IL-23: a master regulator in Crohn disease

CTLA-4-expressing ILC3s restrain interleukin-23-mediated inflammation

Interleukin (IL-)23 is a major mediator and therapeutic target in chronic inflammatory diseases that also elicits tissue protection in the intestine at homeostasis or following acute infection1-4. However, the mechanisms that shape these beneficial versus pathological outcomes remain poorly understood. To address this gap in knowledge, we performed single-cell RNA sequencing on all IL-23 receptor-expressing cells in the intestine and their acute response to IL-23, revealing a dominance of T cells and group 3 innate lymphoid cells (ILC3s). Unexpectedly, we identified potent upregulation of the immunoregulatory checkpoint molecule cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) on ILC3s. This pathway was activated by gut microbes and IL-23 in a FOXO1- and STAT3-dependent manner. Mice lacking CTLA-4 on ILC3s exhibited reduced regulatory T cells, elevated inflammatory T cells and more-severe intestinal inflammation. IL-23 induction of CTLA-4+ ILC3s was necessary and sufficient to reduce co-stimulatory molecules and increase PD-L1 bioavailability on intestinal myeloid cells. Finally, human ILC3s upregulated CTLA-4 in response to IL-23 or gut inflammation and correlated with immunoregulation in inflammatory bowel disease. These results reveal ILC3-intrinsic CTLA-4 as an essential checkpoint that restrains the pathological outcomes of IL-23, suggesting that disruption of these lymphocytes, which occurs in inflammatory bowel disease5-7, contributes to chronic inflammation.

Inflammatory Bowel Disease: From Conventional Immunosuppression to Biologic Therapy

BACKGROUND

Inflammatory bowel diseases (IBDs) are chronic, recurrent inflammatory diseases with partly understood etiology and pathogenesis. The course of IBD, both ulcerative colitis and Crohn's disease, is characterized by periods of relapse and remission with the possible occurrence of extraintestinal manifestations.

SUMMARY

During the last decades, therapeutic goals in IBD evolved toward endoscopic remission and mucosal healing creating the need for early administration of disease-modifying agents (DMAs). DMAs include conventional immunosuppressants (thiopurines, methotrexate), biologic drugs (anti-TNF, anti-integrin, and anti-IL-12/23 monoclonal antibodies), and small molecules (JAK inhibitors, S1P receptor modulators). Patients with aggressive course of disease and risk factors for poor prognosis should be treated with biologic therapy early, while conventional immunomodulators should be used in those with milder course of disease in the absence of risk factors.

KEY MESSAGES

Challenges in the treatment of IBD patients include the choice of effective yet safe drug and prevention or overcoming loss of response.

Dendritic cells resist to disulfiram-induced cytotoxicity, but reduced interleukin-12/23(p40) production

Disulfiram (DSF), a medication for alcoholism, has recently been used as a repurposing drug owing to its anticancer effects. Despite the crucial role of dendritic cells (DCs) in immune homeostasis and cancer therapy, the effects of DSF on the survival and function of DCs have not yet been studied. Therefore, we treated bone marrow-derived DCs with DSF and lipopolysaccharide (LPS) and performed various analyses. DCs are resistant to DSF and less cytotoxic than bone marrow cells and spleen cells. The viability and metabolic activity of DCs hardly decreased after treatment with DSF in the absence or presence of LPS. DSF did not alter the expression of surface markers (MHC II, CD86, CD40, and CD54), antigen uptake capability, or the antigen-presenting ability of LPS-treated DCs. DSF decreased the production of interleukin (IL)-12/23 (p40), but not IL-6 or tumor necrosis factor-α, in LPS-treated DCs. We considered the granulocyte-macrophage colony-stimulating factor (GM-CSF) as a factor to make DCs resistant to DSF-induced cytotoxicity. The resistance of DCs to DSF decreased when GM-CSF was not given or its signaling was inhibited. Also, GM-CSF upregulated the expression of a transcription factor XBP-1 which is essential for DCs' survival. This study demonstrated for the first time that DSF did not alter the function of DCs, had low cytotoxicity, and induced differential cytokine production.

Ustekinumab Trough Concentrations Are Associated with Biochemical Outcomes in Patients with Crohn's Disease

OBJECTIVE

It is unknown whether ustekinumab (UST) levels can predict clinical outcomes in Crohn's disease (CD) patients. We assessed the exposure-response relationship of UST trough concentrations with biochemical outcomes at week 24 in a prospective, real-world setting.

METHODS

We performed a prospective study in patients with CD starting UST in four academic centres in the Netherlands. All patients received a weight-adjusted intravenous (IV) UST induction dose, followed by one subcutaneous (SC) dose of 90 mg UST at 8 weeks. Maintenance therapy consisted of 90 mg subcutaneous UST every 8 or 12 weeks. Individual UST concentration time course during treatment were estimated using a population pharmacokinetic (PK) model. Quartile analysis and logistic regression were performed to analyse if UST concentrations at week 8 were associated with biochemical remission rates at week 24 (C-reactive protein (CRP) ≤ 5 mg/L and / or faecal calprotectin (FC) ≤ 250 mg/kg).

RESULTS

In total, 124 patients with CD were included. Patients achieving biochemical remission at week 12 and 24 had significantly higher UST levels at week 8 compared to patients without biochemical remission (6.6 µg/mL versus 3.9 µg/mL, P < 0.01 and 6.3 µg/mL versus 3.9 µg/mL, P < 0.01, respectively). In quartile analysis, patients with UST levels in the highest quartile (≥ 6.3 µg/mL at week 8) had higher biochemical remission rates at week 12 and week 24. There was no association between UST levels at and corticosteroid-free clinical remission rates.

CONCLUSION

In this real-world cohort of patients with CD, UST levels in the highest quartile (≥ 6.3 µg/mL) at week 8 were associated with higher biochemical remission rates at week 24.

Literature Overview of the Relation Between Psoriasis and Alzheimer

The most common type of dementia disease is Alzheimer, which placing a heavy burden on the healthcare system all over the world. At the same time, psoriasis is also one of the most common health problems, as a skin disease. Alzheimer's disease (AD) is more often in patients with psoriasis than in the general people. Several evidence has proved the relation between AD and psoriasis through immune-mediated pathophysiologic processes. This review aims to summary the potential relation between AD and psoriasis, and provide suggestions based on the relationship at the same time. Neurologists, dermatologists should pay attention to the relationship between Alzheimer's disease and psoriasis. Dermatology and neurology need referral each other when it is necessary.

Real-world effectiveness and safety of ustekinumab induction therapy for Korean patients with Crohn's disease: a KASID prospective multicenter study

BACKGROUND/AIMS

We investigated the real-world effectiveness and safety of ustekinumab (UST) as induction treatment for Koreans with Crohn's disease (CD).

METHODS

CD patients who started UST were prospectively enrolled from 4 hospitals in Korea. All enrolled patients received intravenous UST infusion at week 0 and subcutaneous UST injection at week 8. Clinical outcomes were assessed using Crohn's Disease Activity Index (CDAI) scores at weeks 8 and 20 among patients with active disease (CDAI ≥150) at baseline. Clinical remission was defined as a CDAI <150, and clinical response was defined as a reduction in CDAI ≥70 points from baseline. Safety and factors associated with clinical remission at week 20 were also analyzed.

RESULTS

Sixty-five patients were enrolled between January 2019 and December 2020. Among 49 patients with active disease at baseline (CDAI ≥150), clinical remission and clinical response at week 8 were achieved in 26 (53.1%) and 30 (61.2%) patients, respectively. At week 20, 27 (55.1%) and 35 (71.4%) patients achieved clinical remission and clinical response, respectively. Twenty-seven patients (41.5%) experienced adverse events, with serious adverse events in 3 patients (4.6%). One patient (1.5%) stopped UST therapy due to poor response. Underweight (body mass index <18.5 kg/m2) (odds ratio [OR], 0.085; 95% confidence interval [CI], 0.014-0.498; P=0.006) and elevated C-reactive protein at baseline (OR, 0.133; 95% CI, 0.022-0.823; P=0.030) were inversely associated with clinical remission at week 20.

CONCLUSIONS

UST was effective and well-tolerated as induction therapy for Korean patients with CD.

Modulation of macrophage inflammatory function through selective inhibition of the epigenetic reader protein SP140

Background

SP140 is a bromodomain-containing protein expressed predominantly in immune cells. Genetic polymorphisms and epigenetic modifications in the SP140 locus have been linked to Crohn’s disease (CD), suggesting a role in inflammation.

Results

We report the development of the first small molecule SP140 inhibitor (GSK761) and utilize this to elucidate SP140 function in macrophages. We show that SP140 is highly expressed in CD mucosal macrophages and in in vitro-generated inflammatory macrophages. SP140 inhibition through GSK761 reduced monocyte-to-inflammatory macrophage differentiation and lipopolysaccharide (LPS)-induced inflammatory activation, while inducing the generation of CD206⁺ regulatory macrophages that were shown to associate with a therapeutic response to anti-TNF in CD patients. SP140 preferentially occupies transcriptional start sites in inflammatory macrophages, with enrichment at gene loci encoding pro-inflammatory cytokines/chemokines and inflammatory pathways. GSK761 specifically reduces SP140 chromatin binding and thereby expression of SP140-regulated genes. GSK761 inhibits the expression of cytokines, including TNF, by CD14⁺ macrophages isolated from CD intestinal mucosa.

Conclusions

This study identifies SP140 as a druggable epigenetic therapeutic target for CD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-022-01380-6.

Treatment of Inflammatory Bowel Disease: A Comprehensive Review

Inflammatory bowel disease (IBD), as a global disease, has attracted much research interest. Constant research has led to a better understanding of the disease condition and further promoted its management. We here reviewed the conventional and the novel drugs and therapies, as well as the potential ones, which have shown promise in preclinical studies and are likely to be effective future therapies. The conventional treatments aim at controlling symptoms through pharmacotherapy, including aminosalicylates, corticosteroids, immunomodulators, and biologics, with other general measures and/or surgical resection if necessary. However, a considerable fraction of patients do not respond to available treatments or lose response, which calls for new therapeutic strategies. Diverse therapeutic options are emerging, involving small molecules, apheresis therapy, improved intestinal microecology, cell therapy, and exosome therapy. In addition, patient education partly upgrades the efficacy of IBD treatment. Recent advances in the management of IBD have led to a paradigm shift in the treatment goals, from targeting symptom-free daily life to shooting for mucosal healing. In this review, the latest progress in IBD treatment is summarized to understand the advantages, pitfalls, and research prospects of different drugs and therapies and to provide a basis for the clinical decision and further research of IBD.

New agents for immunosuppression

The human abdomen harbors organs that the host's immune system can attack easily. This immunological storm front leads to diseases like Crohn's Disease, Ulcerative Colitis or Autoimmune Hepatitis. Serious symptoms like pain, diarrhea, fatigue, or malnutrition accompany these diseases. Moreover, many patients have an increased risk for developing special kind of malignancies and some autoimmune disease can show a high mortality. The key to treat them consists of a deep understanding of their pathophysiology. In vitro and especially in vivo basic research laid the foundation for our increasing knowledge about it during the past years. This enabled the development of new therapeutic approaches that interact directly with cytokines or immune cells instead of building the treatment on a total immunosuppression. Different kind of antibodies, kinase inhibitors, and regulatory T cells build the base for these approaches. This review shows new therapeutical approaches in gastrointestinal autoimmune diseases in context to their pathophysiological basis.

Oral delivery of natural active small molecules by polymeric nanoparticles for the treatment of inflammatory bowel diseases

The incidence of inflammatory bowel disease (IBD) is rapidly rising throughout the world. Although tremendous efforts have been made, limited therapeutics are available for IBD management. Natural active small molecules (NASMs), which are a gift of nature to humanity, have been widely used in the prevention and alleviation of IBD; they have numerous advantageous features, including excellent biocompatibility, pharmacological activity, and mass production potential. Oral route is the most common and acceptable approach for drug administration, but the clinical application of NASMs in IBD treatment via oral route has been seriously restricted by their inherent limitations such as high hydrophobicity, instability, and poor bioavailability. With the development of nanotechnology, polymeric nanoparticles (NPs) have provided a promising platform that can efficiently encapsulate versatile NASMs, overcome multiple drug delivery barriers, and orally deliver the loaded NASMs to targeted tissues or cells while enhancing their stability and bioavailability. Thus, NPs can enhance the preventive and therapeutic effects of NASMs against IBD. Herein, we summarize the recent knowledge about polymeric matrix-based carriers, targeting ligands for drug delivery, and NASMs. We also discuss the current challenges and future developmental directions.

Evaluation of ustekinumab trough levels during induction and maintenance therapy with regard to disease activity status in difficult to treat Crohn disease patients

Ustekinumab (UST) is approved for the treatment of moderate and severe Crohn disease (CD). Therapeutic drug monitoring (TDM) can help monitor the therapeutic effects of biologics. Therefore, the aim of this study was to evaluate the clinical outcomes of UST-treated CD patients and to determine the UST trough level in clinical and corticosteroid-free remission.This retrospective study included patients with moderate and severe active disease (AD) treated intravenously with a weight-adapted induction dose of UST. The maintenance therapy consisted of 90 mg UST subcutaneously at week 8 and thereafter every 8 or 12 weeks, depending on the clinical response. Clinical and corticosteroid-free remission, Harvey-Bradshaw-Index (HBI), UST trough level, and further laboratory parameters were measured just before the injection of UST at each follow-up evaluation until week 40.37 CD patients with a median HBI of 9 at week 0 were included in the study. Starting from 24% at the beginning of the monitoring period, and 38% of patients at the end of the monitoring period were treated with an 8-week interval (P = .18). There was a significant improvement in clinical (P = .0004), corticosteroid-free remission (P = .03), and HBI (P < .0001) from week 0 until the end of the observation period. The serum UST trough level decreased significantly from 2.0 at week 8 to 0.3, in the maintenance therapy and 0.4 μg/ml at the end of the therapy (P < .0001). Neither UST trough level nor levels of C-reactive protein (CRP) or fecal calprotectin (FC) were associated with disease outcome. Concomitant immunomodulator therapy did not appear to affect the UST trough level or clinical course.UST is an effective treatment option for difficult-to-treat patients with CD. UST trough levels may not be associated with treatment efficacy or the prediction of treatment outcomes in patients with CD. Further prospective randomized trials should be conducted to evaluate whether UST trough levels are associated with treatment outcomes in patients with CD.

Effects of pharmacological calcimimetics on colorectal cancer cells over-expressing the human calcium-sensing receptor

The calcium-sensing receptor (CaSR) is a ubiquitously expressed multifunctional G protein-coupled receptor. Several studies reported that the CaSR plays an anti-inflammatory and anti-tumorigenic role in the intestine, and that it is down-regulated during colorectal carcinogenesis. We hypothesized that positive allosteric CaSR modulators (type II calcimimetics) selectively targeting the intestinal cells could be used for the treatment of intestinal pathologies. Therefore, the aim of this study was to determine the effect of pharmacological stimulation of CaSR on gene expression in vitro and on tumor growth in vivo. We stably transduced two colon cancer cell lines (HT29 and Caco2) with lentiviral vectors containing either the CaSR fused to GFP or GFP only. Using RNA sequencing, RT-qPCR experiments and ELISA, we determined that CaSR over-expression itself had generally little effect on gene expression in these cells. However, treatment with 1 μM of the calcimimetic NPS R-568 increased the expression of pro-inflammatory factors such as IL-23α and IL-8 and reduced the transcription of various differentiation markers in the cells over-expressing the CaSR. In vivo, neither the presence of the CaSR nor p.o. treatment of the animals with the calcimimetic cinacalcet affected tumor growth, tumor cell proliferation or tumor vascularization of murine HT29 xenografts. In summary, CaSR stimulation in CaSR over-expressing cells enhanced the expression of inflammatory markers in vitro, but was not able to repress colorectal cancer tumorigenicity in vivo. These findings suggest potential pro-inflammatory effects of the CaSR and type II calcimimetics in the intestine.

Optimizing the Use of Current Treatments and Emerging Therapeutic Approaches to Achieve Therapeutic Success in Patients with Inflammatory Bowel Disease

The current goal of inflammatory bowel disease (IBD) treatment is a symptom-free everyday life accompanied by mucosal healing with minimal use of corticosteroids. Recent therapeutic advances, particularly, the emergence of anti-tumor necrosis factor (anti-TNF) antibodies, have changed the natural history of IBD. Additionally, these advances also led to the emergence of the therapeutic concept of the “treat to target” strategy. With the development of new drugs and clinical trials, not only biologics but also small molecules have been applied to clinical practice to better individualize and optimize therapy. However, if newer drugs, including anti-TNF therapies, are recommended for all patients diagnosed with IBD, a significant number of patients will be overtreated. The basic goal of IBD treatment is still to make the best use of conventional treatments based on IBD pathophysiology. Thus, physicians should be familiar with the modes of action of the available drugs. In this review, the author discusses the existing data for many approved drugs and provide insights for optimizing current treatments for the management of patients with IBD in the era of biologics.

All are Equal, Some are More Equal: Targeting IL 12 and 23 in IBD - A Clinical Perspective

Chronic inflammatory diseases like inflammatory bowel diseases (IBD) or psoriasis represents a worldwide health burden. Researchers provided great achievements in understanding the origin of these diseases leading to improved therapeutic options. The discovery of cytokines like tumor necrosis factor-α or transforming growth factor-β are examples for these efforts. Interleukin 12 (IL 12) and interleukin 23 (IL 23) represent different important cytokines in this regard. They both belong to the interleukin 12 family and are related by sharing the subunit p40. Ustekinumab is an antibody that blocks p40 and thereby interleukins 12 and 23. Trials showed promising results in treating IBD patients with this drug. Consequently, new questions arose about the distinct features of IL 12 and 23. This review focuses on these interleukins regarding their functions in the healthy and inflamed gut and provides an overview about the results from in vitro and in vivo studies as well as clinical trials.

Master regulator genes and their impact on major diseases

Master regulator genes (MRGs) have become a hot topic in recent decades. They not only affect the development of tissue and organ systems but also play a role in other signal pathways by regulating additional MRGs. Because a MRG can regulate the concurrent expression of several genes, its mutation often leads to major diseases. Moreover, the occurrence of many tumors and cardiovascular and nervous system diseases are closely related to MRG changes. With the development in omics technology, an increasing amount of investigations will be directed toward MRGs because their regulation involves all aspects of an organism’s development. This review focuses on the definition and classification of MRGs as well as their influence on disease regulation.

The Interplay Between Genetic Risk Factors and Proteolytic Dysregulation in the Pathophysiology of Inflammatory Bowel Disease

Crohn's disease [CD] and ulcerative colitis [UC] are the two main forms of inflammatory bowel disease [IBD]. Previous studies reported increased levels of proteolytic activity in stool and tissue samples from IBD patients, whereas the re-establishment of the proteolytic balance abrogates the development of experimental colitis. Furthermore, recent data suggest that IBD occurs in genetically predisposed individuals who develop an abnormal immune response to intestinal microbes once exposed to environmental triggers. In this review, we highlight the role of proteases in IBD pathophysiology, and we showcase how the main cellular pathways associated with IBD influence proteolytic unbalance and how functional proteomics are allowing the unambiguous identification of dysregulated proteases in IBD, paving the way to the development of new protease inhibitors as a new potential treatment.

Zinc Deficiency Activates the IL-23/Th17 Axis to Aggravate Experimental Colitis in Mice

BACKGROUND AND AIMS

Patients with inflammatory bowel disease [IBD], especially Crohn's disease, often develop zinc deficiency. However, the precise mechanisms by which zinc deficiency affects IBD pathology, particularly intestinal macrophage function, remain unclear. We studied the effects of zinc deficiency on the development and progression of colitis in mice.

METHODS

To induce colitis, mice were treated with 2,4,6-trinitrobenzene sulphonic acid. Rag1-/- mice were then given injections of naïve CD4+CD62L+ T cells. The respective degrees of mucosal injury of mice that had received a zinc chelator (TPEN; N,N,N',N'-tetrakis [2-pyridylmethyl]ethylenediamine) and of control mice were subsequently compared. Colonic lamina propria mononuclear cells were isolated by enzymatic digestion and were examined using flow cytometry. To generate mouse bone marrow-derived macrophages [BMDMs], bone marrow cells were stimulated with mouse macrophage-colony stimulating factor.

RESULTS

Zinc deficiency aggravates colonic inflammation through the activation of type 17 helper T [Th17] cells in mice. Flow cytometric analysis revealed that zinc deficiency significantly increases the proportion of pro-inflammatory [M1] macrophages in colonic lamina propria mononuclear cells obtained from inflamed colon. Interferon-γ plus lipopolysaccharide-mediated M1 skewing alters the expression of zinc transporters in BMDMs and thereby decreases the intracellular free zinc. TPEN treatment mimicking the effects of the M1 skewing up-regulates IL-23p19 expression, which is strongly related to Th17 development. Furthermore, the nuclear accumulation of interferon-regulatory factor 5 is closely involved in IL-23p19 induction in zinc-deficient macrophages.

CONCLUSIONS

Zinc deficiency aggravates colonic inflammation through activation of the IL-23/Th17 axis. This activation is controlled by subcellular distribution of interferon-regulatory factor 5.

Ustekinumab Serum Trough Levels May Identify Suboptimal Responders to Ustekinumab in Crohn's Disease

INTRODUCTION

The aim of this study was to evaluate the association between serum ustekinumab (UST) trough levels and response to induction and maintenance UST treatment in refractory Crohn's Disease (CD) patients.

METHODS

We performed a prospective study including CD patients who received UST from September 2015 to January 2017. Patients received 90 mg of UST subcutaneously at weeks 0, 4, and 12, then every 8 weeks. Two cohorts of patients were analyzed: an induction cohort and a maintenance cohort. We evaluated clinical, biological, and imaging/endoscopic response to UST treatment. UST trough levels and anti-UST antibodies were dosed at weeks 12 and 28 in the induction cohort, and at a single time point in the maintenance cohort.

RESULTS

Forty-nine patients were enrolled in the maintenance cohort. Mean concentrations of UST were 1.88 ± 1.40 µg/mL. UST trough levels were not significantly different in patients with or without clinical, biological, or imaging/endoscopic responses to UST treatment (p > 0.11). Twenty-three consecutive patients were included in the induction cohort. At week 12, mean UST concentrations were 1.45 ± 1.15 µg/mL. Patients with a biological response to UST treatment had significant higher serum UST trough concentration (median 1.72 µg/mL) than non-responders (median 0.56 µg/mL, p = 0.02). A UST trough level ≥ 1.10 µg/mL at week 12 was associated with a biological response to UST treatment at 6 months.

CONCLUSION

UST trough levels were associated with a biological response at the end of the induction phase. In patients with low levels of UST, optimization treatment may be necessary to obtain a sustained response.

Mycobacterium avium Subspecies paratuberculosis Drives an Innate Th17-Like T Cell Response Regardless of the Presence of Antigen-Presenting Cells

The gastrointestinal disease of ruminants is clinically known as Johne's disease (JD) and is caused by Mycobacterium avium subspecies paratuberculosis (MAP). An accumulative effect by insensitive diagnostic tools, a long subclinical stage of infection, and lack of effective vaccines have made the control of JD difficult. Currently lacking in the model systems of JD are undefined correlates of protection and the sources of inflammation due to JD. As an alternative to commonly studied immune responses, such as the Th1/Th2 paradigm, a non-classical Th17 immune response to MAP has been suggested. Indeed MAP antigens induce mRNAs encoding the Th17-associated cytokines IL-17A, IL-17F, IL-22, IL-23, IL-27, and IFNγ in CD3+ T cell cultures as determined by RT-qPCR. Although not as robust as when cultured with monocyte-derived macrophages (MDMs), MAP is able to stimulate the upregulation of these cytokines from sorted CD3+ T cells in the absence of antigen-presenting cells (APCs). CD4+ and CD8+ T cells are the main contributors of IL-17A and IL-22 in the absence of APCs. However, MAP-stimulated MDMs are the main contributor of IL-23. In vivo, JD+ cows have more circulating IL-23 than JD– cows, suggesting that this proinflammatory cytokine may be important in the etiology of JD. Our data in this study continue to suggest that Th17-like cells and associated cytokines may indeed play an important role in the immune responses to MAP infection and the development or control of JD.

The CSF-1-receptor inhibitor, JNJ-40346527 (PRV-6527), reduced inflammatory macrophage recruitment to the intestinal mucosa and suppressed murine T cell mediated colitis

BACKGROUND & AIMS

Originally believed to be primarily a disorder of T-cell signaling, evidence shows that macrophage-lineage cells also contribute to the pathogenesis of Crohn's disease (CD). Colony stimulating factor-1 (CSF-1) is a key regulator of the macrophage lineage, but its role in CD has not been well established. We examined transcriptional data from CD mucosa for evidence of CSF-1 pathway activation and tested JNJ-40346527 (PRV-6527), a small molecule inhibitor of CSF-1 receptor kinase (CSF-1R), for its ability to inhibit disease indices in murine colitis.

METHODS

A CSF-1 pathway gene set was created from microarray data of human whole blood cultured ex vivo with CSF-1 and compared to a TNFα-induced gene set generated from epithelial-lineage cells. Gene set variation analysis was performed using existing Crohn's mucosa microarray data comparing patients who either responded or failed to respond to anti-TNFα therapy. Commencing day 14 or day 21, mice with T-cell transfer colitis were treated with vehicle or JNJ-40346527 until study termination (day 42). Endpoints included colon weight/length ratios and histopathology scores, and macrophage and T cells were assessed by immunohistochemistry. Mucosal gene expression was investigated using RNAseq.

RESULTS

Both the CSF-1 and the TNFα gene sets were enriched in the colonic mucosal transcriptomes of Crohn's disease and in mouse colitis, and expression of both gene sets was highest in patients who did not respond to anti-TNFα therapy. In these patients neither set was reduced by therapy. In the mouse model, JNJ-40346527 inhibited the increase in colon weight/length ratio by ∼50%, reduced histological disease scores by ∼60%, and reduced F4/80+ mononuclear cell and CD3+ lymphocyte numbers. RNAseq analysis confirmed the CSF-1 gene set was sharply reduced in treated mice, as were gene sets enriched in "M1" inflammatory and "M0" resident macrophages and in activated T cells.

CONCLUSIONS

CSF-1 biology is activated in Crohn's disease and in murine T cell transfer colitis. Inhibition of CSF-1R by JNJ-40346527 was associated with attenuated clinical disease scores and reduced inflammatory gene expression in mice. These data provide rationale for testing JNJ-40346527 (PRV-6527) in human inflammatory bowel disease.

Inflammatory Th17 responses to infection with Mycobacterium avium subspecies paratuberculosis (MAP) in cattle and their potential role in development of Johne's disease

Chronic intestinal inflammation typically associated with late stage Johne's disease (JD) in cattle occurs despite a lack of significant expression of the typical proinflammatory cytokines IFNγ and TNFα derived from Th1- like T cells. In contrast, these cytokines appear to be relatively abundant during early infections with Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of JD in cattle. The roles of non-classical immune responses, such as those associated with Th17 cells, in response to MAP infection and development of clinical JD are less clear. In this review, we examine literature suggesting that Mycobacterial infections, including Mycobacterium tuberculosis, Mycobacterium bovis, and MAP, are all associated with expression of Th17 promoting cytokines (IL-23, IL-22, IL-17a). We discuss the possibility that Th17 associated cytokines, particularly IL-23, may act as contributing factors in development and maintenance of inflammation characteristic of clinical JD. An as yet relatively unexplored source of chronic inflammation due to over expression of IL-1α and IL-1β is also presented. We further discuss the fact that, as with the typical Th1-like cytokines IFNγ and TNFα , IL-17a is not significantly expressed in CD4+ T cells from cows with clinical JD, possibly due to T cell exhaustion. Finally, we present the notion that the Th17 driving cytokine IL-23 expressed by infected macrophages and associated epithelial cells may contribute to chronic inflammation during later stages of JD.

Mycobacterium avium sp. paratuberculosis (MAP) induces IL-17a production in bovine peripheral blood mononuclear cells (PBMCs) and enhances IL-23R expression in-vivo and in-vitro

Johne's disease (JD) is a chronic inflammatory gastrointestinal disease of ruminants caused by Mycobacterium avium subspecies paratuberculosis (MAP). Control of JD is difficult largely due to insensitive diagnostic tools, a long subclinical stage of infection, and lack of effective vaccines. Correlates of protection are lacking in model systems of JD and the sources of inflammation due to JD are not well characterized. Commonly studied immune responses, such as the Th1/Th2 paradigm, do not adequately explain host responses to MAP. A potential role for non-classical immune responses to MAP, such as that mediated by Th17 cells, has been suggested. Indeed, MAP antigens induce mRNAs encoding the cytokines IL-23 and IL-17a in bovine peripheral blood mononuclear cells (PBMCs). IL-23 and IL-17a production have both been associated with Th17-like immune responses. Th17 cells are also defined by surface expression of the IL-23 receptor (IL-23R). To determine the relative prevalence of potential Th17 cells in PBMCs from MAP test positive and MAP test negative cows, PBMCs were isolated and analyzed by immunostaining and flow cytometry. Fresh PBMCs from MAP test positive cows (n = 12) contained a significantly higher proportion of IL-23R positive cells in populations of CD4+, CD8+, and Yδ + T cells than in cells from MAP test negative cows (n = 12; p < 0.05). Treatment with MAP antigens increased the percentage of all T cell subsets with surface expression of IL-23R when compared to untreated (n = 12; p < 0.05) cells. ELISA results for IL-17a secretion revealed a higher concentration of IL-17a secreted from PBMCs treated with MAP antigen (n = 20) than from PBMCs not treated with MAP antigens (n = 20) (p < 0.001), regardless of the JD test status of source cows. Also, we observed a moderate negative correlation between JD diagnostic scores for JD + cows and plasma IL-17a concentration (n = 42; r = -0.437; p-value < 0.004). Plasma with low and mid JD- scores (n = 31; n = 9; 0.1 ≤ X < 0.3) had significantly more IL-17a when compared to plasma with high JD- scores (n = 10; 0.3 ≤ X < 0.46; p-values < 0.05). Similarly, plasma with low JD + score values (0.55 ≤ X < 1.0; n = 9) had significantly more IL-17a when compared to plasma with high JD + score values (X ≥ 2.0; n = 21; p < 0.05). Overall, plasma from JD + cows (0.55 < X ≤ 2.86; n = 41) had significantly less IL-17a than plasma from JD- cows (0 < X ≤ 0.46; n = 70). Our data suggests that Th17-like cells may indeed play a role in early immune responses to MAP infection and development or control of JD.

Macrophages in intestinal inflammation and resolution: a potential therapeutic target in IBD

Macrophages are the gatekeepers of intestinal immune homeostasis as they discriminate between innocuous antigens and potential pathogens to maintain oral tolerance. However, in individuals with a genetic and environmental predisposition, regulation of intestinal immunity is impaired, leading to chronic relapsing immune activation and pathologies of the gastrointestinal tract, such as IBD. As evidence suggests a causal link between defects in the resolution of intestinal inflammation and altered monocyte-macrophage differentiation in patients with IBD, macrophages have been considered as a novel potential target to develop new treatment approaches. This Review discusses the molecular and cellular mechanisms involved in the differentiation and function of intestinal macrophages in homeostasis and inflammation, and their role in resolving the inflammatory process. Understanding the molecular pathways involved in the specification of intestinal macrophages might lead to a new class of targets that promote remission in patients with IBD.

Adaptive and Innate Immunity in Psoriasis and Other Inflammatory Disorders

Over the past three decades, a considerable body of evidence has highlighted T cells as pivotal culprits in the pathogenesis of psoriasis. This includes the association of psoriasis with certain MHC (HLA) alleles, oligoclonal expansion of T cells in some cases, therapeutic response to T cell-directed immunomodulation, the onset of psoriasis following bone marrow transplantation, or induction of psoriasis-like inflammation by T cells in experimental animals. There is accumulating clinical and experimental evidence suggesting that both autoimmune and autoinflammatory mechanisms lie at the core of the disease. Indeed, some studies suggested antigenic functions of structural proteins, and complexes of self-DNA with cathelicidin (LL37) or melanocytic ADAMTSL5 have been proposed more recently as actual auto-antigens in some cases of psoriasis. These findings are accompanied by various immunoregulatory mechanisms, which we increasingly understand and which connect innate and adaptive immunity. Specific adaptive autoimmune responses, together with our current view of psoriasis as a systemic inflammatory disorder, raise the question of whether psoriasis may have connections to autoimmune or autoinflammatory disorders elsewhere in the body. While such associations have been suspected for many years, compelling mechanistic evidence in support of this notion is still scant. This review sets into context the current knowledge about innate and adaptive immunological processes in psoriasis and other autoimmune or autoinflammatory diseases.

Identification of genetic biomarkers for alloimmunization in sickle cell disease

Most sickle cell disease (SCD) patients rely on blood transfusion as their main treatment strategy. However, frequent blood transfusion poses the risk of alloimmunization. On average, 30% of SCD patients will alloimmunize while other patient groups form antibodies less frequently. Identification of genetic markers may help to predict which patients are at risk to form alloantibodies. The aim of this study was to evaluate whether genetic variations in the Toll-like receptor pathway or in genes previously associated with antibody-mediated conditions are associated with red blood cell (RBC) alloimmunization in a cohort of SCD patients. In this case-control study, cases had a documented history of alloimmunization while controls had received ≥20 RBC units without alloantibody formation. We used a customized single nucleotide polymorphism (SNP) panel to genotype 690 SNPs in 275 (130 controls, 145 cases) patients. Frequencies were compared using multiple logistic regression analysis. In our primary analysis, no SNPs were found to be significantly associated with alloimmunization after correction for multiple testing. However, in a secondary analysis with a less stringent threshold for significance we found 19 moderately associated SNPs. Among others, SNPs in TLR1/TANK and MALT1 were associated with a higher alloimmunization risk, while SNPs in STAM/IFNAR1 and STAT4 conferred a lower alloimmunization risk.

T lymphocytes in the intestinal mucosa: defense and tolerance

Although lymphocytes are known to circulate throughout lymphoid tissues and blood, they also establish residency in nonlymphoid organs, most prominently in barrier tissues, such as the intestines. The adaptation of T lymphocytes to intestinal environments requires constant discrimination between natural stimulation from commensal flora and food and pathogens that need to be cleared. Genetic variations that cause a defective defense or a break in tolerance along with environmental cues, such as infection or imbalances in the gut microbiota known as dysbiosis, can trigger several immune disorders via the activation of T lymphocytes in the intestines. Elucidation of the immune mechanisms that distinguish between commensal flora and pathogenic organisms may reveal therapeutic targets for the prevention or modulation of inflammatory diseases and boost the efficacy of cancer immunotherapy. In this review, we discuss the development and adaptation of T lymphocytes in the intestine, how these cells protect the host against pathogenic infections while tolerating food antigens and commensal microbiota, and the potential implications of targeting these cells for disease management and therapeutics.

IL-23 in inflammatory bowel diseases and colon cancer

Studies in recent years have identified a pivotal role of the cytokine IL-23 in the pathogenesis of inflammatory bowel diseases (IBD: Crohn´s disease, ulcerative colitis) and colitis-associated colon cancer. Genetic studies revealed that subgroups of IBD patients have single nucleotide polymorphisms in the IL-23R gene suggesting that IL-23R signaling affects disease susceptibility. Furthermore, increased production of IL-23 by macrophages, dendritic cells or granulocytes has been observed in various mouse models of colitis, colitis-associated cancer and IBD patients. Moreover, in several murine models of colitis, suppression of IL-12/IL-23 p40, IL-23 p19 or IL-23R function led to marked suppression of gut inflammation. This finding was associated with reduced activation of IL-23 target cells such as T helper 17 cells, innate lymphoid cells type 3, granulocytes and natural killer cells as well as with impaired production of proinflammatory cytokines. Based on these findings, targeting of IL-23 emerges as important concept for suppression of gut inflammation and inflammation-associated cancer growth. Consistently, neutralizing antibodies against IL-12/IL-23 p40 and IL-23 p19 have been successfully used in clinical trials for therapy of Crohn´s disease and pilot studies in ulcerative colitis are ongoing. These findings underline the crucial regulatory role of IL-23 in chronic intestinal inflammation and colitis-associated cancer and indicate that therapeutic strategies aiming at IL-23 blockade may be of key relevance for future therapy of IBD patients.

Granulomonocytapheresis as a cell-dependent treatment option for patients with inflammatory bowel disease: Concepts and clinical features for better therapeutic outcomes

Ulcerative colitis (UC) and Crohn's disease (CD) are major phenotypes of the chronic inflammatory bowel disease (IBD), which afflicts millions of individuals throughout the world with debilitating symptoms. The chronic nature of IBD means that patients require life-long medications, and this may lead to drug dependency, loss of response together with adverse side effects as additional morbidity factors. The efficacy of antitumour necrosis factor (TNF)-α biologics has validated the role of inflammatory cytokines notably TNF-α in the exacerbation and perpetuation of IBD. However, cytokines are released by myeloid lineage leucocytes like the CD14⁺ CD16⁺ monocyte phenotype. Additionally in IBD, myeloid leucocytes are elevated with activation behavior, while lymphocytes are compromised. Therefore, patients' leucocytes appear logical targets of therapy. Adsorptive granulomonocytapheresis (GMA) with an Adacolumn uses carriers, which interact with the Fcγ receptor expressing leucocytes and deplete the elevated myeloid leucocytes, while the neutrophils, which re-enter the circulation via the Adacolumn outflow (≥40%) are phagocytosed by CD19 B-cells to become interleukin (IL)-10 producing Bregs or CD19^high CD1D^high B-cells. IL-10 is an anti-inflammatory cytokine. GMA has been applied to treat patients with IBD. The efficacy outcomes have been impressive as well as disappointing, the clinical response to GMA defines the patients' disease course and severity at entry. Efficacy outcomes in patients with deep ulcers together with extensive loss of the mucosal tissue are not encouraging, while patients without these features respond well and attain a favorable long-term disease course. Accordingly, for responder patients, GMA fulfills a desire to be treated without drugs.

Subcutaneous rather than intravenous ustekinumab induction is associated with comparable circulating drug levels and early clinical response: a pilot study

BACKGROUND

Ustekinumab (USK) is licenced for intravenous induction and subcutaneous (S/C) maintenance in Crohn's disease.

AIM

To evaluate ustekinumab trough concentrations and clinical response with exclusive subcutaneous ustekinumab induction.

METHODS

Patients with Crohn's disease who initiated treatment with subcutaneous ustekinumab at a single academic centre were included in this pilot study. A dosage of 360 mg ustekinumab was given subcutaneously in divided doses; 180 mg at Week 0, 90 mg at Week 1 and 90 mg at Week 2, with corresponding ustekinumab trough concentrations assessed to Week 8. The primary outcome measures were trough serum ustekinumab levels and clinical remission at Week 8. Secondary outcome measures were trough serum ustekinumab levels at Week 1 & 2 and changes in C-reactive protein, albumin and faecal calprotectin at Week 8.

RESULTS

Nineteen patients were included. Median Week 8 ustekinumab trough concentrations were 6.1 μg/mL (Inter-quartile range 4-9.8 μg/mL). There was a significant improvement in Harvey Bradshaw index from Week 0 (median HBI 5; interquartile range 2-8) to Week 8 (median HBI 1; interquartile range 0-3) (P = 0.002). C-reactive protein levels did not change significantly but faecal calprotectin improved significantly; median faecal calprotectin at Week 0 was 533 μg/g; at Week 8, it was 278 μg/g (P = 0.038).

CONCLUSIONS

Ustekinumab trough concentrations are comparable whether ustekinumab induction treatment was administered subcutaneously or intravenously. A significant improvement in symptoms and faecal calprotectin was noted. These results support the use of subcutaneous induction as an alternative if there are barriers to intravenous induction.

The Interleukin-23/Interleukin-17 Axis Links Adaptive and Innate Immunity in Psoriasis

Research into the pathophysiology of psoriasis has shed light onto many fascinating immunological interactions and underlying genetic constellations. Most prominent among these is the crosstalk between components of the innate and the adaptive immune system and the crucial role of interleukins (IL)-23 and -17 within this network. While it is clear that IL-23 drives and maintains the differentiation of Th17 lymphocytes, many aspects of the regulation of IL-23 and IL-17 are not quite as straightforward and have been unraveled only recently. For example, we know now that Th17 cells are not the only source of IL-17 but that cells of the innate immune system also produce considerable amounts of this central effector cytokine. In addition, there is IL-23-independent production of IL-17. Besides other innate immune cells, neutrophilic granulocytes prominently contribute to IL-17-related immune regulations in psoriasis, and it appears that they employ several mechanisms including the formation of neutrophil extracellular traps. Here, we strive to put the central role of the IL-23/IL-17 axis into perspective within the crosstalk between components of the innate and the adaptive immune system. Our aim is to better understand the complex immune regulation in psoriasis, a disorder that has become a model disease for chronic inflammation.

Andrographolide affects Th1/Th2/Th17 responses of peripheral blood mononuclear cells from ulcerative colitis patients

Ulcerative colitis (UC) is a chronic, idiopathic, inflammatory bowel disease of the colon. T cell responses have been associated with the pathology of UC. Andrographis paniculata (AP) extract has been previously reported as an effective treatment of UC. The present study aimed to explore the effects of andrographolide, the primary active component of AP, on the T cell responses of patients with UC. Peripheral blood mononuclear cells (PBMCs) were isolated from patients with UC and treated with various concentrations of andrographolide (0, 10, 20 and 30 µg/ml). Andrographolide decreased interferon γ, interleukin (IL)‑23 and IL‑17A, however it increased IL‑4 in a dose‑dependent manner, as indicated by ELISA assay. Andrographolide treatment resulted in a decreased percentage of T helper (Th)1 and Th17 cells and an increased proportion of Th2 cells, as demonstrated by flow cytometry analysis. T‑bet (a Th1‑specific transcription factor) and RAR‑related orphan receptor γt (key transcription factor of Th17 cells) expression was decreased, but GATA‑3 (Th2 lineage‑specific transcription factor) expression was increased following andrographolide treatment as indicated by western blot analysis. These results demonstrated the inhibitory effects on Th1/Th17 responses and the promoting effects on Th2 responses of andrographolide. Experiments on IL‑23‑treated PBMCs from healthy donors revealed similar effects of andrographolide on Th1/Th2/Th17 responses. In summary, these results suggest that andrographolide may be an effective candidate for the treatment of IL‑23‑mediated diseases.

Pharmacokinetics and Exposure Response Relationships of Ustekinumab in Patients With Crohn's Disease

BACKGROUND & AIMS

Ustekinumab is a monoclonal antibody that binds with high affinity to the p40 subunit of human interleukin 12 (IL12 and IL23) that has been approved for treatment of patients with moderate to severe Crohn's disease (CD). However, there are few data on its pharmacokinetic properties or the relationship between drug exposure levels and patient response. We collected data from 2 Phase 3 induction studies and 1 maintenance study to determine ustekinumab's pharmacokinetic features, relationship between exposure and response, and optimal serum concentrations for efficacy.

METHODS

We collected data on serum concentrations of ustekinumab and efficacy from induction studies of patients with moderate to severe CD given ustekinumab for 8 weeks following a single intravenous dose (either 130 mg or approximately 6 mg/kg). We collected the same data from a maintenance study of patients with a response to ustekinumab in the induction study who then received subcutaneous injections (90 mg) every 8 or 12 weeks for 44 weeks. At week 44 of the maintenance study (52 weeks after treatment began), patients were evaluated for the primary endpoint of clinical remission (defined as a CD activity index score below 150 points), endoscopic markers of efficacy, and serum level of C-reactive protein. Ustekinumab concentration data were categorized into quartiles and relationships between exposure and response were assessed. Optimal concentration cutoff values were evaluated using receiver operating characteristic curve analysis.

RESULTS

Serum concentrations of ustekinumab over time were proportional to dose and did not differ significantly between the induction studies. In the maintenance study, ustekinumab concentration reached the steady state by the second maintenance dose; the median trough concentration was approximately threefold higher in patients given ustekinumab at 8-week intervals compared with 12-week intervals. Ustekinumab serum concentrations associated with rates of clinical remission and endoscopic efficacy endpoints, correlated inversely with level of C-reactive protein, and did not associate with use of immunomodulators. Trough concentrations of ustekinumab of 0.8 (or even up to 1.4 μg/mL) or greater were associated with maintenance of clinical remission in a higher proportion of patients than patients with lower trough concentrations.

CONCLUSIONS

In an analysis of data from Phase 3 studies of patients with moderate to severe CD, we found serum concentrations of ustekinumab to be proportional to dose and associate with treatment efficacy. Concentrations of ustekinumab did not seem to be affected by cotreatment with immunomodulators. Clinicaltrials.gov no. NCT01369329 (UNITI 1), NCT01369342 (UNITI 2), and NCT01369355 (IM-UNITI).

Enrichment of IL-17A+ IFN-γ+ and IL-22+ IFN-γ+ T cell subsets is associated with reduction of NKp44+ ILC3s in the terminal ileum of Crohn's disease patients

Crohn's disease (CD) is a chronic inflammatory condition of the human gastrointestinal tract whose aetiology remains largely unknown. Dysregulated adaptive immune responses and defective innate immunity both contribute to this process. In this study, we demonstrated that the interleukin (IL)-17A+ interferon (IFN)-γ+ and IL-22+ IFN-γ+ T cell subsets accumulated specifically in the inflamed terminal ileum of CD patients. These cells had higher expression of Ki-67 and were active cytokine producers. In addition, their proportions within both the IL-17A-producer and IL-22-producer populations were increased significantly. These data suggest that IL-17A+ IFN-γ+ and IL-22+ IFN-γ+ T cell subsets might represent the pathogenic T helper type 17 (Th17) population in the context of intestinal inflammation for CD patients. In the innate immunity compartment we detected a dramatic alteration of both phenotype and function of the intestinal innate lymphoid cells (ILCs), that play an important role in the maintenance of mucosal homeostasis. In the inflamed gut the frequency of the NKp44- CD117- ILC1s subset was increased significantly, while the frequency of NKp44+ ILC3s was reduced. Furthermore, the frequency of human leucocyte antigen D-related (HLA-DR)-expressing-NKp44+ ILC3s was also reduced significantly. Interestingly, the decrease in the NKp44+ ILC3s population was associated with an increase of pathogenic IL-17A+ IFN-γ+ and IL-22+ IFN-γ+ T cell subsets in the adaptive compartment. This might suggest a potential link between NKp44+ ILC3s and the IL-17A+ IFN-γ+ and IL-22+ IFN-γ+ T cell subsets in the terminal ileum of CD patients.

Positioning Ustekinumab in Crohn's Disease: From Clinical Evidence to Clinical Practice

Biological medicines have revolutionised the treatment of Crohn's disease [CD]. Yet, the management of patients not responding to tumour necrosis factor [TNF] antagonists remains a clinical challenge. Ustekinumab is a human monoclonal antibody blocking the biological activity of interleukins 12 and 23, which regulate the immune system and immune-mediated inflammatory disorders. Ustekinumab has recently been approved for the treatment of adult patients with moderately to severely active CD, who have had an inadequate response with, lost response to, or were intolerant to either conventional therapy or a TNF antagonist, or have medical contraindications to such therapies. Herein, we review the new biological drug's efficacy and safety data reported from randomised controlled trials and real-world observational studies conducted in populations with CD, in order to identify the patient groups most likely to benefit, and to appropriately place ustekinumab into treatment algorithms for CD.

Association Between Ustekinumab Trough Concentrations and Clinical, Biomarker, and Endoscopic Outcomes in Patients With Crohn's Disease

BACKGROUND & AIMS

Ustekinumab, an inhibitor of the p40 subunit of interleukins 12 and 23, is an effective treatment for patients with Crohn's disease (CD). Trough concentrations of tumor necrosis factor (TNF) antagonists and presence of anti-drug antibodies are associated with important clinical and endoscopic outcomes. We investigated associations between trough concentrations of ustekinumab and clinical, biomarker, and endoscopic outcomes of real-world patients with CD.

METHODS

We recruited 62 patients with CD who were either refractory or intolerant to TNF antagonists, treated with ustekinumab from April 2014 to September 2015. Patients received 90 mg of ustekinumab subcutaneously at weeks 0, 1, and 2 during induction and 90 mg every 4 or 8 weeks during maintenance. Clinical, biomarker, and endoscopic outcomes, trough concentrations of ustekinumab, and anti-drug antibodies were assessed at both week 10 postinduction therapy and at week 26 or later during maintenance therapy in a prospective longitudinal patient cohort or at week 26 or later during maintenance therapy in a cross-sectional patient cohort. Analysis was performed on data combined from both maintenance cohorts, which had similar outcomes at week 26 or later. A primary analysis determined if ustekinumab drug trough concentrations were associated with clinical response (reduction in Harvey Bradshaw Index score of 3 or greater), clinical remission (Harvey Bradshaw Index score <5), steroid-free clinical remission, biomarker (serum level of C-reactive protein [CRP] or level of fecal calprotectin) reduction, biomarker normalization (serum level of CRP below 5 mg/L or level of fecal calprotectin below 200 μg/g), endoscopic response (simple endoscopic score for CD reduced by 50% or more), or endoscopic remission (simple endoscopic score for CD of 2 or less).

RESULTS

At week 26 or beyond, 80.7% of patients had a clinical response, 66.1% were in clinical remission, 50.0% were in steroid-free clinical remission, 58.9% had an endoscopic response, and 19.6% were in endoscopic remission. The mean trough concentration of ustekinumab at this time point was higher in patients with an endoscopic response (4.7 μg/mL) than without (3.8 ug/mL; P = .03). An optimal ustekinumab threshold trough concentration at week 26 or later was found to be 4.5 μg/mL (area under the curve, 0.67). A greater proportion of patients with trough concentrations of ustekinumab above 4.5 μg/mL at week 26 or later had an endoscopic response (75.9%) than did patients with trough concentrations below this level (40.7%; P = .008). Patients with trough concentrations of ustekinumab above 4.5 μg/mL at week 26 or later also had a lower mean level of CRP (12.6 mg/L) than did patients with trough concentrations below this level (mean level of CRP, 23.9 mg/L; P = .04). We did not detect antibodies against ustekinumab in any patient.

CONCLUSIONS

Ustekinumab therapy was effective in patients with CD who had not responded to or were intolerant to treatment with a TNF antagonist. Maintenance trough concentrations of ustekinumab above 4.5 μg/mL at 26 weeks or later were associated with biomarker reduction and endoscopic response.

New treatment strategies for ulcerative colitis

INTRODUCTION

Therapeutic strategies in ulcerative colitis are evolving. A personalized and optimal use of available drugs and the integration of new drug classes are the cornerstones underpinning the new treatment paradigms. Areas covered: A structured literature search in Medline and PubMed, Cochrane meta-analyses, and abstracts of international congresses has been performed to review therapeutic approaches to ulcerative colitis. The primary therapeutic objective of therapy is to achieve clinical remission since persistence of active disease, even if mild, leads to a significant reduction in quality of life. Current treatment paradigms of ulcerative colitis are based on the use of 5-aminosalycilates, corticosteroids, thiopurines, TNF-α inhibitors and α4ß7 integrin blockers. The main determinants for drug class selection are disease extension, disease severity, and previous drug history. New drug classes that will likely become available in the foreseeable future include inhibitors of Janus kinases, modulators of sphingosine-1-phosphate receptors, SMAD-7 antisense oligonucleotides, interleukin-12/23 blockers, and fecal microbiota transplantation. Expert commentary: Increasing therapeutic options for ulcerative colitis make predictors of response highly relevant. While these are not available, judicious use of therapies, avoidance of underdosing, or persistent therapy when criteria for drug failure are met are essential.

Current and emerging therapeutic targets for IBD

Various therapeutic advances have led to a paradigm shift in the clinical management of patients with IBD. The introduction of immunosuppressive (such as azathioprine) and biologic agents (such as TNF blockers) has markedly reduced the need to use corticosteroids for therapy. Furthermore, the α4β7 integrin blocker vedolizumab has been introduced for clinical IBD therapy. Moreover, various new inhibitors of cytokines (for example, IL-6-IL-6R and IL-12-IL-23 blockers or apremilast), modulators of cytokine signalling events (for example, JAK inhibitors or SMAD7 blocker), inhibitors of transcription factors (for example, GATA3 or RORγt) and new anti-adhesion and anti-T-cell-activation and migration strategies (for example, β7 integrin, sphingosine 1-phosphate receptors and MAdCAM1 inhibitors, regulatory T-cell therapy and stem cells) are currently being evaluated in controlled clinical trials. This Review aims to provide a comprehensive overview about current and future therapeutic approaches for IBD therapy. Furthermore, potential mechanisms of action of these therapeutic approaches and their implications for clinical therapy in IBD are discussed.

Induction therapy with the selective interleukin-23 inhibitor risankizumab in patients with moderate-to-severe Crohn's disease: a randomised, double-blind, placebo-controlled phase 2 study

BACKGROUND

The interleukin-23 pathway is implicated genetically and biologically in the pathogenesis of Crohn's disease. We aimed to assess the efficacy and safety of risankizumab (BI 655066, Boehringer Ingelheim, Ingelheim, Germany), a humanised monoclonal antibody targeting the p19 subunit of interleukin-23, in patients with moderately-to-severely active Crohn's disease.

METHODS

In this randomised, double-blind, placebo-controlled phase 2 study, we enrolled patients at 36 referral sites in North America, Europe, and southeast Asia. Eligible patients were aged 18-75 years, with a diagnosis of Crohn's disease for at least 3 months, assessed as moderate-to-severe Crohn's disease at screening, defined as a Crohn's Disease Activity Index (CDAI) of 220-450, with mucosal ulcers in the ileum or colon, or both, and a Crohn's Disease Endoscopic Index of Severity (CDEIS) of at least 7 (≥4 for patients with isolated ileitis) on ileocolonoscopy scored by a masked central reader. Patients were randomised 1:1:1 using an interactive response system to a double-blind investigational product, and stratified by previous exposure to TNF antagonists (yes vs no). Patients received intravenous 200 mg risankizumab, 600 mg risankizumab, or placebo, at weeks 0, 4, and 8. The primary outcome was clinical remission (CDAI <150) at week 12 (intention-to-treat population). Safety was assessed in patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number NCT02031276.

FINDINGS

Between March, 2014, and September, 2015, 213 patients were screened, and 121 patients randomised. At baseline, 113 patients (93%) had been previously treated with at least one tumour necrosis factor (TNF) antagonist (which had failed in 96 [79%]). At week 12, 25 (31%) of 82 risankizumab patients (pooled 41 patients in 200 mg and 41 patients in 600 mg arms) had clinical remission versus six (15%) of 39 placebo patients (difference vs placebo 15·0%, 95% CI 0·1 to 30·1; p=0·0489). Ten (24%) of 41 patients who received 200 mg risankizumab had clinical remission (9·0%, -8·3 to 26·2; p=0·31) and 15 (37%) of 41 who received the 600 mg dose (20·9%, 2·6 to 39·2; p=0·0252). 95 (79%) patients had adverse events (32 in the placebo group, 32 randomised to 200 mg risankizumab, 31 randomised to 600 mg risankizumab); 18 had severe adverse events (nine, six, three); 12 discontinued (six, five, one); 24 had serious adverse events (12, nine, three). The most common adverse event was nausea and most common serious adverse event was worsening of underlying Crohn's disease. No deaths occurred.

INTERPRETATION

In this short-term study, risankizumab was more effective than placebo for inducing clinical remission in patients with active Crohn's disease. Therefore, selective blockade of interleukin-23 via inhibition of p19 might be a viable therapeutic approach in Crohn's disease.

FUNDING

Boehringer Ingelheim.

Protease-activated Receptor 1 Plays a Proinflammatory Role in Colitis by Promoting Th17-related Immunity

BACKGROUND

Proteolytic cleavage of protease-activated receptor 1 (PAR1) can result in potent downstream regulatory effects on inflammation. Although PAR1 is expressed throughout the gastrointestinal tract and activating proteases are increased in inflammatory bowel disease, the effect of PAR1 activation on colitis remains poorly understood, and has not previously been studied in pediatric disease.

METHODS

Expression of PAR1 and inflammatory cytokines in colonic biopsies from pediatric patients with Crohn's disease exhibiting active moderate to severe colitis was measured by quantitative PCR. The functional relevance of these clinical data was further studied in a mouse model of Citrobacter rodentium-induced colitis.

RESULTS

PAR1 expression was significantly upregulated in the inflamed colons of pediatric patients with Crohn's disease, with expression levels directly correlating to disease severity. In patients with severe colitis, PAR1 expression uniquely correlated with Th17-related (IL17A, IL22, and IL23A) cytokines. Infection of PAR1-deficient (PAR1) and wildtype mice with colitogenic C. rodentium revealed that disease severity and colonic pathology were strongly attenuated in mice lacking PAR1. Furthermore, Th17-type immune response was completely abolished in the colons of infected PAR1 but not wildtype mice. Finally, PAR1 was shown to be essential for secretion of the Th17-driving cytokine IL-23 by C. rodentium-stimulated macrophages.

CONCLUSIONS

This study demonstrates a strong link between PAR1 expression, Th17-type immunity, and disease severity in both pediatric patients with Crohn's disease and C. rodentium-induced colitis in mice. The data presented suggest PAR1 exerts a proinflammatory role in colitis in both humans and mice by promoting a Th17-type immune response, potentially by supporting the production of IL-23.

[Pathogenesis of psoriasis]

Psoriasis is an inflammatory T cell-mediated autoimmune disease of skin and joints that affects 2-4 % of the adult population and 0.1-1 % of children. Genetic susceptibility, environmental triggering factors, and innate immune processes initiate psoriasis pathogenesis that results in an adaptive autoreactive response. The T cell response is orchestrated by CD 8(+) T cells in the epidermis and by CD 4(+) T cells in the dermis that predominantly produce interleukin-17 (IL‑17). Research of the past 15 years unraveled cellular and molecular mechanisms as well as cytokines like TNF-α or IL‑23 that contribute to psoriatic inflammation. This knowledge has been translated into clinical practice and a number of antipsoriatic small molecules and immunobiologics are now available. Here, we discuss the current principles of psoriasis pathogenesis in the context of modern therapies.

Mapping the Energetic Epitope of an Antibody/Interleukin-23 Interaction with Hydrogen/Deuterium Exchange, Fast Photochemical Oxidation of Proteins Mass Spectrometry, and Alanine Shave Mutagenesis

Epitope mapping the specific residues of an antibody/antigen interaction can be used to support mechanistic interpretation, antibody optimization, and epitope novelty assessment. Thus, there is a strong need for mapping methods, particularly integrative ones. Here, we report the identification of an energetic epitope by determining the interfacial hot-spot that dominates the binding affinity for an anti-interleukin-23 (anti-IL-23) antibody by using the complementary approaches of hydrogen/deuterium exchange mass spectrometry (HDX-MS), fast photochemical oxidation of proteins (FPOP), alanine shave mutagenesis, and binding analytics. Five peptide regions on IL-23 with reduced backbone amide solvent accessibility upon antibody binding were identified by HDX-MS, and five different peptides over the same three regions were identified by FPOP. In addition, FPOP analysis at the residue level reveals potentially key interacting residues. Mutants with 3-5 residues changed to alanine have no measurable differences from wild-type IL-23 except for binding of and signaling blockade by the 7B7 anti-IL-23 antibody. The M5 IL-23 mutant differs from wild-type by five alanine substitutions and represents the dominant energetic epitope of 7B7. M5 shows a dramatic decrease in binding to BMS-986010 (which contains the 7B7 Fab, where Fab is fragment antigen-binding region of an antibody), yet it maintains functional activity, binding to p40 and p19 specific reagents, and maintains biophysical properties similar to wild-type IL-23 (monomeric state, thermal stability, and secondary structural features).

Alterations in cytokine gene expression profile in colon mucosa of Inflammatory Bowel Disease patients on different therapeutic regimens

Inflammatory bowel disease (IBD) is assumed to be caused by genetic and environmental factors that interact together in promoting intestinal immune dysregulation where cytokines have validated role. However, the underlying intimate mechanisms in the human IBD involving cytokines still needs to be supplemented especially in the clinical context. The aim of this study was to investigate the expression of some inflammatory and regulatory cytokines (IL-17A, IL-23, IL-6, TGFβ1, and IL-10) as well as of the transcription factor FoxP3 in mucosal samples of IBD and non-IBD patients. We assessed the mRNA relative quantities (RQ) of the above-mentioned cytokines and the transcription factor FoxP3 in paired colonic samples (inflamed and adjacent normal mucosa) from 37 patients with IBD and in normal mucosal tissue in 12 persons without IBD by performing a qRT-PCR assay and tested the protein levels of target cytokines in serum samples. The patients were divided into three groups: without any therapy (n=10), on 5-ASA (n=11) and on immunosuppressants (Azathioprine±5-ASA/corticosteroids) (n=16) in order to compare the RQ values for each therapeutic group. All investigated genes were found upregulated in the inflamed mucosa of IBD patients in the following order: IL-6>FoxP3>TGFβ1>IL-23>IL-17A>IL-10. We also observed that the gene expression of FoxP3 and IL-6 were substantially higher in the inflamed mucosal tissue of the IBD patients than the adjacent normal mucosa (p=0.035, p=0.03 respectively). Differences between higher mRNA expression of FoxP3 and IL-6 in inflamed tissue were considered significant in patients with ulcerative colitis (UC) (p=0.011, p=0.000 respectively) and with Crohn's disease (CD) (p=0.008, p=0.000 respectively) in comparison to the normal mucosa of non-IBD persons and we found increased TGFβ1 in CD patients alone (p=0.041). Furthermore, IL-6 and TGFβ1 were overexpressed (RQ>10) in non-inflamed mucosa from IBD patients compared to the normal mucosa from the controls. When we compared the gene expression for paired mucosa in the immunosuppressive treated group with the 5-ASA treated group we observed opposite changes in IL-6 and TGFβ1 expression. Additionally, we found higher serum levels of IL-23 (p=0.008), TGFβ1 and IL-6 in IBD patients compared to non-IBD patients. The obtained specific expression profile consisting of IL-6, TGFβ1, IL-10 and FoxP3 may represent a transcriptional hallmark for IBD. Furthermore, we found that treatment with immunosuppressive therapy was more beneficial for driving cytokine expression to restore immune regulation in patients with IBD, unlike the 5-ASA therapy.

Effects of humanin on experimental colitis induced by 2,4,6-trinitrobenzene sulphonic acid in rats

BACKGROUND/AIM

The excessive apoptosis of intestinal epithelial cells (IECs) partly accounts for the development of colonic inflammation and eventually results in ulcerative colitis (UC). Humanin, an endogenous anti-apoptotic peptide, has previously been shown to protect against Alzheimer's disease and a variety of cellular insults. The present study aimed to investigate the effects of glysin variant of humanin (HNG) on 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats.

MATERIALS AND METHODS

Rats were divided into four groups as follows: Group 1 (n = 8): control; isotonic saline solution 0.1 ml/rat rectally, Group 2 (n = 8): TNBS colitis; 0.1 ml of a 2.5% (w/v) TNBS solution in 50% ethanol rectally, Group 3 (n = 8): 10 μM HNG, and Group 4 (n = 8): 20 μM HNG intraperitoneal (ip) on day 2 and 6 after rectal TNBS administration. Rats were sacrificed 7 days after the induction of colitis. Blood and tissue samples were harvested for biochemical and histopathological analysis.

RESULTS

HNG treatment significantly ameliorated weight loss and macroscopic and microscopic scores. TNBS-induced colitis significantly increased the colonic mRNA expression of tumor necrosis factor-alpha (TNF-α), interleukin-1beta (IL-1β), and caspase-3 activities in group II in comparison to the group I. HNG treatment was associated with an inhibition of mRNA expression of TNF-α and IL-1β, and a decrease in caspase-3 activities in colon tissues in group III and IV when compared to group II.

CONCLUSION

The results of this study indicate that HNG treatment may exert beneficial effects in UC by decreasing inflammatory reactions and apoptosis.

Toll-like receptor-mediated immune responses in intestinal macrophages; implications for mucosal immunity and autoimmune diseases

Monocytes are precursors of macrophages and key players during inflammation and pathogen challenge in the periphery, whereas intestinal resident macrophages act as innate effector cells to engulf and clear bacteria, secrete cytokines, and maintain intestinal immunity and homeostasis. However, perturbation of toll-like receptor signaling pathway in intestinal macrophages has been associated with tolerance breakdown in autoimmune diseases. In the present review, we have summarized and discussed the role of toll-like receptor signals in human intestinal macrophages, and the role of human intestinal macrophages in keeping human intestinal immunity, homeostasis, and autoimmune diseases.

Targeting the complex interactions between microbiota, host epithelial and immune cells in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory intestinal disorder that includes two distinct disease categories: ulcerative colitis and Crohn's disease. Epidemiological, genetic, and experimental studies have revealed many important aspects of IBD. Genetic susceptibility, inappropriate immune responses, environmental changes, and intestinal microbiota are all associated with the development of IBD. However, the exact mechanisms of the disease and the interactions among these pathogenic factors are largely unknown. Here we introduce recent findings from experimental colitis models that investigated the interactions between host genetic susceptibility and gut microbiota. In addition, we discuss new strategies for the treatment of IBD, focusing on the complex interactions between microbiota and host epithelial and immune cells.