Serum calprotectin (S100A8/A9): a promising biomarker in diagnosis and follow-up in different subgroups of juvenile idiopathic arthritis.

INTRODUCTION: In the management of juvenile idiopathic arthritis (JIA), there is a lack of diagnostic and prognostic biomarkers. This study assesses the use of serum calprotectin (sCal) as a marker to monitor disease activity, and as a classification and prognosis tool of response to treatment or risk of flares in patients with JIA. METHODS: Eighty-one patients with JIA from the CAP48 multicentric cohort were included in this study, as well as 11 non-paediatric healthy controls. An ELISA method was used to quantify sCal with a commercial kit. RESULTS: Patients with an active disease compared with healthy controls and with patients with inactive disease showed an eightfold and a twofold increased level of sCal, respectively. sCal was found to be correlated with the C-reactive protein (CRP) and even more strongly with the erythrocyte sedimentation rate. Evolution of DAS28 scores correlated well with evolution of sCal, as opposed to evolution of CRP. With regard to CRP, sCal could differentiate forms with active oligoarthritis from polyarthritis and systemic forms. However, sCal brought an added value compared with the CRP as a prognosis marker. Indeed, patients with active disease and reaching minimal disease activity (according to Juvenile Arthritis Disease Activity Score) at 6 months following the test had higher sCal levels, while patients with inactive disease had higher sCal levels if a flare was observed up to 3-9 months following the test. CONCLUSIONS: This study confirms the potential uses of sCal as a biomarker in the diagnosis and follow-up of JIA.

CD8 Binding of MHC-Peptide Complexes in cis or trans Regulates CD8+ T-cell Responses.

The coreceptor CD8αß can greatly promote activation of T cells by strengthening T-cell receptor (TCR) binding to cognate peptide-MHC complexes (pMHC) on antigen presenting cells and by bringing p56Lck to TCR/CD3. Here, we demonstrate that CD8 can also bind to pMHC on the T cell (in cis) and that this inhibits their activation. Using molecular modeling, fluorescence resonance energy transfer experiments on living cells, biochemical and mutational analysis, we show that CD8 binding to pMHC in cis involves a different docking mode and is regulated by posttranslational modifications including a membrane-distal interchain disulfide bond and negatively charged O-linked glycans near positively charged sequences on the CD8ß stalk. These modifications distort the stalk, thus favoring CD8 binding to pMHC in cis. Differential binding of CD8 to pMHC in cis or trans is a means to regulate CD8+ T-cell responses and provides new translational opportunities.

Rapid and Sustained Long-Term Efficacy and Safety of Canakinumab in Patients With Cryopyrin-Associated Periodic Syndrome Ages Five Years and Younger.

OBJECTIVE: To assess long-term efficacy and safety of canakinumab and the response to vaccination in children ages ≤5 years with cryopyrin-associated periodic syndrome (CAPS). METHODS: CAPS patients (ages ≤5 years) received 2 mg/kg canakinumab subcutaneously every 8 weeks; patients with neonatal-onset multisystem inflammatory disease (NOMID) received a starting dose of 4 mg/kg in this open-label trial. Efficacy was evaluated using physician global assessment of disease activity and serum levels of C-reactive protein (CRP) and amyloid A (SAA). Adverse events (AEs) were recorded. Vaccination response was evaluated using postvaccination antibody titers at 4 and 8 weeks after immunization. RESULTS: Of the 17 patients enrolled, 12 (71%) had Muckle-Wells syndrome, 4 (24%) had NOMID, and 1 (6%) had familial cold autoinflammatory syndrome. All 17 patients had a complete response to canakinumab. Disease activity improved according to the physician global assessment, and for 65% of the patients autoinflammatory disease was characterized as "absent" at the end of the study. Median CRP levels decreased over time. No such change was evident in SAA levels. During the extension study, postvaccination antibody titers increased above protective levels in 16 (94%) of 17 assessable vaccinations. Ten of the patients (59%) had AEs suspected to be related to canakinumab; 8 (47%) experienced at least 1 serious AE (SAE). None of the AEs or SAEs required interruption of canakinumab therapy. CONCLUSION: Our findings indicate that canakinumab effectively maintains efficacy through 152 weeks and appears to have no effect on the ability to produce antibodies against standard childhood non-live vaccines. The safety profile of canakinumab was consistent with previous studies, supporting long-term use of canakinumab for CAPS in children ≤5 years of age.

Imaging of Juvenile Idiopathic Arthritis.

Juvenile idiopathic arthritis is an umbrella term covering several distinct categories that share common features. The European League Against Rheumatism and the Pediatric Rheumatology European Society have published a consensus article with recommendations to guide radiologists and clinicians in choosing the best imaging technique for each particular clinical setting. A reproducible, accurate, validated, and long-established scoring system to use in everyday practice for monitoring and predicting long-term response to therapy is still to be developed on MR imaging for each joint.

Discovery and characterization of a novel humanized anti-IL-15 antibody and its relevance for the treatment of refractory celiac disease and eosinophilic esophagitis.

Interleukin-15 (IL-15) is a critical regulator of immune responses, especially at mucosal interfaces within the gastro-intestinal tract. Here, we describe the discovery and characterization of a humanized antibody to IL-15. Data from its epitope and mode of action, cell biology and primate pharmacology, as well as translational studies in human samples and in vivo proof-of-concept experiments in mouse models demonstrate the therapeutic potential of this new antibody targeting IL-15 for refractory celiac disease and eosinophilic esophagitis.

Anti-MMP-9 Antibody: A Promising Therapeutic Strategy for Treatment of Inflammatory Bowel Disease Complications with Fibrosis.

BACKGROUND: Despite medical treatments or surgical options, more than one-third of patients with Crohn's disease suffer from recurring fistulae. Matrix metalloprotease 9 (MMP-9), a type IV collagenase that cleaves components of the extracellular matrix leading to tissue remodeling, is upregulated in crypt abscesses and around fistulae suggesting an important role for this enzyme in fistula formation. Our aims were (1) to correlate serum levels of MMP-9 degradation products in patients with CD with the presence of fistulae and (2) to investigate the impact of selective MMP-9 inhibition in a mouse model of intestinal fibrosis. METHODS: Serum MMP-9 degradation products were quantified in subjects affected with nonstricturing and nonpenetrating CD (n = 50), stricturing CD (n = 41), penetrating CD (n = 22), CD with perianal fistula (n = 29), and healthy controls (n = 10). Therapeutic efficacy of anti-MMP-9 monoclonal antibodies was assessed in a heterotopic xenograft model of intestinal fibrosis. RESULTS: C3M, an MMP-9 degradation product of collagen III, demonstrated the highest serum levels in patients with penetrating CD and differentiated penetrating CD from other CD subgroups and healthy controls, P = 0.0005. Anti-MMP-9 treatments reduced collagen deposition and hydroxyproline content in day-14 intestinal grafts indicating reduced fibrosis. CONCLUSIONS: The serologic biomarker C3M can discriminate penetrating CD from other CD subgroups and could serve as marker for the development of penetrating CD. Anti-MMP-9 antibody has therapeutic potential to prevent intestinal fibrosis in CD complications.

Protective effect of TSLP delivered at the gut mucosa level by recombinant lactic acid bacteria in DSS-induced colitis mouse model.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) is a cytokine known to mature dendritics cells, lower pro-inflammatory IL-12 secretion, induce differentiation of anti-inflammatory FoxP3+ regulatory T cells (Treg). Moreover, Crohn's disease patients have shown a reduction of intestinal TSLP expression. To understand the role of TSLP in inflammation, we constructed Lactococcus lactis strain producing TSLP (LL-TSLP) and investigated the effect of its administration on dextran sulfate sodium (DSS)-induced colitis model in mice. RESULTS: LL-TSLP secrete an active molecule which lowers secretion of IL-12 by dendritic cells. Treatment with LL-TSLP, increases the amount of TGF-ß secreted by T cells in Mesenteric Lymph Node in healthy mice. In acute DSS-induced colitis, LL-TSLP delayed the Disease Activity Index and lowered histological score and colonic INF-γ production. In a DSS-recovery model, LL-TSLP induced a better protective effect if the strain was administered at the beginning of the colitis. At Day 4 of colitis we observed an induction of Treg by LL-TSLP. CONCLUSIONS: TSLP showed an anti-inflammatory protective role in DSS-induced colitis. We have demonstrated that a short and early administration of LL-TSLP is more efficient than a long lasting treatment.

Two randomized trials of canakinumab in systemic juvenile idiopathic arthritis.

BACKGROUND: Interleukin-1 is pivotal in the pathogenesis of systemic juvenile idiopathic arthritis (JIA). We assessed the efficacy and safety of canakinumab, a selective, fully human, anti-interleukin-1ß monoclonal antibody, in two trials. METHODS: In trial 1, we randomly assigned patients, 2 to 19 years of age, with systemic JIA and active systemic features (fever; ≥2 active joints; C-reactive protein, >30 mg per liter; and glucocorticoid dose, ≤1.0 mg per kilogram of body weight per day), in a double-blind fashion, to a single subcutaneous dose of canakinumab (4 mg per kilogram) or placebo. The primary outcome, termed adapted JIA ACR 30 response, was defined as improvement of 30% or more in at least three of the six core criteria for JIA, worsening of more than 30% in no more than one of the criteria, and resolution of fever. In trial 2, after 32 weeks of open-label treatment with canakinumab, patients who had a response and underwent glucocorticoid tapering were randomly assigned to continued treatment with canakinumab or to placebo. The primary outcome was time to flare of systemic JIA. RESULTS: At day 15 in trial 1, more patients in the canakinumab group had an adapted JIA ACR 30 response (36 of 43 [84%], vs. 4 of 41 [10%] in the placebo group; P<0.001). In trial 2, among the 100 patients (of 177 in the open-label phase) who underwent randomization in the withdrawal phase, the risk of flare was lower among patients who continued to receive canakinumab than among those who were switched to placebo (74% of patients in the canakinumab group had no flare, vs. 25% in the placebo group, according to Kaplan-Meier estimates; hazard ratio, 0.36; P=0.003). The average glucocorticoid dose was reduced from 0.34 to 0.05 mg per kilogram per day, and glucocorticoids were discontinued in 42 of 128 patients (33%). The macrophage activation syndrome occurred in 7 patients; infections were more frequent with canakinumab than with placebo. CONCLUSIONS: These two phase 3 studies show the efficacy of canakinumab in systemic JIA with active systemic features. (Funded by Novartis Pharma; ClinicalTrials.gov numbers, NCT00889863 and NCT00886769.).

Transcriptional regulation of matrix metalloproteinase-1 and collagen 1A2 explains the anti-fibrotic effect exerted by proteasome inhibition in human dermal fibroblasts.

INTRODUCTION: Extracellular matrix (ECM) turnover is controlled by the synthetic rate of matrix proteins, including type I collagen, and their enzymatic degradation by matrix metalloproteinases (MMPs). Fibrosis is characterized by an unbalanced accumulation of ECM leading to organ dysfunction as observed in systemic sclerosis. We previously reported that proteasome inhibition (PI) in vitro decreases type I collagen and enhances MMP-1 production by human fibroblasts, thus favoring an antifibrotic fibroblast phenotype. These effects were dominant over the pro-fibrotic phenotype induced by transforming growth factor (TGF)-beta. Here we investigate the molecular events responsible for the anti-fibrotic phenotype induced in fibroblasts by the proteasome inhibitor bortezomib. METHODS: The steady-state mRNA levels of COL1A1, COL1A2, TIMP-1, MMP-1, and MMP-2 were assessed by quantitative PCR in human dermal fibroblasts cultured in the presence of TGF-beta, bortezomib, or both. Transient fibroblast transfection was performed with wild-type and mutated COL1A1 and MMP-1 promoters. Chromatin immunoprecipitation, electrophoretic mobility shift assay (EMSA), and DNA pull-down assays were used to assess the binding of c-Jun, SP1, AP2, and Smad2 transcription factors. Immunoblotting and immunofluorescent microscopy were performed for identifying phosphorylated transcription factors and their cellular localization. RESULTS: Bortezomib decreased the steady-state mRNA levels of COL1A1 and COL1A2, and abrogated SP1 binding to the promoter of COL1A2 in both untreated and TGF-beta-activated fibroblasts. Reduced COL1A2 expression was not due to altered TGF-beta-induced Smad2 phosphorylation, nuclear translocation, or binding to the COL1A2 promoter. In contrast to collagen, bortezomib specifically increased the steady-state mRNA levels of MMP-1 and enhanced the binding of c-Jun to the promoter of MMP-1. Furthermore, disruption of the proximal AP-1-binding site in the promoter of MMP-1 severely impaired MMP-1 transcription in response to bortezomib. CONCLUSIONS: By altering the binding of at least two transcription factors, c-Jun and SP1, proteasome inhibition results in increased production of MMP-1 and decreased synthesis of type I collagen in human dermal fibroblasts. Thus, the antifibrotic phenotype observed in fibroblasts submitted to proteasome inhibition results from profound modifications in the binding of key transcription factors. This provides a novel rationale for assessing the potential of drugs targeting the proteasome for their anti-fibrotic properties.

Antifibroblast antibodies in systemic sclerosis induce fibroblasts to produce profibrotic chemokines, with partial exploitation of toll-like receptor 4.

OBJECTIVE: Previous studies have revealed the presence of IgG antifibroblast antibodies (AFAs) capable of binding to the surface of fibroblasts in systemic sclerosis (SSc) sera. Since chemokines may directly or indirectly affect the development of fibrosis, this study was undertaken to investigate the production of chemokines induced by AFAs in fibroblasts, and to characterize the signaling pathways and surface molecules involved. METHODS: AFA-positive and AFA-negative IgG were tested on fibroblasts. Chemokine messenger RNA expression was screened by microarray and quantitative reverse transcription-polymerase chain reaction. Production of CCL2, CXCL8, and CXCL10 proteins was assessed by enzyme-linked immunosorbent assay. Pharmacologic inhibitors were used to study signal transduction, with results assessed by Western blotting and immunofluorescence analysis. Fibroblasts with defective expression of Toll-like receptors (TLRs) and anti-TLR monoclonal antibodies (mAb) were used to assess AFA specificity. RESULTS: In human fibroblasts, AFA-positive IgG induced the preferential transcription of chemokines with profibrotic and proangiogenic potential, including, but not exclusively, CCL2, CXCL1, CXCL8, CKLF, and ECGF1, which were distinctly different from those induced by interferon-gamma. Levels of CCL2 and CXCL8 proteins were increased in AFA-stimulated fibroblast culture supernatants. AFA binding to fibroblasts resulted in concomitant activation of ERK-1/2, c-Jun, and NF-kappaB. CCL2 production was sensitive to inhibition of both proteasome and JNK, while CXCL8 production was sensitive only to inhibition of proteasome. AFAs failed to up-regulate CCL2 expression in TLR-4-deficient fibroblasts but not in TLR-6- or TLR-2-deficient fibroblasts. Moreover, anti-TLR-4 mAb, but not anti-TLR-2 mAb, partially inhibited the production of CCL2 induced by AFAs in human fibroblasts. CONCLUSION: Autoantibodies that bind to the surface of fibroblasts may contribute to the pathogenesis of SSc by up-regulating the fibroblast production of profibrotic and proangiogenic chemokines, in a proteasome- and TLR-4-dependent manner.

In vivo investigations on anti-fibrotic potential of proteasome inhibition in lung and skin fibrosis.

In systemic sclerosis (SSc), a disease characterized by fibrosis of the skin and internal organs, the occurrence of interstitial lung disease is responsible for high morbidity and mortality. We previously demonstrated that proteasome inhibitors (PI) show anti-fibrotic properties in vitro by reducing collagen production and favoring collagen degradation in a c-jun N-terminal kinase (JNK)-dependent manner in human fibroblasts. Therefore, we tested whether PI could control fibrosis development in bleomycin-induced lung injury, which is preceded by massive inflammation. We extended the study to test PI in TSK-1/+ mice, where skin fibrosis develops in the absence of overt inflammation. C57Bl/6 mice received bleomycin intratracheally and were treated or not with PI. Lung inflammation and fibrosis were assessed by histology and quantification of hydroxyproline content, type I collagen mRNA, and TGF-beta at Days 7, 15, and 21, respectively. Histology was used to detect skin fibrosis in TSK-1/+mice. The chymotryptic activity of 20S proteasome was assessed in mice blood. JNK and Smad2 phosphorylation were evaluated by Western blot on lung protein extracts. PI reduced collagen mRNA levels in murine lung fibroblasts, without affecting their viability in vitro. In addition, PI inhibited the chymotryptic activity of proteasome and enhanced JNK and TGF-beta signaling in vivo. PI failed to prevent bleomycin-induced lung inflammation and fibrosis and to attenuate skin fibrosis in TSK-1/+mice. In conclusion, our results provide direct evidence that, despite promising in vitro results, proteasome blockade may not be a strategy easily applicable to control fibrosis development in diseases such as lung fibrosis and scleroderma.

The unfolded protein response transducer Ire1p contains a nuclear localization sequence recognized by multiple beta importins.

The Ire1p transmembrane receptor kinase/endonuclease transduces the unfolded protein response (UPR) from the endoplasmic reticulum (ER) to the nucleus in Saccharomyces cerevisiae. In this study, we analyzed the capacity of a highly basic sequence in the linker region of Ire1p to function as a nuclear localization sequence (NLS) both in vivo and in vitro. This 18-residue sequence is capable of targeting green fluorescent protein to the nucleus of yeast cells in a process requiring proteins involved in the Ran GTPase cycle that facilitates nuclear import. Mutagenic analysis and importin binding studies demonstrate that the Ire1p linker region contains overlapping potential NLSs: at least one classical NLS (within sequences 642KKKRKR647 and/or 653KKGR656) that is recognized by yeast importin alpha (Kap60p) and a novel betaNLS (646KRGSRGGKKGRK657) that is recognized by several yeast importin beta homologues. Kinetic binding data suggest that binding to importin beta proteins would predominate in vivo. The UPR, and in particular ER stress-induced HAC1 mRNA splicing, is inhibited by point mutations in the Ire1p NLS that inhibit nuclear localization and also requires functional RanGAP and Ran GEF proteins. The NLS-dependent nuclear localization of Ire1p would thus seem to be central to its role in UPR signaling.

CD3 delta establishes a functional link between the T cell receptor and CD8.

T cells expressing T cell receptor (TCR) complexes that lack CD3 delta, either due to deletion of the CD3 delta gene, or by replacement of the connecting peptide of the TCR alpha chain, exhibit severely impaired positive selection and TCR-mediated activation of CD8 single-positive T cells. Because the same defects have been observed in mice expressing no CD8 beta or tailless CD8 beta, we examined whether CD3 delta serves to couple TCR.CD3 with CD8. To this end we used T cell hybridomas and transgenic mice expressing the T1 TCR, which recognizes a photoreactive derivative of the PbCS 252-260 peptide in the context of H-2K(d). We report that, in thymocytes and hybridomas expressing the T1 TCR.CD3 complex, CD8 alpha beta associates with the TCR. This association was not observed on T1 hybridomas expressing only CD8 alpha alpha or a CD3 delta(-) variant of the T1 TCR. CD3 delta was selectively co-immunoprecipitated with anti-CD8 antibodies, indicating an avid association of CD8 with CD3 delta. Because CD8 alpha beta is a raft constituent, due to this association a fraction of TCR.CD3 is raft-associated. Cross-linking of these TCR-CD8 adducts results in extensive TCR aggregate formation and intracellular calcium mobilization. Thus, CD3 delta couples TCR.CD3 with raft-associated CD8, which is required for effective activation and positive selection of CD8(+) T cells.