severe acute drug induced liver injury and their prognostic significance

Background & AimsDrug induced liver injury (DILI) is challenging because of the lack of biomarkers to predict mortality. Our aim was to describe miRNA changes in sera of subjects with acute idiosyncratic DILI and determine if levels of miRNAs were associated with 6 month mortality.MethodsClinical data and sera were collected from subjects enrolled in the Drug Induced Liver Injury Network prospective study. miRNAs were isolated from serum obtained from 78 subjects within 2 weeks of acute DILI and followed up for 6 months or longer. miRNAs were compared to 40 normal controls and 6 month survivors vs non‐survivors.ResultsThe mean age of the DILI cohort was 48 years, and 55% were female. Eleven (14.1%) subjects died, 10 within 6 months of DILI onset, 5 (45%) liver related. Lower levels of miRNAs‐122, ‐4463 and ‐4270 were associated with death within 6 months (P<.05). None of the subjects with miRNA‐122 greater than the median value died within 6 months for a sensitivity of 100% and specificity of 57%. In subjects with a serum albumin <2.8 g/dL and miR‐122<7.89 RFU the sensitivity, specificity, positive and negative predictive values for death within 6 months were 100%, 57%, 38% and 100% respectively.ConclusionsSerum miRNA‐122 combined with albumin accurately identified subjects who died within 6 months of drug induced liver injury. If confirmed prospectively, miRNA‐122 and albumin may be useful in identifying patients at high risk for mortality or liver transplantation.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136681/1/liv13312_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136681/2/liv13312.pd

Transcriptional Analysis of Murine Macrophages Infected with Different Toxoplasma Strains Identifies Novel Regulation of Host Signaling Pathways

Most isolates of Toxoplasma from Europe and North America fall into one of three genetically distinct clonal lineages, the type I, II and III lineages. However, in South America these strains are rarely isolated and instead a great variety of other strains are found. T. gondii strains differ widely in a number of phenotypes in mice, such as virulence, persistence, oral infectivity, migratory capacity, induction of cytokine expression and modulation of host gene expression. The outcome of toxoplasmosis in patients is also variable and we hypothesize that, besides host and environmental factors, the genotype of the parasite strain plays a major role. The molecular basis for these differences in pathogenesis, especially in strains other than the clonal lineages, remains largely unexplored. Macrophages play an essential role in the early immune response against T. gondii and are also the cell type preferentially infected in vivo. To determine if non-canonical Toxoplasma strains have unique interactions with the host cell, we infected murine macrophages with 29 different Toxoplasma strains, representing global diversity, and used RNA-sequencing to determine host and parasite transcriptomes. We identified large differences between strains in the expression level of known parasite effectors and large chromosomal structural variation in some strains. We also identified novel strain-specifically regulated host pathways, including the regulation of the type I interferon response by some atypical strains. IFNβ production by infected cells was associated with parasite killing, independent of interferon gamma activation, and dependent on endosomal Toll-like receptors in macrophages and the cytoplasmic receptor retinoic acid-inducible gene 1 (RIG-I) in fibroblasts.National Institutes of Health (U.S.) (R01-AI080621)New England Regional Center of Excellence for Biodefense and Emerging Infectious Diseases (Developmental Grant AIO57159)Pew Charitable Trusts (Biomedical Scholars Program)Robert A. Swanson Career Development awardThe Knights Templar Eye Foundation, Inc.Pre-Doctoral Grant in the Biological Sciences (5-T32-GM007287-33)Cleo and Paul Schimmel Foundatio

Cellular and molecular mechanisms TLR9-dependent activated by Toxoplasma gondii in the gut associated lymphoid tissue

Lors de l’infection orale par le parasite T. gondii, la réponse immunitaire intestinale fait intervenir des acteurs cellulaires et moléculaires initiateurs de l’inflammation servant à combattre l’infection. Cette réponse inflammatoire requiert l’intervention de mécanismes immuno-régulateurs pour permettre le maintien de l’homéostasie intestinale. Nous avons étudié le rôle du TLR9 dans l’initiation de la réponse immunitaire à T. gondii. Ce récepteur de l’immunité innée est largement distribué dans le système lymphoïde associé à la muqueuse intestinale, à la fois par les cellules constituant la barrière épithéliale et dans la lamina propria. L’expression du TLR9 est requise dans ces différents compartiments pour initier une réponse immunitaire protectrice contre l’infection par T. gondii. L’activation des voies de signalisation du TLR9, par la reconnaissance directe de motifs moléculaires exprimés par T. gondii, induit la production d’interférons (IFNs) de type I a et ß dans l’intestin grêle des souris infectées. Ces cytokines stimulent la production de Cryptdines (Crp-3 et -5) par les cellules de Paneth et leur libération dans la lumière intestinale. Au-delà de leur activité antimicrobienne, les Crps participent au recrutement de lymphocytes T CD4+ producteurs d’IFN-? en renforçant la production de chimiokines inflammatoires comme CCL2, CCL3 et CCL5. Dans la lamina propria, les cellules dendritiques initient la réponse inflammatoire au parasite par des mécanismes TLR9-depéndants. L’engagement de ce récepteur par T. gondii polarise la réponse immunitaire au parasite, induite par les cellules dendritiques, vers un profil Th1. Les lymphocytes B, bien qu’exprimant le TLR9, ne participent pas à l’initiation de la réponse inflammatoire à T. gondii. En revanche consécutivement à l’infection orale par le parasite, les cellules B activées amplifient d’une part le recrutement de cellules T CD4+ dans la lamina propria par la production de la chimiokine CCL3. D’autre part renforcent la production de la cytokine inflammatoire IFN-?, par les cellules T effectrices, par des interactions de contact faisant intervenir leur TNF-a membranaire. La réponse immunitaire à T. gondii dégénère chez les souris C57BL/6 en iléite létale. Les lymphocytes T régulateurs sont naturellement générés au cours de l’infection. La sensibilisation des cellules T regs par des antigènes de T. gondii, préalablement à l’infection par le parasite, protège dans notre modèle de la génération de l’iléite. Les T regs sensibilisés ont une expression renforcée des marqueurs de domiciliation intestinale CCR5 et a4ß7. Ils rééquilibrent la balance cytokinique dans le système lymphoïde associé à la muqueuse intestinale des souris infectées en limitant la production de cytokines Th1 par les lymphocytes purifiés de la lamina propria et renforçant leur production de cytokines Th2 et Th3.We have investigated the role of TLR9 in the initiation of the immune response in the gut against Toxoplasma gondii. This innate immune receptor is widely expressed in the gut associated lymphoid tissue (GALT) : at the epithelial barrier and in the lamina propria. Expression of TLR9 is requiered in both these compartments to initiate a protective immune response against T. Gondii. Activation of TLR9 signaling pathways, by direct recognition of molecular motives expressed by T. gondii, induces the production of type I interferons (IFNs) in the small intestine. These interferons tregger the production of cryptdines (Crp-3 and -5) by paneth cells and their released into the lumen. Crps indirectly promote T cells (CD4 + IFN-y+) recruitmnent by enhancing the production of inflammatory chemokines. B-lymphocites express the TLR9 but do not contribute to the initiation of inflammatory response against T. gondii. However consecutively to the oral infection by the parasite, activated B cells amplify the inflammatory cytokine production (IFN-y), by effector T cells, via cell-cell interactions involving their mambrane bound TNF-a. In C57BL/6 mice, immune response against T. Gondii degenerates into a lethal ileitis. Regulatory T cells are naturally generated during infection. The sensibilisation of T regs by T. Gondii antigens, prior infection by the parasite, protects against the ileitis in our model. Sensibilized T regs overexpress gut homing receptors such as CCR5 AND a4ß7. By increasing their Th2 and Th3 cytokines production, sensibilized T regs readjust the cytokine balance in GALT of infected mice

Mécanismes cellulaires et moléculaires TLR9-dépendants activés par T. gondii dans le système lymphoïde associé à la muqueuse intestinale

Lors de l infection orale par le parasite T. gondii, la réponse immunitaire intestinale fait intervenir des acteurs cellulaires et moléculaires initiateurs de l inflammation servant à combattre l infection. Cette réponse inflammatoire requiert l intervention de mécanismes immuno-régulateurs pour permettre le maintien de l homéostasie intestinale. Nous avons étudié le rôle du TLR9 dans l initiation de la réponse immunitaire à T. gondii. Ce récepteur de l immunité innée est largement distribué dans le système lymphoïde associé à la muqueuse intestinale, à la fois par les cellules constituant la barrière épithéliale et dans la lamina propria. L expression du TLR9 est requise dans ces différents compartiments pour initier une réponse immunitaire protectrice contre l infection par T. gondii. L activation des voies de signalisation du TLR9, par la reconnaissance directe de motifs moléculaires exprimés par T. gondii, induit la production d interférons (IFNs) de type I a et ß dans l intestin grêle des souris infectées. Ces cytokines stimulent la production de Cryptdines (Crp-3 et -5) par les cellules de Paneth et leur libération dans la lumière intestinale. Au-delà de leur activité antimicrobienne, les Crps participent au recrutement de lymphocytes T CD4+ producteurs d IFN-? en renforçant la production de chimiokines inflammatoires comme CCL2, CCL3 et CCL5. Dans la lamina propria, les cellules dendritiques initient la réponse inflammatoire au parasite par des mécanismes TLR9-depéndants. L engagement de ce récepteur par T. gondii polarise la réponse immunitaire au parasite, induite par les cellules dendritiques, vers un profil Th1. Les lymphocytes B, bien qu exprimant le TLR9, ne participent pas à l initiation de la réponse inflammatoire à T. gondii. En revanche consécutivement à l infection orale par le parasite, les cellules B activées amplifient d une part le recrutement de cellules T CD4+ dans la lamina propria par la production de la chimiokine CCL3. D autre part renforcent la production de la cytokine inflammatoire IFN-?, par les cellules T effectrices, par des interactions de contact faisant intervenir leur TNF-a membranaire. La réponse immunitaire à T. gondii dégénère chez les souris C57BL/6 en iléite létale. Les lymphocytes T régulateurs sont naturellement générés au cours de l infection. La sensibilisation des cellules T regs par des antigènes de T. gondii, préalablement à l infection par le parasite, protège dans notre modèle de la génération de l iléite. Les T regs sensibilisés ont une expression renforcée des marqueurs de domiciliation intestinale CCR5 et a4ß7. Ils rééquilibrent la balance cytokinique dans le système lymphoïde associé à la muqueuse intestinale des souris infectées en limitant la production de cytokines Th1 par les lymphocytes purifiés de la lamina propria et renforçant leur production de cytokines Th2 et Th3.We have investigated the role of TLR9 in the initiation of the immune response in the gut against Toxoplasma gondii. This innate immune receptor is widely expressed in the gut associated lymphoid tissue (GALT) : at the epithelial barrier and in the lamina propria. Expression of TLR9 is requiered in both these compartments to initiate a protective immune response against T. Gondii. Activation of TLR9 signaling pathways, by direct recognition of molecular motives expressed by T. gondii, induces the production of type I interferons (IFNs) in the small intestine. These interferons tregger the production of cryptdines (Crp-3 and -5) by paneth cells and their released into the lumen. Crps indirectly promote T cells (CD4 + IFN-y+) recruitmnent by enhancing the production of inflammatory chemokines. B-lymphocites express the TLR9 but do not contribute to the initiation of inflammatory response against T. gondii. However consecutively to the oral infection by the parasite, activated B cells amplify the inflammatory cytokine production (IFN-y), by effector T cells, via cell-cell interactions involving their mambrane bound TNF-a. In C57BL/6 mice, immune response against T. Gondii degenerates into a lethal ileitis. Regulatory T cells are naturally generated during infection. The sensibilisation of T regs by T. Gondii antigens, prior infection by the parasite, protects against the ileitis in our model. Sensibilized T regs overexpress gut homing receptors such as CCR5 AND a4ß7. By increasing their Th2 and Th3 cytokines production, sensibilized T regs readjust the cytokine balance in GALT of infected mice.TOURS-Bibl.électronique (372610011) / SudocSudocFranceF

Structural investigation of heteroyohimbine alkaloid synthesis reveals active site elements that control stereoselectivity

International audienc

Deep sustained response to daratumumab monotherapy associated with T-cell expansion in triple refractory myeloma

Abstract Background Daratumumab, a human CD38 monoclonal antibody that has direct on-tumor and immunomodulatory mechanisms of action, demonstrated clinical benefit as monotherapy or in combination with established regimens in patients with multiple myeloma with one or more prior lines of therapy. Case presentation A male patient, who was 70 years of age at the time of diagnosis of multiple myeloma in 2011, relapsed after five lines of therapy, including autologous stem cell transplantation. The patient’s disease, which was considered high risk with a deletion of chromosome 17p, advanced quickly and was triple refractory 2 years after diagnosis leaving few treatment options. He was treated with daratumumab monotherapy in the SIRIUS clinical trial resulting in a stringent complete response and clearance of minimal residual disease. The duration of the patient’s clinical response is now over 3.5 years without relapse, compared with a median of 7.6 months for similarly treated patients. The patient’s immunophenotype revealed CD8+ T-cell expansion, clonal expansion of the T-cell receptor repertoire, and decreases in regulatory T cells during daratumumab therapy, suggesting a robust adaptive immune response. This immune response was still present 32 months into daratumumab therapy. Conclusions The results from this case report showed that a patient with advanced multiple myeloma, who had exhausted all treatment options with existing regimens, mounted an ongoing, deep, and durable response to daratumumab monotherapy. Further investigation of the immunologic profile provided additional patient-level evidence of an immunomodulatory mechanism of action of daratumumab. Trial registration ClinicalTrials.gov Identifier number NCT01985126. Submitted 22 July 201

TLR9-dependent induction of intestinal alpha-defensins by Toxoplasma gondii.

International audienceAlpha-defensins (or Cryptdins [Crps]) are a group of antimicrobial peptides produced as a component of Paneth cell (PC) secretory granules in the small intestine. In vivo ligation of TLR9 by synthetic agonists leads to PC degranulation, although the mechanism by which this occurs remains uncertain. In this report, we investigated TLR9-dependent mechanisms, triggered by the parasite Toxoplasma gondii, inducing Crp release in the lumen. Oral challenge of C57BL/6J (B6) wild-type (WT) mice with T. gondii induced TLR9 mRNA upregulation associated with a marked increase of type I IFN mRNA expression. PC secretory granules were released, and Crp-3/-5 mRNA expression by purified epithelial cells was increased following oral challenge of B6 WT mice. Although PCs failed to degranulate in infected B6 TLR9-/- mice, i.p. injection of mouse IFN-beta alone led to Crp-3/-5 mRNA upregulation in B6 WT and TLR9-/- mice. In addition, modulation of Crp mRNA expression in response to T. gondii infection was abrogated in B6 IFNAR-/- mice, which lack a functional type I IFN receptor. Taken together, these data demonstrate that T. gondii induces Crp-3/-5 production and release by PCs via a TLR9-dependent production of type I IFNs. Crps have a limited direct effect against T. gondii but may indirectly affect the early control of T. gondii invasiveness by promoting the initiation of a protective Th1 response against the parasite