Anti-Interleukin-23 Autoantibodies in Adult-Onset Immunodeficiency

BACKGROUND

Autoantibodies against interleukin-12 (anti-interleukin-12) are often identified in patients with thymoma, but opportunistic infections develop in only some of these patients. Interleukin-12 (with subunits p40 and p35) shares a common subunit with interleukin-23 (subunits p40 and p19). In a patient with disseminated Burkholderia gladioli infection, the identification of both anti-interleukin-23 and anti-interleukin-12 prompted further investigation.

METHODS

Among the patients (most of whom had thymoma) who were known to have anti-interleukin-12, we screened for autoantibodies against interleukin-23 (anti-interleukin-23). To validate the potential role of anti-interleukin-23 with respect to opportunistic infection, we tested a second cohort of patients with thymoma as well as patients without either thymoma or known anti-interleukin-12 who had unusual infections.

RESULTS

Among 30 patients with anti-interleukin-12 who had severe mycobacterial, bacterial, or fungal infections, 15 (50%) also had autoantibodies that neutralized interleukin-23. The potency of such neutralization was correlated with the severity of these infections. The neutralizing activity of anti-interleukin-12 alone was not associated with infection. In the validation cohort of 91 patients with thymoma, the presence of anti-interleukin-23 was associated with infection status in 74 patients (81%). Overall, neutralizing anti-interleukin-23 was detected in 30 of 116 patients (26%) with thymoma and in 30 of 36 patients (83%) with disseminated, cerebral, or pulmonary infections. Anti-interleukin-23 was present in 6 of 32 patients (19%) with severe intracellular infections and in 2 of 16 patients (12%) with unusual intracranial infections, including Cladophialophora bantiana and Mycobacterium avium complex.

CONCLUSIONS

Among patients with a variety of mycobacterial, bacterial, or fungal infections, the presence of neutralizing anti-interleukin-23 was associated with severe, persistent opportunistic infections. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

An Oral Interleukin-23-Receptor Antagonist Peptide for Plaque Psoriasis

BACKGROUND

The use of monoclonal antibodies has changed the treatment of several immune-mediated inflammatory diseases, including psoriasis. However, these large proteins must be administered by injection. JNJ-77242113 is a novel, orally administered interleukin-23-receptor antagonist peptide that selectively blocks interleukin-23 signaling and downstream cytokine production.

METHODS

In this phase 2 dose-finding trial, we randomly assigned patients with moderate-to-severe plaque psoriasis to receive JNJ-77242113 at a dose of 25 mg once daily, 25 mg twice daily, 50 mg once daily, 100 mg once daily, or 100 mg twice daily or placebo for 16 weeks. The primary end point was a reduction from baseline of at least 75% in the Psoriasis Area and Severity Index (PASI) score (PASI 75 response; PASI scores range from 0 to 72, with higher scores indicating greater extent or severity of psoriasis) at week 16.

RESULTS

A total of 255 patients underwent randomization. The mean PASI score at baseline was 19.1. The mean duration of psoriasis was 18.2 years, and 78% of the patients across all the trial groups had previously received systemic treatments. At week 16, the percentages of patients with a PASI 75 response were higher among those in the JNJ-77242113 groups (37%, 51%, 58%, 65%, and 79% in the 25-mg once-daily, 25-mg twice-daily, 50-mg once-daily, 100-mg once-daily, and 100-mg twice-daily groups, respectively) than among those in the placebo group (9%), a finding that showed a significant dose-response relationship (P<0.001). The most common adverse events included coronavirus disease 2019 (in 12% of the patients in the placebo group and in 11% of those across the JNJ-77242113 dose groups) and nasopharyngitis (in 5% and 7%, respectively). The percentages of patients who had at least one adverse event were similar in the combined JNJ-77242113 dose group (52%) and the placebo group (51%). There was no evidence of a dose-related increase in adverse events across the JNJ-77242113 dose groups.

CONCLUSIONS

After 16 weeks of once- or twice-daily oral administration, treatment with the interleukin-23-receptor antagonist peptide JNJ-77242113 showed greater efficacy than placebo in patients with moderate-to-severe plaque psoriasis. (Funded by Janssen Research and Development; FRONTIER 1 ClinicalTrials.gov number, NCT05223868.).

The effects of Malassezia in the activation of Interleukin (IL)-23/IL-17 axis in Psoriasis

We explore the association of Malassezia and IL-23/IL-17 axis in the skin lesions of patients with Psoriasis. From October 2018 to October 2020, 202 psoriasis patients were hospitalized in the dermatology department of Yantaishan hospital. The patients' skin lesions were collected, and Malassezia-specific mRNA in the skin lesions was determined. The patients were subdivided into Malassezia high and low distribution groups as per the Malassezia-specific mRNA results. Psoriasis Area and Severity Index (PASI) scores between the two groups were performed. LL-37, IL-23, IL-17A, and tumor necrosis factor α (TNF-α) expression in the skin lesions of the two groups were determined. Malassezia mRNA and the correlation of LL-37 with inflammatory factors TNF-α, IL-23, and IL-17A were determined. The relevance of inflammatory factors, Malassezia infection, and LL-37 content with PASI score were studied. The Malassezia high distribution group was treated with etoconazole, and the effects of treatment on the PASI score, IL-23, TNF-α, and IL-17A were determined. The PASI score, neutrophil, eosinophil, and peripheral blood white blood cell counts, and lgG in the Malassezia high distribution group were significantly higher than in the low distribution group (P<0.05). IL-23, LL-37, TNF-α, and IL-17A levels in the Malassezia high distribution group were significantly higher than in the low distribution group (P<0.05). Malassezia and LL-37 levels had a moderate positive correlation (R=0.5009, P<0.0001). Malassezia and LL-37, IL-17A, TNF-a, and IL- 23 correlated positively. Malassezia, IL-17A, LL37, TNF-a, and IL-23 correlated positively with the PASI score of Psoriasis. Ketoconazole therapy inhibited the PASI score, IL-23, TNF-a, and IL-17A expressions in patients. Malassezia enhances the progression of Psoriasis through the aberrant activation of the IL-23/IL-17 axis.

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.

Interleukin-23 instructs protective multifunctional CD4 T cell responses after immunization with the Mycobacterium tuberculosis subunit vaccine H1 DDA/TDB independently of interleukin-17A

Interleukin (IL)-17A-producing T helper (Th)17 cells are increasingly being acknowledged to be associated with protective immunity to Mycobacterium tuberculosis (Mtb). Subunit vaccines potently promote protective immune responses against Mtb infection that correlate with an expansion of IL-23-dependent Th17 cells. Previous studies revealed that after vaccination, IL-23 is required for protection against challenge with Mtb but the underlying IL-23-dependent-and possibly IL-17A-mediated-mechanisms remain elusive. Therefore, we here analyzed the early outcome of Mtb infection in C57BL/6, IL-23p19-deficient (-/-), and IL-17A-/- mice after vaccination with the subunit vaccine H1-DDA/TDB to investigate the role of the IL-23-Th17 immune axis for the instruction of vaccine-induced protection. While in IL-23p19-/- mice the protective effect was reduced, protection after vaccination was maintained in IL-17A-/- animals for the course of infection of 6 weeks, indicating that after vaccination with H1-DDA/TDB early protection against Mtb is-although dependent on IL-23-not mediated by IL-17A. In contrast, IL-17A deficiency appears to have an impact on maintaining long-term protection. In fact, IL-23 instructed the vaccine-induced memory immunity in the lung, in particular the sustained expansion of tumor necrosis factor (TNF)+IL-2+ multifunctional T cells, independently of IL-17A. Altogether, a targeted induction of IL-23 during vaccination against Mtb might improve the magnitude and quality of vaccine-induced memory immune responses. KEY MESSAGES: After subunit Mtb vaccination with H1-DDA/TDB, IL-23 but not IL-17A contributes to vaccine-induced early protection against infection with Mtb. IL-17F does not compensate for IL-17A deficiency in terms of H1-DDA/TDB-induced protection against Mtb infection. IL 23 promotes the H1-DDA/TDB-induced accumulation of effector memory T cells independently of IL 17A. IL-23 arbitrates the induction of H1-specific IFN-γ-TNF+IL-2+ double-positive multifunctional CD4 T cells after subunit Mtb vaccination in an IL-17A-independent manner.

Rosmarinic acid protects mice from imiquimod induced psoriasis-like skin lesions by inhibiting the IL-23/Th17 axis via regulating Jak2/Stat3 signaling pathway

IL-23/Th17 (IL-17) axis plays a critical role in psoriasis. Rosmarinic acid (RA) was proved the inhibitory effect of T cell infiltration in the skin. However, whether and how RA has beneficial effects on psoriasis did not really know yet. So lipopolysaccharide (LPS)-induced abnormal proliferation Hacat cell line and Imiquimod (IMQ)-induced psoriasis-like mouse dermatitis were used to assess the pharmacological effects and mechanisms of RA by Psoriasis Area Severity Index (PASI) score, histopathology, flow cytometry, reverse transcription-polymerase chain reaction (RT-PCR) and western blotting. The results showed that RA inhibited LPS-induced aberrant expression of Hacat cell line, and significantly alleviated IMQ-induced skin inflammation. Although RA had no obviously effect on the ratio of epidermal Langerhans cell (LC) and LC migration from the skin to the skin draining lymph nodes, RA inhibited the expression of IL-23 in skin lesions, as well as reduced the differentiation of Th17 cells and producing of IL-17A by down regulating the transcriptor factor RORγt and JAK2/Stat3 signal pathway, comparing to IMQ treated group. The findings suggest that RA inhibits psoriasis-like skin inflammation in vivo and in vitro by reducing the expression of IL-23, inhibiting Th17 dominated inflammation and down regulating the Jak2/Stat3 signal pathway.

Drug Survival of IL-12/23, IL-17 and IL-23 Inhibitors for Psoriasis Treatment: A Retrospective Multi-Country, Multicentric Cohort Study

BACKGROUND

Drug survival analysis of biologic agents in psoriasis is of extreme importance, as it allows not only the evaluation of objective clinical outcomes (such as effectiveness and safety) but also of factors that are associated with patients' adherence to treatment. The aim of this study was to evaluate and compare the drug survival of the most recent biologic agents approved for the treatment of moderate-to-severe psoriasis-ustekinumab, secukinumab, ixekizumab, brodalumab, guselkumab, and risankizumab-and to identify clinical predictors that can influence the drug survival of these drugs.

METHODS

This retrospective multicentric cohort study from 16 dermatology centers in Portugal, Spain, Italy, Switzerland, Czech Republic, Canada, and the United States included patients that started IL-12/23, IL-17 (IL-17A and IL-17R) and IL-23 inhibitors for the treatment of psoriasis between January 1, 2012 and December 31, 2019. Survival analysis was performed using a Kaplan-Meier estimator, to obtain descriptive survival curves, and proportional hazard Cox regression models.

RESULTS

A total of 3312 treatment courses (total patients: 3145) were included in the study; 1118 (33.8%) with an IL-12/23 inhibitor (ustekinumab), 1678 (50.7%) with an IL-17 inhibitor [911 (27.5%) on secukinumab, 651 (19.7%) on ixekizumab, 116 (3.5%) on brodalumab], and 516 (15.5%) with an IL-23 inhibitor [398 (12.0%) on guselkumab, 118 (3.5%) on risankizumab]. At 18 months, the cumulative probability of survival was 96.4% for risankizumab, 91.1% for guselkumab, 86.3% for brodalumab, 86.1% for ustekinumab, 82.0% for ixekizumab, and 79.9% for secukinumab. Using ustekinumab as reference, drug survival of guselkumab was higher (HR 0.609; 95% CI 0.418-0.887) and that of secukinumab was lower (HR 1.490; 95% CI 1.257-1.766). In the final multivariable model, secukinumab, female sex, higher BMI, and prior exposure to biologic agents significantly increased the risk of drug discontinuation, whereas risankizumab was protective.

CONCLUSION

In this multinational cohort with 8439 patient-years of follow-up, the cumulative probability of drug survival for all drugs was >79% at 18 months. Prescribed biologic, female sex, higher BMI, and previous exposure to biologic agents were predictors of drug discontinuation. Drug survival of guselkumab and risankizumab was higher than that of ustekinumab, and secukinumab was lower.

The Role of the IL-23/IL-17 Axis in Disease Initiation in Spondyloarthritis: Lessons Learned From Animal Models

Spondyloarthritis (SpA) is a spectrum of chronic inflammatory joint diseases that frequently presents with inflammation of the axial skeleton, peripheral joints, entheses, skin, and gut. Understanding SpA pathogenesis has been proven challenging due to the limited availability of human target tissues. In recent years, the interleukin (IL)-23/IL-17 pathway has been implicated in the pathogenesis of SpA, in addition to the Tumor Necrosis Factor Alpha (TNF-α) cytokine. The underlying molecular mechanisms by which the IL-23/IL-17 pathway triggers disease initiation, both in the joints as well as at extra-musculoskeletal sites, are not precisely known. Animal models that resemble pathological features of human SpA have provided possibilities for in-depth molecular analyses of target tissues during various phases of the disease, including the pre-clinical initiation phase of the disease before arthritis and spondylitis are clinically present. Herein, we summarize recent insights gained in SpA animal models on the role of the IL-23/IL-17 pathway in immune activation across affected sites in SpA, which include the joint, entheses, gut and skin. We discuss how local activation of the IL-23/IL-17 axis may contribute to the development of tissue inflammation and the onset of clinically manifest SpA. The overall aim is to provide the reader with an overview of how the IL-23/IL-17 axis could contribute to the onset of SpA pathogenesis. We discuss how insights from animal studies into the initiation phase of disease could instruct validation studies in at-risk individuals and thereby provide a perspective for potential future preventive treatment.

HMGB1-TLR4-IL-23-IL-17A axis accelerates renal ischemia-reperfusion injury via the recruitment and migration of neutrophils

Renal ischemia-reperfusion injury (IRI) is an important cause of setting off acute kidney injury. Neutrophil-mediated immunomodulation has a pivotal role in the evolving of IRI. The HMGB1-TLR4-IL-23-IL-17A axis gives rise to neutrophil activation. Therefore, in the study, the role of the HMGB1-TLR4-IL-23-IL-17A axis in IRI was evaluated. Cell viability, inflammation, apoptosis, oxidative stress, survival, renal function and pathology, and the activation of macrophages and neutrophils were measured. Moreover, we evaluated the acetylation, translocation, and secretion of HMGB1 as well as levels of TLR-4, IL-23, IL-17A, and neutrophil chemokines (KC, LIX, and MIP-2). In vivo, anti-HMGB1 antibody decreased the acetylation, translocation, and secretion of HMGB1, reduced the expression of TLR-4, IL-23, IL-17A, KC, LIX, and MIP-2, alleviated the activation of macrophages and neutrophils, improved the survival rate and renal dysfunction, and decreased inflammation, apoptosis, oxidative stress, and pathological injury of the kidney. However, the intervention with recombinant HMGB1(R-HMGB1) significantly abolish the above effect of anti-HMGB1 in IRI. Neutralization IL-23 or IL-17A can alleviated the neutrophils mediated renal dysfunction by suppressing inflammation, apoptosis, and oxidative stress in IRI. In vitro, we confirmed that hypoxic/deoxygenation (H/R) induces the secretion of HMGB1 though acetylation on HK-2 and HMGB1 promotes the secretion of IL-23 in a HMGB1/TLR-4-dependent manner on macrophages. Together, these results implied that the HMGB1-TLR4-IL-23-IL-17A axis regulates inflammation, oxidative stress, apoptosis, and renal injury in IRI by promoting the recruitment and migration of neutrophils.

Management of Crohn's disease in an immunosuppressed COVID-19-positive patient: safety-driven prioritisation of nutritional therapy as a bridge to restarting immunosuppression

Active inflammatory bowel disease (IBD), combined immunosuppression and corticosteroid therapy have all been identified as risk factors for a poor outcome in COVID-19 infection. The management of patients with both COVID-19 infection and active IBD is therefore complex. We present the case of a 31-year-old patient with Crohn's disease, on dual immunosuppression with infliximab and mercaptopurine presenting with inflammatory small bowel obstruction and COVID-19 infection. The case highlights the use of nutritional therapy, which remains underused in the management of adults with IBD, to manage his flare acutely. Following negative SARS-CoV-2 PCR testing and SARS-CoV-2 IgG testing confirming an antibody response, ustekinumab (anti-interleukin 12/23) was prescribed for long-term maintenance.

Suppression of Serum Interferon-γ Levels as a Potential Measure of Response to Ustekinumab Treatment in Patients With Systemic Lupus Erythematosus

OBJECTIVE

In a previously reported phase II randomized, placebo-controlled, interventional trial, we demonstrated that treatment with ustekinumab, an anti-interleukin-12 (IL-12)/IL-23 p40 neutralizing monoclonal antibody, improved global and organ-specific measures of disease activity in patients with active systemic lupus erythematosus (SLE). Utilizing the biomarker data from this phase II clinical study, we sought to determine whether modulation of the expression of IL-12, IL-23, or both cytokines by ustekinumab is associated with clinical efficacy in patients with SLE.

METHODS

This phase II randomized, placebo-controlled study enrolled 102 patients with autoantibody-positive SLE whose disease remained active despite standard-of-care therapy. Patients were randomized at a 3:2 ratio to receive ~6 mg/kg ustekinumab intravenously or placebo at week 0, followed by subcutaneous injections of 90 mg ustekinumab or placebo every 8 weeks, with placebo crossover to 90 mg ustekinumab every 8 weeks. The SLE Responder Index 4 (SRI-4) at week 24 was used to determine which patients could be classified as ustekinumab responders and which could be classified as nonresponders. In addition to measurements of p40 and IL-23, serum levels of interferon-γ (IFNγ), IL-17A, IL-17F, and IL-22, as a proxy for the IL-12 and IL-23 pathways, were quantified by immunoassay.

RESULTS

Changes in the serum levels of IL-17A, IL-17F, and IL-22 at different time points after treatment were not consistently significantly associated with an SRI-4 clinical response to ustekinumab in patients with SLE. In contrast, an SRI-4 response to ustekinumab was significantly associated (P < 0.01) with durable reductions in the serum IFNγ protein levels at several time points relative to baseline, which was not observed in ustekinumab nonresponders or patients who received placebo.

CONCLUSION

While not diminishing a potential role of IL-23, these serum biomarker assessments indicate that IL-12 blockade has an important role in the mechanism of action of ustekinumab treatment in patients with SLE.

FUT8 Remodeling of EGFR Regulates Epidermal Keratinocyte Proliferation during Psoriasis Development

α-(1,6)-fucosyltransferase 8 (FUT8) is implicated in the pathogenesis of several malignancies, but its role in psoriasis is poorly understood. In this study, we show that FUT8 remodeling of EGFR plays a critical role in the development of psoriasis phenotypes. Notably, elevated FUT8 expression was associated with disease severity in the lesional epidermis of a patient with psoriasis. FUT8 gain of function promoted HaCaT cell proliferation, whereas short hairpin FUT8 reduced cell proliferation and induced a longer S phase with downregulation of cyclin A1 expression. Furthermore, cell proliferation, which is controlled by the activation of EGFR, was shown to be regulated by FUT8 core fucosylation of EGFR. Short hairpin FUT8 significantly reduced EGFR/protein kinase B signaling and slowed EGF‒EGFR complex trafficking to the perinuclear region. Moreover, short hairpin FUT8 reduced ligand-induced EGFR dimerization. Overactivated EGFR was observed in the lesional epidermis of both human patient and psoriasis-like mouse model, whereas conditional knockout of FUT8 in an IL-23 psoriasis-like mouse model ameliorated disease phenotypes and reduced EGFR activation in the epidermis. These findings implied that elevated FUT8 expression in the lesional epidermis is implicated in the development of psoriasis phenotypes, being required for EGFR overactivation and leading to keratinocyte hyperproliferation.

Suppression of IL-23-mediated psoriasis-like inflammation by regulatory B cells

Psoriasis is an inflammatory cutaneous disease mediated by T-cell dependent immune responses; however, B cells are also considered to play an important role its development. Regulatory B cells (Bregs) regulate immune responses negatively through interleukin-10 (IL-10) production. This study aimed to investigate the role of Bregs in IL-23-mediated psoriasis-like inflammation in mice. Psoriasis-like inflammation was induced in B cell-specific phosphatase and tensin homolog (PTEN)-deficient mice, in which Bregs were significantly expanded, and in their controls, by intradermal injection of 20 μL phosphate-buffered saline (PBS) containing 0.5 μg rmIL-23 into one ear, every other day for 16 days. IL-23-mediated psoriasis-like inflammation was suppressed in B cell-specific PTEN-deficient mice along with decreased ear thickness and epidermal thickness on day 15. Moreover, adoptive transfer of B1 B cells suppressed IL-23-mediated psoriasis-like inflammation. rmIL-23-injected B cell-specific PTEN-deficient mice showed expanded regulatory T cells (Tregs) in the spleen and draining lymph nodes along with increased Bregs. Further, T helper (Th) 17 differentiation in the rmIL-23-injected ear was suppressed in B cell-specific PTEN-deficient mice. Overall, these results indicate that increased Bregs suppress IL-23-mediated psoriasis-like inflammation through Treg expansion and inhibition of Th17 differentiation. Thus, targeting Bregs may be a feasible treatment strategy for psoriasis.

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.

IL-23/IL-17 axis in the pathogenesis and treatment of systemic lupus erythematosus and rheumatoid arthritis

Interleukin-23 (IL-23) and IL-17 are the gatekeepers of CD4+ T helper 17 (Th17) cells where IL-23 is required for the development and expansion of Th17 cells that subsequently produce IL-17 to promote inflammation. Owing to such pro-inflammatory properties, the IL-23/IL-17 axis has emerged as an important mechanism in the pathogenesis of autoimmune diseases including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). In recent years, therapeutic antibodies targeting IL-23 (e.g. ustekinumab, tildrakizumab, guselkumab) or IL-17 (e.g. brodalumab, secukinumab, ixekizumab) have been approved for the treatment of various autoimmune diseases. In this review, we describe the pathogenic mechanisms of IL-23/IL-17 axis in SLE and RA, as well as summarising the findings from phase II and III clinical trials of anti-IL-23/IL-17 therapeutic antibodies in SLE and RA patients. In particular, phase II study has demonstrated that the anti-IL-23 antibody (ustekinumab) confers enhanced treatment outcomes in SLE patients, while anti-IL-17 antibodies (secukinumab and ixekizumab) have shown improved clinical benefits for RA patients in phase II/III studies. Our review highlights the emerging importance of targeting the IL-23/IL-17 axis in SLE and RA patients.

Human Mesenchymal Stromal Cell Secretome Promotes the Immunoregulatory Phenotype and Phagocytosis Activity in Human Macrophages

Human mesenchymal stromal/stem cells (hMSCs) show great promise in cell therapy due to their immunomodulatory properties. The overall immunomodulatory response of hMSCs resembles the resolution of inflammation, in which lipid mediators and regulatory macrophages (Mregs) play key roles. We investigated the effect of hMSC cell-cell contact and secretome on macrophages polarized and activated toward Mreg phenotype. Moreover, we studied the effect of supplemented polyunsaturated fatty acids (PUFAs): docosahexaenoic acid (DHA) and arachidonic acid, the precursors of lipid mediators, on hMSC immunomodulation. Our results show that unlike hMSC cell-cell contact, the hMSC secretome markedly increased the CD206 expression in both Mreg-polarized and Mreg-activated macrophages. Moreover, the secretome enhanced the expression of programmed death-ligand 1 on Mreg-polarized macrophages and Mer receptor tyrosine kinase on Mreg-activated macrophages. Remarkably, these changes were translated into improved Candida albicans phagocytosis activity of macrophages. Taken together, these results demonstrate that the hMSC secretome promotes the immunoregulatory and proresolving phenotype of Mregs. Intriguingly, DHA supplementation to hMSCs resulted in a more potentiated immunomodulation with increased CD163 expression and decreased gene expression of matrix metalloproteinase 2 in Mreg-polarized macrophages. These findings highlight the potential of PUFA supplementations as an easy and safe method to improve the hMSC therapeutic potential.

Gastric Juice Expression of Th-17 and T-Reg Related Cytokines in Scleroderma Esophageal Involvement

BACKGROUND

Systemic sclerosis (SSc) is a connective tissue disorder which key feature is a fibrotic process. The role of Endothelin-1 (ET-1) and T-helper (Th)-1 cells in lung and skin fibrosis is well known, although Th17- and Treg-cells were found to be involved. However, no studies analyzed cytokines expression in gastric-juice of SSc patients. Our study aimed to evaluate proinflammatory and profibrotic cytokines in gastric-juice of SSc patients and to investigate their correlations with esophageal dysmotility.

METHODS

Patients performed upper-gastrointestinal-endoscopy with gastric-juice collection, esophageal manometry and thoracic CT-scan. GM-CSF, ET-1, Th-1 (IFN-γ, IL-1β, TNF-α, IL-2, IL-6, IL-9), Th-17 (IL-17, IL-21, IL-22, IL-23) and T-reg (IL-10, TGF-β) related cytokines were measured in 29 SSc-patients and 20 healthy-controls.

RESULTS

Patients showed significant lower levels of IL-6, IL-17, IL-22 and ET-1 (p < 0.005) compared with controls. Patients with atrophic gastritis presented significant lower levels of IL-2, IL-9, IL-6, TGF-β, GM-CSF, IL-17 and ET-1 (p < 0.005) compared to patients without gastritis. Increased values of IL-2, IL-9, IL-1β, IL-17, ET-1 and GM-CSF (p < 0.005) were observed in patients with esophageal impairment. This is the first report of cytokines measurement in gastric juice of patients with SSc. The high IL-17 concentrations in gastric-juice of scleroderma patients with esophageal dysmotility support the signature of Th-17 cells in scleroderma esophageal fibrosis.

Nutrition and Psoriasis

Psoriasis is a chronic inflammatory skin disease characterized by accelerated tumor necrosis factor-α/interleukin-23/interleukin-17 axis, hyperproliferation and abnormal differentiation of epidermal keratinocytes. Psoriasis patients are frequently associated with obesity, diabetes, dyslipidemia, cardiovascular diseases, or inflammatory bowel diseases. Psoriasis patients often show unbalanced dietary habits such as higher intake of fat and lower intake of fish or dietary fibers, compared to controls. Such dietary habits might be related to the incidence and severity of psoriasis. Nutrition influences the development and progress of psoriasis and its comorbidities. Saturated fatty acids, simple sugars, red meat, or alcohol exacerbate psoriasis via the activation of nucleotide-binding domain, leucine-rich repeats containing family, pyrin domain-containing-3 inflammasome, tumor necrosis factor-α/interleukin-23/interleukin-17 pathway, reactive oxygen species, prostanoids/leukotrienes, gut dysbiosis or suppression of regulatory T cells, while n-3 polyunsaturated fatty acids, vitamin D, vitamin B12, short chain fatty acids, selenium, genistein, dietary fibers or probiotics ameliorate psoriasis via the suppression of inflammatory pathways above or induction of regulatory T cells. Psoriasis patients are associated with dysbiosis of gut microbiota and the deficiency of vitamin D or selenium. We herein present the update information regarding the stimulatory or regulatory effects of nutrients or food on psoriasis and the possible alleviation of psoriasis by nutritional strategies.

Skin expression of IL-23 drives the development of psoriasis and psoriatic arthritis in mice

Psoriasis (PS) is a chronic skin inflammation. Up to 30% of the patients with PS develop psoriatic arthritis (PsA), a condition characterized by inflammatory arthritis that affects joints or entheses. Although there is mounting evidence for a critical role of interleukin-23 (IL-23) signaling in the pathogenesis of both PS and PsA, it remains unclear whether IL-23-induced skin inflammation drives joint disease. Here, we show that mice expressing increased levels of IL-23 in the skin (K23 mice) develop a PS-like disease that is characterized by acanthosis, parakeratosis, hyperkeratosis, and inflammatory infiltrates in the dermis. Skin disease preceded development of PsA, including enthesitis, dactylitis, and bone destruction. The development of enthesitis and dactylitis was not due to high circulating levels of IL-23, as transgenic animals and controls had similar levels of this cytokine in circulation. IL-22, a downstream cytokine of IL-23, was highly increased in the serum of K23 mice. Although IL-22 deficiency did not affect skin disease development, IL-22 deficiency aggravated the PsA-like disease in K23 mice. Our results demonstrate a central role for skin expressed IL-23 in the initiation of PS and on pathogenic processes leading to PsA.

IL-23 and IL-2 activation of STAT5 is required for optimal IL-22 production in ILC3s during colitis

Signal transducer and activator of transcription (STAT) proteins have critical roles in the development and function of immune cells. STAT signaling is often dysregulated in patients with inflammatory bowel disease (IBD), suggesting the importance of STAT regulation during the disease process. Moreover, genetic alterations in STAT3 and STAT5 (e.g., deletions, mutations, and single-nucleotide polymorphisms) are associated with an increased risk for IBD. In this study, we elucidated the precise roles of STAT5 signaling in group 3 innate lymphoid cells (ILC3s), a key subset of immune cells involved in the maintenance of gut barrier integrity. We show that mice lacking either STAT5a or STAT5b are more susceptible to Citrobacter rodentium-mediated colitis and that interleukin-2 (IL-2)- and IL-23-induced STAT5 drives IL-22 production in both mouse and human colonic lamina propria ILC3s. Mechanistically, IL-23 induces a STAT3-STAT5 complex that binds IL-22 promoter DNA elements in ILC3s. Our data suggest that STAT5a/b signaling in ILC3s maintains gut epithelial integrity during pathogen-induced intestinal disease.

Interleukin 23 and autoimmune diseases: current and possible future therapies

PURPOSE

IL-23 is a central proinflammatory cytokine with a wide range of influence over immune response. It is implicated in several autoimmune diseases due to the infinite inflammatory loops it can create through the positive feedbacks of both IL-17 and IL-22 arms. This made IL-23 a key target of autoimmune disorders therapy, which indeed was proven to inhibit inflammation and ameliorate diseases. Current autoimmune treatments targeting IL-23 are either by preventing IL-23 ligation to its receptor (IL-23R) via antibodies or inhibiting IL-23 signaling by signaling downstream mediators' inhibitors, with each approach having its own pros and cons.

METHODS

Literature review was done to further understand the biology of IL-23 and current therapies.

RESULTS

In this review, we discuss the biological features of IL-23 and its role in the pathogenesis of autoimmune diseases including psoriasis, rheumatoid arthritis and inflammatory bowel diseases. Advantages, limitations and side effects of each concept will be reviewed, suggesting several advanced IL-23-based bio-techniques to generate new and possible future therapies to overcome current treatments problems.

New insights into the IL-12 and IL-23: From a molecular basis to clinical application in immune-mediated inflammation and cancers

The cytokines interleukin-12 (IL-12) and IL-23 share a common IL-12/IL-23p40 subunit in structure and play a central role in T cell-mediated responses in inflammation. Over-activated IL-12 and IL-23 signaling drives aberrant T helper (Th) 1 and Th17 immune responses and contributes to immune-mediated diseases. Evidence from genome-wide association studies has shown that genetic alterations in the IL-12/IL-23 signaling pathways have significant links with chronic inflammation. In addition, accumulating evidence from animal models and clinical trials has provided insights into the effectiveness of blocking the IL-12/IL-23 pathways in immune regulation, broadening the clinical indications of IL-12/IL-23 pathway effectors in immune-mediated diseases. More recently, it has been addressed that the balance between IL and 12 and IL-23 is also critical in carcinogenesis. IL-12- and IL-23-driven T cell cytokines are especially important in controlling tumor initiation, growth, and metastasis, and thus, the IL-12/IL-23 pathway may be a promising target for immunotherapy. This review focuses on IL-12/IL-23 signal transduction and biological functionality in autoimmunity and oncoimmunology. We discuss the therapeutic rationale for targeting these cytokines to treat immune-mediated diseases and issues regarding their inadvertent consequences in the balance of host defense and tumor surveillance and summarize their recent clinical applications in immune-mediated diseases.

Immunohistochemical evaluation of interleukin-23 and cyclooxygenase-2 in the muscles of mice infected with Trichinella spiralis

The course of Trichinella (T.) spiralis infection includes intestinal and muscle phases. The aims of this work were to evaluate IL-23 and cyclooxygenase-2 (COX-2) by immunohistochemistry in the muscles of T. spiralis infected mice in a time-course study and to correlate their level with the serum levels of IL-23, IFN-γ, IL-4 and IL-10 cytokines. The mice were divided into an un-infected control group (UC) (10 mice) and 5 infected mouse groups (each 10 mice/group. Each mouse was infected with 200 T. spiralis larvae) and sacrificed on days 7, 14, 21, 28 and 35 post-infection (dpi). IL-23 showed weak expression (+1) on the 21^st dpi, then it became moderately expressed (+2) on the 28^th dpi and on day 35 pi, the immunoreactivity was strong (+3). COX-2 expressed weakly on 14 dpi, while the other mouse groups (21, 28 and 35) showed strong (+3) expression. IL-23 serum concentrations increased gradually in a significant pattern, in comparison to that of UC mice, from the 21^st dpi to the end of the experiment. IFN-γ increased gradually and was significantly higher than those of UC mice from the 7^th dpi, reached its maximum level on the 21^st dpi, after which it decreased non-significantly. IL-4 up-regulated significantly in all infected groups in comparison to UC mice achieving its highest level on the 21^st dpi and decreased after that. IL-10 increased significantly on the 7^th dpi, but dropped at the 14^th dpi, then reached its peak on the 21^st dpi, and decreased again on the 28^th and 35^th dpi. In conclusion, T. spiralis infection caused increased expression of IL-23 and COX-2 in the muscle of infected mice, the effect being strongest on the 35^th day. Also, the infection induced a mixed Th1/Th2 profile with a predominance of Th2 at the early muscle phase, after which the immune repose became mainly Th2.

Interleukin-17A Serves a Priming Role in Autoimmunity by Recruiting IL-1β-Producing Myeloid Cells that Promote Pathogenic T Cells

Interleukin-17A (IL-17A) is a major mediator of tissue inflammation in many autoimmune diseases. Anti-IL-17A is an effective treatment for psoriasis and is showing promise in clinical trials in multiple sclerosis. In this study, we find that IL-17A-defective mice or mice treated with anti-IL-17A at induction of experimental autoimmune encephalomyelitis (EAE) are resistant to disease and have defective priming of IL-17-secreting γδ T (γδT17) cells and Th17 cells. However, T cells from Il17a^-/- mice induce EAE in wild-type mice following in vitro culture with autoantigen, IL-1β, and IL-23. Furthermore, treatment with IL-1β or IL-17A at induction of EAE restores disease in Il17a^-/- mice. Importantly, mobilization of IL-1β-producing neutrophils and inflammatory monocytes and activation of γδT17 cells is reduced in Il17a^-/- mice. Our findings demonstrate that a key function of IL-17A in central nervous system (CNS) autoimmunity is to recruit IL-1β-secreting myeloid cells that prime pathogenic γδT17 and Th17 cells.

IL23 induces IL23R recycling and amplifies innate receptor-induced signalling and cytokines in human macrophages, and the IBD-protective IL23R R381Q variant modulates these outcomes

OBJECTIVE

The interleukin (IL)23 pathway contributes to IBD pathogenesis and is being actively studied as a therapeutic target in patients with IBD. Unexpected outcomes in these therapeutic trials have highlighted the importance of understanding the cell types and mechanisms through which IL23 regulates immune outcomes. How IL23 regulates macrophage outcomes and the consequences of the IL23R R381Q IBD-protective variant on macrophages are not well defined; macrophages are key players in IBD pathogenesis and inflammation.

DESIGN

We analysed protein and RNA expression, signalling and localisation in human monocyte-derived macrophages (MDMs) through western blot, ELISA, real-time PCR, flow cytometry, immunoprecipitation and microscopy.

RESULTS

IL23R was critical for optimal levels of pattern-recognition receptor (PRR)-induced signalling and cytokines in human MDMs. In contrast to the coreceptor IL12Rβ1, IL23 induced dynamic IL23R cell surface regulation and this required clathrin and dynamin-mediated endocytosis and endocytic recycling-dependent pathways; these pathways were essential for IL23R-mediated outcomes. The IBD-protective IL23R R381Q variant showed distinct outcomes. Relative to IL23R R381, HeLa cells expressing IL23R Q381 showed decreased IL23R recycling and reduced assembly of IL23R Q381 with Janus kinase/signal transducer and activator of transcription pathway members. In MDMs from IL23R Q381 carriers, IL23R accumulated in late endosomes and lysosomes on IL23 treatment and cells demonstrated decreased IL23R- and PRR-induced signalling and cytokines relative to IL23R R381 MDMs.

CONCLUSION

Macrophage-mediated inflammatory pathways are key contributors to IBD pathogenesis, and we identify an autocrine/paracrine IL23 requirement in PRR-initiated human macrophage outcomes and in human intestinal myeloid cells, establish that IL23R undergoes ligand-induced recycling, define mechanisms regulating IL23R-induced signalling and determine how the IBD-protective IL23R R381Q variant modulates these processes.

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.

Ginsenoside Rg1 abolish imiquimod-induced psoriasis-like dermatitis in BALB/c mice via downregulating NF-κB signaling pathway

This animal experiment was framed to evaluate the beneficial effect of ginsenoside Rg1 (GRg1) against imiquimod (IMQ)-induced psoriasis-like dermatitis model to reveal the underpinning mechanism. Fifty healthy BALB/c mice were divided into five groups as control, GRg1, IMQ induced, oral treatment of GRg1 (50 mg/kg), or dexamethasone (DXM; 10 mg/kg) in IMQ-induced mice. Treatment with GRg1 or DXM significantly mitigates (p < .01) psoriasis area severity index (PASI) score, skin thickness, lipid peroxidation, and inflammatory markers (IL-23, 22, 17A, 1β, and TNF-α). Moreover, administration of GRg1 or DXM considerably reversed the morphological changes induced by IMQ with improved (p < .01) antioxidant activity (SOD, CAT). In addition, a marked downregulation (p < .01) of protein expressions of pIκB and NF-κB p65 (NF-κB signaling pathway) were noted in GRg1 group. Collectively, GRg1 or DXM treatment significantly abolishes IMQ-induced psoriasis-like dermatitis by lowering PASI score, inflammation through downregulating NF-κB signaling pathway. PRACTICAL APPLICATIONS: This is the very first study to explore the efficacy of ginsenoside Rg1 (GRg1) against IMQ-induced psoriasis in the mice model to reveal the underpinning mechanism. The results clearly showed that GRg1 potent anti-psoriasis activity by lowering PASI score, inflammation through downregulating NF-κB signaling pathway. Hence, this study helps in the development of novel nutraceutical/functional food against psoriasis and thus could improve the quality of life in psoriasis patients. However, further clinical trials are needed to justify the above results before developing a commercial functional food using GRg1 against psoriasis.

Interleukin 22 disrupts pancreatic function in newborn mice expressing IL-23

Neonatal inflammatory diseases are associated with severe morbidity, but the inflammatory factors underlying them and their potential effector mechanisms are poorly defined. Here we show that necrotizing enterocolitis in neonate mice is accompanied by elevation of IL-23 and IL-22 and decreased production of pancreatic enzymes. These phenotypes are mirrored in neonate mice overexpressing IL-23 in CX3CR1+ myeloid cells or in keratinocytes. The mice fail to grow and die prematurely, displaying systemic inflammation, nutrient malabsorption and decreased expression of intestinal and pancreatic genes mediating digestion and absorption of carbohydrates, proteins, and lipids. Germ-free environment improves, and genetic ablation of IL-22 restores normal growth in mice overexpressing IL-23. Mechanistically, IL-22 acts directly at the level of pancreatic acinar cells to decrease expression of the pancreas associated transcription factor 1a (PTF1a). These results show that augmented production of IL-23 and IL-22 in early life has a negative impact on pancreatic enzyme secretion and food absorption.

Biological and synthetic target DMARDs in psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic multi-faceted immune-mediated systemic disorder, characterized by articular, cutaneous, enthesis, nail and spine involvement. Articular manifestations of PsA are particularly common and highly disabling for patients, while the heterogeneous clinical subsets of the disease are challenging for clinicians. In recent years, research has made many advances in understanding the pathogenesis of the disease from genetic, epigenetic and molecular points of view. New drugs are now available for the treatment of this condition, and, in particular, TNF-alfa inhibitors, historically the first biologicals approved in PsA, are now juxtaposed by new biological disease modifying anti-rheumatic drugs (bDMARDs) with different modes of action. Targeting IL-12/IL-23 p40 common subunit with ustekinumab, IL-17A with secukinumab and ixekizumab, T cells co-stimulation with abatacept, is now possible, safe and effective. Moreover, targeted synthetic molecules with oral administration are available, with the possibility to interfere with phosphodiesterase-4 and JAK/STAT pathways. Indeed, new drugs are under development, with the possibility to target selectively IL-17 receptor, IL-23, and other key molecular targets in the pathogenesis of this condition. In this narrative review, we provide an up-to-date overview of the current application of biological and targeted synthetic DMARDs in the field of PsA, with particular regard to the clinical significance of this possibility to target a higher number of distinct immune-pathways.

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.

Feruloylated Oligosaccharides Alleviate Dextran Sulfate Sodium-Induced Colitis in Vivo

The imbalance of T lymphocyte subsets substantially conduces to disturbed intestinal immune system and succeeding colonic tissue damage in inflammatory bowel diseases. It is considered that regulation of phytochemicals on cytokine production potentially provides a broad prospect for the exploitation of immunomodulatory agents. Here, we reported that oral administration of feruloylated oligosaccharides (FOs) effectively alleviated mice colitis disease induced by dextran sulfate sodium (DSS). FOs decreased the percentage of T helper (Th)17 cells and downregulated the production of Th17-specific cytokines. In contrast, FOs increased the percentage of regulatory T (Treg) cells and elevated the production of Treg-specific cytokines in colons of DSS-challenged mice. These results indicated that FOs restored the immunologic equilibrium of Th17 and Treg subsets, hereby ameliorating the deterioration of colitis. Furthermore, FOs diminished the secretion of interleukin (IL)-23 and IL-6 but enhanced the transforming growth factor-β1 (TGF-β1) in dendritic cells in vitro and in vivo, which contributed to the restoration of Th17 and Treg cells immune balance. The mechanistic analysis showed that the regulation of FOs on IL-23 and IL-6 was associated with the nuclear factor-κ-gene binding signaling pathway and TGF-β1 with mitogen-activated protein kinase-activator protein 1 signaling pathway. Taken together, oral administration of FOs exerted potent immunomodulatory effects against mice colitis via restoring the immune balance of Th17 and Treg cells.

Immunoregulatory Functions of the IL-12 Family of Cytokines in Antiviral Systems

Members of the interleukin 12 (IL-12) family have been known to be inflammatory factors since their discovery. The IL-12 family consists of IL-12, IL-23, IL-27, IL-35, and a new member, IL-39, which has recently been identified and has not yet been studied extensively. Current literature has described the mechanisms of immunity of these cytokines and potential uses for therapy and medical cures. IL-12 was found first and is effective in combatting a wide range of naturally occurring viral infections through the upregulation of various cytokines to clear the infected cells. IL-23 has an essential function in immune networks, can induce IL-17 production, and can antagonize inhibition from IL-12 in the presence of T helper (Th) 17 cells, resulting in type II IFN (IFN-γ) regulation. IL-27 has a competitive relationship to IL-35 because they both include the same subunit, the Epstein–Barr virus-induced gene3 (EBi3). This review provides a simple introduction to the IL-12 family and focuses on their functions relevant to their actions to counteract viral infections.

Effect of Biological Treatment on Fatigue in Psoriasis: A Systematic Review and Meta-Analysis

BACKGROUND

Fatigue is frequent in patients with psoriasis. Though conventional drugs in general have no effect on fatigue, biological agents have demonstrated beneficial effects in several other chronic inflammatory diseases.

OBJECTIVE

The objective of the present study was to evaluate the effect of biological drugs on fatigue in patients with psoriasis vulgaris.

METHODS

We conducted a meta-analysis of randomized controlled trials in which anti-interleukin-12/23, anti-interleukin-23, anti-interleukin-17, or anti-tumor necrosis factor-α agents were used for psoriasis vulgaris and fatigue was an outcome measure.

RESULTS

A total of eight randomized controlled trials fulfilled criteria for inclusion in the meta-analysis. The studies used two fatigue reporting scales: the Functional Assessment of Chronic Illness Therapy-Fatigue and the Short Form 36 Health Survey Vitality Subscale. Treatment by biological agents in general compared with placebo led to a significant reduction in fatigue, with a standardized mean difference of - 0.40 (95% confidence interval - 0.46 to - 0.34; p < 0.001).

CONCLUSION

Biological drugs used for the treatment of psoriasis vulgaris have a consistently small-to-moderate beneficial effect on fatigue independent of the type of drug.

Intestinal parasitic infection alters bone marrow derived dendritic cell inflammatory cytokine production in response to bacterial endotoxin in a diet-dependent manner

Giardia lamblia is a common intestinal parasitic infection that although often acutely asymptomatic, is associated with debilitating chronic intestinal and extra-intestinal sequelae. In previously healthy adults, a primary sporadic Giardia infection can lead to gut dysfunction and fatigue. These symptoms correlate with markers of inflammation that persist well after the infection is cleared. In contrast, in endemic settings, first exposure occurs in children who are frequently malnourished and also co-infected with other enteropathogens. In these children, Giardia rarely causes symptoms and associates with several decreased markers of inflammation. Mechanisms underlying these disparate and potentially enduring outcomes following Giardia infection are not presently well understood. A body of work suggests that the outcome of experimental Giardia infection is influenced by the nutritional status of the host. Here, we explore the consequences of experimental Giardia infection under conditions of protein sufficiency or deficiency on cytokine responses of ex vivo bone marrow derived dendritic cells (BMDCs) to endotoxin stimulation. We show that BMDCs from Giardia- challenged mice on a protein sufficient diet produce more IL-23 when compared to uninfected controls whereas BMDCs from Giardia challenged mice fed a protein deficient diet do not. Further, in vivo co-infection with Giardia attenuates robust IL-23 responses in endotoxin-stimulated BMDCs from protein deficient mice harboring enteroaggregative Escherichia coli. These results suggest that intestinal Giardia infection may have extra-intestinal effects on BMDC inflammatory cytokine production in a diet dependent manner, and that Giardia may influence the severity of the innate immune response to other enteropathogens. This work supports recent findings that intestinal microbial exposure may have lasting influences on systemic inflammatory responses, and may provide better understanding of potential mechanisms of post-infectious sequelae and clinical variation during Giardia and enteropathogen co-infection.

Effects of early enteral nutrition on Th17/Treg cells and IL-23/IL-17 in septic patients

BACKGROUND

The imbalance of Th17/Treg cells and the IL-23/IL-17 axis have been confirmed to be associated with sepsis and various inflammatory diseases. Early enteral nutrition (EEN) can modulate the inflammatory response, improve immune dysfunction, and prevent enterogenic infection in critically ill patients; however, the precise mechanisms remain unclear. Considering the important roles of Th17 and Treg lymphocytes in the development of inflammatory and infectious diseases, we hypothesized that EEN could improve the immune dysfunction in sepsis by maintaining a balanced Th17/Treg cell ratio and by regulating the IL-23/IL-17 axis.

AIM

To investigate the effects of EEN on the Th17/Treg cell ratios and the IL-23/IL-17 axis in septic patients.

METHODS

In this prospective clinical trial, patients were randomly divided into an EEN or delayed enteral nutrition (DEN) group. Enteral feeding was started within 48 h in the EEN group, whereas enteral feeding was started on the 4th day in the DEN group. The Th17 and Treg cell percentages and the interleukin levels were tested on days 1, 3, and 7 after admission. The clinical severity and outcome variables were also recorded.

RESULTS

Fifty-three patients were enrolled in this trial from October 2017 to June 2018. The Th17 cell percentages, Th17/Treg cell ratios, IL-17, IL-23, and IL-6 levels of the EEN group were lower than those of the DEN group on the 7th day after admission (P < 0.05). The duration of mechanical ventilation and of the intensive care unit stay of the EEN group were shorter than those of the DEN group (P < 0.05). However, no difference in the 28-d mortality was found between the two groups (P = 0.728).

CONCLUSION

EEN could regulate the imbalance of Th17/Treg cell ratios and suppress the IL-23/IL-17 axis during sepsis. Moreover, EEN could reduce the clinical severity of sepsis but did not reduce the 28-d mortality of septic patients.

IL-23-producing IL-10Rα-deficient gut macrophages elicit an IL-22-driven proinflammatory epithelial cell response

Cytokines maintain intestinal health, but precise intercellular communication networks remain poorly understood. Macrophages are immune sentinels of the intestinal tissue and are critical for gut homeostasis. Here, we show that in a murine inflammatory bowel disease (IBD) model based on macrophage-restricted interleukin-10 (IL-10) receptor deficiency (Cx3cr1Cre:Il10rafl/fl mice), proinflammatory mutant gut macrophages cause severe spontaneous colitis resembling the condition observed in children carrying IL-10R mutations. We establish macrophage-derived IL-23 as the driving factor of this pathology. Specifically, we report that Cx3cr1Cre:Il10rafl/fl:Il23afl/fl mice harboring macrophages deficient for both IL-10R and IL-23 are protected from colitis. By analyzing the epithelial response to proinflammatory macrophages, we provide evidence that T cells of colitic animals produce IL-22, which induces epithelial chemokine expression and detrimental neutrophil recruitment. Collectively, we define macrophage-specific contributions to the induction and pathogenesis of colitis, as manifested in mice harboring IL-10R deficiencies and human IBDs.

Biologicals targeting T helper cell subset differentiating cytokines are effective in the treatment of murine anti-myeloperoxidase glomerulonephritis

Anti-myeloperoxidase nephritogenic autoimmunity induces severe glomerulonephritis. To assess the therapeutic potential of monoclonal antibodies targeting T helper (Th) subset differentiation determining cytokines, we studied a murine model of anti-myeloperoxidase glomerulonephritis. The temporal participation of T helper subsets was determined by quantitating gene expression of CD4⁺ T-cells isolated from nephritic kidneys and cytokine production by lymphocytes from nodes draining myeloperoxidase immunization sites. Th17 cytokines (IL-17A and IL-6) rose rapidly but declined as autoimmunity matured when Th1 cytokines (IL-12 and TNF) predominated. Therefore, T helper subset participation in anti-myeloperoxidase autoimmunity is biphasic, with Th17 early and Th1 late. To confirm the functional relevance of this biphasic pattern, we compared systemic anti-myeloperoxidase autoimmunity in wild type, Th17 deficient and Th1 deficient mice. Early, Th1 deficient mice developed similar autoimmunity and glomerulonephritis to wild type mice. However, Th17 deficient mice had significantly reduced anti-myeloperoxidase autoimmunity. In late autoimmunity, Th1 deficient mice developed reduced autoimmunity and were protected from anti-myeloperoxidase glomerulonephritis. The therapeutic potential of these findings were demonstrated by neutralizing monoclonal antibodies. Targeting IL-23p19 attenuated early Th17 dominated anti-myeloperoxidase autoimmunity and glomerulonephritis but not late phase disease. Targeting IL-12p35 attenuated late phase Th1 dominated anti-myeloperoxidase autoimmunity and glomerulonephritis but not early autoimmunity or glomerulonephritis. Targeting both T helper subsets with an anti-IL-12p40 monoclonal antibody was effective during both early and late phases of anti-myeloperoxidase glomerulonephritis. Thus, definition of dominant T helper differentiating subsets in anti-myeloperoxidase glomerulonephritis by renal CD4⁺ T-cell cytokine gene expression allows effective proper phase monoclonal antibody treatment of anti-myeloperoxidase glomerulonephritis.

IL-1β, IL-23, and TGF-β drive plasticity of human ILC2s towards IL-17-producing ILCs in nasal inflammation

Innate lymphoid cells (ILCs) are crucial for the immune surveillance at mucosal sites. ILCs coordinate early eradication of pathogens and contribute to tissue healing and remodeling, features that are dysfunctional in patients with cystic fibrosis (CF). The mechanisms by which ILCs contribute to CF-immunopathology are ill-defined. Here, we show that group 2 ILCs (ILC2s) transdifferentiated into IL-17-secreting cells in the presence of the epithelial-derived cytokines IL-1β, IL-23 and TGF-β. This conversion is abrogated by IL-4 or vitamin D3. IL-17 producing ILC2s induce IL-8 secretion by epithelial cells and their presence in nasal polyps of CF patients is associated with neutrophilia. Our data suggest that ILC2s undergo transdifferentiation in CF nasal polyps in response to local cytokines, which are induced by infectious agents.

Tumor-associated Macrophage-derived Interleukin-23 Interlinks Kidney Cancer Glutamine Addiction with Immune Evasion

BACKGROUND

Glutamine addiction is a hallmark of clear cell renal cell carcinoma (ccRCC); yet whether glutamine metabolism impacts local immune surveillance is unclear. This knowledge may yield novel immunotherapeutic opportunities.

OBJECTIVE

To seek a potential therapeutic target in glutamine-addicted ccRCC.

DESIGN, SETTING, AND PARTICIPANTS

Tumors from ccRCC patients from a Shanghai cohort and ccRCC tumor data from The Cancer Genome Atlas (TCGA) cohort were analyzed. In vivo and in vitro studies were conducted with fresh human ccRCC tumors and murine tumor cells.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Immune cell numbers and functions were analyzed by flow cytometry. Glutamine and cytokine concentrations were determined. Survival was compared between different subpopulations of patients using Kaplan-Meier and Cox regression analyses.

RESULTS AND LIMITATIONS

We found that in ccRCC, high interleukin (IL)-23 expression was significantly associated with poor survival in both TCGA (overall survival [OS] hazard ratio [HR]=2.04, cancer-specific survival [CSS] HR=2.95; all p<0.001) and Shanghai (OS HR=2.07, CSS HR=3.92; all p<0.001) cohorts. IL-23 blockade prolongs the survival of tumor-bearing mice, promotes T-cell cytotoxicity in in vitro cultures of human ccRCC tumors, and augments the therapeutic benefits of anti-PD-1 antibodies. Mechanistically, glutamine consumption by ccRCC tumor cells results in the local deprivation of extracellular glutamine, which induces IL-23 secretion by tumor-infiltrating macrophages via the activation of hypoxia-inducible factor 1α (HIF1α). IL-23 activates regulatory T-cell proliferation and promotes IL-10 and transforming growth factor β expression, thereby suppressing tumor cell killing by cytotoxic lymphocytes. The positive correlations between glutamine metabolism, IL-23 levels, and Treg responses are confirmed in both TCGA cohort and tumors from Shanghai ccRCC patients. Study limitations include the unclear impacts of glutamine deprivation and IL-23 on other immune cells.

CONCLUSIONS

Macrophage-secreted IL-23 enhanced Treg functions in glutamine-addicted tumors; thus, IL-23 is a promising target for immunotherapy in ccRCC.

PATIENT SUMMARY

In this study, we analyzed the immune components in glutamine-addicted clear cell renal cell carcinoma (ccRCC) tumors from two patient cohorts and conducted both in vitro and in vivo studies. We found that ccRCC tumor cell-intrinsic glutamine metabolism orchestrates immune evasion via interleukin (IL)-23, and IL-23-high patients had significantly poorer survival than IL-23-low patients. IL-23 should thus be considered a therapeutic target in ccRCC, either alone or in combination with immune checkpoint inhibitors.

Induction of autophagy in Cx3cr1+ mononuclear cells limits IL-23/IL-22 axis-mediated intestinal fibrosis

Intestinal fibrosis is an excessive proliferation of myofibroblasts and deposition of collagen, a condition frequently seen in Crohn's disease (CD). The mechanism underlying myofibroblast hyper-proliferation in CD needs to be better understood. In this report, we found that mTOR inhibitor rapamycin or mTOR deletion in CX3Cr1+ mononuclear phagocytes inhibits expression of interleukin (IL)-23, accompanied by reduced intestinal production of IL-22 and ameliorated fibrosis in the TNBS-induced fibrosis mouse model. This inhibition of IL-23 expression is associated with elevated autophagy activity. Ablating the autophagy gene Atg7 increases the expression of IL-23, leading to increased expression of IL-22 and increased fibrosis. Both induction of IL-22 and intestinal fibrosis occurred in RAG-/- mice and depletion of innate lymphoid cells (ILCs) attenuates the fibrotic reaction, suggesting that the pro-fibrotic process is independent of T and B cells. Moreover, IL-22 facilitates the transformation of fibroblasts into myofibroblasts. Finally, the fibrotic reaction was attenuated upon neutralization of either IL-23 or IL-22. Altogether, this study elucidated a signaling cascade underlying intestinal fibrosis in which altered mTOR/autophagy in CX3Cr1+ mononuclear phagocytes up-regulates the IL-23/IL-22 axis, leading to an excessive fibrotic response. Thus, our findings suggest that this cascade could be a therapeutic target for alleviation of CD fibrosis.

IL-23 and dendritic cells: What are the roles of their mutual attachment in immune response and immunotherapy?

Interleukin-23 (IL-23) is a cytokine that is composed of the subunits p19 and p40, while its receptor (IL-23R) consists of two subunits, that is, IL-23Rα and IL-12Rβ1. The interaction between IL-23 and IL-23R is necessary for exerting cardinal biological effects upon certain cell types, including promotion of memory T cell proliferation and Th17 cell-mediated IL-17 secretion. Accordingly, dendritic cells (DCs) are one of the main sources for IL-23 secretion. Interestingly, IL-23R is also present on the DC plasma membrane, suggesting that IL-23 potentially acts on DCs via an autocrine manner. In this review, we have summarized a variety of IL-23-mediated effects on the intracellular signaling pathways such as Janus kinase 2, tyrosine kinase 2, signal transducer and activator of transcription (STAT), mitogen-activated protein kinase signaling, and so forth, which may underlie numerous processes such as DC maturation, antigen presentation, T cell proliferation/activation, and cytokine secretion, which may be implicated in many immune-related diseases through IL-23/DC interactions. Accordingly, these signaling pathways are extensively involved in the pathogenesis and progression of numerous diseases, including autoimmune disease (e.g., atopic dermatitis, asthma, and multiple sclerosis) and infection (e.g., bacterial, fungal, and viral infections). Taken together, they are potentially applicable to novel but promising strategies for treating numerous diseases associated with the mutual attachment of IL-23 and DCs.

Functions of adipose-resident immune subsets and the impact on metabolic syndrome

There is a growing appreciation of the role in the aetiology of metabolic syndrome that is played by the interplay of diet, microbiota and the interactions of immune cells and adipose cells in visceral adipose tissue. Recent studies have highlighted the programmes, properties and roles of the specialized, resident immune subsets that are abundant in adipose tissue, which may be considered a newly identified lymphoid compartment for immunology research. The findings indicate important roles for resident T effector and regulatory cells, innate lymphoid cells (ILCs), invariant natural killer T (iNKT) cells and macrophages, among others. Immunologists are at the very beginning of trying to narrate a story of complex interactions, with the need to unravel cause from effect. The enterprise will require studies in humans as well as mice, and needs to bring together the collaborative efforts of scientists and clinicians from diverse spheres including metabolic disease, diet and microbiology.

Guselkumab: A Review in Moderate to Severe Plaque Psoriasis

Guselkumab (Tremfya^®) is a human immunoglobulin G1 λ (IgG1λ) monoclonal antibody (mAb) that blocks the interleukin-23 (IL-23)-mediated signalling pathway and is the first in its class to be approved in adults with moderate to severe plaque psoriasis in several countries, including the USA and EU. In the VOYAGE trials, guselkumab was superior to placebo and to adalimumab at week 16 in terms of the proportion of patients achieving an Investigator Global Assessment (IGA) score of 0/1 and ≥ 90% improvement from baseline in Psoriasis Area and Severity index score (PASI 90 response), with benefits of guselkumab over adalimumab maintained at week 24. To date, the beneficial effects of guselkumab treatment in these trials were maintained for up to 2 years. Inadequate responders to ustekinumab who were then randomized to guselkumab in NAVIGATE showed better responses than those randomized to ustekinumab between weeks 28-40, with a significantly greater mean number of visits at which patients had IGA 0/1 and ≥ 2-grade improvement in IGA score, as well as higher proportions of patients achieving PASI 90 and PASI 100 at week 52. Treatment with guselkumab improved health-related quality of life (HR-QOL) and patient-reported outcomes in all trials and was generally well tolerated. Guselkumab, administered by subcutaneous injection, is a useful new option for patients with moderate to severe plaque psoriasis.

Stat3 activation in epidermal keratinocytes induces Langerhans cell activation to form an essential circuit for psoriasis via IL-23 production

BACKGROUND

Psoriasis is an inflammatory disease associated with aberrant crosstalk between the epidermis and immune system. However, the role of Langerhans cells (LCs) in psoriasis remains controversial.

OBJECTIVES

To elucidate whether LCs are functionally involved in the development of psoriasis using a mouse model.

METHODS

Two lines of transgenic mice were used and crossed. They included K5.Stat3C, the psoriasis-model mouse and langerin DTR knock-in (KI) mouse. We performed immunofluorescence staining for LCs in psoriatic lesion of human and model mice. Flow cytometric analyses were performed to compare between dendritic cells (DCs) and LCs in the epidermis and skin-draining lymph nodes (sDLNs). To assess cytokine/chemokine expression in the skin lesion or primary cultured keratinocytes, we performed RT-PCR, microarray analysis or intracellular staining on the flow cytometer.

RESULTS

LCs were activated in psoriatic lesion of patients with psoriasis and K5.Stat3C mice. Compared with non-transgenic mice, K5.Stat3C mice constitutively showed an increased number of LCs in the sDLNs before psoriasis-like lesion developed. Stat3C transgenic keratinocytes expressed an elevated level of IL-1α. Psoriasis-like lesion in K5.Stat3C mice were attenuated in the absence of LCs, indicating that LCs were essential to the development of psoriasis-like lesion. Furthermore, we also recognized that epidermal LCs in psoriatic lesion of not only K5.Stat3C mice but also psoriasis patients produced IL-23.

CONCLUSIONS

Our study suggests that Stat3 activation in keratinocytes may impact on LC activation in situ via IL-1α stimulation, at least in part, and that their presence may be essential for the pathogenesis of psoriasis through producing IL-23.

Cutting Edge: Quantitative Determination of CD40L Threshold for IL-12 and IL-23 Production from Dendritic Cells

Early secretion of IL-12 by mouse dendritic cells (DCs) instructs T cells to make IFN-γ. However, only activated, but not naive T cells are able to license DCs for IL-12 production. We hypothesized that it might be due to different levels of CD40L expression on the surface of these cells, as CD40 signals are required for IL-12 production. Using quantitative cell-free systems incorporating CD40L in lipid bilayers combined with total internal reflection fluorescence microscopy and flow cytometry, we show that as low as ∼200 CD40L molecules/μm2 in combination with IL-4 is sufficient to induce IL-12 production by DCs. Remarkably, CD40L alone is adequate to induce IL-23 secretion by DCs. Thus, although activated T cells have somewhat higher levels of CD40L, it is the combination of CD40L and the cytokines they secrete that licenses DCs and influences the effector class of the immune response.

Risankizumab: an anti-IL-23 antibody for the treatment of psoriasis

Risankizumab, a fully human IgG monoclonal antibody inhibitor of IL-23, is a therapeutic agent currently in late stage development for use in the treatment of moderate-to-severe plaque psoriasis. It is a biologic agent similar to guselkumab and tildrakizumab which targets IL-23 specifically, and has been primarily developed for use in moderate-to-severe psoriasis. USA-based pharmaceutical company Abbvie submitted it for a Biologics License Application to the US Food and Drug Administration (FDA) in April 2018. Risankizumab is the result of a collaboration between the German company Boehringer Ingelheim and Abbvie, which together are leading the future development and commercialization of risankizumab globally. The results from Phase I to Phase III clinical trials of risankizumab show it is highly effective and its FDA-approval in 2018 is likely. In this article we provide an independent expert opinion on the efficacy and safety of risankizumab in psoriasis based on a full review of the literature.