RESUMEN
In the intestine, epithelial factors condition incoming immune cells including monocytes to adapt their threshold of activation and prevent undesired inflammation. Colonic epithelial cells express Secretory Leukocyte Protease Inhibitor (SLPI), an inhibitor of NF kappa light chain enhancer of activated B cells (NF-κB) that mediates epithelial hyporesponsiveness to microbial stimuli. Uptake of extracellular SLPI by monocytes has been proposed to inhibit monocyte activation. We questioned whether monocytes can produce SLPI and whether endogenous SLPI can inhibit monocyte activation. We demonstrate that human THP-1 monocytic cells produce SLPI and that CD68+ SLPI-producing cells can be detected in human intestinal lamina propria. Knockdown of SLPI in human THP-1 cells significantly increased NF-κB activation and subsequent C-X-C motif chemokine ligand 8 (CXCL8) and TNF-α production in response to microbial stimulation. Reconstitution of SLPI-deficient cells with either full-length SLPI or SLPI lacking its signal peptide rescued inhibition of NF-κB activation and cytokine production, demonstrating that endogenous SLPI inhibits monocytic cell activation. Unexpectedly, exogenous SLPI did not inhibit CXCL8 or TNF-α production, despite efficient uptake. Our data argue that endogenous SLPI can regulate the threshold of activation in monocytes, thereby preventing activation by commensal bacteria in mucosal tissues.
Asunto(s)
FN-kappa B , Inhibidor Secretorio de Peptidasas Leucocitarias , Humanos , FN-kappa B/metabolismo , Monocitos/metabolismo , Factor de Necrosis Tumoral alfa , Transducción de SeñalRESUMEN
Intact interleukin-10 receptor (IL-10R) signaling on effector and T regulatory (Treg) cells are each independently required to maintain immune tolerance. Here we show that IL-10 sensing by innate immune cells, independent of its effects on T cells, was critical for regulating mucosal homeostasis. Following wild-type (WT) CD4(+) T cell transfer, Rag2(-/-)Il10rb(-/-) mice developed severe colitis in association with profound defects in generation and function of Treg cells. Moreover, loss of IL-10R signaling impaired the generation and function of anti-inflammatory intestinal and bone-marrow-derived macrophages and their ability to secrete IL-10. Importantly, transfer of WT but not Il10rb(-/-) anti-inflammatory macrophages ameliorated colitis induction by WT CD4(+) T cells in Rag2(-/-)Il10rb(-/-) mice. Similar alterations in the generation and function of anti-inflammatory macrophages were observed in IL-10R-deficient patients with very early onset inflammatory bowel disease. Collectively, our studies define innate immune IL-10R signaling as a key factor regulating mucosal immune homeostasis in mice and humans.
Asunto(s)
Colitis Ulcerosa/genética , Colitis Ulcerosa/inmunología , Interleucina-10/inmunología , Receptores de Interleucina-10/inmunología , Traslado Adoptivo , Animales , Diferenciación Celular/inmunología , Proliferación Celular , Células Cultivadas , Proteínas de Unión al ADN/deficiencia , Proteínas de Unión al ADN/genética , Humanos , Tolerancia Inmunológica/genética , Tolerancia Inmunológica/inmunología , Inmunidad Innata/genética , Inmunidad Innata/inmunología , Inflamación/inmunología , Macrófagos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Interleucina-10/deficiencia , Receptores de Interleucina-10/genética , Transducción de Señal/inmunología , Linfocitos T Reguladores/inmunologíaRESUMEN
OBJECTIVE: In newly diagnosed paediatric patients with moderate-to-severe Crohn's disease (CD), infliximab (IFX) is initiated once exclusive enteral nutrition (EEN), corticosteroid and immunomodulator therapies have failed. We aimed to investigate whether starting first-line IFX (FL-IFX) is more effective to achieve and maintain remission than conventional treatment. DESIGN: In this multicentre open-label randomised controlled trial, untreated patients with a new diagnosis of CD (3-17 years old, weighted Paediatric CD Activity Index score (wPCDAI) >40) were assigned to groups that received five infusions of 5 mg/kg IFX at weeks 0, 2, 6, 14 and 22 (FL-IFX), or EEN or oral prednisolone (1 mg/kg, maximum 40 mg) (conventional). The primary outcome was clinical remission on azathioprine, defined as a wPCDAI <12.5 at week 52, without need for treatment escalation, using intention-to-treat analysis. RESULTS: 100 patients were included, 50 in the FL-IFX group and 50 in the conventional group. Four patients did not receive treatment as per protocol. At week 10, a higher proportion of patients in the FL-IFX group than in the conventional group achieved clinical (59% vs 34%, respectively, p=0.021) and endoscopic remission (59% vs 17%, respectively, p=0.001). At week 52, the proportion of patients in clinical remission was not significantly different (p=0.421). However, 19/46 (41%) patients in the FL-IFX group were in clinical remission on azathioprine monotherapy without need for treatment escalation vs 7/48 (15%) in the conventional group (p=0.004). CONCLUSIONS: FL-IFX was superior to conventional treatment in achieving short-term clinical and endoscopic remission, and had greater likelihood of maintaining clinical remission at week 52 on azathioprine monotherapy. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT02517684).
Asunto(s)
Enfermedad de Crohn/tratamiento farmacológico , Fármacos Gastrointestinales/uso terapéutico , Infliximab/uso terapéutico , Adolescente , Antiinflamatorios/uso terapéutico , Azatioprina/uso terapéutico , Niño , Preescolar , Femenino , Humanos , Inmunosupresores/uso terapéutico , Masculino , Prednisolona/uso terapéutico , Inducción de Remisión , Índice de Severidad de la EnfermedadRESUMEN
Under homeostatic conditions, dendritic cells (DCs) continuously patrol the intestinal lamina propria. Upon antigen encounter, DCs initiate C-C motif chemokine receptor 7 (CCR7) expression and migrate into lymph nodes to direct T cell activation and differentiation. The mechanistic underpinnings of DC migration from the tissues to lymph nodes have been largely elucidated, contributing greatly to our understanding of DC functionality and intestinal immunity. In contrast, the molecular mechanisms allowing DCs to efficiently migrate through the complex extracellular matrix of the intestinal lamina propria prior to antigen encounter are still incompletely understood. Here we show that small intestinal murine CD11b+ CD103+ DCs express Placenta-expressed transcript 1 (Plet1), a glycophoshatidylinositol (GPI)-anchored surface protein involved in migration of keratinocytes during wound healing. In the absence of Plet1, CD11b+ CD103+ DCs display aberrant migratory behavior, and accumulate in the small intestine, independent of CCR7 responsiveness. RNA-sequencing indicated involvement of Plet1 in extracellular matrix-interactiveness, and subsequent in-vitro migration assays revealed that Plet1 augments the ability of DCs to migrate through extracellular matrix containing environments. In conclusion, our findings reveal that expression of Plet1 facilitates homeostatic interstitial migration of small intestinal DCs.
Asunto(s)
Movimiento Celular/inmunología , Células Dendríticas/metabolismo , Regulación de la Expresión Génica/inmunología , Intestino Delgado/inmunología , Proteínas Gestacionales/inmunología , Animales , Antígenos CD/genética , Antígenos CD/inmunología , Movimiento Celular/genética , Ratones , Ratones Noqueados , Proteínas Gestacionales/genéticaRESUMEN
Sialic acids are negatively charged nine-carbon carboxylated monosaccharides that often cap glycans on glycosylated proteins and lipids. Because of their strategic location at the cell surface, sialic acids contribute to interactions that are critical for immune homeostasis via interactions with sialic acid-binding Ig-type lectins (siglecs). In particular, these interactions may be of importance in cases where sialic acids may be overexpressed, such as on certain pathogens and tumors. We now demonstrate that modification of antigens with sialic acids (Sia-antigens) regulates the generation of antigen-specific regulatory T (Treg) cells via dendritic cells (DCs). Additionally, DCs that take up Sia-antigen prevent formation of effector CD4(+) and CD8(+)T cells. Importantly, the regulatory properties endowed on DCs upon Sia-antigen uptake are antigen-specific: only T cells responsive to the sialylated antigen become tolerized. In vivo, injection of Sia-antigen-loaded DCs increased de novo Treg-cell numbers and dampened effector T-cell expansion and IFN-γ production. The dual tolerogenic features that Sia-antigen imposed on DCs are Siglec-E-mediated and maintained under inflammatory conditions. Moreover, loading DCs with Sia-antigens not only inhibited the function of in vitro-established Th1 and Th17 effector T cells but also significantly dampened ex vivo myelin-reactive T cells, present in the circulation of mice with experimental autoimmune encephalomyelitis. These data indicate that sialic acid-modified antigens instruct DCs in an antigen-specific tolerogenic programming, enhancing Treg cells and reducing the generation and propagation of inflammatory T cells. Our data suggest that sialylation of antigens provides an attractive way to induce antigen-specific immune tolerance.
Asunto(s)
Adaptación Fisiológica/inmunología , Antígenos/inmunología , Proliferación Celular , Ácido N-Acetilneuramínico/química , Linfocitos T Reguladores/inmunología , Animales , Antígenos/química , Ratones , Ratones Endogámicos C57BL , Linfocitos T Reguladores/citologíaRESUMEN
Background: Carriage of Mycoplasma pneumoniae (Mp) in the nasopharynx is considered a prerequisite for pulmonary infection. It is interesting to note that Mp carriage is also detected after infection. Although B cells are known to be involved in pulmonary Mp clearance, their role in Mp carriage is unknown. Methods: In this study, we show in a mouse model that Mp persists in the nose after pulmonary infection, similar to humans. Results: Infection of mice enhanced Mp-specific immunoglobulin (Ig) M and IgG levels in serum and bronchoalveolar lavage fluid. However, nasal washes only contained elevated Mp-specific IgA. These differences in Ig compartmentalization correlated with differences in Mp-specific B cell responses between nose- and lung-draining lymphoid tissues. Moreover, transferred Mp-specific serum Igs had no effect on nasal carriage in B cell-deficient µMT mice, whereas this enabled µMT mice to clear pulmonary Mp infection. Conclusions: We report the first evidence that humoral immunity is limited in clearing Mp from the upper respiratory tract.
Asunto(s)
Linfocitos B/inmunología , Portador Sano/inmunología , Mycoplasma pneumoniae/inmunología , Nasofaringe/inmunología , Nasofaringe/microbiología , Neumonía por Mycoplasma/inmunología , Animales , Anticuerpos Antibacterianos/sangre , Inmunoglobulina A/análisis , Inmunoglobulina G/sangre , Ratones Endogámicos C57BL , Mucosa Nasal/inmunologíaRESUMEN
OBJECTIVE: Monogenic defects in the interleukin-10 (IL-10) pathway are extremely rare and cause infantile-onset inflammatory bowel disease (IBD)-like pathology. Understanding how immune responses are dysregulated in monogenic IBD-like diseases can provide valuable insight in "classical" IBD pathogenesis. Here, we studied long-term immune cell development and function in an adolescent IL-10 receptor (IL10RA)-deficient patient who presented in infancy with severe colitis and fistulizing perianal disease and is currently treated with immune suppressants. METHODS: Biomaterial was collected from the IL10RA-deficient patient, pediatric patients with IBD, and healthy controls. The frequency and phenotype of immune cells were determined in peripheral blood and intestinal biopsies by flow cytometry and immunohistochemistry. Functional changes in monocyte-derived dendritic cells and T cells were assessed by in vitro activation assays. RESULTS: The IL10RA-deficient immune system developed normally with respect to numbers and phenotype of circulating immune cells. Despite normal co-stimulatory molecule expression, bacterial lipopolysaccharide-stimulated monocyte-derived dendritic cells from the IL10RA-deficient patient released increased amounts of tumor necrosis factor α compared to healthy controls. Upon T-cell receptor ligation, IL10RA-deficient peripheral blood mononuclear cells released increased amounts of T-cell cytokines interferon γ and IL-17 agreeing with high numbers of T-bet and IL-17 cells in intestinal biopsies taken at disease onset. In vitro, the immunosuppressive drug thalidomide used to treat the patient's decreased peripheral blood mononuclear cell-derived tumor necrosis factor production. CONCLUSIONS: With time and during immunosuppressive treatment the IL10RA-deficient immune system develops relatively normally. Upon activation, IL-10 is crucial for controlling excessive inflammatory cytokine release by dendritic cells and preventing interferon γ and IL-17-mediated T-cell responses.
Asunto(s)
Inmunidad Adaptativa/fisiología , Células Dendríticas/metabolismo , Inmunidad Innata/fisiología , Enfermedades Inflamatorias del Intestino/inmunología , Subunidad alfa del Receptor de Interleucina-10/deficiencia , Subgrupos de Linfocitos T/metabolismo , Adolescente , Adulto , Biomarcadores/metabolismo , Estudios de Casos y Controles , Niño , Preescolar , Codón sin Sentido , Femenino , Mutación del Sistema de Lectura , Marcadores Genéticos , Humanos , Lactante , Enfermedades Inflamatorias del Intestino/genética , Subunidad alfa del Receptor de Interleucina-10/genética , Masculino , Persona de Mediana EdadRESUMEN
OBJECTIVE: Guillain-Barré syndrome (GBS) is a postinfectious neuropathy most frequently caused by Campylobacter jejuni. Lipo-oligosaccharides (LOS), expressed by C. jejuni induce antibodies that cross-react with self-glycolipids in peripheral nerves, causing neuropathy. Less than 1 in 1,000 persons infected with C. jejuni develop GBS, and the factors that determine GBS susceptibility are poorly understood. We hypothesized that these persons have a high intrinsic dendritic cell (DC) response to C. jejuni LOS through Toll-like receptor 4 (TLR4) activation. METHODS: Intrinsic DC responsiveness to C. jejuni LOS was investigated first in 20 healthy controls at three time points with a 3-month interval, and second in patients, who previously developed GBS after a C. jejuni infection (n = 27) and controls (n = 26). RESULTS: The DC response to C. jejuni LOS was highly variable between, but not within, healthy individuals, suggesting that intrinsic factors determine the magnitude of TLR4-mediated innate response. High responsiveness to C. jejuni LOS by former GBS patients was evidenced by increased expression of CD38 and CD40. Frequency of CD38, CD40 and type I interferon high responders was significantly increased in the GBS group. INTERPRETATION: These results suggest that a strong response to TLR4 stimulation is a critical host condition for the development of GBS after an infection with C. jejuni.
Asunto(s)
Infecciones por Campylobacter/inmunología , Campylobacter jejuni/inmunología , Células Dendríticas/inmunología , Síndrome de Guillain-Barré/inmunología , Inmunidad Innata/inmunología , Receptor Toll-Like 4/inmunología , Adulto , Anciano , Anciano de 80 o más Años , Infecciones por Campylobacter/diagnóstico , Infecciones por Campylobacter/epidemiología , Femenino , Estudios de Seguimiento , Síndrome de Guillain-Barré/diagnóstico , Síndrome de Guillain-Barré/epidemiología , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The intestinal influx oligopeptide transporter peptide transporter 1 (PEPT1) (SLC15A1) is best known for nutrient-derived di- and tripeptide transport. Its role in drug absorption is increasingly recognized. To better understand the disposition of PEPT1 substrate drugs in young infants, we studied intestinal PEPT1 mRNA expression and tissue localization across the pediatric age range. PEPT1 mRNA expression was determined using real-time reverse-transcription polymerase chain reaction in small intestinal tissues collected from surgical procedures (neonates and infants) or biopsies (older children and adolescents). PEPT1 mRNA relative to villin mRNA expression was compared between neonates/infants and older children/adolescents. PEPT1 was visualized in infant tissue using immunohistochemical staining. Other transporters [multidrug resistance protein 1 (MDR1), multidrug resistance-like protein 2 (MRP2), and organic anion transporter polypeptide 2B1 (OATP2B1)] were also stained to describe the localization in relation to PEPT1. Twenty-six intestinal samples (n = 20 neonates/infants, n = 2 pediatric, n = 4 adolescents) were analyzed. The young infant samples were collected at a median (range) gestational age at birth of 29.2 weeks (24.7-40) and postnatal age of 2.4 weeks (0-16.6). The PEPT1 mRNA expression of the neonates/infants was only marginally lower (0.8-fold) than the older children (P < 0.05). Similar and clear apical PEPT1 and MRP2 staining, apical and lateral MDR1 staining, and intraepithelial OATP2B1 staining at the basolateral membrane of the enterocyte were detected in 12 infant and 2 adolescent samples. Although small intestinal PEPT1 expression tended to be lower in neonates than in older children, this difference is small and tissue distribution is similar. This finding suggests similar oral absorption of PEPT1 substrates across the pediatric age range.
Asunto(s)
Recien Nacido Prematuro , Intestino Delgado/metabolismo , Transportador de Péptidos 1/metabolismo , Nacimiento Prematuro , Nacimiento a Término , Subfamilia B de Transportador de Casetes de Unión a ATP/metabolismo , Adolescente , Factores de Edad , Niño , Preescolar , Enterocitos/metabolismo , Femenino , Regulación del Desarrollo de la Expresión Génica , Edad Gestacional , Humanos , Lactante , Recién Nacido , Masculino , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Transportadores de Anión Orgánico/metabolismo , Transportador de Péptidos 1/genética , ARN Mensajero/genética , ARN Mensajero/metabolismoRESUMEN
OBJECTIVE: Repetitive interaction with microbial stimuli renders epithelial cells (ECs) hyporesponsive to microbial stimulation. Previously, we have reported that buccal ECs from a subset of paediatric patients with Crohn's disease are not hyporesponsive and spontaneously released chemokines. We now aimed to identify kinetics and mechanisms of acquisition of hyporesponsiveness to microbial stimulation using primary human buccal epithelium. DESIGN: Buccal ECs collected directly after birth and in later stages of life were investigated. Chemokine release and regulatory signalling pathways were studied using primary buccal ECs and the buccal EC line TR146. Findings were extended to the intestinal mucosa using murine model systems. RESULTS: Directly after birth, primary human buccal ECs spontaneously produced the chemokine CXCL-8 and were responsive to microbial stimuli. Within the first weeks of life, these ECs attained hyporesponsiveness, associated with inactivation of the NF-κB pathway and upregulation of the novel NF-κB inhibitor SLPI but no other known NF-κB inhibitors. SLPI protein was abundant in the cytoplasm and the nucleus of hyporesponsive buccal ECs. Knock-down of SLPI in TR146-buccal ECs induced loss of hyporesponsiveness with increased NF-κB activation and subsequent chemokine release. This regulatory mechanism extended to the intestine, as colonisation of germfree mice elicited SLPI expression in small intestine and colon. Moreover, SLPI-deficient mice had increased chemokine expression in small intestinal and colonic ECs. CONCLUSIONS: We identify SLPI as a new player in acquisition of microbial hyporesponsiveness by buccal and intestinal epithelium in the first weeks after microbial colonisation.
Asunto(s)
Envejecimiento/inmunología , Epitelio/inmunología , Epitelio/microbiología , Mucosa Bucal/citología , Mucosa Bucal/microbiología , Inhibidor Secretorio de Peptidasas Leucocitarias/metabolismo , Adulto , Animales , Células Cultivadas , Quimiocina CXCL2/metabolismo , Regulación hacia Abajo , Epitelio/metabolismo , Técnicas de Silenciamiento del Gen , Humanos , Tolerancia Inmunológica , Lactante , Recién Nacido , Interleucina-8/metabolismo , Mucosa Intestinal/citología , Mucosa Intestinal/microbiología , Ratones , Persona de Mediana Edad , FN-kappa B/metabolismo , Peptidoglicano/farmacologíaRESUMEN
Campylobacter jejuni is the most common bacterial cause of human gastroenteritis and often precedes development of Guillain-Barré syndrome (GBS), a life-threatening paralytic disease. The incorporation of the carbohydrate sialic acid into C. jejuni lipooligosaccharides (LOS) is associated with increased severity of gastroenteritis and with induction of GBS; however, the underlying mechanisms remain completely unknown. In this study, we demonstrate that sialic acids in C. jejuni endotoxin enhance the rapid production of IFN-ß and TNF-α by human dendritic cells (DCs). Using neutralizing Abs and receptors it was shown that these DC-derived cytokines promote the proliferation of human mucosal B cells in a T cell-independent manner. The production of both IFN-ß and TNF-α by DCs in response to LOS requires CD14, and the amplified response of DCs to sialylated C. jejuni LOS is CD14 dependent. Together, these results indicate that sialylation of C. jejuni LOS increases DC activation and promotes subsequent B cell responses through CD14-driven production of IFN-ß and TNF-α. This enhanced DC/B cell response may explain the increased pathogenicity of sialylated C. jejuni and may be key to the initiation of B cell-mediated autoimmunity in GBS.
Asunto(s)
Linfocitos B/inmunología , Infecciones por Campylobacter/inmunología , Campylobacter jejuni/inmunología , Células Dendríticas/inmunología , Gastroenteritis/inmunología , Síndrome de Guillain-Barré/inmunología , Infecciones por Campylobacter/complicaciones , Células Cultivadas , Células Dendríticas/microbiología , Endotoxinas/química , Endotoxinas/inmunología , Gastroenteritis/etiología , Síndrome de Guillain-Barré/etiología , Humanos , Interferón beta/metabolismo , Mucosa Intestinal/patología , Receptores de Lipopolisacáridos/metabolismo , Activación de Linfocitos , Ácido N-Acetilneuramínico/química , Ácido N-Acetilneuramínico/inmunología , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Many drugs prescribed to children are drug transporter substrates. Drug transporters are membrane-bound proteins that mediate the cellular uptake or efflux of drugs and are important to drug absorption and elimination. Very limited data are available on the effect of age on transporter expression. Our study assessed age-related gene expression of hepatic and intestinal drug transporters. Multidrug resistance protein 2 (MRP2), organic anion transporting polypeptide 1B1 (OATP1B1), and OATP1B3 expression was determined in postmortem liver samples (fetal n = 6, neonatal n = 19, infant n = 7, child n = 2, adult n = 11) and multidrug resistance 1 (MDR1) expression in 61 pediatric liver samples. Intestinal expression of MDR1, MRP2, and OATP2B1 was determined in surgical small bowel samples (neonates n = 15, infants n = 3, adults n = 14). Using real-time reverse-transcription polymerase chain reaction, we measured fetal and pediatric gene expression relative to 18S rRNA (liver) and villin (intestines), and we compared it with adults using the 2(-∆∆Ct) method. Hepatic expression of MRP2, OATP1B1, and OATP1B3 in all pediatric age groups was significantly lower than in adults. Hepatic MDR1 mRNA expression in fetuses, neonates, and infants was significantly lower than in adults. Neonatal intestinal expressions of MDR1 and MRP2 were comparable to those in adults. Intestinal OATP2B1 expression in neonates was significantly higher than in adults. We provide new data that show organ- and transporter-dependent differences in hepatic and intestinal drug transporter expression in an age-dependent fashion. This suggests that substrate drug absorption mediated by these transporters may be subject to age-related variation in a transporter dependent pattern.
Asunto(s)
Expresión Génica/genética , Mucosa Intestinal/metabolismo , Hígado/metabolismo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Adolescente , Adulto , Transporte Biológico/genética , Niño , Preescolar , Femenino , Ontología de Genes , Humanos , Lactante , Recién Nacido , Transportador 1 de Anión Orgánico Específico del Hígado , Masculino , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Transportadores de Anión Orgánico/genética , Transportadores de Anión Orgánico/metabolismo , Transportadores de Anión Orgánico Sodio-Independiente/genética , Transportadores de Anión Orgánico Sodio-Independiente/metabolismo , Miembro 1B3 de la Familia de los Transportadores de Solutos de Aniones OrgánicosRESUMEN
OBJECTIVES: We report on the therapeutic management of early-onset severe neurologic symptoms in cytotoxic T lymphocyte antigen-4 haploinsufficiency (CTLA-4h) and the presence of antibodies to the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) as an important finding. METHODS: This is a case report from a Dutch academic hospital. Repeated clinical examinations, repeated brain MRI and extended diagnostics on serum and CSF were performed. We used the CARE checklist. RESULTS: A 7-year-old boy was diagnosed with CTLA-4h based on family screening. On diagnosis, he had mild chronic diarrhea and autism spectrum disorder, but no abnormalities in extensive laboratory screening. Six months later, he presented with sudden-onset autoimmune encephalitis. Repeated brain MRI revealed no abnormalities, but immunohistochemistry analysis on serum and CSF showed the presence of AMPAR antibodies. Treatment was initially focused on immunomodulation and targeted CTLA-4 replacement therapy. Because of the persistent fluctuating cerebellar and neuropsychiatric symptoms and the potential clinical significance of the AMPAR antibodies, treatment was intensified with repetition of first-line immunomodulation and rituximab. This combined therapy resulted in sustained clinical improvement and served as a bridge to curative hematopoietic stem cell transplantation. DISCUSSION: This case illustrates the rare early onset of autoimmune encephalitis and presence of AMPAR antibodies in CTLA-4h. Targeted CTLA-4 replacement therapy resulted in a partial response. However, awaiting its optimal therapeutic effect, refractory CNS symptoms required intensification of immunomodulation. The identification of AMPAR antibodies guided our treatment decisions. CLASSIFICATION OF EVIDENCE: This provides Class IV evidence. It is a single observational study without controls.
Asunto(s)
Autoanticuerpos , Antígeno CTLA-4 , Encefalitis , Haploinsuficiencia , Enfermedad de Hashimoto , Receptores AMPA , Humanos , Masculino , Niño , Encefalitis/diagnóstico , Encefalitis/tratamiento farmacológico , Encefalitis/inmunología , Enfermedad de Hashimoto/diagnóstico , Enfermedad de Hashimoto/tratamiento farmacológico , Autoanticuerpos/sangre , Autoanticuerpos/líquido cefalorraquídeo , Receptores AMPA/inmunología , Rituximab/administración & dosificación , Rituximab/uso terapéutico , Factores InmunológicosRESUMEN
Molecular mimicry between Campylobacter jejuni sialylated lipooligosaccharides (LOS) and human nerve gangliosides can trigger the production of cross-reactive antibodies which induce Guillain-Barré syndrome (GBS). To better understand the immune events leading to GBS, it is essential to know how sialylated LOS are recognized by the immune system. Here, we show that GBS-associated C. jejuni strains bind to human sialoadhesin (hSn), a conserved, mainly macrophage-restricted I-type lectin. Using hSn-transduced THP-1 cells, we observed that C. jejuni strains with α(2,3)-sialylated LOS, including strains expressing GM1a- and GD1a-like epitopes, bind to hSn. This observation is of importance, as these epitopes are frequently the targets of the cross-reactive antibodies detected in GBS patients. Interestingly, the Sn binding domains were not constitutively exposed on the surface of C. jejuni. Heat inactivation and the environmental conditions which food-borne C. jejuni encounters during its passage through the intestinal tract, such as low pH and contact with bile constituents, exposed LOS and facilitated Sn binding. Sn binding enhanced bacterial uptake and increased the production of interleukin-6 (IL-6) by primary human Sn-expressing monocyte-derived macrophages compared to control conditions, where Sn was blocked using neutralizing antibodies or when nonsialylated C. jejuni was used. Sn-mediated uptake has been reported to enhance humoral immune responses. As C. jejuni strains expressing ganglioside mimics GD1a and GM1a are closely associated with GBS, Sn binding may be a determining event in the production of cross-reactive antibodies and the development of GBS.
Asunto(s)
Campylobacter jejuni/inmunología , Síndrome de Guillain-Barré/microbiología , Macrófagos/microbiología , Lectina 1 Similar a Ig de Unión al Ácido Siálico/metabolismo , Anticuerpos Antibacterianos/biosíntesis , Anticuerpos Antibacterianos/inmunología , Adhesión Bacteriana , Campylobacter jejuni/clasificación , Campylobacter jejuni/metabolismo , Células Cultivadas , Reacciones Cruzadas , Gangliósidos/química , Gangliósidos/inmunología , Síndrome de Guillain-Barré/inmunología , Humanos , Interferón-alfa/inmunología , Interleucina-6/metabolismo , Lipopolisacáridos/química , Lipopolisacáridos/inmunología , Imitación Molecular/inmunología , Fagocitosis , Lectina 1 Similar a Ig de Unión al Ácido Siálico/inmunologíaRESUMEN
IL-12 and IL-23 are heterodimeric cytokines involved in the induction of Th1 and Th17 immune responses. Previous work indicated that a region on chromosome 11 encoding the IL-12p40 subunit regulates strain differences in susceptibility to murine trinitrobenzene sulfonic acid-induced colitis. In addition, this region determines strain differences in LPS-induced IL-12 responses. In this study, we investigated how polymorphisms in the coding region of murine Il12b influence IL-12 and IL-23 heterodimer formation. Transfection studies using constructs containing IL-12p35 linked to IL-12p40 from the colitis-resistant C57BL/6 strain or to the polymorphic p40 variant from the colitis-susceptible SJL/J strain demonstrated that SJL/J-derived p40 constructs synthesized significantly more IL-12p70 than did constructs harboring the C57BL/6-p40 variant. This could not be attributed to differences in synthesis rate or secretion, implicating a greater affinity of SJL/J-derived IL-12p40 for its IL-12p35 subunit. This greater affinity is also associated with increased IL-23 synthesis. In addition, C57BL/6 mice transgenic for the SJL/J 40 variant synthesized significantly more IL-12p70 upon LPS challenge and were more prone to develop colonic inflammation than did C57BL/6 mice transgenic for the C57BL/6-p40 variant. The more efficient binding of the polymorphic Il12b variant to p35 and p19 is most likely due to conformational changes following differential glycosylation as a consequence of the polymorphism. The high synthesis rate of the mature cytokines resulting from this efficient binding can lead to rapid proinflammatory skewing of immune responses and distortion of the homeostatic balance underlying the greater susceptibility for colitis.
Asunto(s)
Codón/inmunología , Colitis/inmunología , Subunidad p40 de la Interleucina-12/genética , Interleucina-23/genética , Polimorfismo Genético/inmunología , Multimerización de Proteína/genética , Multimerización de Proteína/inmunología , Sustitución de Aminoácidos/genética , Sustitución de Aminoácidos/inmunología , Animales , Línea Celular Tumoral , Colitis/genética , Colitis/metabolismo , Modelos Animales de Enfermedad , Femenino , Predisposición Genética a la Enfermedad , Variación Genética/inmunología , Inmunidad Innata/genética , Subunidad p40 de la Interleucina-12/química , Subunidad p40 de la Interleucina-12/metabolismo , Interleucina-23/biosíntesis , Interleucina-23/química , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Unión Proteica/genética , Unión Proteica/inmunología , Procesamiento Proteico-Postraduccional/genética , Procesamiento Proteico-Postraduccional/inmunologíaRESUMEN
BACKGROUND: Despite its efficacy, rational guidance for starting/stopping first-line biologic treatment in individual paediatric Crohn's disease [CD] patients is needed. We assessed how serum immune profiles before and after first-line infliximab [FL-IFX] or conventional [CONV] induction therapy associate with disease remission at week 52. METHODS: Pre- [nâ =â 86], and 10-14-week post-treatment [nâ =â 84] sera were collected from patients with moderate-to-severe paediatric CD in the TISKids trial, randomized to FL-IFX [nâ =â 48; five 5-mg/kg infusions over 22 weeks] or CONV [nâ =â 43; exclusive enteral nutrition or oral prednisolone]; both groups received azathioprine maintenance. The relative concentrations of 92 inflammatory proteins were determined with Olink Proteomics; fold changes [FC] with |log2FC| > 0.5 after false discovery rate adjustment were considered significant. RESULTS: FL-IFX modulated a larger number of inflammatory proteins and induced stronger suppression than CONV; 18/30 proteins modulated by FL-IFX were not regulated by CONV. Hierarchical clustering based on IFX-modulated proteins at baseline revealed two clusters of patients: CD-hi patients had significantly higher concentrations of 23/30 IFX-modulated proteins [including oncostatin-M, TNFSF14, HGF and TGF-α], and higher clinical disease activity, C-reactive protein and blood neutrophils at baseline than CD-lo patients. Only 24% of CD-hi FL-IFX-treated patients maintained remission without escalation at week 52 vs 58% of CD-lo FL-IFX-treated patients. Similarly, 6% of CD-hi CONV-treated patients achieved remission vs 20% of CONV-treated CD-lo patients. Clustering based on immune profiles post-induction therapy did not relate to remission at week 52. CONCLUSION: FL-IFX leads to stronger reductions and modulates more immune proteins than CONV. Stratification on pre-treatment profiles of IFX-modulated proteins directly relates to maintenance of remission without treatment escalation. TRIAL REGISTRATION NUMBER: NCT02517684.
Asunto(s)
Enfermedad de Crohn , Niño , Humanos , Infliximab/uso terapéutico , Enfermedad de Crohn/metabolismo , Azatioprina/uso terapéutico , Proteína C-Reactiva , Inducción de Remisión , Resultado del Tratamiento , Fármacos Gastrointestinales/uso terapéuticoRESUMEN
The cytokine interleukin-23 (IL-23) is involved in the pathogenesis of inflammatory and autoimmune conditions including inflammatory bowel disease (IBD). IL23R is enriched in intestinal Tregs, yet whether IL-23 modulates intestinal Tregs remains unknown. Here, investigating IL-23R signaling in Tregs specifically, we show that colonic Tregs highly express Il23r compared with Tregs from other compartments and their frequency is reduced upon IL-23 administration and impairs Treg suppressive function. Similarly, colonic Treg frequency is increased in mice lacking Il23r specifically in Tregs and exhibits a competitive advantage over IL-23R-sufficient Tregs during inflammation. Finally, IL-23 antagonizes liver X receptor pathway, cellular cholesterol transporter Abca1, and increases Treg apoptosis. Our results show that IL-23R signaling regulates intestinal Tregs by increasing cell turnover, antagonizing suppression, and decreasing cholesterol efflux. These results suggest that IL-23 negatively regulates Tregs in the intestine with potential implications for promoting chronic inflammation in patients with IBD.
Asunto(s)
Colitis , Enfermedades Inflamatorias del Intestino , Animales , Humanos , Ratones , Colitis/patología , Factores de Transcripción Forkhead/metabolismo , Inflamación/patología , Enfermedades Inflamatorias del Intestino/patología , Interleucina-23/metabolismo , Linfocitos T ReguladoresRESUMEN
BACKGROUND & AIMS: Patients with celiac disease have permanent intolerance to gluten. Because of the high frequency of this disorder (approximately 1 in 100 individuals), we investigated whether oral tolerance to gluten differs from that to other food proteins. METHODS: Using transgenic mice that express human HLA-DQ2 and a gliadin-specific, humanized T-cell receptor, we compared gluten-specific T-cell responses with tolerogenic mucosal T-cell responses to the model food protein ovalbumin. RESULTS: Consistent with previous findings, the ovalbumin-specific response occurred in the mesenteric lymph nodes and induced Foxp3(+) regulatory T cells. In contrast, ingestion of deamidated gliadin induced T-cell proliferation predominantly in the spleen but little in mesenteric lymph nodes. The gliadin-reactive T cells had an effector-like phenotype and secreted large amounts of interferon gamma but also secreted interleukin-10. Despite their effector-like phenotype, gliadin-reactive T cells had regulatory functions, because transfer of the cells suppressed a gliadin-induced, delayed-type hypersensitivity response. CONCLUSIONS: Ingestion of deamidated gliadin induces differentiation of tolerogenic, type 1 regulatory T cells in spleens of HLA-DQ2 transgenic mice. These data indicate that under homeostatic conditions, the T-cell response to deamidated gliadin is tolerance, which is not conditioned by the mucosal immune system but instead requires interleukin-10 induction by antigen presentation in the spleen.
Asunto(s)
Gliadina/inmunología , Tolerancia Inmunológica/inmunología , Bazo/inmunología , Linfocitos T Reguladores/inmunología , Animales , Quimiocina CCL2/metabolismo , Factores de Transcripción Forkhead/inmunología , Gliadina/farmacología , Antígenos HLA-DQ/genética , Antígenos HLA-DQ/inmunología , Antígenos HLA-DQ/metabolismo , Interferón gamma/metabolismo , Interleucina-1/metabolismo , Interleucina-10/metabolismo , Interleucina-12/metabolismo , Ganglios Linfáticos/inmunología , Mesenterio , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Ovalbúmina/inmunología , Bazo/efectos de los fármacos , Linfocitos T Reguladores/metabolismo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
Chronic inflammatory T-cell-mediated diseases such as inflammatory bowel disease (IBD) are often treated with immunosuppressants including corticosteroids. In addition to the intended T-cell suppression, these farmacons give rise to many side effects. Recently, immunosuppressive phospholipids have been proposed as less-toxic alternatives. We aimed to investigate the immunoregulatory capacities of the naturally occurring phospholipid phosphatidylinositol (PI). Systemic PI treatment dramatically reduced disease severity and intestinal inflammation in murine 2,4,6-trinitrobenzene sulfonic acid (TNBS) colitis. Moreover, PI treatment inhibited the inflammatory T-cell response in these mice, as T cells derived from colon-draining LN of PI-treated mice secreted less IL-17 and IFN-γ upon polyclonal restimulation when compared to those of saline-treated mice. Further characterization of the suppressive capacity of PI revealed that the phospholipid suppressed Th cell differentiation in vitro irrespective of their cytokine profile by inhibiting proliferation and IL-2 release. In particular, PI diminished IL-2 mRNA expression and inhibited ERK1-, ERK-2-, p38- and JNK-phosphorylation. Crucially, PI did not ablate Treg differentiation or the antigen-presenting capacity of DCs in vitro. These data validate PI as a pluripotent inhibitor that can be applied mucosally as well as systemically. Its compelling functions render PI a promising novel physiological immune suppressant.