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AND KEY WORDSBackgroundOne therapeutic option with limited data among patients with active moderate-to-severe ulcerative colitis (UC) and Crohn’s disease (CD) despite biologic monotherapy is using a combination of a biologic with Tofacitinib (TBT). Our aim was to examine the effectiveness and safety of TBT in this subset of patients.MethodsData of IBD patients at 2 referral centers on TBT were extracted. The primary outcome was clinical response (>50% reduction in symptoms) at week 8 and/or 16 determined by Physician Global Assessment. Secondary outcome was clinical remission (resolution of symptoms), corticosteroid-free clinical response and remission, normalization of CRP and endoscopic/radiographic response and remission. Adverse events (AEs) including any abnormal lipid profile or surgical complications were also assessed.ResultsThirty-five patients (25UC, 10CD) were included. Biologics combined with tofacitinib were vedolizumab (68.6%), ustekinumab (17.1%), and infliximab (14.3%) and the median follow-up duration was 4 months. A majority (57.2%) had failed at least two biologics prior to starting TBT. At weeks 8 and/or 16, 37.1% achieved clinical response with 5.7% in clinical remission. Among the 23 patients with endoscopically/radiographically active disease at baseline, 56.5% had endoscopic/radiographic response and 34.8% achieved remission. Three AEs occurred in 2 (5.7%) patients, with an IR of 20.5 (15.0–47.2)/100PYF. No VTE and herpes zoster was reported.ConclusionsTBT is effective at inducing endoscopic/radiographic response and a modest clinical response in UC and CD patients with active clinical symptoms despite prior biologic monotherapy. No new safety signals were detected beyond those reported with tofacitinib monotherapy.

The safety and efficacy of tofacitinib in Crohn's disease (CD) has been studied in 2 phase II trials in patients with moderate-to-severe CD with no new safety signals observed, but no significant difference from placebo in the primary efficacy endpoint of clinical response.1-3 However, post hoc analyses and smaller studies have observed clinical and biologic response to tofacitinib in patients with CD.2,4,5 There is a paucity of real-world effectiveness and safety data for tofacitinib in non-Food and Drug Administration label usage in patients with CD and patients with inflammatory bowel disease-unclassified (IBD-U).

Background & Aims Adverse events (AEs) including reactivation of herpes zoster (HZ) and venous thromboembolism (VTE) have been reported from clinical trials of tofacitinib in ulcerative colitis (UC). We investigated the incidence rates of AEs in a real-world study of UC patients given tofacitinib. Methods We collected data from 260 patients with UC in the Tofacitinib Real-world Outcomes in Patients with ulceratIve colitis and Crohn’s disease consortium study, performed at 6 medical centers in the United States. Patients were followed up for a median of 6 months (interquartile range, 2.7–11.5 mo). AEs were captured using a standardized data collection instrument before study initiation and at weeks 8, 16, 26, 39, and 52. Serious AEs were defined as life-threatening or resulting in a hospitalization, disability, or discontinuation of therapy. Logistic regression was performed to examine risk factors for AEs. Results AEs occurred in 41 patients (15.7%); most were infections (N = 13; 5.0%). The incidence rate of any AE was 27.2 (95% CI, 24.4–30.7 per 100 patient-years of follow-up evaluation). Fifteen were serious AEs (36.6% of AEs), and tofacitinib was discontinued for 12 patients (4.6% of cohort). The incidence rates of serious AEs was 10.0 (95% CI, 8.9–11.2 per 100 patient-years of follow-up evaluation). Five patients developed HZ infection and 2 developed VTE (all receiving 10 mg tofacitinib, twice per day). Conclusions Real-world safety signals for tofacitinib are similar to those for clinical trials, with AEs reported from almost 16% of patients. HZ infection and VTE occurred in patients receiving 10 mg tofacitinib twice per day. These results support dose de-escalation after induction therapy, to reduce the risk of AEs.

Background and Aims Inflammation of the pouch after ileal pouch-anal anastomosis (IPAA) can significantly impact quality of life and be difficult to treat. We assessed the effectiveness and safety of vedolizumab in Crohn’s disease (CD) of the pouch and chronic antibiotic-dependent or antibiotic-refractory pouchitis. Methods This was a retrospective, multicenter cohort study at 5 academic referral centers in the United States. Adult patients with endoscopic inflammation of the pouch who received vedolizumab were included. The primary outcome was clinical response at any time point. Secondary outcomes included clinical remission, endoscopic response, and remission. Univariate analysis and multivariate analysis were performed for the effect of the following variables on clinical response: fistula, onset of pouchitis less than 1 year after IPAA, younger than 35 years old, gender, previous tumor necrosis factor inhibitor-alpha use, and BMI >30. Results Eighty-three patients were treated with vedolizumab for inflammation of the pouch between January 2014 and October 2017. Median follow-up was 1.3 years (interquartile range 0.7–2.1). The proportion of patients that achieved at least a clinical response was 71.1%, with 19.3% achieving clinical remission. Of the 74 patients with a follow-up pouchoscopy, the proportion of patients with endoscopic response and mucosal healing was 54.1% and 17.6%, respectively. Patients who developed pouchitis symptoms less than 1 year after undergoing IPAA were less likely to respond to vedolizumab, even after controlling for other risk factors. Conclusions Vedolizumab is safe and effective in the management of CD of the pouch and chronic pouchitis. Further studies are needed to compare vedolizumab with other biologic therapies for pouchitis and CD of the pouch.

Background Crohn's disease (CD) of the pouch and chronic pouchitis occur in approximately 10% of patients after ileal pouch-anal anastomosis (IPAA) for refractory ulcerative colitis (UC) or UC-related dysplasia. The efficacy of anti-tumor necrosis factor (anti-TNF) agents and vedolizumab have been reported for the treatment of CD of the pouch and chronic pouchitis, but little is known regarding the use of ustekinumab in these settings. Our primary aim was to evaluate the efficacy of ustekinumab for these conditions. Methods This is a retrospective, multicenter cohort study evaluating the efficacy of ustekinumab in patients with CD of the pouch and chronic pouchitis. Clinical response or remission was judged by the treating physician's assessment at 6 months. Results Fifty-six patients (47 with CD of the pouch and 9 with chronic pouchitis) were included the study. Of these, 73% had previously been treated with either anti-TNF therapy, vedolizumab, or both after IPAA. Among patients with CD of the pouch and chronic pouchitis, 83% demonstrated clinical response 6 months after induction with ustekinumab. Responders demonstrated significantly less pouch inflammation on endoscopy when compared with nonresponders (29% vs 100%; P = 0.023). Higher mean body mass index at induction (26.3 vs 23.7; P = 0.033) and male sex (83% vs 30%; P = 0.014) were significant predictors of nonresponse to ustekinumab in those with CD of the pouch. Conclusion In this refractory patient population, ustekinumab appears to be a safe and effective treatment for chronic pouchitis and CD of the pouch in biologic-naive patients and those with prior anti-TNF or vedolizumab therapy failure. 10.1093/ibd/izx005_video1 izy302.video1 5844889626001.

Background: Non-Langerhans histiocytosis is a group of inflammatory lymphoproliferative disorders originating from non-clonal expansion of hematopoietic stem cells into cytokine-secreting dendritic cells or macrophages. Erdheim-Chester Disease (ECD) is a rare type of non-Langerhans cell histiocytosis characterized by tissue inflammation and injury caused by macrophage infiltration and histologic findings of foamy histiocytes. Often ECD involves the skeleton, retroperitoneum and the orbits. This is the first report documenting ECD manifesting as segmental colitis and causing cytokine-release syndrome.Case presentation: A 68-year old woman presented with persistent fever without infectious etiology and hematochezia. Endoscopy showed segmental colitis and pathology revealed infiltration of large foamy histiocytes CD3-/CD20-/CD68+/CD163+/S100- consistent with ECD. The patient was empirically treated with steroids but continued to have fever and developed progressive distributive shock.Conclusion: This case report describes the differential diagnosis of infectious and immune-mediated inflammatory and rheumatologic segmental colitis. Non-Langerhans histiocytosis and ECD are rare causes of gastrointestinal inflammation. Prompt diagnosis is imperative for the appropriate treatment to prevent hemodynamic compromise due to distributive shock or gastrointestinal bleeding. Importantly, gastrointestinal ECD might exhibit poor response to steroid treatment and other potential treatments including chemotherapy, and biologic treatments targeting IL-1 and TNF-alpha signaling should be considered.Abbreviations: AFB: acid-fast bacilli; ECD: Erdheim-Chester Disease; IBD: inflammatory bowel disease; PASD: periodic acid-Schiff with diastase; TB: tuberculosis

Ulcerative colitis (UC) is an immune-mediated disease of the colon that is character- ized by diffuse and continuous inflammation contiguous from the rectum. Half of UC patients have inflammation limited to the distal colon (proctitis or proctosigmoiditis) that primarily causes symptoms of bloody diarrhea and urgency. Mild-to-moderate distal UC can be effectively treated with topical formulations (rectal suppositories, enemas, or foam) of mesalamine or steroids to reduce mucosal inflammation and alleviate symptoms. Enemas or foam formulations adequately reach up to the splenic flexure, have a minimal side-effect profile, and induce remis- sion alone or in combination with systemic immunosuppressive therapy. Herein, we compare the efficacy, cost, patient tolerance, and side-effect profiles of steroid and mesalamine rectal formulations in distal UC. Patients with distal mild-to-moderate UC have a remission rate of approximately 75% (NNT =2) after treatment for 6 weeks with mesalamine enemas. Rectal budesonide foam induces remission in 41.2% of patients with mild-to-moderate active distal UC compared to 24% of patient treated with placebo (NNT =5). However, rectal budesonide has better patient tolerance profile compared to enema formulations. Despite its favorable efficacy, safety, and cost profiles, patients and physicians significantly underuse topical treat- ments for treating distal colitis. This necessitates improved patient education and physician familiarity regarding the indications, effectiveness, and potential financial and tolerability barriers in using rectal formulations.

We have previously described reduced myelination and corresponding myelin basic protein (MBP) expression in the central nervous system of Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1) deficient motheaten (me/me) mice compared with normal littermate controls. Deficiency in myelin and MBP expression in both brains and spinal cords of motheaten mice correlated with reduced MBP mRNA expression levels in vivo and in purified oligodendrocytes in vitro. Therefore, SHP-1 activity seems to be a critical regulator of oligodendrocyte gene expression and function. Consistent with this role, this study demonstrates that oligodendrocytes of motheaten mice and SHP-1-depleted N20.1 cells produce higher levels of reactive oxygen species (ROS) and exhibit corresponding markers of increased oxidative stress. In agreement with these findings, we demonstrate that increased production of ROS coincides with ROS-induced signaling pathways known to affect myelin gene expression in oligodendrocytes. Antioxidant treatment of SHP-1-deficient oligodendrocytes reversed the pathological changes in these cells, with increased myelin protein gene expression and decreased expression of nuclear factor (erythroid-2)-related factor 2 (Nrf2) responsive gene, heme oxygenase-1 (HO-1). Furthermore, we demonstrate that SHP-1 is expressed in human white matter oligodendrocytes, and there is a subset of multiple sclerosis subjects that demonstrate a deficiency of SHP-1 in normal-appearing white matter. These studies reveal critical pathways controlled by SHP-1 in oligodendrocytes that relate to susceptibility of SHP-1-deficient mice to both developmental defects in myelination and to inflammatory demyelinating diseases. GLIA 2015;63:1753–1771

Sarcoidosis is an immune-mediated multisystem disease characterized by the formation of non-caseating granulomas. The pathogenesis of sarcoidosis is unclear, with proposed infectious or environmental antigens triggering an aberrant immune response in susceptible hosts. Multiple pro-inflammatory signaling pathways have been implicated in mediating macrophage activation and granuloma formation in sarcoidosis, including IFN-γ/STAT-1, IL-6/STAT-3, and NF-κB. It is difficult to distinguish sarcoidosis from other granulomatous diseases or assess disease severity and treatment response with histopathology alone. Therefore, development of improved diagnostic tools is imperative. Herein, we describe an efficient and reliable technique to classify granulomatous disease through selected gene expression and identify novel genes and cytokine pathways contributing to the pathogenesis of sarcoidosis. We quantified the expression of twenty selected mRNAs extracted from formalin-fixed paraffin embedded (FFPE) tissue (n = 38) of normal lung, suture granulomas, sarcoid granulomas, and fungal granulomas. Utilizing quantitative real-time RT-PCR we analyzed the expression of several genes, including IL-6, COX-2, MCP-1, IFN-γ, T-bet, IRF-1, Nox2, IL-33, and eotaxin-1 and revealed differential regulation between suture, sarcoidosis, and fungal granulomas. This is the first study demonstrating that quantification of target gene expression in FFPE tissue biopsies is a potentially effective diagnostic and research tool in sarcoidosis.

Background: Cytokine signaling pathways play a central role in the pathogenesis of inflammatory bowel disease (IBD). Ulcerative colitis (UC) and Crohn's disease (CD) have unique as well as overlapping phenotypes, susceptibility genes, and gene expression profiles. This study aimed to delineate patterns within cytokine signaling pathways in colonic mucosa of UC and CD patients, explore molecular diagnostic markers, and identify novel immune mediators in IBD pathogenesis. Methods: We quantified 70 selected immune genes that are important in IBD signaling from formalin-fixed, paraffin-embedded (FFPE) colon biopsy samples from normal control subjects and UC and CD patients having either severe colitis or quiescent disease (n = 98 subjects). We utilized and validated a new modified real-time reverse-transcription polymerase chain reaction (RT-PCR) technique for gene quantification. Results: Expression levels of signaling molecules including IL-6/10/12/13/17/23/33, STAT1/3/6, T-bet, GATA3, Foxp3, SOCS1/3, and downstream inflammatory mediators such as chemokines CCL-2/11/17/20, oxidative stress inducers, proteases, and mucosal genes were differentially regulated between UC and CD and between active and quiescent disease. We also document the possible role of novel genes in IBD, including SHP-1, IRF-1,TARC, Eotaxin, NOX2, arginase I, and ADAM 8. Conclusions: This comprehensive approach to quantifying gene expression provides insights into the pathogenesis of IBD by elucidating distinct immune signaling networks in CD and UC. Furthermore, this is the first study demonstrating that gene expression profiling in FFPE colon biopsies might be a practical and effective tool in the diagnosis and prognosis of IBD and may help identify molecular markers that can predict and monitor response to individualized therapeutic treatments. (Inflamm Bowel Dis 2012;)

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS). Here we document for the first time that the cytokine IL-33 is upregulated in both the periphery and the CNS of MS patients. Plasma IL-33 was elevated in MS patients compared to normal subjects and a three-month treatment of MS patients with interferon β-1a resulted in a significant decrease of IL-33 levels. Similarly, stimulated cultured lymphocytes and macrophages from MS patients had elevated IL-33 levels compared to normal subjects. In parallel, the transcription factor NF-κB that mediates IL-33 transcription was also elevated in leukocytes of MS patients. IL-33 was elevated in normal-appearing white matter and plaque areas from MS brains and astrocytes were identified as an important source of IL-33 expression in the CNS. In summary, IL-33 levels are elevated in the periphery and CNS of MS patients, implicating IL-33 in the pathogenesis of MS.

Summary Colonic wound repair is an orchestrated process, beginning with barrier re-establishment and followed by wound channel formation and crypt regeneration. Elevated levels of prostaglandin E2 (PGE2) promote barrier re-establishment; however, we found that persistently elevated PGE2 hinders subsequent repair phases. The bacterial metabolite deoxycholate (DCA) promotes transition through repair phases via PGE2 regulation. During barrier re-establishment, DCA levels are locally diminished in the wound, allowing enhanced PGE2 production and barrier re-establishment. However, during transition to the wound channel formation phase, DCA levels increase to inhibit PGE2 production and promote crypt regeneration. Altering DCA levels via antibiotic treatment enhances PGE2 levels but impairs wound repair, which is rescued with DCA treatment. DCA acts via its receptor, farnesoid X receptor, to inhibit the enzyme cPLA2 required for PGE2 synthesis. Thus, colonic wound repair requires temporally regulated signals from microbial metabolites to coordinate host-associated signaling cascades. Video Abstract Download : Download video (19MB)

SHP-1 is a protein tyrosine phosphatase that negatively regulates cytokine signaling and inflammatory gene expression. Mice genetically lacking SHP-1 (me/me) display severe inflammatory demyelinating disease following intracranial inoculation with the BeAn strain of Theiler's murine encephalomyelitis virus (TMEV) compared to infected wild-type mice. Furthermore, SHP-1-deficient mice show a profound and predominant infiltration of blood-derived macrophages into the CNS following intracerebral injection of TMEV, and these macrophages are concentrated in areas of demyelination in brain and spinal cord. In the present study we investigated the role of SHP-1 in controlling CNS inflammatory demyelination following a peripheral instead of an intracerebral inoculation of TMEV. Surprisingly, we found that while wild-type mice were entirely refractory to intraperitoneal (IP) infection by TMEV, in agreement with previous studies, all SHP-1-deficient mice displayed profound macrophage neuroinvasion and macrophage-mediated inflammatory demyelination. Moreover, SHP-1 deficiency led to increased expression of inflammatory molecules in macrophages, serum, and CNS following IP infection with TMEV. Importantly, pharmacological depletion of peripheral macrophages significantly decreased both paralysis and CNS viral loads in SHP-1-deficient mice. In addition, peripheral MCP-1 neutralization attenuated disease severity, decreased macrophage infiltration into the CNS, and decreased monocyte numbers in the blood of SHP-1-deficient mice, implicating MCP-1 as an important mediator of monocyte migration between multiple tissues. These results demonstrate that peripheral TMEV infection results in a unique evolution of macrophage-mediated demyelination in SHP-1-deficient mice, implicating SHP-1 in the control of neuroinvasion of inflammatory macrophages and neurotropic viruses into the CNS.

Interferon-beta is a current treatment for multiple sclerosis (MS). Interferon-beta is thought to exert its therapeutic effects on MS by down-modulating the immune response by multiple potential pathways. Here, we document that treatment of MS patients with interferon beta-1a (Rebif) results in a significant increase in the levels and function of the protein tyrosine phosphatase SHP-1 in PBMCs. SHP-1 is a crucial negative regulator of cytokine signaling, inflammatory gene expression, and CNS demyelination as evidenced in mice deficient in SHP-1. In order to examine the functional significance of SHP-1 induction in MS PBMCs, we analyzed the activity of proinflammatory signaling molecules STAT1, STAT6, and NF-kappaB, which are known SHP-1 targets. Interferon-beta treatment in vivo resulted in decreased NF-kappaB and STAT6 activation and increased STAT1 activation. Further analysis in vitro showed that cultured PBMCs of MS patients and normal subjects had a significant SHP-1 induction following interferon-beta treatment that correlated with decreased NF-kappaB and STAT6 activation. Most importantly, experimental depletion of SHP-1 in cultured PBMCs abolished the anti-inflammatory effects of interferon-beta treatment, indicating that SHP-1 is a predominant mediator of interferon-beta activity. In conclusion, interferon-beta treatment upregulates SHP-1 expression resulting in decreased transcription factor activation and inflammatory gene expression important in MS pathogenesis.

The protein tyrosine phosphatase SHP-1 is a crucial negative regulator of cytokine signaling and inflammatory gene expression, both in the immune system and in the central nervous system (CNS). Mice genetically lacking SHP-1 (me/me) display severe inflammatory demyelinating disease following inoculation with the Theiler's murine encephalomyelitis virus (TMEV) compared to infected wild-type mice. Therefore, it became essential to investigate the mechanisms of TMEV-induced inflammation in the CNS of SHP-1-deficient mice. Herein, we show that the expression of several genes relevant to inflammatory demyelination in the CNS of infectedme/memice is elevated compared to that in wild-type mice. Furthermore, SHP-1 deficiency led to an abundant and exclusive increase in the infiltration of high-level-CD45-expressing (CD45hi) CD11b+Ly-6Chimacrophages into the CNS ofme/memice, in concert with the development of paralysis. Histological analyses of spinal cords revealed the localization of these macrophages to extensive inflammatory demyelinating lesions in infected SHP-1-deficient mice. Sorted populations of CNS-infiltrating macrophages from infectedme/memice showed increased amounts of viral RNA and an enhanced inflammatory profile compared to wild-type macrophages. Importantly, the application of clodronate liposomes effectively depleted splenic and CNS-infiltrating macrophages and significantly delayed the onset of TMEV-induced paralysis. Furthermore, macrophage depletion resulted in lower viral loads and lower levels of inflammatory gene expression and demyelination in the spinal cords ofme/memice. Finally,me/memacrophages were more responsive than wild-type macrophages to chemoattractive stimuli secreted byme/meglial cells, indicating a mechanism for the increased numbers of infiltrating macrophages seen in the CNS ofme/memice. Taken together, these findings demonstrate that infiltrating macrophages in SHP-1-deficient mice play a crucial role in promoting viral replication by providing abundant viral targets and contribute to increased proinflammatory gene expression relevant to the effector mechanisms of macrophage-mediated demyelination.

IL-33 is a novel member of the IL-1 cytokine family and a potent inducer of type 2 immunity, as mast cells and Th2 CD4+ T cells respond to IL-33 with the induction of type 2 cytokines such as IL-13. IL-33 mRNA levels are extremely high in the CNS, and CNS glia possess both subunits of the IL-33R, yet whether IL-33 is produced by and affects CNS glia has not been studied. Here, we demonstrate that pathogen-associated molecular patterns (PAMPs) significantly increase IL-33 mRNA and protein expression in CNS glia. Interestingly, IL-33 was localized to the nucleus of astrocytes. Further, CNS glial and astrocyte-enriched cultures treated with a PAMP followed by an ATP pulse had significantly higher levels of supernatant IL-1β and IL-33 than cultures receiving any single treatment (PAMP or ATP). Supernatants from PAMP + ATP-treated glia induced the secretion of IL-6, IL-13, and MCP-1 from the MC/9 mast cell line in a manner similar to exogenous recombinant IL-33. Further, IL-33 levels and activity were increased in the brains of mice infected with the neurotropic virus Theiler’s murine encephalomyelitis virus. IL-33 also had direct effects on CNS glia, as IL-33 induced various innate immune effectors in CNS glia, and this induction was greatly amplified by IL-33-stimulated mast cells. In conclusion, these results implicate IL-33-producing astrocytes as a potentially critical regulator of innate immune responses in the CNS.

We have previously shown that the protein tyrosine phosphatase SHP-1 is highly expressed in CNS glia and is an important modulator of cytokine signaling. As such, mice genetically lacking SHP-1 display constitutive myelin abnormalities, severe virus-induced demyelinating disease, and defects in innate anti-viral responses in the CNS. In this study, we show the differential distribution of the SHP-1 promoter-specific transcripts and demonstrate that several cytokines significantly induce SHP-1 expression in CNS glia. Consistent with these cytokine effects, infection with a neurotropic virus both in vitro and in vivo up-regulates SHP-1 transcripts and protein in CNS cells. Using CNS glial cultures of gene knockout mice, we show that interferons-β and interferons-γ act through STAT-1 and interferon regulatory factor-1 to induce the SHP-1 promoter I transcripts. Conversely, interferons-β and IL-6 act through STAT-3 to induce SHP-1 promoter II transcripts. This study demonstrates that interferons and other cytokines associated with virus infections in the CNS can significantly induce the expression of SHP-1 through STAT-1/3 activity and provides a better understanding of the molecular mechanisms regulating cytokine-induced expression important for multiple homeostatic functions of SHP-1 in the CNS.

Recent studies in mice have demonstrated that the protein tyrosine phosphatase SHP-1 is a crucial negative regulator of cytokine signaling, inflammatory gene expression, and demyelination in central nervous system. The present study investigates a possible similar role for SHP-1 in the human disease multiple sclerosis (MS). The levels of SHP-1 protein and mRNA in PBMCs of MS patients were significantly lower compared to normal subjects. Moreover, promoter II transcripts, expressed from one of two known promoters, were selectively deficient in MS patients. To examine functional consequences of the lower SHP-1 in PBMCs of MS patients, we measured the intracellular levels of phosphorylated STAT6 (pSTAT6). As expected, MS patients had significantly higher levels of pSTAT6. Accordingly, siRNA to SHP-1 effectively increased the levels of pSTAT6 in PBMCs of controls to levels equal to MS patients. Additionally, transduction of PBMCs with a lentiviral vector expressing SHP-1 lowered pSTAT6 levels. Finally, multiple STAT6-responsive inflammatory genes were increased in PBMCs of MS patients relative to PBMCs of normal subjects. Thus, PBMCs of MS patients display a stable deficiency of SHP-1 expression, heightened STAT6 phosphorylation, and an enhanced state of activation relevant to the mechanisms of inflammatory demyelination.

Kallikrein 6 is a serine protease expressed abundantly in normal adult human and rodent CNS, and therein is regulated by injury. In the case of CNS demyelinating disease, K6 expression in CNS occurs additionally in perivascular and parenchymal inflammatory cells suggesting a role in pathogenesis. Herein we describe two unique transcripts that occur within the human and mouse K6 genes that differ in their 5'-untranslated regions. These transcripts have identical translation initiation sites in exon 3, are expressed in a tissue-specific fashion and are differentially regulated in response to CNS injury. While the human and mouse 5'-transcripts differ in sequence they are identical in genomic organization and tissue-specific expression. The most 5'-transcript, designated transcript 1, includes exon 1-7, and was detectable in all CNS regions, but not in any non-CNS tissues examined (spleen, thymus, liver, kidney, pancreas, submandibular gland and peripheral nerve). In contrast, transcript 2 lacks exon 1, but contains a unique sequence at the 5'-end of exon 2, designated exon 2A. Transcript 2 was expressed both in CNS and in each peripheral tissue. In a murine model of human CNS demyelinating inflammatory disease induced by Theiler's picornovirus, mouse K6 transcript 1 was up-regulated in brain and spinal cord at acute and more chronic phases of CNS inflammation and demyelination, while overall transcript 2 expression was not significantly altered. However, in isolated splenocyte cultures, transcript 2 was up-regulated two-fold by cellular activation. Tissue-specific expression patterns and differential regulation in CNS disease indicates that each K6 5'-transcript is probably regulated by unique promoter elements and may serve as a molecular target to treat inflammatory demyelinating disease.

We have previously described reduced myelination and corresponding myelin basic protein (MBP) expression in the central nervous system of Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1) deficient motheaten (me/me) mice compared with normal littermate controls. Deficiency in myelin and MBP expression in both brains and spinal cords of motheaten mice correlated with reduced MBP mRNA expression levels in vivo and in purified oligodendrocytes in vitro. Therefore, SHP-1 activity seems to be a critical regulator of oligodendrocyte gene expression and function. Consistent with this role, this study demonstrates that oligodendrocytes of motheaten mice and SHP-1-depleted N20.1 cells produce higher levels of reactive oxygen species (ROS) and exhibit corresponding markers of increased oxidative stress. In agreement with these findings, we demonstrate that increased production of ROS coincides with ROS-induced signaling pathways known to affect myelin gene expression in oligodendrocytes. Antioxidant treatment of SHP-1-deficient oligodendrocytes reversed the pathological changes in these cells, with increased myelin protein gene expression and decreased expression of nuclear factor (erythroid-2)-related factor 2 (Nrf2) responsive gene, heme oxygenase-1 (HO-1). Furthermore, we demonstrate that SHP-1 is expressed in human white matter oligodendrocytes, and there is a subset of multiple sclerosis subjects that demonstrate a deficiency of SHP-1 in normal-appearing white matter. These studies reveal critical pathways controlled by SHP-1 in oligodendrocytes that relate to susceptibility of SHP-1-deficient mice to both developmental defects in myelination and to inflammatory demyelinating diseases.

In this issue of the Journal of Clinical Gastroenterology Jiang and colleagues report a randomized, placebo controlled, double-blind study evaluating the efficacy of low-dose (3.5 mg/kg) infliximab for induction and maintenance treatment in Chinese patients with active moderate-severe ulcerative colitis (UC).1 The experimental design was modeled after the ACT 2 trial2 but included both a 5 mg/kg (standard-dose) group and a 3.5 mg/kg (low-dose) group, as well as a placebo control arm. 123 UC patients were distributed equally among the cohorts. The authors report similar rates of clinical response at week 8 (73% vs 78%) and at week 30 (51% vs 53%) in both the low and standard infliximab dose treatment arms respectively. Placebo rates were 37% at week 8 and 27% at week 30 with response defined as a ≥3 point drop in the Mayo score. Differences in mucosal healing were also significantly greater in both infliximab groups. The study was not adequately powered to detect a difference between the low- and standard-dose groups, but the authors limit their conclusions to state that both doses are more effective than placebo. The ACT 1 and 2 studies demonstrated a 61–64% clinical response at week 8 and 31–41% clinical remission at week 30 in UC patients receiving 5mg/kg of Infliximab. These studies did not identify a statistically significant clinical benefit to using 10 mg/kg over 5 mg/kg dosing as a starting dose, although 10 mg/kg over 5 mg/kg dosing resulted in higher serum infliximab levels.2, 3 A lowest-effective dose was not demonstrated in the ACT studies. Jiang et al used this as impetus in designing their study testing a dose lower than 5 mg/kg. A similar “low-dose” infliximab strategy was also recently evaluated and confirmed in psoriatic arthritis, where a recent observational cohort study of 462 patients showed that low dose infliximab (3 mg/kg) resulted in similar clinical response and drug levels following 12 months treatment.4 If the efficacy and long-term outcomes of this study’s findings are confirmed, this low-dose strategy could have important health care economic implications. While biosimilars may eventually change this, a 100 mg vial of infliximab costs ~$900 in the United States.5 At this cost, an 80 kg person receiving 5mg/kg generates a drug cost of almost $47,000 in the first year of treatment. In contrast, that same individual receiving the low-dose (3.5mg/kg) infliximab strategy would require 280mg per infusion corresponding to less than $33,000 for the first year. This is a $14,000 per first year, per patient savings! The economic benefit is potentially staggering considering that tens of thousands of UC patients receive Infliximab for multiple years. This low-dose is probably not for all UC patients. Jiang and colleagues enrolled patients with an average Mayo score of 6.0 compared to 8.4 used in ACT 1.1, 2 A Mayo score of 6 is at the border between mild and moderate ulcerative colitis. Patients with severe UC are often treated with higher doses of Infliximab. In severe colitis, infliximab may be lost through the leaky gut barrier,6 requiring higher infusion dose to maintain adequate serum levels. Additionally, infliximab systemic disposition is influenced by body weight, serum albumin levels (which are often decreased in severe UC), and formation of antibodies to Infliximab (ATI).7 Serum concentration of Infliximab is associated with efficacy in patients with moderate-to-severe ulcerative colitis.3 Unfortunately, Jiang et al did not measure or report drug levels. However, they did evaluate for ATIs and UC patients with 3.5mg/Kg vs 5 mg/Kg did not show any difference in formation of ATI (5 %) at 30 weeks and compared similarly to ACT 1 and 2 studies (6%).2 How might this study influence our current practice? Based on this single center study, we are probably not yet ready to implement this low-dose strategy, at least in the US. However, we do propose that the results of this study support consideration of a few practical management tips for use of infliximab in UC patients. First, infliximab does not need to be “maxed-out” or given at high dose in all patients, especially in those with moderate disease severity or limited extent. Second, these results further validate an approach where patients initially receive standard dose Infliximab that is escalated as needed based on clinical and endoscopic response.8, 9 Third, for patients maintained on Infliximab who are in long-term “deep” remission, consideration should be given to reducing or spacing out their dose, especially if they are on a concomitant immunomodulator. In conclusion, these results suggest that a low-dose infliximab induction strategy may be both an effective and cost-advantageous option in patients with moderately active ulcerative colitis. Confirmative studies are warranted in this same population before management is likely to change. Larger, confirmative studies are needed and should also include data on long-term outcomes. Given the potential cost savings, perhaps governmental medical payers (CMS) or commercial health insurers would be interested in sponsoring such a trial.

Recent studies provide a functional link between kallikrein 6 (Klk6) and the development and progression of disease in patients with multiple sclerosis (MS) and in its murine models. To evaluate the involvement of additional kallikrein family members, we compared Klk6 expression with four other kallikreins (Klk1, Klk7, Klk8, and Klk10) in the brain and spinal cord of mice infected with Theiler’s murine encephalomyelitis virus, an experimental model of progressive MS. The robust upregulation of Klk6 and Klk8 in the brain during the acute phase of viral encephalitis and in the spinal cord during disease development and progression points to their participation in inflammation, demyelination, and progressive axon degeneration. More limited changes in Klk1, Klk7, and Klk10 were also observed. In addition, Klk1, Klk6, and Klk10 were dynamically regulated in T cells in vitro as a recall response to viral antigen and in activated monocytes, pointing to their activities in the development of adaptive and innate immune function. Together, these results point to overlapping and unique roles for multiple kallikreins in the development and progression of virus-mediated central nervous system inflammatory demyelinating disease, including activities in the development of the adaptive and innate immune response, in demyelination, and in progressive axon degeneration.

Kallikrein 6 (K6, MSP) is a newly identified member of the Kallikrein family of serine proteases that is preferentially expressed in the adult central nervous system (CNS). We have previously demonstrated that K6 is abundantly expressed by inflammatory cells at sites of CNS inflammation and demyelination in animal models of multiple sclerosis (MS) and in human MS lesions. To test the hypothesis that this novel enzyme is a mediator of pathogenesis in CNS inflammatory disease, we have evaluated whether autonomously generated K6 antibodies alter the clinicopathological course of disease in murine proteolipid protein139-151-induced experimental autoimmune encephalomyelitis (PLP139-151 EAE). We demonstrate that immunization of mice with recombinant K6 generates antibodies that block K6 enzymatic activity in vitro, including the breakdown of myelin basic protein (MBP), and that K6-immunized mice exhibit significantly delayed onset and severity of clinical deficits. Reduced clinical deficits were reflected in significantly less spinal cord pathology and meningeal inflammation and in reduced Th1 cellular responses in vivo and in vitro. These data demonstrate for the first time that K6 participates in enzymatic cascades mediating CNS inflammatory disease and that this unique enzyme may represent a novel therapeutic target for the treatment of progressive inflammatory disorders, including MS.

Interferon-β (IFN-β) is a current effective treatment for multiple sclerosis (MS) and exerts its therapeutic effects by down-modulating the systemic immune response and cytokine signaling. In clinical practice there are several formulations of interferon including a low dose of IFN-β 1a formulation of 30 μg IM once weekly (Avonex) and a high dose formulation of 44 μg SC three times weekly (Rebif). Recent studies suggest that Rebif is more efficacious compared to Avonex in preventing relapses and decreasing MRI activity in relapsing remitting MS (RRMS) patients. This study examines whether there are quantitative gene expression changes in interferon-treated RRMS patients that can explain the difference in efficacy and side effects between Rebif and Avonex. Herein, RRMS patients were treated for three months with IFN-β 1a and the levels of plasma cytokines and gene expression in peripheral blood mononuclear cells were examined. Thirty-two normal subjects were compared to thirty-two RRMS patients, of which ten were treated with Rebif and ten with Avonex. Rebif and Avonex both significantly and equally suppressed plasma TNF-α and IL-6 levels. Rebif suppressed IL-13 significantly more than Avonex. Rebif also significantly suppressed the levels of the chemokines CCL17 and RANTES, the protease ADAM8, and COX-2 at a higher degree compared to Avonex. The STAT1-inducible genes IP-10 and caspase 1 were significantly increased with Rebif compared to Avonex. In conclusion, the higher dosed, more frequently administered IFN-β 1a Rebif when compared to IFN-β 1a Avonex has more potent immunomodulatory effects. These quantitative results might relate to efficacy and side-effect profile of the two IFN-β 1a formulations and provide prospective practical clinical tools to monitor treatment and adjust dosage.

Recent studies in mice have demonstrated that the protein tyrosine phosphatase SHP-1 is a crucial negative regulator of proinflammatory cytokine signaling, TLR signaling, and inflammatory gene expression. Furthermore, mice genetically lacking SHP-1 (me/me) display a profound susceptibility to inflammatory CNS demyelination relative to wild-type mice. In particular, SHP-1 deficiency may act predominantly in inflammatory macrophages to increase CNS demyelination as SHP-1-deficient macrophages display coexpression of inflammatory effector molecules and increased demyelinating activity in me/me mice. Recently, we reported that PBMCs of multiple sclerosis (MS) patients have a deficiency in SHP-1 expression relative to normal control subjects indicating that SHP-1 deficiency may play a similar role in MS as to that seen in mice. Therefore, it became essential to examine the specific expression and function of SHP-1 in macrophages from MS patients. Herein, we document that macrophages of MS patients have deficient SHP-1 protein and mRNA expression relative to those of normal control subjects. To examine functional consequences of the lower SHP-1, the activation of STAT6, STAT1, and NF-kappaB was quantified and macrophages of MS patients showed increased activation of these transcription factors. In accordance with this observation, several STAT6-, STAT1-, and NF-kappaB-responsive genes that mediate inflammatory demyelination were increased in macrophages of MS patients following cytokine and TLR agonist stimulation. Supporting a direct role of SHP-1 deficiency in altered macrophage function, experimental depletion of SHP-1 in normal subject macrophages resulted in an increased STAT/NF-kappaB activation and increased inflammatory gene expression to levels seen in macrophages of MS patients. In conclusion, macrophages of MS patients display a deficiency of SHP-1 expression, heightened activation of STAT6, STAT1, and NF-kappaB and a corresponding inflammatory profile that may be important in controlling macrophage-mediated demyelination in MS.

The protein tyrosine phosphatase SHP-1 is a critical regulator of cytokine signaling and inflammation. Mice homozygous for a null allele at the SHP-1 locus have a phenotype of severe inflammation and are hyper-responsive to the TLR4 ligand LPS. TLR4 stimulation in the CNS has been linked to both neuropathic pain and sickness behaviors. To determine if reduction in SHP-1 expression affects LPS-induced behaviors, responses of heterozygous SHP-1-deficient (me/+) and wild-type (+/+) mice to LPS were measured. Chronic (4-week) treatment with LPS induced avoidant behaviors indicative of fear/anxiety in me/+, but not +/+, mice. These behaviors were correlated with a LPS-induced type 2 cytokine, cytokine receptor, and immune effector arginase profile in the brains of me/+ mice not found in +/+ mice. Me/+ mice also had a constitutively greater level of TLR4 in the CNS than +/+ mice. Additionally, me/+ mice displayed constitutively increased thermal sensitivity compared to +/+ mice, measured by the tail-flick test. Moreover, me/+ glial cultures were more responsive to LPS than +/+ glia. Therefore, the reduced expression of SHP-1 in me/+ imparts haploinsufficiency with respect to the control of CNS TLR4 and pain signaling. Furthermore, type 2 cytokines become prevalent during chronic TLR4 hyperstimulation in the CNS and are associated positively with behaviors that are usually linked to type 1 pro-inflammatory cytokines. These findings question the notion that type 2 immunity is solely anti-inflammatory in the CNS and indicate that type 2 immunity induces/potentiates CNS inflammatory processes.