Therapeutic targeting of the IL-12/23 pathways: generation and characterization of ustekinumab

Biologics for Psoriasis

Biologic therapies targeting tumor necrosis factor alpha (TNF-α) (infliximab, adalimumab, certolizumab, etanercept), the p40 subunit shared by IL-12 and IL-23 (ustekinumab), the p19 subunit of IL-23 (guselkumab, tildrakizumab, risankizumab), IL-17A (secukinumab, ixekizumab), IL-17-RA (brodalumab) and both IL-17A and IL-17F (bimekizumab) have revolutionized the treatment of psoriasis. In both the short and long term, risankizumab had highest Psoriasis Area and Severity Index 90 scores compared to other oral and injectable biologics. IL-23 inhibitors had lowest rates of short-term and long-term adverse events and most favorable long-term risk-benefit profile compared to IL-17, IL-12/23, and TNF-α inhibitors.

Interleukin inhibitors and the associated risk of candidiasis

Interleukins (ILs) are vital in regulating the immune system, enabling to combat fungal diseases like candidiasis effectively. Their inhibition may cause enhanced susceptibility to infection. IL inhibitors have been employed to control autoimmune diseases and inhibitors of IL-17 and IL-23, for example, have been associated with an elevated risk of Candida infection. Thus, applying IL inhibitors might impact an individual's susceptibility to Candida infections. Variations in the severity of Candida infections have been observed between individuals with different IL inhibitors, necessitating careful consideration of their specific risk profiles. IL-1 inhibitors (anakinra, canakinumab, and rilonacept), IL-2 inhibitors (daclizumab, and basiliximab), and IL-4 inhibitors (dupilumab) have rarely been associated with Candida infection. In contrast, tocilizumab, an inhibitor of IL-6, has demonstrated an elevated risk in the context of coronavirus disease 2019 (COVID-19) treatment, as evidenced by a 6.9% prevalence of candidemia among patients using the drug. Furthermore, the incidence of Candida infections appeared to be higher in patients exposed to IL-17 inhibitors than in those exposed to IL-23 inhibitors. Therefore, healthcare practitioners must maintain awareness of the risk of candidiasis associated with using of IL inhibitors before prescribing them. Future prospective studies need to exhaustively investigate candidiasis and its associated risk factors in patients receiving IL inhibitors. Implementing enduring surveillance methods is crucial to ensure IL inhibitors safe and efficient utilization of in clinical settings.

The IL-21/IL-21R signaling axis regulates CD4+ T cell responsiveness to IL-12 to promote bacterial-induced colitis

IL-21/IL-21R signaling dysregulation is linked to multiple chronic intestinal inflammatory disorders in humans and animal models of human diseases. In addition to its critical requirement for the generation and development of germinal center B cells, IL-21/IL-21R signaling can also regulate the effector functions of a variety of T cell subsets. The antibody-mediated abrogation of IL-21/IL-21R signaling led to the impaired expression of IFN-γ by mucosal CD4+ T cells from human subjects with colitis, suggesting an IL-21/IL-21R-triggered positive feedback loop of the TH1 immune response in the colon. Despite recent advances in our understanding of the mechanisms underpinning the regulation of pro-inflammatory immune responses by the IL-21/IL-21R signaling axis, it remains unclear how this pathway or its downstream molecules contribute to inflammation during bacterial-induced colitis. This study found that IL-21 enhances the surface expression of IL-12Rβ2, but not IL-12Rβ1, in CD4+ T cells, leading to TH1 differentiation and stability. Consistently, these findings also point to an indispensable role of the IL-12Rβ2 signaling axis in promoting pro-inflammatory immune responses during Citrobacter rodentium-induced colitis. Genetic deletion of the IL-12Rβ2 signaling pathway led to the attenuation of C. rodentium-induced colitis in vivo. The genetic deletion of the IL-12Rβ2 signaling pathway did not alter the host's ability to respond adequately to C. rodentium infection or the ability of Il12rb2-/- mice to express antigen-specific cytokines (IFN-γ, IL-17A). IL-21 is a pleiotropic cytokine exerting a wide range of immunomodulatory functions in multiple tissues, and its direct targeting may result in undesirable off-target consequences. These findings highlight the possibility for targeted manipulations of signaling cascades downstream of main regulators of pro-inflammatory responses to control invading pathogens while preserving the integrity of host immune responses. A better understanding of the novel mechanisms by which IL-21/IL-21R signaling regulates bacterial-induced colitis will provide insights into the development of new therapeutic and preventive strategies to harness IL-21/IL-21R signaling or its downstream molecules to treat infectious colitis.

Ustekinumab in the Treatment of Inflammatory Bowel Diseases: Evolving Paradigms

Inflammatory bowel diseases, comprising Crohn's disease (CD) and ulcerative colitis (UC), are chronic, relapsing, and remitting immune-mediated inflammatory diseases affecting the gastrointestinal tract. Ustekinumab (UST) is a monoclonal antibody that blocks the p40 subunit of the anti-interleukin (IL) 12/23. Pivotal trials (CERTIFI and UNITI-IM for CD, UNIFI for UC) established the efficacy of UST for the induction and maintenance of remission in both CD and UC, with the most favorable results in naïve patients to biologics. In recent years, a wealth of 'real-world' data has emerged supporting positive clinical, endoscopic, and histological outcomes in patients treated with UST, as well as reassuring safety data. More recently, the results of the first head-to-head trials of UST and tumor necrosis factor (TNF) antagonists were reported. Moreover, a number of studies exploring the role of UST in specific clinical settings, such as perianal CD, postoperative complications and recurrence, extraintestinal manifestations, chronic antibiotic-refractory pouchitis, and pregnancy, were reported. This review explores the results reported to date on UST, including those from pivotal trials, real-world data, and emerging studies regarding therapeutic drug monitoring and immunogenicity. The safety profile of UST was also reviewed.

Polymorphism of IL-12/IL-23 axis is associated with coronary heart disease

IL12B encodes the shared p40 subunit (IL-12p40) of IL-12 and IL-23, which have diverse immune functions and are closely related to the occurrence and development of atherosclerosis (AS). However, the exact role of IL12B in coronary heart disease (CHD) was still unknown. A case-control association analysis was performed between five single nucleotide polymorphisms (SNPs) of IL12B (rs1003199, rs3212219, rs2569254, rs2853694 and rs3212227) and CHD in Chinese Han population (1824 patients with CHD vs. 2784 controls). Logistic regression analyses were used to study the relationships between SNPs and CHD, while multiple linear regression analyses were used to test the association between the SNP and the severity of CHD. In addition, the plasma IL12B concentration of CHD patients were detected by ELISA. We detected a significant association between one of the SNPs, rs2853694-G and CHD (padj  = 2.075 × 10-5 , OR, 0.773 [95% CI, 0.686-0.870]). Stratified analysis showed that rs2853694 was associated with CHD in both male and female populations and was significantly associated with both early- and late-onset CHD. In addition, rs2853694 is also related to the different types of CHD including clinical-CHD and anatomical-CHD. Moreover, there are significant differences in serum IL12B concentrations between rs2853694-TT carriers and rs2853694-GT carriers in CHD patients (p = 0.010). A common variant of IL12B was found significantly associated with CHD and its subgroups. As a shared subunit of IL-12 and IL-23, IL-12p40 may play a key role in IL-12/IL-23 axis mediated AS, which is expected to be an effective therapeutic target for CHD.

Monitoring islet specific immune responses in type 1 diabetes clinical immunotherapy trials

The number of immunotherapeutic clinical trials in type 1 diabetes currently being conducted is expanding, and thus there is a need for robust immune-monitoring assays which are capable of detecting and characterizing islet specific immune responses in peripheral blood. Islet- specific T cells can serve as biomarkers and as such can guide drug selection, dosing regimens and immunological efficacy. Furthermore, these biomarkers can be utilized in patient stratification which can then benchmark suitability for participation in future clinical trials. This review focusses on the commonly used immune-monitoring techniques including multimer and antigen induced marker assays and the potential to combine these with single cell transcriptional profiling which may provide a greater understanding of the mechanisms underlying immuno-intervention. Although challenges remain around some key areas such as the need for harmonizing assays, technological advances mean that multiparametric information derived from a single sample can be used in coordinated efforts to harmonize biomarker discovery and validation. Moreover, the technologies discussed here have the potential to provide a unique insight on the effect of therapies on key players in the pathogenesis of T1D that cannot be obtained using antigen agnostic approaches.

Intestinal Behcet's Disease: A Review of the Immune Mechanism and Present and Potential Biological Agents

Behcet's disease (BD) is a chronic and recurrent systemic vasculitis involving almost all organs and tissues. Intestinal BD is defined as BD with predominant gastrointestinal involvement, presenting severe complications such as massive gastrointestinal hemorrhage, perforation, and obstruction in some cases. To some extent, intestinal BD is classified as a member of inflammatory bowel disease (IBD), as it has a lot in common with classical IBD including Crohn's disease (CD) and ulcerative colitis (UC). Certainly, the underlying pathogenesis is not the same and dysregulation of immune function is believed to be one of the main pathogeneses in intestinal BD, although the etiology has not been clear up to now. Biological agents are an emerging category of pharmaceuticals for various diseases, including inflammatory diseases and cancers, in recent decades. Based on the deep understanding of the immune mechanism of intestinal BD, biological agents targeting potential pathogenic cells, cytokines and pathways are optimized options. Recently, the adoption of biological agents such as anti-tumor necrosis factor agents has allowed for the effective treatment of patients with refractory intestinal BD who show poor response to conventional medications and are faced with the risk of surgical treatment. In this review, we have tried to summarize the immune mechanism and present potential biological agents of intestinal BD.

Guselkumab More Effectively Neutralizes Psoriasis-Associated Histologic, Transcriptomic, and Clinical Measures than Ustekinumab

Given the key role of the IL-23/Th17 axis in the pathogenesis of moderate-to-severe plaque psoriasis, several specific inhibitors of the p19 subunit of IL-23 have been approved to treat this chronic inflammatory disease. Clinical data indicate that guselkumab, one such selective IL-23 inhibitor, achieves greater clinical efficacy compared with ustekinumab, which inhibits both IL-12 and IL-23 via binding their shared p40 subunit. To understand mechanisms underlying the enhanced efficacy observed with the p19 subunit of IL-23-specific inhibition, we explored cellular and molecular changes in skin of psoriasis patients treated with ustekinumab or guselkumab and in ustekinumab inadequate responders (Investigator's Global Assessment of psoriasis score ≥ 2) subsequently treated with guselkumab (ustekinumab→guselkumab). Skin biopsies were collected pretreatment and posttreatment to assess histologic changes and molecular responses in ustekinumab- and guselkumab-treated patients. Serum cytokines and skin transcriptomics from the subset of ustekinumab→guselkumab-treated patients were also analyzed to characterize differential treatment effects. Ustekinumab and guselkumab demonstrated differential effects on secretion of pathogenic Th17-related cytokines induced by IL-23 in in vitro assays, which suggest guselkumab is a more potent therapeutic agent. Consistent with these findings, guselkumab elicited a significantly greater reduction in cellular and molecular psoriasis-related disease indicators than ustekinumab. In ustekinumab→guselkumab patients, suppression of serum IL-17A and IL-17F levels and neutralization of molecular scar and psoriasis-related gene markers in skin were significantly greater compared with patients continuing ustekinumab. This comparative study demonstrates that guselkumab inhibits psoriasis-associated pathology, suppresses Th17-related serum cytokines, and normalizes the psoriasis skin gene expression profile more effectively than ustekinumab.

Predictive models assessing the response to ustekinumab highlight the value of therapeutic drug monitoring in Crohn's disease

BACKGROUND

Despite the therapeutic efficacy of Ustekinumab (UST) in Crohn's disease (CD), loss of response (LOR) is observed over time. This study aims to evaluate the impact of the UST pharmacokinetics (PK) at induction on clinical and endoscopic outcomes, as well as to find predictive markers of UST response.

METHODS

This retrospective study included 80 CD patients. Pharmacokinetics data (trough levels (TLs)) combined with clinical and biological parameters were fed into tailored logistic regression and tree-based ensemble techniques to predict clinical and endoscopic outcomes at one year of follow-up.

RESULTS

TLs at week 16 were significantly lower among patients with moderate to severe endoscopic activity during the follow-up (p = 0.04). The best model to predict endoscopic outcome was obtained at week 16 by Random Forest with an area under the receiver operating characteristic curve of 0.92 ± 0.08, sensitivity 91% and specificity 75%, with key inputs such as lymphocyte and monocyte counts at week 8, and UST TLs and CRP at week 16.

CONCLUSIONS

This real-world study confirms the relationship between early UST TLs and both clinical and endoscopic outcomes. Models were developed for the task of predicting clinical and endoscopic remission in CD patients treated with UST, highlighting the clinical relevance of UST TLs at week 16.

Epidermolysis bullosa acquisita treated with ustekinumab: A case report

Epidermolysis bullosa acquisita is a rare autoimmune disease involving cutaneous blistering and scarring associated with collagen VII autoantibodies. Similarly, collagen VII autoantibodies are present in the majority of Crohn’s disease patients and approximately a quarter of epidermolysis bullosa acquisita patients have coexisting Crohn’s disease. Treatment options for epidermolysis bullosa acquisita are limited and are largely ineffective. Here, we describe a 36-year-old female with a history of Crohn’s disease presenting with a 7-year history of severe blistering and scarring of acral surfaces. Diagnostic workup revealed subepidermal cleavage on skin biopsy and elevated serum collagen VII autoantibodies, indicative of epidermolysis bullosa acquisita. She was given ustekinumab for her coexisting Crohn’s disease and, afterwards, her epidermolysis bullosa acquisita resolved as evidenced by a lack of new blisters or scarring. Further studies are required to evaluate the effects of ustekinumab on epidermolysis bullosa acquisita.

Suppression of IL-12/IL-23 p40 subunit in the skin and blood of psoriasis patients by Tofacitinib is dependent on active interferon-γ signaling in dendritic cells: implications for the treatment of psoriasis and interferon-driven diseases

Interleukin (IL)‐12 and IL‐23 are pro‐inflammatory cytokines produced by dendritic cells (DCs) and associated with Psoriasis (Pso) and Psoriatic Arthritis (PsA) pathogenesis. Tofacitinib, a Janus kinase inhibitor, effectively suppresses inflammatory cascades downstream the IL‐12/IL‐23 axis in Pso and PsA patients. Here, we investigated whether Tofacitinib directly regulates IL‐12/IL‐23 production in DCs, and how this regulation reflects responses to Tofacitinib in Pso patients. We treated monocyte‐derived dendritic cells and myeloid dendritic cells with Tofacitinib and stimulated cells with either lipopolysaccharide (LPS) or a combination of LPS and IFN‐γ. We assessed gene expression by qPCR, obtained skin microarray and blood Olink data and clinical parameters of Pso patients treated with Tofacitinib from public data sets. Our results indicate that in DCs co‐stimulated with LPS and IFN‐γ, but not with LPS alone, Tofacitinib leads to the decreased expression of IL‐23/IL‐12 shared subunit IL12B (p40). In Tofacitinib‐treated Pso patients, IL‐12 expression and psoriasis area and severity index (PASI) are significantly reduced in patients with higher IFN‐γ at baseline. These findings demonstrate for the first time that Tofacitinib suppresses IL‐23/IL‐12 shared subunit IL12B in DCs upon active IFN‐γ signaling, and that Pso patients with higher IFN‐γ baseline levels display improved clinical response after Tofacitinib treatment.

Probing the binding of interleukin-23 to individual receptor components and the IL-23 heteromeric receptor complex in living cells using NanoBRET

Interleukin-23 (IL-23) is a pro-inflammatory cytokine involved in the host defense against pathogens but is also implicated in the development of several autoimmune disorders. The IL-23 receptor has become a key target for drug discovery, but the exact mechanism of the receptor ligand interaction remains poorly understood. In this study the affinities of IL-23 for its individual receptor components (IL23R and IL12Rβ1) and the heteromeric complex formed between them have been measured in living cells using NanoLuciferase-tagged full-length proteins. Here, we demonstrate that TAMRA-tagged IL-23 has a greater than 7-fold higher affinity for IL12Rβ1 than IL23R. However, in the presence of both receptor subunits, IL-23 affinity is increased more than three orders of magnitude to 27 pM. Furthermore, we show that IL-23 induces a potent change in the position of the N-terminal domains of the two receptor subunits, consistent with a conformational change in the heteromeric receptor structure.

Ustekinumab Improves Active Crohn's Disease by Suppressing the T Helper 17 Pathway

BACKGROUND

Ustekinumab (UST), an antibody targeting the p40 subunit of interleukin (IL)-12 and IL-23, is effective in treating Crohn's disease (CD). To clarify the mechanism of UST, we investigated T-cell differentiation in CD patients treated with UST.

METHODS

Twenty-seven patients with active CD were enrolled in this study. Seventeen patients were treated with UST, and 10 patients were treated with anti-tumor necrosis factor (TNF)-alpha therapy. The changes in the proportions of T-cell subsets after these therapies were analyzed by flow cytometry. Comprehensive gene expression changes in the colonic mucosa were also evaluated.

RESULTS

The frequency of T helper (Th) 17 cells was significantly decreased in the peripheral blood of patients with active CD after UST therapy. Anti-TNF therapy had a minimal effect on Th17 cells but increased the proportion of regulatory T cells. Enrichment analysis showed the expression of genes involved in the Th17 differentiation pathway was downregulated in the colonic mucosa after UST but not anti-TNF therapy. There were no common differentially expressed genes between CD patients treated with UST and anti-TNF therapy, suggesting a clear difference in their mechanism of action.

CONCLUSION

In patients with active CD, UST therapy suppressed Th17 cell differentiation both in the peripheral blood and colonic tissues.

Application of a newly-developed cynomolgus macaque BiTE-mediated cytotoxic T-lymphocyte activity assay to various immunomodulatory agents in vitro

The immunotoxic potential of drug candidates is assessed through the examination of results from a variety of in vitro and in vivo immunophenotyping and functional study endpoints in pre-clinical studies. CD8⁺ cytotoxic T-lymphocyte (CTL) activity impairment by immunosuppressive agents is recognized to be a potentiating factor for decreased antiviral defense and increased cancer risk. A bi-specific T-cell engager (BiTE^®)-mediated CTL activity assay that applies to ex vivo experimentation in non-human primates in the context of toxicology studies was successfully developed and applied in cynomolgus monkey regulatory studies. While an ex vivo analysis conducted in the context of repeat-dose toxicology studies focuses on the long-term impact on CTL function, an in vitro assay with the same experimental design captures acute effects in the presence of the test article. Here, the in vitro assay was applied to a list of drugs with known clinical immunomodulatory impact to understand the applicability of the assay. The results showed this assay was sensitive to a wide range of immunosuppressants directly targeting cell-intrinsic signaling pathways in activated CTL. However, agents executing immuno-modulation through inhibiting cytokines/cytokine receptors, co-stimulatory molecules, and cell adhesion and migration pathways did not impair the CTL activity in this short-term in vitro culture. In addition, anti-PD-1/PD-L1 immune checkpoint blockers enhanced the CTL activity. Taken together, the results here demonstrate that in concordance with their mechanism of action, the in vitro BiTE^®-mediated CTL assay is applicable and sensitive to immunomodulatory agents acting via a variety of mechanisms.

Safety evaluation of ustekinumab for moderate-to-severe ulcerative colitis

INTRODUCTION

Ustekinumab is a human IgG1 kappa monoclonal antibody that targets the p40 subunit of interleukin (IL)-12 and IL-23 and blocks the binding of these cytokines to the IL-12Rβ1 chain of their receptors. Ustekinumab is approved for treating moderate-to-severe ulcerative colitis (UC).

AREAS COVERED

We reviewed the mechanism of action, pharmacokinetics, efficacy, and safety of ustekinumab. Future challenges for optimizing UC treatment with ustekinumab are discussed.

EXPERT OPINION

Ustekinumab has favorable clinical efficacy and safety profiles for moderately-to-severely active UC. Ustekinumab is the first biologic for targeting IL-12/IL-23 pathways. Therefore, ustekinumab can be a therapeutic option following the failure of other biologics, including anti-tumor necrosis factor-α antagonists and anti-α₄ß₇ integrin antagonists. However, the positioning of ustekinumab in the therapeutic strategy for UC remains unclear. The efficacy of combinations of ustekinumab and immunomodulators over ustekinumab monotherapy has not been supported in studies. Ustekinumab is a human immunoglobulin G monoclonal antibody with low immunogenicity. Therefore, ustekinumab monotherapy, which should be safe, could be sufficient for treating UC. Further studies are required to understand the efficacy and safety of ustekinumab in patients with UC, particularly in special situations, and to optimize UC treatment with ustekinumab.

A Review of the Efficacy and Safety for Biologic Agents Targeting IL-23 in Treating Psoriasis With the Focus on Tildrakizumab

Psoriasis is a chronic and debilitating inflammatory immune-mediated skin disorder. Several cytokines including interleukin (IL)-23 were demonstrated to play a central role in the pathogenesis of this disease. Treatment options for psoriasis range from topical to systemic modalities, depending on the extent, anatomical locations involved and functional impairment level. Targeting cytokines or their cognate receptors that are involved in disease pathogenesis such as IL-12/23 (i.e., targeting the IL-12p40 subunit shared by these cytokines), IL-17A, IL-17F, IL-17RA, and TNF-α using biologic agents emerged in recent years as a highly effective therapeutic option for patients with moderate-to-severe disease. This review provides an overview of the important role of IL-23 signaling in the pathogenesis of psoriasis. We describe in detail the available IL-23 inhibitors for chronic plaque psoriasis. The efficacy, pharmacokinetic properties, and the safety profile of one of the most recent IL-23 biologic agents (tildrakizumab) are evaluated and reviewed in depth.

Alternative uses of ustekinumab for non-indicated dermatological conditions: a systematic review

Ustekinumab is approved for the treatment of psoriasis and Crohn's disease. Because many dermatological conditions are due to immune-mediated development, ustekinumab may be effective in other conditions. A systematic review of the off-label uses of ustekinumab, as well as on-label adverse effect, was performed, reporting on clinical improvement. MEDLINE, Embase, Web of Science, and Cochrane databases were searched for studies regarding ustekinumab treatment of rativa (HS), lichen planus (LP), pyoderma gangrenosum (PG), pityriasis rubra pilaris (PRP), cutalopecia areata (AA), atopic dermatitis (AD), Bechet's disease, bullous pemphigoid (BP), hidradenitis suppuaneous sarcoidosis, cutaneous systemic lupus erythematosus (SLE), and vitiligo. Descriptive statistics were performed. 74 articles of 4596 screened were included, and reported on 212 patients receiving ustekinumab treatment. Across all studies, ustekinumab showed promise in treating patients: AA (10/12 patients; 83.3% improvement), AD (28/74 patients; 37.8% improvement), HS (42/52 patients; 80.8% improvement), and PRP (25/27 patients; 92.6% improvement), among others. Adverse events were noted with the use of ustekinumab, including development of AA (four patients), AD (three patients), and BP (four patients), among others. Ustekinumab can be a promising option for patients with dermatological conditions refractory to traditional therapies. Adverse events must be monitored in certain patients.

Caspase-1 inhibition ameliorates murine acute graft versus host disease by modulating the Th1/Th17/Treg balance

Our previous studies have implicated Caspase-1 signaling in driving the proinflammatory state of acute graft versus host disease (aGVHD). Therefore, we aimed to elucidate the mechanism of Caspase-1 in in murine models of aGVHD through specific inhibition of its activity with the decoy peptide Ac-YVAD-CMK. We transplanted bone marrow from donor C57BL/6 (H-2b) mice into recipient BALB/c (H-2Kd) mice and randomized the recipients into the following treatment cohorts: (1) allogeneic hematopoietic stem cell transplantation and splenic cell infusion control (PBS group); (2) low dose Ac-YVAD-CMK (AC low group); (3) and high dose Ac-YVAD-CMK (AC high group). Indeed, we observed that Caspase-1 inhibition by Ac-YVAD-CMK ameliorated pathological damage and inflammation in the liver, lungs, and colon elicited by aGVHD. This was associated with reduced mortality secondary to aGVHD. Mechanistically, we found that Caspase-1 inhibition modulated donor T cell expansion, restored the balance of Th1/Th17/Treg subsets, and markedly decreased serum levels and aGVHD target organ mRNA expression of IL-1β, IL-18, and HMGB1. Thus, we demonstrate that inhibition of Caspase-1 by Ac-YVAD-CMK mitigates murine aGVHD by regulating Th1/Th17/Treg balance and attenuating its characteristic proinflammatory state.

Persistent expression of interleukin-17 and downstream effector cytokines in recalcitrant psoriatic lesions after ustekinumab treatment

The interleukin (IL)-23/T-helper (Th)17 axis is considered central to the pathogenesis of psoriasis, with IL-36γ considered a marker for histological differential diagnosis. However, expression data regarding key cytokines in the pathogenesis of psoriasis, as well as data on the effects of IL-23 inhibition on downstream cytokines in human psoriatic skin, are limited. We investigated the expression profile of key cytokines and the effect of ustekinumab (UST) on cytokine expression in human psoriatic tissue. Tumor necrosis factor (TNF)-α, IL-23, IL-17A, and IL-22 were highly expressed in the epidermis, dermal papillae, and upper dermis in patients with psoriasis compared with controls; IL-36γ was strongly expressed in the upper epidermis. Compared with the untreated group, expression intensity and area of IL-23 were significantly decreased in the UST group; expression areas of TNF-α, IL-17A, IL-22, and IL-36γ did not differ. This study identified the distribution and quantitative expression levels of key cytokines in psoriatic lesions and demonstrated that only IL-23 was downregulated without blocking downstream effector cytokines in recalcitrant psoriatic lesions during UST treatment. Our results suggest that, although IL-23 is inhibited, the persistent expression of IL-17 through an alternative pathway maintains the vicious cycle of the TNF-α/IL-23/IL-17 axis with IL-36γ, inducing refractory psoriatic lesions in patients with well-controlled psoriasis.

Structural basis for IL-12 and IL-23 receptor sharing reveals a gateway for shaping actions on T versus NK cells

Interleukin-12 (IL-12) and IL-23 are heterodimeric cytokines that are produced by antigen-presenting cells to regulate the activation and differentiation of lymphocytes, and they share IL-12Rβ1 as a receptor signaling subunit. We present a crystal structure of the quaternary IL-23 (IL-23p19/p40)/IL-23R/IL-12Rβ1 complex, together with cryoelectron microscopy (cryo-EM) maps of the complete IL-12 (IL-12p35/p40)/IL-12Rβ2/IL-12Rβ1 and IL-23 receptor (IL-23R) complexes, which reveal "non-canonical" topologies where IL-12Rβ1 directly engages the common p40 subunit. We targeted the shared IL-12Rβ1/p40 interface to design a panel of IL-12 partial agonists that preserved interferon gamma (IFNγ) induction by CD8+ T cells but impaired cytokine production from natural killer (NK) cells in vitro. These cell-biased properties were recapitulated in vivo, where IL-12 partial agonists elicited anti-tumor immunity to MC-38 murine adenocarcinoma absent the NK-cell-mediated toxicity seen with wild-type IL-12. Thus, the structural mechanism of receptor sharing used by IL-12 family cytokines provides a protein interface blueprint for tuning this cytokine axis for therapeutics.

Total Recall: Intestinal TRM Cells in Health and Disease

Tissue-resident memory T cells (T_RM cells) have crucial functions in host defense in mucosal tissues. They provide local adaptive immune surveillance and allow the fast initiation of targeted adaptive immune responses in case of antigen re-exposure. Recently, an aberrant activation in the case of immunologically mediated diseases has been increasingly acknowledged. As the organ with the largest interface to the environment, the gastrointestinal tract faces billions of antigens every day. Tightly balanced processes are necessary to ensure tolerance towards non-hazardous antigens, but to set up a powerful immune response against potentially dangerous ones. In this complex nexus of immune cells and their mediators, T_RM cells play a central role and have been shown to promote both physiological and pathological events. In this review, we will summarize the current knowledge on the homeostatic functions of T_RM cells and delineate their implication in infection control in the gut. Moreover, we will outline their commitment in immune dysregulation in gastrointestinal chronic inflammatory conditions and shed light on T_RM cells as current and potential future therapeutic targets.

A non-clinical comparative study of IL-23 antibodies in psoriasis

Four antibodies that inhibit interleukin (IL)-23 are approved for the treatment of moderate-to-severe plaque psoriasis. Here, we present non-clinical data comparing ustekinumab, guselkumab, tildrakizumab and risankizumab with regard to thermostability, IL-23 binding affinity, inhibitory-binding mode, in vitro potency and in vivo efficacy. Risankizumab and guselkumab exhibited 5-fold higher affinity for IL-23 and showed more potent inhibition of IL-23 signaling than ustekinumab and tildrakizumab. Risankizumab and guselkumab completely blocked the binding of IL-23 to IL-23Rα as expected, whereas tildrakizumab did not. In vitro, risankizumab and guselkumab blocked the terminal differentiation of TH17 cells in a similar manner, while tildrakizumab had minimal impact on TH17 differentiation. In a human IL-23-induced ear-swelling mouse model, risankizumab and guselkumab were more effective than ustekinumab and tildrakizumab at reducing IL-17, IL-22, and keratinocyte gene expression. Our results indicate that the four clinically approved antibodies targeting IL-23 differ in affinity and binding epitope. These attributes contribute to differences in in vitro potency, receptor interaction inhibition mode and in vivo efficacy in preclinical studies as described in this report, and similarly may affect the clinical performance of these drugs.

A Comprehensive Review of Biological Agents for Lupus: Beyond Single Target

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple immune cells. Due to its complex pathogenesis, the effectiveness of traditional treatment methods is limited. Many patients have developed resistance to conventional treatment or are not sensitive to steroid and immunosuppressant therapy, and so emerging therapeutic antibodies have become an alternative and have been shown to work well in many patients with moderate and severe SLE. This review summarizes the biological agents that are in the preclinical and clinical trial study of SLE. In addition to the various monoclonal antibodies that have been studied for a long time, such as belimumab and rituximab, we focused on another treatment for SLE, bispecific antibodies (BsAbs) such as tibulizumab, which simultaneously targets multiple pathogenic cytokines or pathways. Although the application of BsAbs in cancer has been intensively studied, their application in autoimmune diseases is still in the infant stage. This unique combined mechanism of action may provide a novel therapeutic strategy for SLE.

Biological therapy in pediatric age

Biological therapies, especially blocking tumor necrosis factor-α (TNFα) agents have radically changed the therapeutic approach and disease course of pediatric inflammatory bowel disease (IBD). In particular, drugs such as infliximab (IFX) and adalimumab (ADA) have been demonstrated to be effective in inducing and maintaining corticosteroid-free remission in both adult and pediatric patients with Crohns Disease (CD) and Ulcerative colitis (UC). Biosimilar biological (BioS) therapy is increasingly being used in pediatric age even though most knowledge on the safety and efficacy of these agents is based on IFX in adult IBD data. Studies show high rates of clinical response and remission in both IFX naïve patients and in patients switched from originator to BioS with similar risks of adverse events (AEs) as those reported with IFX originator. In the present review indications, efficacy and AEs of biological therapy in pediatric IBD will be discussed, as well as the role of other biological agents such as Golimumab, Vedolizumab and Ustekinumab, the role of BioS biological therapy and utility of therapeutic drug monitoring in clinical practice.

Extending the small-molecule similarity principle to all levels of biology with the Chemical Checker

Small molecules are usually compared by their chemical structure, but there is no unified analytic framework for representing and comparing their biological activity. We present the Chemical Checker (CC), which provides processed, harmonized and integrated bioactivity data on ~800,000 small molecules. The CC divides data into five levels of increasing complexity, from the chemical properties of compounds to their clinical outcomes. In between, it includes targets, off-targets, networks and cell-level information, such as omics data, growth inhibition and morphology. Bioactivity data are expressed in a vector format, extending the concept of chemical similarity to similarity between bioactivity signatures. We show how CC signatures can aid drug discovery tasks, including target identification and library characterization. We also demonstrate the discovery of compounds that reverse and mimic biological signatures of disease models and genetic perturbations in cases that could not be addressed using chemical information alone. Overall, the CC signatures facilitate the conversion of bioactivity data to a format that is readily amenable to machine learning methods.

Clinical Consequences of Antibody Formation, Serum Concentrations, and HLA-Cw6 Status in Psoriasis Patients on Ustekinumab

BACKGROUND

Ustekinumab for the treatment of psoriasis is currently administered in a standard dosing regimen. However, some patients tend to benefit from alternative dosing regimens, a step toward personalized medicine.

METHODS

To investigate the role of ustekinumab serum concentrations, anti-ustekinumab antibodies [AUA] and HLA-Cw6 status as tools for optimizing ustekinumab treatment, a multicenter prospective cohort study was conducted at an academic hospital with affiliated nonacademic hospitals in Belgium (cohort 1) and 2 academic hospitals in the Netherlands (cohort 2 and 3). Patients with plaque-type psoriasis were eligible if treated with ustekinumab for ≥16 weeks. Serum samples and Psoriasis Area and Severity Index scores were obtained at baseline, week 16, 28, 40, 52, and/or ≥64 of ustekinumab treatment.

RESULTS

A total of 137 patients with 229 observations for serum concentrations and AUA and 61 observations for HLA-Cw6 status were included. Presence of AUA (prevalence of 8.7%) was significantly associated with a diminished clinical response (P = 0.032). The median ustekinumab trough concentration was 0.3 mcg/mL (<0.02-3.80). No differences in serum concentrations were observed between moderate to good responders and nonresponders (P = 0.948). Serum trough concentrations were not affected by methotrexate comedication. Prevalence of HLA-Cw6 positivity was 41% with no statistically significant difference in clinical response between HLA-Cw6-positive and HLA-Cw6-negative patients (P = 0.164).

CONCLUSIONS

The presence of AUA was associated with treatment failure in this patient population; measurement of AUA may therefore be a candidate marker for personalized pharmacotherapy. The clinical utility of ustekinumab serum trough concentrations or HLA-Cw6 status determination remains less clear. Further exploration on the potential of measuring ustekinumab serum concentrations and other biomarkers in predicting therapy outcomes should be encouraged.

Crescentic IgA nephropathy after administration of human monoclonal interleukin-12/23p40 antibody in a patient with Crohn's disease: a case report

Ustekinumab (UST), an interleukin (IL)-12/IL-23-blocking monoclonal antibody, is a novel therapeutic option for Crohn's disease (CD). We describe a 24-year-old man with CD who showed an abrupt decline in renal function after administration of UST. Twenty-nine months previously, the patient was diagnosed with CD, and abnormal urinalysis findings in health checkup were coincidentally found at that time. Three months previously, treatment for CD was switched from infliximab to UST because of therapy-resistant severe diarrhea and bloody stools. A single dose of UST (260 mg) was initially intravenously administered, followed by single subcutaneous administration (90 mg) 2 months later. Thereafter, the patient exhibited rapid renal dysfunction with significant urinary abnormalities, although his gastrointestinal symptoms had completely disappeared. He was admitted to our hospital for further examination and treatment. Renal pathologic findings were compatible with crescentic glomerulonephritis consisting of almost fibro-cellular crescents. Immunofluorescent study showed IgA and C3 deposition in the glomerular mesangial area and IgA subclass staining revealed predominant IgA1 with concomitant mild IgA2 deposition. Furthermore, galactose-deficient IgA1 (Gd-IgA1) was also positive in the mesangial area. In addition, serum-Gd-IgA1 level was moderately increased. UST treatment was stopped and he responded to intensive steroid therapy with a parallel reduction of serum creatinine and Gd-IgA1 levels without flare of gastrointestinal symptoms. To our knowledge, this is the first case of immunoglobulin A nephropathy (IgAN) in patient with CD that might be aggravated by UST treatment. We presume that inhibition of IL-12/23 signaling with UST may cause to form crescentic IgAN by enhancing Gd-IgA1 production.

Comprehensive expression patterns of inflammatory cytokines in aqueous humor of patients with neovascular age-related macular degeneration

Neovascular age-related macular degeneration (nAMD) is a complex and multi-factorial disease, and low-grade inflammation is associated with pathogenesis of nAMD. Aqueous humor could reflect intraocular immune environments in various eye diseases. The research so far used aqueous humor samples and revealed that inflammation is involved in pathophysiology of nAMD, although immunological roles of cytokines were evaluated inadequately with aspect to individual effects. Here we used 27 kinds of cytokines covering general immunologic reactions, examined specific expression patterns of cytokines, and assessed relationships between inflammation and pathophysiology of nAMD by multivariate analyses. In nAMD eyes, principal component analysis showed that IL-7, MCP-1, MIP-1β and VEGF had high principal component loadings of over 0.6 in the first principal component constituting 32.6% of all variability of the data. In exploratory factor analysis, IL-6, MCP-1 and MIP-1β had high factor loadings (FL) of over 0.5 in Factor 1 constituting 32.6% of all variability, while VEGF had FL of over 1.0 in Factor 3 constituting 10.7% of all variability. In hierarchical cluster analysis, MCP-1 and VEGF were located in the cluster of first proximate mutual distance to central retinal thickness. These data could suggest that low-grade inflammation is a principal contributor in nAMD.

Anti-IL-12/23p40 antibodies for maintenance of remission in Crohn's disease

BACKGROUND

Ustekinumab and briakinumab are monoclonal antibodies that target the standard p40 subunit of cytokines interleukin-12 and interleukin-23 (IL-12/23p40), which are involved in the pathogenesis of Crohn's disease (CD). A significant proportion of people with Crohn's disease fail conventional therapy or therapy with biologics (e.g. infliximab) or develop significant adverse events. Anti-IL-12/23p40 antibodies such as ustekinumab may be an effective alternative for these individuals.

OBJECTIVES

The objectives of this review were to assess the efficacy and safety of anti-IL-12/23p40 antibodies for maintenance of remission in CD.

SEARCH METHODS

We searched the Cochrane IBD Group Specialized Register, CENTRAL, MEDLINE, Embase, and trials registers from inception to 17 September 2019. We searched references and conference abstracts for additional studies.

SELECTION CRITERIA

We considered for inclusion randomized controlled trials in which monoclonal antibodies against IL-12/23p40 were compared to placebo or another active comparator in participants with quiescent CD.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies for inclusion, extracted data, and assessed bias using the Cochrane 'Risk of bias' tool. The primary outcome measure was failure to maintain clinical remission, defined as a Crohn's disease activity index (CDAI) of < 150 points. Secondary outcomes included failure to maintain clinical response, adverse events (AE), serious adverse events (SAE), and withdrawals due to AEs. Clinical response was defined as a decrease in CDAI score of ≥ 100 points from baseline score. We calculated the risk ratio (RR) and 95% confidence intervals (95% CI) for each outcome. We analyzed all data on an intention-to-treat basis. We used GRADE to evaluate the overall certainty of the evidence supporting the outcomes.

MAIN RESULTS

Three randomized controlled trials (646 participants) met the inclusion criteria. Two trials assessed the efficacy of ustekinumab (542 participants), and one study assessed the efficacy of briakinumab (104 participants). We assessed all of the included studies as at low risk of bias. One study (N = 145) compared subcutaneous ustekinumab (90 mg) administered at 8 and 16 weeks compared to placebo. Fifty-eight per cent (42/72) of ustekinumab participants failed to maintain clinical remission at 22 weeks compared to 73% (53/73) of placebo participants (RR 0.80, 95% CI 0.63 to 1.02; moderate-certainty evidence). Failure to maintain clinical response at 22 weeks was seen in 31% (22/72) of ustekinumab participants compared to 58% (42/73) of placebo participants (RR 0.53, 95% CI 0.36 to 0.79; moderate-certainty evidence). One study (N = 388) compared subcutaneous ustekinumab (90 mg) administered every 8 weeks or every 12 weeks to placebo for 44 weeks. Forty-nine per cent (126/257) of ustekinumab participants failed to maintain clinical remission at 44 weeks compared to 64% (84/131) of placebo participants (RR 0.76, 95% CI 0.64 to 0.91; moderate-certainty evidence). Forty-one per cent (106/257) of ustekinumab participants failed to maintain clinical response at 44 weeks compared to 56% (73/131) of placebo participants (RR 0.74, 95% CI 0.60 to 0.91; moderate-certainty evidence). Eighty per cent (267/335) of ustekinumab participants had an AE compared to 84% (173/206) of placebo participants (RR 0.94, 95% CI 0.87 to 1.03; high-certainty evidence). Commonly reported adverse events included infections, injection site reactions, CD event, abdominal pain, nausea, arthralgia, and headache. Eleven per cent of ustekinumab participants had an SAE compared to 16% (32/206) of placebo participants (RR 0.74, 95% CI 0.48 to 1.15; moderate-certainty evidence). SAEs included serious infections, malignant neoplasm, and basal cell carcinoma. Seven per cent (5/73) of ustekinumab participants withdrew from the study due to an AE compared to 1% (1/72) of placebo participants (RR 4.93, 95% CI 0.59 to 41.18; low-certainty evidence). Worsening CD was the most common reason for withdrawal due to an AE. One study compared intravenous briakinumab (200 mg, 400 mg, or 700 mg) administered at weeks 12, 16, and 20 with placebo. Failure to maintain clinical remission at 24 weeks was seen in 51% (32/63) of briakinumab participants compared to 61% (22/36) of placebo participants (RR 0.84, 95% CI 0.58 to 1.20; low-certainty evidence). Failure to maintain clinical response at 24 weeks was seen in 33% (21/63) of briakinumab participants compared to 53% (19/36) of placebo participants (RR 0.64, 95% CI 0.40 to 1.02; low-certainty evidence). Sixty-six per cent (59/90) of briakinumab participants had an AE compared to 64% (9/14) of placebo participants (RR 1.02, 95% CI 0.67 to 1.55; low-certainty evidence). Common AEs included upper respiratory tract infection, nausea, abdominal pain, headache, and injection site reaction. Two per cent (2/90) of briakinumab participants had an SAE compared to 7% (1/14) of placebo participants (RR 0.31, 95% CI 0.03 to 3.21; low-certainty evidence). SAEs included small bowel obstruction, deep vein thrombosis, and respiratory distress. Withdrawal due to an AE was noted in 2% of briakinumab participants compared to 0% (0/14) of placebo participants (RR 0.82, 95% CI 0.04 to 16.34; low-certainty evidence). The AEs leading to study withdrawal were not described.

AUTHORS' CONCLUSIONS

Moderate-certainty evidence suggests that ustekinumab is probably effective for the maintenance of clinical remission and response in people with moderate to severe CD in remission without an increased risk of adverse events (high-certainty evidence) or serious adverse events (moderate-certainty evidence) relative to placebo. The effect of briakinumab on maintenance of clinical remission and response in people with moderate to severe Crohn's disease in remission was uncertain as the certainty of the evidence was low. The effect of briakinumab on adverse events and serious adverse events was also uncertain due to low-certainty evidence. Further studies are required to determine the long-term efficacy and safety of subcutaneous ustekinumab maintenance therapy in Crohn's disease and whether it should be used by itself or in combination with other agents. Future research comparing ustekinumab with other biologic medications will help to determine when treatment with ustekinumab in CD is most appropriate. Currently, there is an ongoing study that compares ustekinumab with adalimumab. This review will be updated when the results of this study become available. The manufacturers of briakinumab have stopped production of this medication, thus further studies of briakinumab are unlikely.

Long-term Clinical Effectiveness of Ustekinumab in Patients with Crohn's Disease Who Failed Biologic Therapies: A National Cohort Study

BACKGROUND

Ustekinumab [UST] was recently approved in Europe for the treatment of moderate to severe Crohn's disease [CD]. Long-term real-world data are currently scarce for CD patients previously exposed to several biologics.

METHODS

This is an observational, national, retrospective multicentre study. Patients received intravenous UST ~6 mg/kg at baseline, with 90 mg subcutaneously thereafter every 8 weeks. Response and remission rates were assessed at Weeks 8, 16, and 52.

RESULTS

Data from 152 patients were analysed. All patients were exposed to at least one anti-TNFα agent, with 69.7% were exposed to even two anti-TNFα and vedolizumab. After 1 year, 42.1% and 25.7% of patients had experienced clinical response and clinical remission, respectively, and 38.8% and 24.3% had achieved steroid-free clinical response and remission, respectively; 38.8% of patients discontinued therapy during the 12 months of follow-up. Colonic location was predictive of clinical response at 1 year, and low body mass index [BMI] at baseline was a negative predictor of clinical remission. Resolution of arthralgia was associated with clinical response over time. De novo arthralgia was reported by 17.9% of patients at Week 8 and 13.5% of patients at Week 52. No impact of UST on arthralgia was observed in patients with concomitant ankylosing spondylitis [n = 17]. Others adverse events were reported in 7.2% of patients.

CONCLUSIONS

This real-world cohort study confirms the effectiveness of UST in CD patients previously exposed to several biologics. Ustekinumab was well tolerated with respect to adverse events.

PODCAST

This article has an associated podcast which can be accessed at https://academic.oup.com/ecco-jcc/pages/podcast.

Role of IL-17 in asthma pathogenesis and its implications for the clinic

Introduction: Asthma is a respiratory disorder typically characterized by T-helper type 2 (Th2) inflammation that is mediated by cytokines, including IL-4, IL-5, and IL-13. Pathophysiologically, airway inflammation involving prominent eosinophilia, elevated IgE synthesis, airway hyperresponsiveness, mucus hypersecretion, and airway remodeling manifest clinically in patients as wheezing, breathlessness, chest tightness and episodic coughing. However, the Th2 paradigm falls short in interpreting the full spectrum of asthma severity. Areas covered: Severe asthmatics represent a distinct phenotype with their mixed pattern of neutrophilic-eosinophilic infiltration and glucocorticoid insensitivity making them refractory to currently available therapies. Th17 cells and their signature cytokine, IL-17, have been implicated in the development of severe asthma. Here, we review the contribution of IL-17 in the pathological features of asthma, gathered from both human and animal studies published in Pubmed during the past 10 years, and briefly discuss the clinical implications of targeting IL-17 imbalance in asthmatic patients. Expert opinion: With advancement in our understanding of the role of IL-17 in asthma pathology, it is clear that IL-17 is a targetable pathway which may lead to improvement in clinical symptoms of asthma. However, further elucidation of the complex interactions unfurled by IL-17 is essential in the empirical development of effective therapeutic options for refractory asthmatics.

The molecular basis of chaperone-mediated interleukin 23 assembly control

The functionality of most secreted proteins depends on their assembly into a defined quaternary structure. Despite this, it remains unclear how cells discriminate unassembled proteins en route to the native state from misfolded ones that need to be degraded. Here we show how chaperones can regulate and control assembly of heterodimeric proteins, using interleukin 23 (IL-23) as a model. We find that the IL-23 α-subunit remains partially unstructured until assembly with its β-subunit occurs and identify a major site of incomplete folding. Incomplete folding is recognized by different chaperones along the secretory pathway, realizing reliable assembly control by sequential checkpoints. Structural optimization of the chaperone recognition site allows it to bypass quality control checkpoints and provides a secretion-competent IL-23α subunit, which can still form functional heterodimeric IL-23. Thus, locally-restricted incomplete folding within single-domain proteins can be used to regulate and control their assembly.

It is unclear how unassembled secretory pathway proteins are discriminated from misfolded ones. Here the authors combine biophysical and cellular experiments to study the folding of heterodimeric interleukin 23 and describe how ER chaperones recognize unassembled proteins and aid their assembly into protein complexes while preventing the premature degradation of unassembled units.

Targeting cytokines to treat asthma and chronic obstructive pulmonary disease

Cytokines play a key role in orchestrating and perpetuating the chronic airway inflammation in asthma and chronic obstructive pulmonary disease (COPD), making them attractive targets for treating these disorders. Asthma and some cases of COPD are mainly driven by type 2 immune responses, which comprise increased airway eosinophils, T helper 2 (T_H2) cells and group 2 innate lymphoid cells (ILC2s) and the secretion of IL-4, IL-5 and IL-13. Clinical trials of antibodies that block these interleukins have shown reduced acute exacerbations and oral corticosteroid use and improvements in lung function and symptoms in selected patients. More recent approaches that block upstream cytokines, such as thymic stromal lymphopoietin (TSLP), show promise in improving patient outcome. Importantly, the clinical trials in cytokine blockade have highlighted the crucial importance of patient selection for the successful use of these expensive therapies and the need for biomarkers to better predict drug responses.

Revisiting the combinatorial potential of cytokine subunits in the IL-12 family

The four core members of the Interleukin-12 (IL-12) family of cytokines, IL-12, IL-23, IL-27 and IL-35 are heterodimers which share α- and β-cytokine subunits. All four cytokines are immune modulators and have been proposed to play divergent roles in inflammatory arthritis. In recent years additional combinations of α- and β-cytokine subunits belonging to the IL-12 family have been proposed to form novel cytokines such as IL-39. However, the actual extent of the combinatorial potential of the cytokine subunits in the human IL-12 family is not known. Here, we identify several combinations of subunits that form secreted heterodimeric assemblies based on a systematic orthogonal approach. The heterodimers are detected in the conditioned media harvested from mammalian cell cultures transfected with unfused pairs of cytokine subunits. While certain previously reported subunit combinations could not be recapitulated, our approach showed robustly that all four of the canonical members could be secreted. Furthermore, we provide evidence for the interaction between Cytokine Receptor Like Factor 1 (CRLF1) and Interleukin-12 subunit alpha (p35). Similar to IL-27 and IL-35 this novel heterodimer is not abundantly secreted rendering isolation from the conditioned medium very challenging, unlike IL-12 and IL-23. Our findings set the stage for fine-tuning approaches towards the biochemical reconstitution of IL-12 family cytokines for biochemical, cellular, and structural studies.

Current advances in the treatment of giant cell arteritis: the role of biologics

Giant cell arteritis (GCA) is the most common form of systemic vasculitis. It is a potentially severe disease with 25% of patients suffering vision loss or stroke. Our treatment paradigm is based on glucocorticoids. Glucocorticoids are required in high doses for prolonged periods and subsequently are associated with a significant amount of treatment-related morbidity. Alternative treatment options are urgently needed to minimize these glucocorticoid adverse events. Many other agents, such as methotrexate and tumour necrosis factor alpha inhibitors have been used in GCA, with limited or no evidence of benefit. Our emerging understanding of the pathogenic processes involved in GCA has led to an increased interest in the use of biologic agents to treat the disease. Two randomized controlled trials have recently reported dramatic effects of the use of the interleukin-6 targeted biologic tocilizumab in GCA, with significant increases in remission rates and decreases in glucocorticoid burden. While encouraging, longer-term and additional outcomes are awaited to clarify the exact positioning of tocilizumab in the treatment approach. Emerging data for other biologic agents, particularly abatacept and ustekinumab, are also encouraging but less well advanced. We are at the dawn of a new era in GCA treatment, but uncertainties and opportunities abound.

Advances in Understanding the Immunological Pathways in Psoriasis

Psoriasis vulgaris is a chronic, immune-mediated, inflammatory, polygenic skin disorder affecting approximately 2% of the population. It has a great impact on quality of life; patients often experience depression, anxiety, stigma as well as suicidal behavior. Even though psoriasis is one of the most studied dermatological conditions, the pathogenesis of the disease is still not completely elucidated. The complex interactions between keratinocytes, dendritic cells, T-lymphocytes, neutrophils and mast cells are responsible for the histopathological changes seen in psoriasis. The pathogenic model leading to the formation of psoriatic plaques has however evolved a lot over the years. There is now enough evidence to support the role of interleukin (IL) -23, IL-17, IL-22, T helper (Th) -17 cells, Th-22 cells, T regulatory cells, transforming growth factor (TGF)-β1 and IL-10 in the pathogenesis of the disease. Moreover, several inflammatory and anti-inflammatory molecules are currently being investigated, some of them showing promising results. The aim of this paper is to look over the most recent advances in the immunological pathways involved in the pathogenesis of psoriasis vulgaris.

Phenotypic changes of lymphocyte populations in psoriasiform dermatitis animal model

Psoriasis is a T cell mediated, chronic inflammatory autoimmune skin disease that affects up to 2-3% of the global population and leads to a decrease in quality of life. Experimental data accumulated in recent years highlighted the important role played by the immune system in the pathogenesis of this disease. Non-human psoriasis models are an important research tool that attempts to reproduce the clinical features of the disease in order to explain the pathogenesis of psoriasis and to identify possible therapeutic targets. Imiquimod-based murine model of psoriatic dermatitis is an alternative to traditional models of experimental psoriasis in mice and the induced dermatitis closely mimics the pathologic changes in human psoriasis. In order to emphasize changes in immune cell populations involved in lesion pathogenesis, we performed a murine model of psoriasiform dermatitis model by topical IMQ application. The progress and the severity of IMQ-induced skin inflammation were clinically (PASI score) and histopathologically evaluated. The immunological changes induced by IMQ treatment in lymphocyte populations from peripheral blood and spleen were evaluated by flow cytometry. The main changes observed in peripheral blood were the significantly increased T-CD8a⁺ lymphocyte and NK1.1⁺ cell percentages and the decreased T-CD4⁺ and B lymphocyte percentages in IMQ-treated mice. In spleen samples, lymphocytes showed the same tendency of variation as in peripheral blood, but without statistical significance. A significant decrease of B cells percentages was observed in spleen suspensions. Data obtained in skin samples may suggest the involvement of CD3ε⁺, CD4⁺ and CD8a⁺ cells in the lesional process. This murine model was analyzed by performing a basic cellular profile at three levels: peripheral blood, spleen and skin. The evaluation aimed to establish the immune framework of this experimental model that could further be used for etipathogenic mechanism identification and/or for studies regarding targeted therapies.

Quetiapine ameliorates collagen-induced arthritis in mice via the suppression of the AKT and ERK signaling pathways

OBJECTIVE AND DESIGN

To investigate the amelioration effects of quetiapine on rheumatoid arthritis with RAW 264.7 macrophage and collagen-induced arthritis (CIA) DBA/1J mouse model.

SUBJECTS

RAW 264.7 macrophage and DBA/1J mice.

TREATMENT

Lipopolysaccharide and collagen.

METHODS

RAW 264.7 macrophages stimulated by lipopolysaccharide (LPS) followed by quetiapine treatments were investigated. Activations of CD80 and CD86 were analyzed by flow cytometry. Pro-inflammatory cytokines such as IL-6, TNF-α and IL-1β were analyzed by ELISA. Proteins involved in signaling pathways related to the formation of rheumatoid arthritis were assayed by Western blotting. Therapeutic efficacy of quetiapine in CIA mouse model was also assayed. ¹⁸F-FDG/micro-PET was used to monitor the inflammation status in the joints, and the severity of bone erosion was evaluated with micro-CT and H&E staining.

RESULTS

The inhibition of pro-inflammatory cytokines by quetiapine was found through the ERK and AKT phosphorylation and subsequent NF-κB and CREB signaling pathways. Pro-inflammatory cytokines such as IL-17, IL-6 and IL-1β were decreased, while immunosuppressive factors such as TGF-β and IL-10 were increased in CIA mice treated with quetiapine. Notably, no uptake of ¹⁸F-FDG and bone erosion was found with micro-PET images on days 32 and 43 in the quetiapine-treated and normal control groups. However, significant uptake of ¹⁸F-FDG could be observed in the CIA group during the same time course. Similar results were further verified with ex vivo autoradiography.

CONCLUSION

Taken together, these results suggest that quetiapine is a potential anti-inflammatory drug, and may be used as an adjuvant for the treatment of rheumatoid arthritis.

The localisation of the heparin binding sites of human and murine interleukin-12 within the carboxyterminal domain of the P40 subunit

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We demonstrate differences in the specificity of heparin binding between human and murine IL-12s.

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Heparin predominantly protects the p40 subunit against proteolysis by LysC.

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A truncated IL-12 polypeptide lacking the carboxyterminal D3 domain fails to bind heparin.

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The C′D′ loop of the D3 domain contains a large cluster of surface accessible basic residues.

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This loop is the region of greatest sequence variation between murine and human p40s.

We have previously shown that the heterodimeric cytokine interleukin-12, and the homodimer of its larger subunit p40, both bind to heparin and heparan sulfate with relatively high affinity. In the present study we characterised these interactions using a series of chemically modified heparins as competitive inhibitors. Human interleukin-12 and p40 homodimer show indistinguishable binding profiles with a panel of heparin derivatives, but that of murine interleukin-12 is distinct. Heparin markedly protects the human and murine p40 subunits, but not the p35 subunits, from cleavage by the bacterial endoprotease LysC, further implicating the larger subunit as the location of the heparin binding site. Moreover the essential role of the carboxyterminal D3 domain in heparin binding is established by the failure of a truncated construct of the p40 subunit lacking this domain to bind. Predictive docking calculations indicate that a cluster of basic residues at the tip of the exposed C′D′ loop within D3 is important in heparin binding. However since the human and murine C′D′ loops differ considerably in length, the mode and three dimensional orientation of heparin binding are likely to differ substantially between the human and murine p40s. Thus overall the binding of IL-12 via its p40 subunit to heparin-related polysaccharides of the extracellular matrix appears to be functionally important since it has been conserved across mammalian species despite this structural divergence.

Structural Activation of Pro-inflammatory Human Cytokine IL-23 by Cognate IL-23 Receptor Enables Recruitment of the Shared Receptor IL-12Rβ1

Interleukin-23 (IL-23), an IL-12 family cytokine, plays pivotal roles in pro-inflammatory T helper 17 cell responses linked to autoimmune and inflammatory diseases. Despite intense therapeutic targeting, structural and mechanistic insights into receptor complexes mediated by IL-23, and by IL-12 family members in general, have remained elusive. We determined a crystal structure of human IL-23 in complex with its cognate receptor, IL-23R, and revealed that IL-23R bound to IL-23 exclusively via its N-terminal immunoglobulin domain. The structural and functional hotspot of this interaction partially restructured the helical IL-23p19 subunit of IL-23 and restrained its IL-12p40 subunit to cooperatively bind the shared receptor IL-12Rβ1 with high affinity. Together with structural insights from the interaction of IL-23 with the inhibitory antibody briakinumab and by leveraging additional IL-23:antibody complexes, we propose a mechanistic paradigm for IL-23 and IL-12 whereby cognate receptor binding to the helical cytokine subunits primes recruitment of the shared receptors via the IL-12p40 subunit.

Next generation of biologics for the treatment of Crohn's disease: an evidence-based review on ustekinumab

The limited efficacy of the currently available medical therapies in a proportion of patients with Crohn’s disease has led to the research and development of molecules that can block new inflammatory pathways. Ustekinumab is a fully human IgG1 monoclonal antibody which targets the common p40 subunit of the cytokines interleukin-12 as well as interleukin-23. Consequently, the Th1 and Th17 inflammatory responses are inhibited. Ustekinumab has been recently approved for its use in patients with Crohn’s disease. Its efficacy and safety was initially proved in patients with psoriasis and psoriatic arthritis. More recently, three Phase III trials have confirmed its efficacy in patients with Crohn’s disease refractory to anti-tumor necrosis factor therapy. This biologic agent appears safe, with no increased risk of infectious or malignant complications, and a low immunogenic profile.

Ustekinumab and Anti-Interleukin-23 Agents in Crohn's Disease

This article reviews the available data regarding the efficacy of ustekinumab across published randomized clinical trials and open-label experience from tertiary medical centers, safety data, including in pregnancy, and its use in patients who have failed tumor necrosis factor (TNF) antagonists as well as patients who have not failed TNF antagonists. We have proposed an algorithm for positioning the use of ustekinumab among other agents (TNF antagonists, vedolizumab) in moderate-severe Crohn's disease. The article also enumerates drugs that are specific interleukin-23 blockers, including brazikumab (MEDI2070), risankizumab, LY3074828, tildrakizumab, and guselkumab, and the current status of their clinical trials.