Expression of IL-27 in human Th1-associated granulomatous diseases

IL-27 expression regulation and its effects on adaptive immunity against viruses

IL-27, a member of the IL-6/IL-12 cytokine superfamily, is primarily secreted by antigen presenting cells, specifically by dendric cells, macrophages and B cells. IL-27 has antiviral activities and modulates both innate and adaptive immune responses against viruses. The role of IL-27 in the setting of viral infections is not well defined and both pro-inflammatory and anti-inflammatory functions have been described. Here, we discuss the latest advancements in the role of IL-27 in several viral infection models of human disease. We highlight important aspects of IL-27 expression regulation, the critical cell sources at different stages of the infection and their impact in cell mediated immunity. Lastly, we discuss the need to better define the antiviral and modulatory (pro-inflammatory vs anti-inflammatory) properties of IL-27 in the context of human chronic viral infections.

Differential Upregulation of Th1/Th17-Associated Proteins and PD-L1 in Granulomatous Mycosis Fungoides

Granulomatous Mycosis Fungoides (GMF) is a rare form of mycosis fungoides (MF) characterized by a granulomatous infiltrate associated with the neoplastic lymphoid population and is considered to have a worse prognosis compared with regular MF. The upregulation of the T helper (Th) axis, especially Th17, plays an important role in the pathogenesis of several inflammatory/infectious granulomatous cutaneous diseases, but its role in GMF is still not elucidated to date. In this study, we evaluated the immunohistochemical expression of Th1 (Tbet), Th2 (GATA-3), Th17 (RORγT), T regulatory (Foxp3), and immune checkpoint (IC) (PD-1 and PD-L1) markers in a cohort of patients with GMF and MF with large cell transformation (MFLCT). Skin biopsies from 49 patients (28 GMF and 21 MFLCT) were studied. Patients with GMF were associated with early clinical stage (p = 0.036) and lower levels of lactate dehydrogenase (p = 0.042). An increased percentage of cells positive for Tbet (p = 0.017), RORγT (p = 0.001), and PD-L1 (p = 0.011) was also observed among the GMF specimens, while a stronger PD-1 intensity was detected in cases of MFLCT. In this cohort, LCT, RORγT < 10%, Foxp3 < 10%, age, and advanced stage were associated with worse overall survival (OS) in univariate analysis. GMF demonstrated Th1 (cellular response) and Th17 (autoimmunity) phenotype, seen in early MF and granulomatous processes, respectively, which may be related to the histopathological appearance and biological behavior of GMF. Further studies involving larger series of cases and more sensitive techniques are warranted.

Deucravacitinib: a novel TYK2 inhibitor for the treatment of moderate-to-severe psoriasis

Background

Deucravacitinib is a first-in-class tyrosine kinase 2 (TYK2) inhibitor recently approved for the treatment of adults with moderate-to-severe plaque psoriasis.

Objective

To discuss the mechanism of action, efficacy, safety, and real-world applications of deucravacitinib for the treatment of psoriasis.

Methods

Literature on the mechanism of action of deucravacitinib is reviewed. The pivotal clinical studies and long-term extension studies for deucravacitinib are also examined.

Results

Deucravacitinib is a novel oral TYK2 inhibitor that binds to the regulatory domain of TYK2, a Janus kinase. By inhibiting TYK2, deucravacitinib interferes with signaling of IL-23, IL-12, and type I interferons, cytokines believed to play important roles in psoriasis pathogenesis. Nearly 60% of patients achieve PASI 75 at 16 weeks of treatment; efficacy improves over 24 weeks and is maintained through 2 years of continuous treatment. In a head-to-head comparison, deucravacitinib efficacy was superior to apremilast, an older yet commonly used oral PDE4 inhibitor approved for the treatment of psoriasis. Of note, patients with moderate-to-severe plaque psoriasis with concomitant involvement of the scalp, nails, and/or palms/soles demonstrated good improvement in these high impact areas. Deucravacitinib has an acceptable safety profile and is generally well-tolerated. Small increases in reactivation of herpesvirus infections, including herpes simplex outbreaks, have been reported. Tuberculosis evaluation, but no other blood tests, is recommended prior to initiation of deucravacitinib. Monitoring of triglyceride levels should be conducted for high-risk patients according to local guidelines.

Conclusion

Deucravacitinib is an effective, safe, and well-tolerated novel oral medication for adults with moderate-to-severe plaque psoriasis.

Interleukin-27 in Tuberculosis: A Sheep in Wolf’s Clothing?

In tuberculosis (TB), protective inflammatory immune responses and the pathological sequelae of chronic inflammation significantly depend on a timely balance of cytokine expression. In contrast to other anti-inflammatory cytokines, interleukin (IL)-27 has fundamental effects in experimental Mycobacterium tuberculosis (Mtb) infection: the absence of IL-27-mediated signalling promotes a better control of mycobacterial growth on the one hand side but also leads to a chronic hyperinflammation and immunopathology later during infection. Hence, in the context of novel host-directed therapeutic approaches and vaccination strategies for the management of TB, the timely restricted blockade of IL-27 signalling may represent an advanced treatment option. In contrast, administration of IL-27 itself may allow to treat the immunopathological consequences of chronic TB. In both cases, a better knowledge of the cell type-specific and kinetic effects of IL-27 after Mtb infection is essential. This review summarizes IL-27-mediated mechanisms affecting protection and immunopathology in TB and discusses possible therapeutic applications.

IL-27 Derived From Macrophages Facilitates IL-15 Production and T Cell Maintenance Following Allergic Hypersensitivity Responses

Crosstalk between T cells, dendritic cells, and macrophages in temporal leukocyte clusters within barrier tissues provides a new concept for T cell activation in the skin. Activated T cells from these leukocyte clusters play critical roles in the efferent phase of allergic contact hypersensitivity (CHS). However, the cytokines driving maintenance and survival of pathogenic T cells during and following CHS remain mostly unknown. Upon epicutaneous allergen challenge, we here report that macrophages produce IL-27 which then induces IL-15 production from epidermal keratinocytes and dermal myeloid cells within leukocyte clusters. In agreement with the known role of IL-15 as a T cell survival factor and growth cytokine, this signaling axis enhances BCL2 and survival of skin T cells. Genetic depletion or pharmacological blockade of IL-27 in CHS mice leads to abrogated epidermal IL-15 production resulting in a decrease in BCL2 expression in T cells and a decline in dermal CD8⁺ T cells and T cell cluster numbers. These findings suggest that the IL-27 pathway is an important cytokine for regulating cutaneous T cell immunity.

Interleukin-27 and Its Diverse Effects on Bacterial Infections

Innate and adaptive immune responses against pathogens are known to be carefully orchestrated by specific cytokines that initiate and down regulate immune cell functions from the initial infection through tissue repair and homeostasis. However, some cytokines, including interleukin-27, are expressed at multiple phases of the infection, such that their pro and anti-inflammatory functions have been difficult to interpret. As elucidation of specific cytokine functions throughout infection is central to our understanding of protective vs. susceptible immunity and return to homeostasis vs. prolonged inflammation leading to septic shock, here we review the literature on IL-27 signaling and the various functions of this heterodimeric ligand member of the IL-12 cytokine family. Canonically, IL-27 is produced by antigen-presenting cells, and is thought of as an immunostimulatory cytokine due to its capacity to induce Th1 differentiation. However, many studies have also identified various immunosuppressive effects of IL-27 signaling, including suppression of Th17 differentiation and induction of co-inhibitory receptors on T cells. Thus, the exact role of IL-27 in the context of infectious diseases remains a topic of debate and active research. Additionally, as recent interest has focused on clinical management of acute vs. chronic infections, and life-threatening “cytokine storm” from sepsis, we propose a hypothetical model to explain the biphasic role of IL-27 during the early and late phases of immune responses to reconcile its known pro and anti-inflammatory functions, which could be therapeutically regulated to improve patient outcomes of infection.

Title of article: Mucosal-associated invariant T cells in lung diseases

The lungs are directly connected to the external environment, which makes them more vulnerable to infection and injury. They are protected by the respiratory epithelium and immune cells to maintain a dynamic balance. Both innate and adaptive immune cells are involved in the pathogenesis of lung diseases. Mucosal-associated invariant T (MAIT) cells are a subset of unconventional T cells, which have attracted increasing attention in recent years. Although MAIT cells account for a small part of the total immune cells in the lungs, evidence suggests that these cells are activated by T cell receptors and/or cytokine receptors and mediate immune response. They play an important role in immunosurveillance and immunity against microbial infection, and recent studies have shown that subsets of MAIT cells play a role in promoting pulmonary inflammation. Emerging data indicate that MAIT cells are involved in the immune response against SARS-CoV-2 and possible immunopathogenesis in COVID-19. Here, we introduce MAIT cell biology to clarify their role in the immune response. Then we review MAIT cells in human and murine lung diseases, including asthma, chronic obstructive pulmonary disease, pneumonia, pulmonary tuberculosis and lung cancer, and discuss their possible protective and pathological effects. MAIT cells represent an attractive marker and potential therapeutic target for disease progression, thus providing new strategies for the treatment of lung diseases.

Sarcoidosis manifesting during treatment with secukinumab for psoriatic arthritis

Sarcoidosis is a multisystem inflammatory disorder of uncertain aetiology. There are numerous case reports of sarcoidosis occurring during treatment with biological immunotherapies. Here, we describe the case of a 52-year-old woman with psoriatic arthritis who developed multisystem sarcoidosis while being treated with secukinumab (anti-interleukin-17A) therapy which, to our knowledge, is the first such case. We discuss existing literature and hypothesise that IL-17 blockade may precipitate the development of granulomatous disease.

The Role of gp130 Cytokines in Tuberculosis

Protective immune responses to Mycobacterium tuberculosis (Mtb) infection substantially depend on a delicate balance within cytokine networks. Thus, immunosuppressive therapy by cytokine blockers, as successfully used in the management of various chronic inflammatory diseases, is often connected with an increased risk for tuberculosis (TB) reactivation. Hence, identification of alternative therapeutics which allow the treatment of inflammatory diseases without compromising anti-mycobacterial immunity remains an important issue. On the other hand, in the context of novel therapeutic approaches for the management of TB, host-directed adjunct therapies, which combine administration of antibiotics with immunomodulatory drugs, play an increasingly important role, particularly to reduce the duration of treatment. In both respects, cytokines/cytokine receptors related to the common receptor subunit gp130 may serve as promising target candidates. Within the gp130 cytokine family, interleukin (IL)-6, IL-11 and IL-27 are most explored in the context of TB. This review summarizes the differential roles of these cytokines in protection and immunopathology during Mtb infection and discusses potential therapeutic implementations with respect to the aforementioned approaches.

Anti-inflammatory cytokines IL-27, IL-10, IL-1Ra and TGF-β in subjects with increasing grades of glucose intolerence (DM-LTB-2)

Anti-inflammatory cytokines act as double edged swords- they can dampen inflammation but can also suppress immunity. The role played by these cytokines in latent TB infected (LTBI) subjects, with various grades of glucose intolerance was studied. Both serum levels and recall-secretion of IL-27, IL-10, IL-1Ra and TGF-β in Normal Glucose Tolerance (NGT), Pre-Diabetes (PDM), Newly diagnosed Diabetes (NDM) and Known Diabetes (KDM) subjects, both with and without LTBI (n = 382), were quantified by ELISA. All the subjects were screened for LTBI by QuantiFERON-TB Gold test. Serum levels of IL-27, IL-10 and IL-1Ra were significantly elevated in the LTB^-PDM, compared to LTB^-NGT group. Increased IL-27 and IL-10 levels and decreased levels of TGF-β were seen in the LTB^-NDM, compared to LTB^-NGT group. Decreased serum levels of IL-27 and increased levels of IL-1Ra and TGF-β were seen in the LTB^-KDM, compared to LTB^-NGT group. TB antigens induced the secretion of IL-1Ra in LTB⁺ subjects in the NGT, PDM and NDM groups, but not in the KDM group. Co-morbidity with LTBI brought about (diabetic) stage-specific modulation, in these cytokine levels. Major defects in the circulating levels and recall secretion of anti-inflammatory cytokines, as seen in LTB⁺KDM subjects, could fuel DM-TB synergy.

IL-27 regulation of innate immunity and control of microbial growth

IL-27 is a pleiotropic cytokine capable of influencing both innate and adaptive immune responses. With anti- and pro-inflammatory activity, IL-27 exerts its opposing effects in a cell-dependent and infectious context-specific manner. Upon pathogenic stimuli, IL-27 regulates innate immune cells, such as monocytes, dendritic cells, macrophages and neutrophils. Immune responses involving these innate cells that are negatively regulated by IL-27 signaling include inflammatory cytokine production, phagolysosomal acidification following phagocytosis, oxidative burst and autophagy. IL-27 signaling is crucial in maintaining the subtle balance between Th1 and Th2 immunity, in which protective inflammation is upregulated within the early stages of infection and subsequently downregulated once microbial growth is controlled. The immunomodulatory effects of IL-27 provide promising therapeutic targets for multiple disease types.

A primary role of IL-27 is to communicate between various immune cells to initiate different immune responses. Among these responses are those involved with destroying and eliminating microbial pathogens and then turning off inflammatory responses when the infectious threat has been resolved. IL-27 possesses both anti- and pro-inflammatory activity that varies with context, immune cell and pathogen stimulus. Depending on the precise formula of these details, there are important implications for IL-27 in disease outcomes. As such, harnessing or opposing IL-27 activity may have the potential to treat a variety of infectious diseases.

The contribution from interleukin-27 towards rheumatoid inflammation: insights from gene expression

We aimed to assess expression of genes encoding the heterodimeric IL-27 cytokine and constituent subunits of the Il-27 receptor in rheumatoid arthritis (RA), including in extra-articular, subcutaneous rheumatoid nodules. Comparing between nodules and joint synovia, significantly elevated expression of IL27A within nodules, and comparable IL27B expression, identified nodules as a significant source of IL-27 in RA. T-lymphocytes were the main source of IL27RA transcript, and IL27RA expression correlated with a number of plasma cytokines, as well as tissue TNF expression in both nodules and RA synovia. In synovia, correlations between IL27A, IL27RA IL17A and CD21L expression, and significantly elevated expression of the genes encoding IL-27, associated the presence of IL-27 with B cell-dominated synovial inflammation. Impact from nodule derived IL-27 on systemic or synovial inflammation in RA remains unknown and further study of these implications is required. Our study raises questions regarding the appropriate circumstances for the blockade or administration of IL-27 as a potential therapeutic adjunct in RA.

Glycosaminoglycans bind human IL-27 and regulate its activity

IL-27 is a cytokine of the IL-12 family, composed of EBI3 and IL-27p28. IL-27 regulates immune responses and also other physiological processes including hematopoiesis, angiogenesis, and bone formation. Its receptor, composed of IL-27Rα and gp130, activates the STAT pathway. Here, we show that different glycosaminoglycans (GAGs) modulate human IL-27 activity in vitro. We find that soluble heparin and heparan sulfate efficiently inhibit human IL-27 activity as shown by decreased STAT signaling and downstream biological effects. In contrast, membrane-bound heparan sulfate seems to positively regulate IL-27 activity. Our biochemical studies demonstrate that soluble GAGs directly bind to human IL-27, consistent with in silico analyses, and prevent its binding to IL-27Rα. Although murine IL-27 also bound to GAGs in vitro, its activity was less efficiently inhibited by soluble GAGs. Lastly, we show that two heparin-derivatives, low molecular weight heparin and fondaparinux, that like unfractionated heparin are used in clinics, had weaker or no effect on human IL-27 activity. Together, our data identify GAGs as new players in the regulation of human IL-27 activity that might act under physiological conditions and may also have a clinical impact in heparin-treated patients.

Evaluating the mechanism underlying antitumor effect of interleukin 27 on B cells of chronic lymphocytic leukemia patients

Chronic lymphocyte leukemia (CLL) is a B-cell malignancy resisted to apoptosis. Recently, some studies indicated that cytokines such as interleukin 27 (IL-27) can reduce B-cell proliferation. The aim of this study is to evaluate the mechanism underlying the proapoptotic effect of IL-27 on B cells of patients with CLL in comparison with B cells of normal subjects. The effect of IL-27 on the antitumor activity of natural killer (NK) and T cells was also evaluated. Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with CLL and 15 normal subjects. B cells and PBMCs were cocultured with IL-27 and B cells apoptosis to evaluate proliferation. Both messenger RNA and protein expression of IL-27 and IL-27 receptor were determined using flow cytometry and real-time polymerase chain reaction analysis. To evaluate the apoptotic effect of IL-27 on B cells of patients with CLL, Annexin V-FITC and 7-AAD (BioLegend) fluorescent dyes were used. In addition, the IL-27 effect on activation of T cell and NK cell was determined by determining CD96 molecule expression. IL-27 and IL-27 receptor expression in patients with CLL was significantly lower than that of normal subjects (p < .05). IL-27 enhanced apoptosis of B cells in patients with CLL (p < .05) but this effect was not significantly observed in B cells of normal subjects (p > .05). Consequently, IL-27 reduced the proliferation of B cells and enhanced NK cell activity (p < .05). IL-27, through inducing apoptosis, can exert an inhibitory effect on cancer B cells of CLL patients with minimal effect on normal B cells.

Plasma levels of interleukin 27 in falciparum malaria is increased independently of co-infection with HIV: potential immune-regulatory role during malaria

Background

The immune response during falciparum malaria mediates both harmful and protective effects on the host; however the participating molecules have not been fully defined. Interleukin (IL)-27 is a pleiotropic cytokine exerting both inflammatory and anti-inflammatory effects, but data on IL-27 in malaria patients are scarce.

Methods

Clinical data and blood samples were collected from adults in Mozambique with P. falciparum infection, with (n = 70) and without (n = 61) HIV-1 co-infection, from HIV-infected patients with similar symptoms without malaria (n = 58) and from healthy controls (n = 52). In vitro studies were performed in endothelial cells and PBMC using hemozoin crystals. Samples were analyzed using enzyme immunoassays and quantitative PCR.

Results

(i) IL-27 was markedly up-regulated in malaria patients compared with controls and HIV-infected patients without malaria, showing no relation to HIV co-infection. (ii) IL-27 was correlated with P. falciparum parasitemia and von Willebrand factor as a marker of endothelial activation, but not with disease severity. (iii) In vitro, IL-27 modulated the hemozoin-mediated cytokine response in endothelial cells and PBMC with enhancing effects on IL-6 and attenuating effects on IL-8.

Conclusion

Our findings show that IL-27 is regulated during falciparum malaria, mediating both inflammatory and anti-inflammatory effects, potentially playing an immune-regulatory role during falciparum malaria.

Interleukin-35 Regulates Immune Microenvironment of Autoimmune Hepatitis Through Inducing the Expansion of Myeloid-Derived Suppressor Cells

Interleukin-35 (IL-35) is a novel anti-inflammatory cytokine of IL12 cytokine family, however, the role of IL-35 in patients with AIH and its effect on myeloid-derived suppressor cells (MDSCs) has not yet been analyzed. The expression of IL-35 subunits (p35 and EBI3) in liver tissues was quantified by immunochemistry and its correlation with clinical parameters was explored in patients with AIH. The expression of MDSCs and IL-35 receptor (gp130 and IL-12Rβ2) were analyzed using flow cytometry and confocal staining. Besides, we utilized in vitro culture to explore the role of IL-35 on MDSCs expansion and activation. We found that the elevated expression of both IL-35 subunits (EBI3 and p35) in liver tissue was positively associated with degrees of hepatic inflammatory and fibrosis in patients with AIH. Furthermore, the expression of EBI3 in liver was positively correlated with patient age, serum IgG levels and serum AST, and was negatively correlated with hemoglobin and albumin. Moreover, our results showed that ratio of MDSC in peripheral blood increased significantly in AIH patients as compared with healthy controls. Further study showed that CD33, a representative marker of MDSCs, co-localized well with gp130 and IL12Rβ2, suggesting MDSCs as target cell for IL-35. Consistently, MDSCs from AIH displayed a substantial higher abundance of gp130 and IL12Rβ2 and were expanded by IL-35 in vitro. IL-35-induced MDSCs showed a significant increase in Nitric oxide (NO) production but not reactive oxygen species (ROS). Conclusions: IL-35 might play an important role in AIH by regulating MDSCs and it could provide new insights into the therapy of AIH.

Activation of mucosal-associated invariant T cells in the lungs of sarcoidosis patients

Although the pathogenesis of sarcoidosis is not fully understood, immunological characterization has elucidated highly polarized expression of the type 1 T helper cell response. Mucosal-associated invariant T (MAIT) cells are innate T cells that recognize bacterial riboflavin and rapidly produce cytokines such as interferon γ and tumor necrosis factor α. We prospectively evaluated the proportion of MAIT cells and the expression levels of cell surface markers in peripheral blood from 40 sarcoidosis patients and 28 healthy controls. MAIT cells in bronchoalveolar lavage fluid (BALF) were also examined in 12 sarcoidosis patients. In peripheral blood, the proportion of MAIT cells was lower (P = 0.0002), but the expression levels of CD69 and programmed death 1 on MAIT cells were higher in sarcoidosis patients than in healthy controls. Moreover, CD69 expression levels were significantly correlated with clinical biomarkers. Sarcoidosis patients with parenchymal infiltration in the lungs showed a significantly higher proportion and number of MAIT cells in BALF compared to patients without parenchymal infiltration. CD69 expression levels on MAIT cells in BALF were higher than levels in peripheral blood. The activation status of MAIT cells might reflect the disease activity of sarcoidosis. Therefore, it is a potential target for sarcoidosis treatment.

Evidence for IL-35 Expression in Diffuse Large B-Cell Lymphoma and Impact on the Patient's Prognosis

IL-35 is an immunosuppressive cytokine of the IL-12 family consisting of two subunits, EBV-induced gene 3 (EBI3) and p35. It has been shown to play a pro-tumor role in murine tumor models, and in various types of human cancer such as colorectal, pancreatic, or liver carcinoma, its expression has been associated with a worse clinical outcome. Here, we show by analyzing gene expression data from public databases and by immunohistochemical studies that IL-35 is overexpressed by tumor cells in diffuse-large B-cell lymphoma (DLBCL) compared to another type of mature aggressive B-cell lymphoma, Burkitt lymphoma. However, while high IL-35 expression was significantly associated with a worse overall survival in DLBCL patients treated with chemotherapy only (cyclophosphamide, doxorubicin, vincristine, prednisone, CHOP), no significant correlation between IL-35 expression levels and the patient outcome was observed in DLBCL patients treated with CHOP combined to rituximab (R-CHOP), the current conventional treatment. In addition, we found that an anti-IL-35 antibody, clone 15k8D10, used to assess IL-35 expression by immunohistochemistry in various human tissues including tumors does not recognize IL-35 heterodimer, nor its individual subunits EBI3 and p35, but cross-reacts with human IgG1, indicating that IL-35 expression in human cancers needs to be re-evaluated.

Polygenic risk assessment reveals pleiotropy between sarcoidosis and inflammatory disorders in the context of genetic ancestry

Sarcoidosis is a complex disease of unknown etiology characterized by the presence of granulomatous inflammation. Though various immune system pathways have been implicated in disease, the relationship between the genetic determinants of sarcoidosis and other inflammatory disorders has not been characterized. Herein, we examined the degree of genetic pleiotropy common to sarcoidosis and other inflammatory disorders to identify shared pathways and disease systems pertinent to sarcoidosis onset. To achieve this, we quantify the association of common variant polygenic risk scores from nine complex inflammatory disorders with sarcoidosis risk. Enrichment analyses of genes implicated in pleiotropic associations were further used to elucidate candidate pathways. In European-Americans, we identify significant pleiotropy between risk of sarcoidosis and risk of asthma (R²=2.03%; p=8.89×10⁻⁹), celiac disease (R²=2.03%; p=8.21×10⁻⁹), primary biliary cirrhosis (R²=2.43%; p=2.01×10⁻¹⁰), and rheumatoid arthritis (R²=4.32%; p=2.50×10⁻¹⁷). These associations validate in African Americans only after accounting for the proportion of genome-wide European ancestry, where we demonstrate similar effects of polygenic risk for African-Americans with the highest levels of European ancestry. Variants and genes implicated in European-American pleiotropic associations were enriched for pathways involving interleukin-12, interleukin-27, and cell adhesion molecules, corroborating the hypothesized immunopathogenesis of disease.

Dual Roles of IL-27 in Cancer Biology and Immunotherapy

IL-27 is a pleiotropic two-chain cytokine, composed of EBI3 and IL-27p28 subunits, which is structurally related to both IL-12 and IL-6 cytokine families. IL-27 acts through a heterodimer receptor consisting of IL-27Rα (WSX1) and gp130 chains, which mediate signaling predominantly through STAT1 and STAT3. IL-27 was initially reported as an immune-enhancing cytokine that supports CD4+ T cell proliferation, T helper (Th)1 cell differentiation, and IFN-γ production, acting in concert with IL-12. However, subsequent studies demonstrated that IL-27 displays complex immune-regulatory functions, which may result in either proinflammatory or anti-inflammatory effects in relationship to the biological context and experimental models considered. Several pieces of evidence, obtained in preclinical tumor models, indicated that IL-27 has a potent antitumor activity, related not only to the induction of tumor-specific Th1 and cytotoxic T lymphocyte (CTL) responses but also to direct inhibitory effects on tumor cell proliferation, survival, invasiveness, and angiogenic potential. Nonetheless, given its immune-regulatory functions, the effects of IL-27 on cancer may be dual and protumor effects may also occur. Here, we will summarize IL-27 biological activities and its functional overlaps with the IFNs and discuss its dual role in tumors in the light of potential applications to cancer immunotherapy.

High Interleukin 27 Production is Associated with Early Clinical Stage and Localized Disease in Patients with Melanoma

BACKGROUND

The immune response in patients with melanoma is an important focus of research due to the tumor's resistance and immunotherapy possibilities. IL-27 is one of the cytokines with antitumor properties. The role of IL-27 in the pathogenesis of melanoma is still unclear. The aim of this study was to examine the association between serum IL-27 levels and the clinical parameters of melanoma patients.

METHODS

The IL-27 concentration was determined by com mercial ELISA in serum samples from melanoma patients (n=72) and healthy control subjects (n=44). Patients were classified according to AJCC clinical stage, TNM stage, the length of progression-free interval (PFI) and the extent of the disease (localized or widespread).

RESULTS

Average IL-27 values were increased in patients with early stages of melanoma compared to patients with terminal stages and control values. The highest IL-27 concentration was found in stage IIa. Patients in stages III and IV had significantly lower values of IL-27 compared to control. Patients with localized melanoma and shorter PFI had insignificantly increased IL-27 levels compared to patients with widespread disease and longer PFI. Patients with metastatic disease and stage TNM4 had significantly lower average IL-27 values compared to control. Patients with high production of IL-27 (>1000 pg/mL) were most numerous in IIa AJCC stage, with initial tumor size TNM2 and in the group of patients with localized disease.

CONCLUSIONS

High levels of IL-27 in patients with melanoma are associated with the initial stages and lo calized disease.

Sarcoidosis activates diverse transcriptional programs in bronchoalveolar lavage cells

Background

Sarcoidosis is a multisystem immuno-inflammatory disorder of unknown etiology that most commonly involves the lungs. We hypothesized that an unbiased approach to identify pathways activated in bronchoalveolar lavage (BAL) cells can shed light on the pathogenesis of this complex disease.

Methods

We recruited 15 patients with various stages of sarcoidosis and 12 healthy controls. All subjects underwent bronchoscopy with lavage. For each subject, total RNA was extracted from BAL cells and hybridized to an Affymetrix U133A microarray. Rigorous statistical methods were applied to identify differential gene expression between subjects with sarcoidosis vs. controls. To better elucidate pathways differentially activated between these groups, we integrated network and gene set enrichment analyses of BAL cell transcriptional profiles.

Results

Sarcoidosis patients were either non-smokers or former smokers, all had lung involvement and only two were on systemic prednisone. Healthy controls were all non-smokers. Comparison of BAL cell gene expression between sarcoidosis and healthy subjects revealed over 1500 differentially expressed genes. Several previously described immune mediators, such as interferon gamma, were upregulated in the sarcoidosis subjects. Using an integrative computational approach we constructed a modular network of over 80 gene sets that were highly enriched in patients with sarcoidosis. Many of these pathways mapped to inflammatory and immune-related processes including adaptive immunity, T-cell signaling, graft vs. host disease, interleukin 12, 23 and 17 signaling. Additionally, we uncovered a close association between the proteasome machinery and adaptive immunity, highlighting a potentially important and targetable relationship in the pathobiology of sarcoidosis.

Conclusions

BAL cells in sarcoidosis are characterized by enrichment of distinct transcriptional programs involved in immunity and proteasomal processes. Our findings add to the growing evidence implicating alveolar resident immune effector cells in the pathogenesis of sarcoidosis and identify specific pathways whose activation may modulate disease progression.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0411-y) contains supplementary material, which is available to authorized users.

Enhanced LPS-induced activation of IL-27 signalling in sarcoidosis

RATIONALE

Granulomas in sarcoidosis have recently been described as containing Interleukin (IL)-27, one of the members of the IL-12 family of cytokines, which also includes IL-35. Levels of these cytokines and the IL-27 receptor subunits were hypothesised to differ between patients with sarcoidosis compared to healthy controls in peripheral blood.

METHODS

Using a cross-sectional study design, plasma and peripheral blood mononuclear cells (PBMC) were collected from patients and control subjects. Protein and mRNA (in PBMC) levels for IL-27 and IL-35 (IL27, EBI3, IL12A subunits) as well as IL-27 receptor (IL6ST and IL27RA subunits) were assessed spontaneously and following direct (LPS) and indirect (anti-CD3/28 activation beads) macrophage stimulation using RT- PCR, ELISA and flow cytometry.

RESULTS

Following stimulation with LPS, PBMC of patients with sarcoidosis displayed significantly enhanced expression of IL27 and EBI3 mRNA (p = 0.020 and p = 0.037 respectively) compared to PBMCs from healthy controls. There was also significantly enhanced production of IL-27 by PBMC from patients with sarcoidosis compared to healthy controls in response to LPS stimulation (p = 0.027). IL6ST mRNA and IL6ST protein were significantly lower in patients with sarcoidosis (mRNA p = 0.0002; MFI p = 0.0015) whilst IL27RA protein levels were significantly higher in patients with sarcoidosis compared to healthy controls (MFI p < 0.0001). Plasma IL-35 protein levels did not differ between control and sarcoidosis subjects (p = 0.23).

CONCLUSION

These results suggest there may be exaggerated activation of IL-27 signalling in response to LPS in sarcoidosis.

Immunogenetics of Disease-Causing Inflammation in Sarcoidosis

Sarcoidosis is a systemic inflammatory disorder characterised by tissue infiltration by mononuclear phagocytes and lymphocytes with associated non-caseating granuloma formation. Originally described as a disorder of the skin, sarcoidosis can involve any organ with wide-ranging clinical manifestations and disease course. Recent studies have provided new insights into the mechanisms involved in disease pathobiology, and we now know that sarcoidosis has a clear genetic basis largely involving human leukocyte antigen (HLA) genes. In contrast to Mendelian-monogenic disorders--which are generally due to specific and relatively rare mutations often leading to a single amino acid change in an encoded protein--sarcoidosis results from genetic variations relatively common in the general population and involving multiple genes, each contributing an effect of varying magnitude. However, an individual may have the necessary genetic profile and yet the disease will not develop unless an environmental or infectious factor is encountered. Genetics appears also to contribute to the huge variability in clinical phenotype and disease behaviour. Moreover, it has been established that sarcoidosis granulomatous inflammation is a highly polarized T helper 1 immune response that starts with an antigenic stimulus followed by T cell activation via a classic HLA class II-mediated pathway. A complex network of lymphocytes, macrophages, and cytokines is pivotal in the orchestration and evolution of the granulomatous process. Despite these advances, the aetiology of sarcoidosis remains elusive and its pathogenesis incompletely understood. As such, there is an urgent need for a better understanding of disease pathogenesis, which hopefully will translate into the development of truly effective therapies.

Increased Frequency of T Follicular Helper Cells and Elevated Interleukin-27 Plasma Levels in Patients with Pemphigus

Pemphigus is an autoimmune disease in which IgG auto-antibodies (auto-ab) against the desmosomal cadherins desmoglein (Dsg) 3 and Dsg1 cause loss of epidermal keratinocyte adhesion. Aim of this study was to investigate cytokines derived from antigen-presenting cells (APC) and their relation to CD4⁺ T cell subpopulations and to the auto-ab response in pemphigus. In this regard, patients with pemphigus were compared to patients with myasthenia gravis (MG), an unrelated auto-ab–mediated autoimmune disease, and healthy controls. In pemphigus and MG, the plasma concentrations of the APC-derived immunomodulatory cytokine IL-27 were highly increased. Strikingly, IL-27 strongly correlated with Dsg-specific IgG auto-ab titers. T helper (Th) 17 cells were augmented in both pemphigus and MG patients while T follicular helper (Tfh) cells, which are essential in providing B cell help, were increased only in pemphigus along with increasing plasma concentrations of IL-21, a cytokine produced by Th17 and Tfh cells. Moreover, we could detect Dsg3-specific autoreactive T cells producing IL-21 upon ex vivo stimulation with Dsg3. These findings suggest that IL-27 and IL-21-producing T cells, are involved in the pathogenesis of pemphigus. The further characterization of IL-21-producing T cells and of the role of IL-27 will lead to a more defined understanding of the auto-ab response in pemphigus.

New Approaches to the Immunotherapy of Type 1 Diabetes Mellitus Using Interleukin-27

Type 1 diabetes (T1D) is a pancreatic beta cell specific autoimmune disease. One of the most significant current discussions in T1D studies is therapy. Since the conventional therapy, islet transplantation and external insulin, e.g., cannot prevent the destructive autoimmune process against original beta cells and persistent hyperglycemia remains, so recent developments in the field of T1D therapy paved the way to a renewed interest in immunotherapy based on the disease process, especially monoclonal antibody therapy. Due to encouraging laboratory results, cytokine antibody-based drugs could be effective in the clinical direction of the T1D disease process. Hence, implementation of this approach can be useful to improve clinical and laboratory manifestations of T1D.

Increased Blood Levels of Growth Factors, Proinflammatory Cytokines, and Th17 Cytokines in Patients with Newly Diagnosed Type 1 Diabetes

The production of several cytokines could be dysregulated in type 1 diabetes (T1D). In particular, the activation of T helper (Th) type 1 (Th1) cells has been proposed to underlie the autoimmune pathogenesis of the disease, although roles for inflammatory processes and the Th17 pathway have also been shown. Nevertheless, despite evidence for the role of cytokines before and at the onset of T1D, the corresponding findings are inconsistent across studies. Moreover, conflicting data exist regarding the blood cytokine levels in T1D patients. The current study was performed to investigate genetic and autoantibody markers in association with the peripheral blood cytokine profiles by xMap multiplex technology in newly diagnosed young T1D patients and age-matched healthy controls. The onset of young-age T1D was characterized by the upregulation of growth factors, including granulocyte macrophage-colony stimulating factor (GM-CSF) and interleukin (IL)-7, the proinflammatory cytokine IL-1β (but not IL-6 or tumor necrosis factor [TNF]-α), Th17 cytokines, and the regulatory cytokines IL-10 and IL-27. Ketoacidosis and autoantibodies (anti-IA-2 and -ZnT8), but not human leukocyte antigen (HLA) genotype, influenced the blood cytokine levels. These findings broaden the current understanding of the dysregulation of systemic levels of several key cytokines at the young-age onset of T1D and provide a further basis for the development of novel immunoregulatory treatments in this disease.

IL-27-induced modulation of autoimmunity and its therapeutic potential

Interleukin-27 (IL-27) is a new member of the IL-12 family. It is produced by activated antigen-presenting cells and plays an important role in the regulation of CD4+ T cell differentiation and immune response. IL-27 activates multiple signaling cascades, including the JAK-STAT and p38 MAPK pathways. Several studies have revealed that IL-27 promotes the differentiation of Th1 and Tr1, but inhibits Th2, Th17, and Treg cells. However, a few studies have shown an opposite effect on certain T cell subsets, such as Treg. IL-27 displays both pro- and anti- inflammatory activities in different autoimmune diseases. Here, we have discussed the role of IL-27 in rheumatoid arthritis, multiple sclerosis, colitis, lupus, psoriasis, type 1 diabetes, and uveitis. Most of this information is derived from experimental models of these autoimmune diseases. The mechanistic basis of the dual role of IL-27 in inflammation and autoimmunity is still not fully defined. In general, the pro-/anti-inflammatory activity of IL-27 is influenced by the underlying immune effector pathways, the phase of the disease, the presence or absence of counter-regulatory cytokines/T cell subsets, and the tissue/cell type under study. Despite a spectrum of outcomes in various autoimmune diseases, mostly anti-inflammatory and immunomodulatory effects of IL-27 have been observed in this category of diseases. Accordingly, IL-27 represents a novel, promising target/agent for the treatment of autoimmune diseases.

Interleukin 27R regulates CD4+ T cell phenotype and impacts protective immunity during Mycobacterium tuberculosis infection

Loss of IL-27R on T cells results in increased protection from Mycobacterium tuberculosis. Torrado et al. demonstrate that IL-27R^−/− T cells show improved fitness that is associated with decreased expression of cell death molecules, maintenance of IL-2 production, and preferential accumulation in the lung parenchyma and around infected macrophages.

CD4⁺ T cells mediate protection against Mycobacterium tuberculosis (Mtb); however, the phenotype of protective T cells is undefined, thereby confounding vaccination efforts. IL-27 is highly expressed during human tuberculosis (TB), and absence of IL-27R (Il27ra) specifically on T cells results in increased protection. IL-27R deficiency during chronic Mtb infection does not impact antigen-specific CD4⁺ T cell number but maintains programmed death-1 (PD-1), CD69, and CD127 expression while reducing T-bet and killer cell lectin-like receptor G1 (KLRG1) expression. Furthermore, T-bet haploinsufficiency results in failure to generate KLRG1⁺, antigen-specific CD4⁺ T cells, and in improved protection. T cells in Il27ra^−/− mice accumulate preferentially in the lung parenchyma within close proximity to Mtb, and antigen-specific CD4⁺ T cells lacking IL-27R are intrinsically more fit than intact T cells and maintain IL-2 production. Improved fitness of IL-27R–deficient T cells is not associated with increased proliferation but with decreased expression of cell death–associated markers. Therefore, during Mtb infection, IL-27R acts intrinsically on T cells to limit protection and reduce fitness, whereas the IL-27R–deficient environment alters the phenotype and location of T cells. The significant expression of IL-27 in TB and the negative influence of IL-27R on T cell function demonstrate the pathway by which this cytokine/receptor pair is detrimental in TB.

T-bet and interleukin-27: possible TH1 immunomodulators of sarcoidosis

Background

Sarcoidosis has often been termed an “immune paradox” as there is peripheral anergy to common recall antigens despite pronounced T_H1-dominant inflammation at disease sites, such as the lung, with up-regulation of interferon γ, IL-27 and transcription factors. Peripheral blood may reflect the anergic state, while exhaled breath condensate (EBC) analysis may offer insights into the lung disease.

Methods

A cross-sectional study was conducted to investigate the expression of T_H1 cytokines and transcription factors (IFNγ, IL-27 and T-bet) in the peripheral blood and/or EBC of sarcoidosis patients and healthy controls. Whole blood and EBC were collected from sarcoidosis patients and healthy controls. T_H1 cytokine expression levels were then measured in peripheral blood mononuclear cells (PBMCs) and/or plasma and EBC using quantitative real-time PCR, ELISA and via Western blotting.

Results

Compared to healthy controls, PBMC IL-27 mRNA was higher in patients (p = 0.0019). There were no significant differences in plasma IL-27 protein between patients and controls (p = 0.20). T-bet mRNA and protein were lower (p = 0.010 and p = 0.0043, respectively) in patients compared to controls. There were no significant differences in PBMC IFNγ mRNA and protein expression (p = 0.68 and p = 0.74, respectively) nor in EBC IL-27 levels.

Conclusions

Our data indicate that depressed T-bet mRNA and protein expression could contribute to the peripheral anergy in sarcoidosis and that IL-27 mRNA levels are elevated in the PBMC from those with sarcoidosis.

Electronic supplementary material

The online version of this article (doi:10.1007/s10787-015-0247-y) contains supplementary material, which is available to authorised users.

Interleukin-35 is upregulated in systemic sclerosis and its serum levels are associated with early disease

OBJECTIVES

IL-35 is a member of the IL-12 family consisting of p35/IL-12a and EBI3/IL-27b subunits. IL-35 exerts immunomodulatory activities in experimental and human autoimmune inflammatory conditions. Our aim was to assess IL-35 expression in the skin and circulation of SSc patients and to characterize its potential association with SSc-related features.

METHODS

Expression of IL-35 in skin and dermal fibroblasts was quantified by quantitative PCR, immunohistochemistry and immunofluorescence. Serum levels of IL-35 (by ELISA), CRP (by turbidimetry), ANA (by immunofluorescence) and autoantibodies of the ENA complex (by immunoblot) were measured in 40 SSc patients. Serum IL-35 was determined in 40 age- and sex-matched healthy controls.

RESULTS

IL-35 expression was increased in SSc skin and dermal fibroblasts in a TGF-β-dependent manner. IL-35 induced an activated phenotype in resting fibroblasts and enhanced the release of collagen. IL-35 serum levels were increased in patients with SSc compared with healthy controls [median 83.9 (interquartile range 45.1-146.1) vs 36.2 (interquartile range 17.2-49.4) pg/ml, P < 0.0001]. Serum IL-35 was negatively correlated with disease duration (r = -0.4339, P = 0.0052). In line with this finding, serum IL-35 was increased in patients with an early SSc pattern on capillaroscopy assessment compared with those with active and late SSc patterns.

CONCLUSION

The present study demonstrates overexpression of IL-35 in SSc skin, dermal fibroblasts and serum. TGF-β induces IL-35, which in turn activates resting fibroblasts and enhances the release of collagen, thereby contributing to aberrant TGF-β signalling in SSc. Increased serum IL-35 is associated with early, inflammatory stages of SSc.

Interleukin-27 and IFNγ regulate the expression of CXCL9, CXCL10, and CXCL11 in hepatitis

Interleukin-27 (IL-27) belongs to the IL-6/IL-12 family of cytokines, associated with different inflammatory diseases and orchestrates its biological activity via common heterodimeric receptor composed of WSX-1 (IL-27Rα) and gp130. The present study was aimed to investigate the regulation of CXCL9, CXCL10, and CXCL11 chemokines in hepatic cells (human LX-2 cell line derived from normal human stellate cells (HSC), primary human hepatocytes, HSC, and HepG2 cells) and concanavalin A (ConA)-induced liver inflammation. We demonstrated that IL-27, but not IL-6, induced/up-regulated CXCR3 ligand genes (CXCL9, CXCL10, and CXCL11; out of 26 selected genes) in a STAT1-dependent manner in hepatic cells in vitro both at transcript and protein levels. In ConA-induced T cell-mediated hepatic model, we showed that soluble IL-27/IFNγ was elevated following ConA hepatitis in association with increased CXCL9, CXCL10, and CXCL11 expression in the liver. The exogenous IL-27 administration induced CXCR3 ligands in mouse liver at 4 h with any significant effect on recruitment of CXCR3(+) immune cells in the liver. The neutralization of IL-27 during ConA hepatitis differentially modulated (transcript vs protein expression) CXCR3 ligands and IFNγ during ConA-induced hepatitis with down-regulated expression of CXCL9 and CXCL10 at transcript level. The IFNγ, complementary regulated the expression of CXCR3 ligands as their up-regulation during ConA hepatitis, was abolished in IFNγ KO mice. In summary, IL-27 up-regulated the CXCL9, CXCL10, and CXCL11 chemokine expression in hepatic cells. IL-27 regulated CXCR3 ligand expression in IFNγ-dependent manner during acute hepatitis suggesting a complementary role of IL-27 and IFNγ to moderate liver inflammation via regulation of CXCR3 ligands.

KEY MESSAGE

IL-27 up-regulated CXCR3 ligand expression in human hepatic cells in vitro. IL-27 up-regulated CXCR3 ligand expression and secretion in ConA hepatitis in vivo. CXCR3 ligand expression was down-regulated by blocking IL-27 or IFNγ deficiency. IL-27 modulated liver injury by regulation of CXCR3 ligands in IFNγ-dependent manner.

Granulomatous interstitial nephritis secondary to chronic lymphocytic leukemia/small lymphocytic lymphoma

Granulomatous interstitial nephritis (GIN) is an uncommon pathologic lesion encountered in 0.5% to 5.9% of renal biopsies. Drugs, sarcoidosis, and infections are responsible for most cases of GIN. Malignancy is not an established cause of GIN. Here, we report a series of 5 patients with GIN secondary to chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Patients were mostly elderly white males with an established history of CLL/SLL who presented with severe renal impairment (median peak serum creatinine, 7.3 mg/dL), leukocyturia, and mild proteinuria. One had nephromegaly. In 2 patients, the development and relapse of renal insufficiency closely paralleled the level of lymphocytosis. Kidney biopsy in all patients showed GIN concomitant with CLL/SLL leukemic interstitial infiltration. Granulomas were nonnecrotizing and epithelioid and were associated with giant cells. One biopsy showed granulomatous arteritis. One patient had a granulomatous reaction in lymph nodes and skin. Steroids with/without CLL/SLL-directed chemotherapy led to partial improvement of kidney function in all patients except 1 who had advanced cortical scarring on biopsy. In conclusion, we report an association between CLL/SLL and GIN. Patients typically present with severe renal failure due to both GIN and leukemic interstitial infiltration, which tends to respond to steroids with/without CLL/SLL-directed chemotherapy. The pathogenesis of GIN in this clinical setting is unknown but may represent a local hypersensitivity reaction to the CLL/SLL tumor cells.

Pro-inflammatory effects of interleukin-35 in rheumatoid arthritis

OBJECTIVE

Interleukin-35 (IL-35) is a heterodimeric member of the IL-12 family consisting of p35/IL-12a and EBI3/IL-27b subunits. Expressed in murine Treg cells, IL-35 controls inflammatory diseases in mouse models. However, human IL-35 is expressed in Teff cells rather than in Treg cells and is shown to be upregulated under inflammatory conditions. Our aim was to examine the involvement of IL-35 in the pathogenesis of rheumatoid arthritis (RA).

METHODS

Immunohistochemical and immunofluorescence analysis was used to determine the expression and localization of IL-35 and its subunits (p35/EBI3) and IL-35 receptor (IL12Rβ2/gp130) in RA, osteoarthritis (OA) and psoriatic arthritis (PsA) synovial tissues. Expression of p35/EBI3 subunits and release of inflammatory cytokines upon stimulation with IL-35 were assessed in RA synovial fibroblasts (SFs) and peripheral blood mononuclear cells (PBMCs).

RESULTS

Both IL-35 and its subunits were upregulated in RA in comparison with OA or PsA synovium. Using cell-specific markers, p35 and EBI3 were identified in macrophages, dendritic cells, SFs, and T as well as B cells in RA synovium. Both p35 and EBI3 were induced by TNFα in RASFs and PBMCs. IL-35 dose-dependently upregulated release of pro-inflammatory mediators IL-1β, IL-6 and MCP-1 in PBMCs. While gp130 receptor subunit was upregulated in RA synovium and was expressed in RASFs and PBMCs, there was no difference in IL12Rβ2 expression subunit among tissues and its presence in RASFs was lacking.

CONCLUSION

Upregulation of IL-35 at sites of inflammation in RA and its pro-inflammatory potential suggests that IL-35 might play an important role in RA pathogenesis.

Biology of IL-27 and its role in the host immunity against Mycobacterium tuberculosis

IL-27, a heterodimeric cytokine of IL-12 family, regulates both innate and adaptive immunity largely via Jak-Stat signaling. IL-27 can induce IFN-γ and inflammatory mediators from T lymphocytes and innate immune cells. IL-27 has unique anti-inflammatory properties via both Tr1 cells dependent and independent mechanisms. Here the role and biology of IL-27 in innate and adaptive immunity are summarized, with special interest with immunity against Mycobacterium tuberculosis.

Interleukin-12 family cytokines and sarcoidosis

Sarcoidosis is a systemic granulomatous disease predominantly affecting the lungs. It is believed to be caused by exposure to pathogenic antigens in genetically susceptible individuals but the causative antigen has not been identified. The formation of non-caseating granulomas at sites of ongoing inflammation is the key feature of the disease. Other aspects of the pathogenesis are peripheral T-cell anergy and disease progression to fibrosis. Many T-cell-associated cytokines have been implicated in the immunopathogenesis of sarcoidosis, but it is becoming apparent that IL-12 cytokine family members including IL-12, IL-23, IL-27, and IL-35 are also involved. Although the members of this unique cytokine family are heterodimers of similar subunits, their biological functions are very diverse. Whilst IL-23 and IL-12 are pro-inflammatory regulators of Th1 and Th17 responses, IL-27 is bidirectional for inflammation and the most recent family member IL-35 is inhibitory. This review will discuss the current understanding of etiology and immunopathogenesis of sarcoidosis with a specific focus on the bidirectional impact of IL-12 family cytokines on the pathogenesis of sarcoidosis.

IL-27 and type 2 immunity in asthmatic patients: association with severity, CXCL9, and signal transducer and activator of transcription signaling

BACKGROUND

Severe asthma (SA) can involve both innate and type 2 cytokine-associated adaptive immunity. Although IL-27 has been reported to potentiate TH1 responses (including the chemokine CXCL9) and suppress TH2 responses, its function in asthmatic patients is unknown.

OBJECTIVE

We sought to evaluate IL-27 expression in human asthma alone and in combination with type 2 immunity to determine the relationship to disease severity and CXCL9 expression. We also sought to model these interactions in vitro in human bronchial epithelial cells.

METHODS

Bronchoalveolar lavage cells from 87 participants were evaluated for IL-27 mRNA and protein alone and in association with epithelial CCL26 (a marker of type 2 activation) in relation to asthma severity and CXCL9 mRNA. Human bronchial epithelial cells cultured at the air-liquid interface and stimulated with IL-27 (1-100 ng/mL) with or without IL-13 (1 ng/mL) were evaluated for CXCL9 expression by using quantitative real-time PCR and ELISA. Phosphorylated and total signal transducer and activator of transcription (STAT) 1/3 were detected by means of Western blotting. Small interfering RNA knockdown of STAT1 or STAT3 was performed.

RESULTS

Bronchoalveolar lavage cell IL-27 mRNA and protein levels were increased in asthmatic patients. Patients with evidence for type 2 pathway activation had higher IL-27 expression (P = .02). Combined IL-27 and CCL26 expression associated with more SA and higher CXCL9 expression (P = .004 and P = .007 respectively), whereas IL-27 alone was associated with milder disease. In vitro IL-13 augmented IL-27-induced CXCL9 expression, which appeared to be due to augmented STAT1 activation and reduced STAT3 activation.

CONCLUSIONS

IL-27, in combination with a type 2/CCL26 signature, identifies a more SA phenotype, perhaps through combined effects of IL-27 and IL-13 on STAT signaling. Understanding these interactions could lead to new targets for asthma therapy.

Associations of IL-27 polymorphisms and serum IL-27p28 levels with osteosarcoma risk

Interleukin (IL)-27 is a novel cytokine secreted by stimulation of antigen-presenting cells. No previous studies currently reported the role of IL-27 in the carcinogenesis of osteosarcoma. We aimed to investigate the association of IL-27 polymorphisms and serum IL-27p28 with osteosarcoma risk in a Chinese population.One hundred and sixty osteosarcoma patients and 250 health controls were selected. IL-27 gene -964 A/G, 2905 T/G, and 4730 T/C polymorphisms were determined by using polymerase chain reaction-restriction fragment length polymorphism. Enzyme-linked immunosorbent assay were used to detect serum IL-27p28 levels.The serum IL-27p28 levels were significantly lower in osteosarcoma patients compared with those in controls (P < 0.01). Serum IL-27p28 levels in stages III-IV were lower than those in stages I-II of osteosarcoma (P < 0.05); similar results were also found in patients with metastasis, that is, patients with metastasis have higher IL-27p28 levels than those without metastasis (P < 0.05). There were no associations between genotype and allele frequencies of IL-27 -964 A/G, 2905 T/G, 4730 T/C, and the risk of osteosarcoma (P > 0.05). Stratification analysis also failed to show the associations between -964 A/G, 2905 T/G, and 4730 T/C polymorphisms and the clinical stage and metastasis of osteosarcoma (P > 0.05). Three possible haplotypes (ATT, GTT, and GGC) were identified, but no associations were found between them and the osteosarcoma risk (P > 0.05).This study indicates that the lower serum IL-27p28 levels may be associated with development and progression of osteosarcoma, but IL-27 gene -964 A/G, 2905 T/G, and 4730 T/C polymorphisms and their haplotypes are not associated with osteosarcoma risk.

A soluble form of IL-27Rα is a natural IL-27 antagonist

IL-27 is a cytokine of the IL-12 family that plays a key role in the regulation of inflammatory and T cell responses. Its receptor is composed of IL-27Rα and gp130 and activates the STAT pathway. We show in this study, using an ELISA that we developed, that a naturally occurring soluble form of IL-27Rα (sIL-27Rα) is produced by human activated CD4(+) and CD8(+) T cells, B cells, myeloid cells, and various cell lines. sIL-27Rα is present at a mean concentration of 10,344 ± 1,274 pg/ml in the sera from healthy individuals. Biochemical studies showed that sIL-27Rα is released as two N-glycosylated variants of ∼ 90 and ∼ 70 kDa. In IL-27Rα-transfected COS7 cells, primary cells, and cell lines, production of sIL-27Rα is inhibited by the metalloprotease inhibitors GM6001 and TAPI-0. Importantly, natural sIL-27Rα binds rIL-27, inhibits IL-27 binding to its cell surface receptor, and is a potent inhibitor of IL-27 signaling, as shown by its ability to specifically block IL-27-mediated STAT activation, at low molar excess over IL-27. Also, we found that serum levels of sIL-27Rα were elevated in patients with Crohn's disease, a Th1-mediated disease. These findings suggest that sIL-27Rα may play important immunoregulatory functions under normal and pathological conditions.

First characterization of a teleost Epstein-Barr virus-induced gene 3 (EBI3) reveals a regulatory effect of EBI3 on the innate immune response of peripheral blood leukocytes

Epstein-Barr virus-induced gene 3 (EBI3) encodes a protein that in mammals is known to be a subunit of interleukin (IL)-27 and IL-35, both which regulate cytokine production and inflammatory response. To date, no studies on fish EBI3 have been documented. In this work, we report the identification of an EBI3 homologue, CsEBI3, from tongue sole (Cynoglossus semilaevis) and analysis of its expression and biological effect. CsEBI3 is composed of 245 amino acid residues and possesses a Fibronectin type 3 (FN3) domain that is preserved in lower and higher vertebrates. Expression of CsEBI3 was detected in a wide range of tissues, in particular those of immune relevant organs, and upregulated in a time-dependent manner by experimental challenge with bacterial and viral pathogens. Bacterial infection of peripheral blood leukocytes (PBL) enhanced CsEBI3 expression and caused extracellular secretion of CsEBI3. Purified recombinant CsEBI3 (rCsEBI3) stimulated the respiratory burst activity of PBL and upregulated the expression of IL-1β, IL-8, Myd88, interferon-induced gene 15, CD28, and chemokines. In contrast, rCsEBI3M, a mutant CsEBI3 that lacks the FN3 domain failed to activate PBL and induced much weaker expression of the immune genes. Treatment of PBL with rCsEBI3, but not with the mutant rCsEBI3M, enhanced cellular resistance against bacterial invasion, whereas antibody blocking of CsEBI3 on PBL significantly reduced cellular resistance against bacterial infection. Taken together, these results indicate for the first time that a teleost EBI3 possesses immunoregulatory property in a manner that is dependent on the conserved FN3 domain, and that CsEBI3 is involved in the innate immune defense of PBL against microbial pathogens.

Expression of IL-27 by tumor cells in invasive cutaneous and metastatic melanomas [corrected]

Interleukin (IL)-27 is a cytokine of the IL-12 family that displays either immunostimulatory or immunosuppressive functions depending on the context. In various murine tumor models including melanoma models, ectopic expression of IL-27 has been shown to play an anti-tumoral role and to favor tumor regression. In this study, we investigated whether IL-27 might play a role in the development of melanoma in humans. We analyzed the in situ expression of IL-27 in melanocytic lesions (n = 82) representative of different stages of tumor progression. IL-27 expression was not observed in nevus (n = 8) nor in in situ melanoma (n = 9), but was detected in 28/46 (61%) cases of invasive cutaneous melanoma, notably in advanced stages (19/23 cases of stages 3 and 4). In most cases, the main source of IL-27 was tumor cells. Of note, when IL-27 was detected in primary cutaneous melanomas, its expression was maintained in metastatic lesions. These in situ data suggested that the immunosuppressive functions of IL-27 may dominate in human melanoma. Consistent with this hypothesis, we found that IL-27 could induce suppressive molecules such as PD-L1, and to a lesser extent IL-10, in melanoma cells, and that the in situ expression of IL-27 in melanoma correlated with those of PD-L1 and IL-10.

Lack of association between IL27 gene variants and type 1 diabetes susceptibility

BACKGROUND

Recently, a new subpopulation of T cells, the Th17 subset, has been implicated in autoimmune diseases. Its development is influenced by IL-27, expressed in macrophages or dendritic cells. IL-27 blockage delays the onset of diabetes in non obese diabetes mouse, but its role in type 1 diabetes (T1D) in human has not been reported yet. The aim of this study was identify variants in the entire coding regions of IL-27 gene, including the 5' proximal region, and their possible association with the disease.

METHODS

Those regions were amplified by polymerase chain reaction followed by automatic sequencing and restriction fragments length polymorphisms. The cohort involved 614 individuals - 318 patients with T1D (19.6 ± 11.2 y, 129M/189F) and 296 healthy control subjects (30.3 ± 13.2 y, 131M/165F).

RESULTS

We identified eight allelic variants in the 5' proximal and coding regions of IL-27 gene, including two new variants: the c.-324 C>T in the 5' proximal region and the c.521 G>C in exon 5. None of these variants compromised transcription factor binding sites or the protein structure. The frequency of the alleles and genotypes of IL-27 variants did not differ between T1D patients and controls. There was no association between IL27 variants with gender, ethnicity, age at diagnosis of diabetes or presence of pancreatic and extrapancreatic autoantibodies.

CONCLUSION

Our findings suggest that allelic variants in IL27 are not associated with susceptibility to T1D in a Brazilian population.

Expression of IL-27, Th1 and Th17 in patients with aplastic anemia

BACKGROUND

Aplastic anemia (AA) is an autoimmune disease and interleukin-27 (IL-27) is an important cytokine involved in the pathogenesis of autoimmune diseases. To date there have been no reports concerning the intrinsic association among IL-27 and Thelper (Th) 1 and Th17 cells in AA.

MATERIALS AND METHODS

Enzyme-linked immunosorbent assay (ELISA) to assay IL-27, interferon gamma (IFN-γ) and IL-17 levels, flow cytometry to measure the percentages of Th1 and Th17 cells among peripheral blood mononuclear cells (PBMCs), real-time reverse transcriptase polymerase chain reaction (PCR) for the mRNA levels of IL-27, IFN-γ, T-bet and IL-17 and retinoid related orphan receptor gamma (RORγt) in PBMCs were performed. In addition, the effect of exogenous rhIL-27 on the differentiation of T cells into Th1 and Th17 cells was investigated in vitro.

RESULTS

Plasma and mRNA levels of IL-27 in PBMCs from AA patients were significantly higher than those in healthy controls. A positive correlation was found between plasma levels of IL27 and IFN-γ. The proportions of Th1 and Th17 cells accompanied by the mRNA expression of RORγt and T-bet were significantly higher in AA patients than in healthy controls. Plasma levels of IL-27 correlated positively with frequencies of Th1 cells in AA patients. Exogenous rhIL-27 could significantly upregulate the frequency of Th1 cells and the mRNA levels of T-bet and IFN-γ and the application of rhIL-27 in vitro could inhibit the expression of RORγt mRNA.

CONCLUSION

The upregulation of IL-27 might cause Th1 differentiation and immune disorders in AA patients. Blocking the expression of IL-27 could therefore be a reasonable therapeutic strategy for AA.

Comparison of interferon-γ-, interleukin (IL)-17- and IL-22-expressing CD4 T cells, IL-22-expressing granulocytes and proinflammatory cytokines during latent and active tuberculosis infection

In this study, we investigated the role and expression of T helper type 17 (Th17) cells and Th17 cytokines in human tuberculosis. We show that the basal proportion of interferon (IFN)-γ-, interleukin (IL)-17- and IL-22-expressing CD4(+) T cells and IL-22-expressing granulocytes in peripheral blood were significantly lower in latently infected healthy individuals and active tuberculosis patients compared to healthy controls. In contrast, CD4(+) T cells expressing IL-17, IL-22 and IFN-γ were increased significantly following mycobacterial antigens stimulation in both latent and actively infected patients. Interestingly, proinflammatory IFN-γ and tumour necrosis factor (TNF)-α were increased following antigen stimulation in latent infection. Similarly, IL-1β, IL-4, IL-8, IL-22 and TNF-α were increased in the serum of latently infected individuals, whereas IL-6 and TNF-α were increased significantly in actively infected patients. Overall, we observed differential induction of IL-17-, IL-22- and IFN-γ-expressing CD4(+) T cells, IL-22-expressing granulocytes and proinflammatory cytokines in circulation and following antigenic stimulation in latent and active tuberculosis.

The immunobiology of IL-27

Like many cytokines, IL-27 has pleiotropic properties that can limit or enhance ongoing immune responses depending on context. Thus, under certain circumstances, IL-27 can promote TH1 differentiation and has been linked to the activation of CD8(+) T cells and enhanced humoral responses. However, IL-27 also has potent inhibitory properties and mice that lack IL-27 mediated signaling develop exaggerated inflammatory responses in the context of infection or autoimmunity. This chapter reviews in depth the biology of IL-27, including the initial discovery, characterization, and signaling mediated by IL-27 as well as more recent insights into the molecular and cellular basis for its pleiotropic effects. Many of these advances are relevant to human diseases and highlight the potential of therapies that harness the regulatory properties of IL-27.