LTßR-RelB signaling in intestinal epithelial cells protects from chemotherapy-induced mucosal damage.

The intricate immune mechanisms governing mucosal healing following intestinal damage induced by cytotoxic drugs remain poorly understood. The goal of this study was to investigate the role of lymphotoxin beta receptor (LTßR) signaling in chemotherapy-induced intestinal damage. LTßR deficient mice exhibited heightened body weight loss, exacerbated intestinal pathology, increased proinflammatory cytokine expression, reduced IL-22 expression, and proliferation of intestinal epithelial cells following methotrexate (MTX) treatment. Furthermore, LTßR-/-IL-22-/- mice succumbed to MTX treatment, suggesting that LTßR- and IL-22- dependent pathways jointly promote mucosal repair. Although both LTßR ligands LIGHT and LTß were upregulated in the intestine early after MTX treatment, LIGHT-/- mice, but not LTß-/- mice, displayed exacerbated disease. Further, we revealed the critical role of T cells in mucosal repair as T cell-deficient mice failed to upregulate intestinal LIGHT expression and exhibited increased body weight loss and intestinal pathology. Analysis of mice with conditional inactivation of LTßR revealed that LTßR signaling in intestinal epithelial cells, but not in Lgr5+ intestinal stem cells, macrophages or dendritic cells was critical for mucosal repair. Furthermore, inactivation of the non-canonical NF-kB pathway member RelB in intestinal epithelial cells promoted MTX-induced disease. Based on these results, we propose a model wherein LIGHT produced by T cells activates LTßR-RelB signaling in intestinal epithelial cells to facilitate mucosal repair following chemotherapy treatment.

A glimpse on the role of IL-21 in psoriatic arthritis pathogenesis.

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy affecting the skin, entheses, and joints. Over the past decade, experimental evidence has revealed the activation of several immune cells and signaling cascades in modulating the pathophysiology of PsA. Recently, targeted therapies have been developed to combat the severity of disease. However, with diverse etiologies, flareups, and relapses, there has been an increased prevalence and mortality associated with PsA in recent years. Therefore, it is imperative to investigate new potential mediators and combination therapies to manage PsA pathogenesis. IL-21, an immunomodulatory cytokine, has pleiotropic effects on immune cells and the protein cascades involved in PsA pathogenesis. Recently, emerging evidence of increased IL-21 levels in patients with PsA has engendered much enthusiasm for its potential as a therapeutic target. Here, we unmasked IL-21 as a significant modulator of PsA pathogenesis and reviewed the comorbidities associated with the disease, further cataloging future therapeutic modalities to ameliorate PsA progression.

A human STAT3 gain-of-function variant drives local Th17 dysregulation and skin inflammation in mice.

Germline gain-of-function (GOF) variants in STAT3 cause an inborn error of immunity associated with early-onset poly-autoimmunity and immune dysregulation. To study tissue-specific immune dysregulation, we used a mouse model carrying a missense variant (p.G421R) that causes human disease. We observed spontaneous and imiquimod (IMQ)-induced skin inflammation associated with cell-intrinsic local Th17 responses in STAT3 GOF mice. CD4+ T cells were sufficient to drive skin inflammation and showed increased Il22 expression in expanded clones. Certain aspects of disease, including increased epidermal thickness, also required the presence of STAT3 GOF in epithelial cells. Treatment with a JAK inhibitor improved skin disease without affecting local Th17 recruitment and cytokine production. These findings collectively support the involvement of Th17 responses in the development of organ-specific immune dysregulation in STAT3 GOF and suggest that the presence of STAT3 GOF in tissues is important for disease and can be targeted with JAK inhibition.

Enhanced abscopal anti-tumor response via a triple combination of thermal ablation, IL-21, and PD-1 inhibition therapy.

Despite the success of immune checkpoint inhibitors (ICIs) in treating solid tumors, lots of patients remain unresponsive to this therapy. Microwave ablation (MWA) stimulates systemic adaptive immunity against tumor cells by releasing tumor antigens. Additionally, IL-21 has demonstrated importance in stimulating T-cell effector function. The combination of these three therapies-MWA, IL-21, and anti-PD-1 monoclonal antibodies (mAbs)-has yet to be explored in the context of cancer treatment.In this study, we explored the impact of thermal ablation on IL-21R expression in tumor-infiltrating lymphocytes (TILs). Subsequently, we assessed alterations in the tumor microenvironment (TME) and peripheral lymphoid organs. Additionally, we conducted a thorough examination of tumor-infiltrating CD45+ immune cells across various treatment groups using single-cell RNA sequencing (scRNA-seq). Moreover, we determined the potential anti-tumor effects of the triple combination involving MWA, IL-21, and anti-PD-1 mAbs.Our findings revealed that MWA upregulated the expression of IL-21R on various immune cells in the untreated tumors. The combination of MWA with IL-21 exhibited a robust abscopal anti-tumor effect, enhancing the effector function of CD8+ T cells and facilitating dendritic cells' maturation and antigen presentation in the untreated tumor. Notably, the observed abscopal anti-tumor effect resulting from the combination is contingent upon T-cell recirculation, indicating the reliance of systemic adaptive immunity for this treatment regimen. Additionally, the combination of MWA, IL-21, and PD-1 mAbs demonstrated profound abscopal anti-tumor efficacy. Our findings provide support for further clinical investigation into a triple combination therapy involving MWA, IL-21, and ICIs for the treatment of metastatic cancer.

Circulating interleukin-27 is associated with the risk of chronic periodontitis and allergic rhinitis: A Mendelian randomization analysis.

BACKGROUND: Chronic periodontitis (CP) and allergic rhinitis (AR) have attracted wide attention as global public health problems with high incidence. Recent studies have shown that circulating interleukin-27 (IL-27) is associated with the risk of CP and AR. The aim of this study is to analyze the causal effect between them using Mendelian randomization (MR). METHODS: Bidirectional MR analyses were performed with the use of publicly available genome-wide association study (GWAS) data. Summary data on circulating IL-27, CP, and AR published in genome-wide association studies were collected. Instrumental variables (IV) were extracted using assumptions of correlation, independence and exclusivity as criteria. Inverse variance weighting (IVW) was used as the main method, combined with weighted median method (WM) and MR-Egger and other MR Analysis methods for causal inference of exposure and outcome. Cochran's Q and MR-Egger intercept were used for sensitivity analysis. RESULTS: The IVW study showed a causal effect between increased circulating IL-27 levels and increased risk of CP (OR = 1.14, 95%CI = 1.02-1.26, p = .020). Similarly, the increase of circulating IL-27 level had a causal effect on the decreased risk of AR (OR = 0.88, 95%CI = 0.80-0.97, p = .012). In addition, IVW study found that there was a causal between the increased risk of CP and circulating IL-27 level (OR = 1.05, 95%CI = 1.01-1.10, p = .016). However, there was no significant causal relationship between the risk of AR and circulating IL-27 levels (OR = 0.97, 95%CI = 0.91-1.02, p = .209). no significant heterogeneity or horizontal pleiotropy was found in sensitivity analysis. CONCLUSIONS: There is a causal effect between circulating IL-27 level and CP, AR, which will help to find new ideas and methods for the diagnosis and treatment of CP and AR.

Interleukin-22 receptor 1-mediated stimulation of T-type Ca2+ channels enhances sensory neuronal excitability through the tyrosine-protein kinase Lyn-dependent PKA pathway.

BACKGROUND: Interleukin 24 (IL-24) has been implicated in the nociceptive signaling. However, direct evidence and the precise molecular mechanism underlying IL-24's role in peripheral nociception remain unclear. METHODS: Using patch clamp recording, molecular biological analysis, immunofluorescence labeling, siRNA-mediated knockdown approach and behavior tests, we elucidated the effects of IL-24 on sensory neuronal excitability and peripheral pain sensitivity mediated by T-type Ca2+ channels (T-type channels). RESULTS: IL-24 enhances T-type channel currents (T-currents) in trigeminal ganglion (TG) neurons in a reversible and dose-dependent manner, primarily by activating the interleukin-22 receptor 1 (IL-22R1). Furthermore, we found that the IL-24-induced T-type channel response is mediated through tyrosine-protein kinase Lyn, but not its common downstream target JAK1. IL-24 application significantly activated protein kinase A; this effect was independent of cAMP and prevented by Lyn antagonism. Inhibition of PKA prevented the IL-24-induced T-current response, whereas inhibition of protein kinase C or MAPK kinases had no effect. Functionally, IL-24 increased TG neuronal excitability and enhanced pain sensitivity to mechanical stimuli in mice, both of which were suppressed by blocking T-type channels. In a trigeminal neuropathic pain model induced by chronic constriction injury of the infraorbital nerve, inhibiting IL-22R1 signaling alleviated mechanical allodynia, which was reversed by blocking T-type channels or knocking down Cav3.2. CONCLUSION: Our findings reveal that IL-24 enhances T-currents by stimulating IL-22R1 coupled to Lyn-dependent PKA signaling, leading to TG neuronal hyperexcitability and pain hypersensitivity. Understanding the mechanism of IL-24/IL-22R1 signaling in sensory neurons may pave the way for innovative therapeutic strategies in pain management.

Increased serum levels of proNGF, mature NGF and interleukins in burn-injured children.

OBJECTIVE: Burns are among the most common injuries in children. In burns of more than 20% of the total body surface area, a systemic inflammatory response involving several chemical mediators occurs. Among them, nerve growth factor (NGF) regulates the inflammatory response related to wound healing and promotes keratinocyte proliferation and angiogenesis. The aim of our study was to investigate the physiological response to injury in children with moderate-severe burns, assaying proNGF, mature NGF (mNGF), interleukins (IL)-1ß, and Il-10 serum levels. PATIENTS AND METHODS: This is a prospective observational study, including twelve children hospitalized for moderate-severe burns at the Gemelli Hospital (Rome). Their laboratory features were compared to those of patients with obstructive hydrocephalus who underwent surgery. RESULTS: Our results showed an increase in proNGF and mNGF serum levels. In burn patients, proNGF levels increased before mNGF, and serum concentrations of both were not correlated with burn extension and depth. The most significant levels of mNGF and proNGF were reported in scalds involving the face. Serum IL-1ß and IL-10 peak levels were reached with a time-course pattern similar to proNGF. CONCLUSIONS: Our preliminary results validate the hypothesis that serum levels of proNGF and mNGF may represent inflammatory biomarkers useful for monitoring burn patients and defining new strategies for their treatment.

IL-4 and IL-13 are not involved in IL-31-induced itch-associated scratching behaviour in mice.

Itchy skin or pruritus is a common cutaneous symptom that causes an urge to scratch, and the role of interleukins (IL) in itchy skin has been widely studied. IL-4 and IL-13 are known to induce chronic itch. Similarly, the direct role of IL-31 in inducing itch has been demonstrated in clinical situations such as atopic dermatitis and prurigo nodularis. Moreover, IL-4 receptor α antibodies (dupilumab) and IL-31 receptor A antibodies (nemolizumab) inhibit pruritus. However, the interplay between these ILs in pruritus remains unclear. Therefore, we investigated the reciprocal effects of these cytokines on pruritus in mice. The intradermal administration of IL-31 induced itch-associated scratching behaviour in a dose-dependent manner. Interestingly, the amount of IL-31 and IL-4/IL-13, co-administration or 30 min pre-administration of IL-4/IL-13 and intradermal or intravenous pre-administration of IL-4 did not affect IL-31-induced itch-associated scratching behaviour when it was observed for 30 min, 2 h, 24 h or 48 h. Pre-administration of neutralising antibodies against IL-4 and IL-13 also did not affect IL-31-induced itch-associated scratching behaviour. These results suggest that IL-31 can induce itching independently of IL-4 and IL-13 in vivo.

From bench to bedside: the past, present and future of IL-21 immunotherapy.

As immunotherapy gains momentum as a promising approach for treating several types of cancer, IL-21 has emerged as the latest discovery within the γ chain cytokine family, known for its decisive effects on innate and adaptive immunity and immunopathology. Through the modulation of immune cells, IL-21 has demonstrated significant anti-tumor effects in preclinical studies. The potential of IL-21 in cancer treatment has been explored in phase I and II clinical trials, where it has been utilized both as monotherapy and in combination with other drug agents. Further investigation, alongside larger studies, is necessary before final evaluation and application of IL-21 as immunotherapy. This review aims to summarize these pre-clinical and clinical studies and to discuss the possible future directions of IL-21 immunotherapy development. Such a study may be helpful to accelerate the process of clinical application for IL21 immunotherapy.

IL-20 is produced by CD3γδ T cells and induced in the mucosal tissues of grass carp during infection with Aeromonas hydrophila.

Interleukin (IL) 20 is a multifunctional cytokine and plays a vital role in regulating autoimmune diseases, inflammation, and immune responses. IL-20 homologs have been described in fish. However, due to the lack of antibodies, cellular sources and immunological functions of fish IL-20 in response to infections have not been fully characterized. In this study, a monoclonal antibody (mAb) was generated against the recombinant grass carp (Ctenopharyngodon idella) IL-20 protein and characterized by immunoblotting, immunofluorescent microscopy and flow cytometry. It was shown that the IL-20 mAb specifically recognized recombinant IL-20 proteins expressed in the E. coli cells and HEK293 cells. Using confocal microscopy, the IL-20+ cells were identified in the head kidney, gills and intestine of grass carp, and induced after infection with Aeromonas hydrophila. Moreover, the IL-20 protein was found to be secreted mainly by CD3γδ T cells which were located predominantly in the gill filaments and intestinal mucosa. Taken together, our results suggest that IL-20 producing T cells are required for the mucosal immunity against bacterial infection in fish.

Estimation of the tissue and serum levels of IL-35 in Mycosis fungoides: a case-control study.

Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma (CTCL) with its etiology not yet fully understood. Interleukin (IL)-35 is an inhibitory cytokine that belongs to the IL-12 family. Elevated IL-35 in the plasma and the tumor microenvironment increases tumorigenesis and indicates poor prognosis in different types of malignancies. The objective of this study is to estimate the expression levels of IL-35 in tissue and serum of MF patients versus healthy controls. This case-control study included 35 patients with patch, plaque, and tumor MF as well as 30 healthy controls. Patients were fully assessed, and serum samples and lesional skin biopsies were taken prior to starting treatment. The IL-35 levels were measured in both serum and tissue biopsies by ELISA technique. Both tissue and serum IL-35 levels were significantly higher in MF patients than in controls (P < 0.001) and tissue IL-35 was significantly higher than serum IL-35 in MF patients (P < 0.001). Tissue IL-35 was significantly higher in female patients and patients with recurrent MF compared to male patients and those without recurrent disease (P < 0.001). Since both tissue and serum IL-35 levels are increased in MF, IL-35 is suggested to have a possible role in MF pathogenesis. IL-35 can be a useful diagnostic marker for MF. Tissue IL-35 can also be an indicator of disease recurrence.

Exploring the impact of interleukins on sarcopenia development: A systematic review and meta-analysis.

BACKGROUND: The role of interleukins in sarcopenia development has been acknowledged, yet the specifics of their involvement remain to be fully understood. This study aimed to explore alterations in interleukin levels among sarcopenia patients. METHODS: Searches were conducted in Embase, Medline, and the Cochrane Library for literature published up to May 2023. Eligible observational studies with a diagnosis of sarcopenia were included. The Newcastle-Ottawa Scale was utilized for quality assessment. For data synthesis, a random-effects model was used, and the Mantel-Haenszel method was used for pooled estimates. RESULTS: Of the 7685 articles screened, 37 met the inclusion criteria. Statistically significant differences in the levels of IL-1ß, IL-6 and IL-10 were detected in sarcopenia patients. Specifically, IL-1ß (95 % CI: 0.33 [0.12, 0.54], P < 0.05), IL-6 (95 % CI: 0.91 [0.59, 1.24], P < 0.05), and IL-10 (95 % CI: 0.11 [0.07,0.15], P < 0.05) were detected. However, no significant associations were found between serum IL-4 (95 % CI: 0.36 [-0.18, 0.42], P = 0.44), IL-8 (95 % CI: -1.05 [-3.06, 0.95], P = 0.3), IL-12 (95 % CI: -3.92 [-8.32,0.48], P = 0.08) or IL-17 (95 % CI: 0.22 [-2.43, 2.88], P = 0.87) and sarcopenia. Subgroup analysis showed no significant difference in IL-6 (95 % CI: -0.03 [-0.72, 0.66], P = 0.93) and IL-10 (95 % CI: 0.1 [-0.44, 0.64], P = 0.72) among patients with European standard sarcopenia. CONCLUSIONS: Inflammation plays a role in sarcopenia, and the serum levels of IL-1ß, IL-6, and IL-10 are associated with sarcopenia. Further research is needed to clarify these associations. CLINICAL TRIALS REGISTRATION NUMBER: CRD42024506656.

Il34 rescues metronidazole-induced impairment of spinal cord regeneration in zebrafish central nervous system.

Metronidazole (MTZ), a commonly used anti-infective drug in clinical practice, has also been employed as a prodrug in cell-targeted ablation systems in scientific research, exhibiting significant application value. However, it has been demonstrated that MTZ can induce neurotoxic symptoms to some extent during its use, and there is currently a lack of effective means to circumvent its toxicity in both clinical and research settings, which limits its application. Therefore, exploring the specific mechanisms underlying MTZ-induced neurotoxic symptoms and elucidating countermeasures will enhance the practical value of MTZ. In this study, using a zebrafish spinal cord injury regeneration model, we confirmed that MTZ neurotoxicity leads to impaired axon regeneration in the central nervous system. By overexpressing il34 in the central nervous system of zebrafish, we eliminated the inhibitory effect of MTZ on axonal regeneration and demonstrated that the pro-regenerative effect against MTZ neurotoxicity is not caused by excessive macrophages/microglia chemoattracted by interleukin 34(Il34). Transcriptome sequencing analysis and GO enrichment analysis of differentially expressed genes between groups revealed that Il34 may counteract MTZ neurotoxicity and promote spinal cord injury repair through biological processes that enhance cellular adhesion and cell location. In summary, our work uncovers a possible cause of MTZ neurotoxicity and provides a new perspective for eliminating MTZ toxicity.

BCG priming followed by a novel interleukin combination activates Natural Killer cells to selectively proliferate and become anti-tumour long-lived effectors.

The short-lived nature and heterogeneity of Natural Killer (NK) cells limit the development of NK cell-based therapies, despite their proven safety and efficacy against cancer. Here, we describe the biological basis, detailed phenotype and function of long-lived anti-tumour human NK cells (CD56highCD16+), obtained without cell sorting or feeder cells, after priming of peripheral blood cells with Bacillus Calmette-Guérin (BCG). Further, we demonstrate that survival doses of a cytokine combination, excluding IL18, administered just weekly to BCG-primed NK cells avoids innate lymphocyte exhaustion and leads to specific long-term proliferation of innate cells that exert potent cytotoxic function against a broad range of solid tumours, mainly through NKG2D. Strikingly, a NKG2C+CD57-FcεRIγ+ NK cell population expands after BCG and cytokine stimulation, independently of HCMV serology. This strategy was exploited to rescue anti-tumour NK cells even from the suppressor environment of cancer patients' bone marrow, demonstrating that BCG confers durable anti-tumour features to NK cells.

Oncolytic Newcastle disease virus carrying the IL24 gene exerts antitumor effects by inhibiting tumor growth and vascular sprouting.

The second-leading cause of death, cancer, poses a significant threat to human life. Innovations in cancer therapies are crucial due to limitations in traditional approaches. Newcastle disease virus (NDV), a nonpathogenic oncolytic virus, exhibits multifunctional anticancer properties by selectively infecting, replicating, and eliminating tumor cells. To enhance NDV's antitumor activity, four oncolytic NDV viruses were developed, incorporating IL24 and/or GM-CSF genes at different gene loci using reverse genetics. In vitro experiments revealed that oncolytic NDV virus augmented the antitumor efficacy of the parental virus rClone30, inhibiting tumor cell proliferation, inducing tumor cell fusion, and promoting apoptosis. Moreover, NDV carrying the IL24 gene inhibited microvessel formation in CAM experiments. Evaluation in a mouse model of liver cancer confirmed the therapeutic efficacy of oncolytic NDV viral therapy. Tumors in mice treated with oncolytic NDV virus significantly decreased in size, accompanied by tumor cell detachment and apoptosis evident in pathological sections. Furthermore, oncolytic NDV virus enhanced T cell and dendritic cell production and substantially improved the survival rate of mice with hepatocellular carcinoma, with rClone30-IL24(P/M) demonstrating significant therapeutic effects. This study establishes a basis for utilizing oncolytic NDV virus as an antitumor agent in clinical practice.

Use of biologics in Chinese pregnant patients with deficiency of interleukin-36 receptor antagonist (DITRA): A case series.

OBJECTIVE: Impetigo herpetiformis (IH) is a rare form of pustular psoriasis which may result in maternal and fetal morbidity and even mortality. Deficiency of interleukin-36 receptor antagonist (DITRA) is the most frequently identified genetic defect of IH. Currently there are no biologics approved for IH despite the revolutionary role of biologics in the treatment of plaque and pustular psoriasis. Anecdotal reports of biologics use in DITRA patients with IH are also limited. CASE REPORTS: We present herein a case series of 6 Chinese IH patients harboring IL36RN gene c.115+6T>C mutation during 8 pregnancies, treated with various biologics, including adalimumab, etanercept and secukinumab. CONCLUSION: Most pregnancy courses were uneventful, except for one woman who had recurrent episodes of decreased fetal heart rate variability after adalimumab injections, which subsided after switching to etanercept. The treatment effectiveness and safety demonstrated in our cases suggested the role of biologics for the treatment of IH in patients with DITRA.

Increased interleukin-26 in the peripheral joints of patients with axial spondyloarthritis and psoriatic arthritis, co-localizing with CD68-positive synoviocytes.

Objectives: IL26 levels are elevated in the blood and synovial fluid of patients with inflammatory arthritis. IL26 can be produced by Th17 cells and locally within joints by tissue-resident cells. IL26 induces osteoblast mineralization in vitro. As osteoproliferation and Th17 cells are important factors in the pathogenesis of axial spondyloarthritis (axSpA), we aimed to clarify the cellular sources of IL26 in spondyloarthritis. Methods: Serum, peripheral blood mononuclear cells (n = 15-35) and synovial tissue (n = 3-9) of adult patients with axSpA, psoriatic arthritis (PsA) and rheumatoid arthritis (RA) and healthy controls (HCs, n = 5) were evaluated by ELISA, flow cytometry including PrimeFlow assay, immunohistochemistry and immunofluorescence and quantitative PCR. Results: Synovial tissue of axSpA patients shows significantly more IL26-positive cells than that of HCs (p < 0.01), but numbers are also elevated in PsA and RA patients. Immunofluorescence shows co-localization of IL26 with CD68, but not with CD3, SMA, CD163, cadherin-11, or CD90. IL26 is elevated in the serum of RA and PsA (but not axSpA) patients compared with HCs (p < 0.001 and p < 0.01). However, peripheral blood CD4+ T cells from axSpA and PsA patients show higher positivity for IL26 in the PrimeFlow assay compared with HCs. CD4+ memory T cells from axSpA patients produce more IL26 under Th17-favoring conditions (IL-1ß and IL-23) than cells from PsA and RA patients or HCs. Conclusion: IL26 production is increased in the synovial tissue of SpA and can be localized to CD68+ macrophage-like synoviocytes, whereas circulating IL26+ Th17 cells are only modestly enriched. Considering the osteoproliferative properties of IL26, this offers new therapeutic options independent of Th17 pathways.

The regulation and potential role of interleukin-32 in tuberculous pleural effusion.

The possible protective effect of interleukin-32 (IL-32) in Mycobacterium tuberculosis (Mtb) infection has been indicated. However, few studies have been focused on IL-32 in tuberculosis patients. Additionally, the regulation of IL-32 production has rarely been reported. In the present study, the production, regulation, and role of IL-32 in tuberculous pleurisy (TBP) were investigated. We found that the content of IL-32 in tuberculous pleural effusion (TPE) was higher than the level in the malignant pleural effusion and transudative pleural effusion. The level of IL-32 mRNA in pleural fluid mononuclear cells (PFMCs) was higher than that in peripheral blood mononuclear cells (PBMCs) of patients with TBP, and this difference was mainly reflected in the splice variants of IL-32α, IL-32ß, and IL-32γ. Compared with the PBMCs, PFMCs featured higher IL-32ß/IL-32γ and IL-32α/IL-32γ ratios. In addition, lipopolysaccharide (LPS), Bacillus Calmette-Guérin (BCG), and H37Ra stimulation could induce IL-32 production in the PFMCs. IL-32 production was positively correlated with the TNF-α, IFN-γ, and IL-1Ra levels in TPE, whereas IFN-γ, but not TNF-α or IL-1Ra, could induce the production of IL-32 in PFMCs. Furthermore, IL-32γ could induce the TNF-α production in PFMCs. Monocytes and macrophages were the main sources of IL-32 in PFMCs. Nevertheless, direct cell-cell contact between lymphocytes and monocytes/macrophages plays an important role in enhancing IL-32 production by monocyte/macrophage cells. Finally, compared with the non-tuberculous pleural effusion, the purified CD4+ and CD8+ T cells in TPE expressed higher levels of intracellular IL-32. Our results suggested that, as a potential biomarker, IL-32 may play an essential role in the protection against Mtb infection in patients with TBP. However, further studies need to be carried out to clarify the functions and mechanisms of the IFN-γ/IL-32/TNF-α axis in patients with TBP.

IL-33 controls IL-22-dependent antibacterial defense by modulating the microbiota.

IL-22 plays a critical role in defending against mucosal infections, but how IL-22 production is regulated is incompletely understood. Here, we show that mice lacking IL-33 or its receptor ST2 (IL-1RL1) were more resistant to Streptococcus pneumoniae lung infection than wild-type animals and that single-nucleotide polymorphisms in IL33 and IL1RL1 were associated with pneumococcal pneumonia in humans. The effect of IL-33 on S. pneumoniae infection was mediated by negative regulation of IL-22 production in innate lymphoid cells (ILCs) but independent of ILC2s as well as IL-4 and IL-13 signaling. Moreover, IL-33's influence on IL-22-dependent antibacterial defense was dependent on housing conditions of the mice and mediated by IL-33's modulatory effect on the gut microbiota. Collectively, we provide insight into the bidirectional crosstalk between the innate immune system and the microbiota. We conclude that both genetic and environmental factors influence the gut microbiota, thereby impacting the efficacy of antibacterial immune defense and susceptibility to pneumonia.