IL-40: A New B Cell-Associated Cytokine Up-Regulated in Rheumatoid Arthritis Decreases Following the Rituximab Therapy and Correlates With Disease Activity, Autoantibodies, and NETosis

Molecular landscape of the interleukin-40 encoding gene, C17orf99, in patients with acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignant hematological disorder in which aberrant cytokine signaling and inflammation play a role in disease initiation and progression. Interleukin-40 (IL-40) is a novel cytokine encoded by the chromosome 17 open reading frame 99 (C17orf99) gene. This cytokine is involved in mediating inflammation but its biological significance in the pathogenesis of AML has not been investigated. In this case-control and observational study, mRNA expression and DNA methylation of the C17orf99 gene were evaluated in the peripheral blood of AML patients. In addition, the polymorphism of two novel intergenic variants of the C17orf99 gene, rs2004339 A/G and rs2310998 G/A, were explored using a real-time polymerase chain reaction assay. The study was conducted on 131 patients with AML and 106 controls and gene expression and DNA methylation were expressed as fold-change (2-ΔΔCt). Results revealed that mRNA expression of the C17orf99 gene was down-regulated in AML patients, particularly in females, while up-regulated expression was found in patients with hypoalbuminemia. For DNA methylation, it was up-regulated in AML patients, particularly in females, AML M5 subtype, and CD4-negative and CD14-positive peripheral blood cells. The mutant A allele and the corresponding homozygous AA genotype of rs2004339 was significantly associated with an increased risk of AML. The AA genotype was also associated with significantly up-regulated C17orf99 mRNA expression and DNA methylation of compared to the wild-type GG genotype. In conclusions, C17orf99 mRNA expression showed down-regulated levels in the peripheral blood of AML patients, while DNA methylation was up-regulated. The intergenic variant rs2004339 was associated with susceptibility to AML and had an effect on mRNA expression and DNA methylation.

Investigating the role of salivary Interleukin-40 levels in diagnosing periodontal diseases

BACKGROUND

The present study aimed to analyze IL-40, IL-1β, and MMP-8 levels in periodontitis as well as gingivitis and periodontal health, and to explore potential correlations between these biomarkers and standard clinical parameters.

MATERIALS AND METHODS

We collected saliva samples from 120 systemically healthy, non-smoking individuals aged between 18 and 63 years. These individuals were divided into three groups: healthy controls [S], gingivitis [G], and stage III grade B periodontitis [P]. IL-40, IL-1β, and MMP-8 levels in saliva samples were analyzed by ELISA.

RESULTS

We observed significantly elevated salivary IL-40 levels in the G group compared to the S group (p = 0.003). We found significantly higher salivary IL-1β levels in the P group compared to both the S and G groups (p = 0.000). Salivary MMP-8 levels were significantly higher in the P group than in the S group (p = 0.016).

CONCLUSION

Our study suggests that IL-40 and IL-1β may serve as effective salivary biomarkers for diagnosing gingivitis, while MMP-8 and IL-1β may be effective for distinguishing periodontitis. Based on our study's findings, it can be stated that IL-40 may serve as a new and effective biomarker for distinguishing individuals with gingivitis from healthy ones.

A Comprehensive Review on the Role of Interleukin-40 as a Biomarker for Diagnosing Inflammatory Diseases

Interleukins are a group of proteins that have a wide range of complex functions and are believed to be involved in several diseases and conditions. In particular, interleukin-40 (IL-40) is a recently identified cytokine associated with B cells that was first introduced by Catalan et al. in 2017. This cytokine has several roles in the body, including functioning in the formation of B cells in the bone marrow, IgA production, and expression in the intestinal microbiome. Moreover, IL-40 appears to be involved in numerous autoimmune and inflammatory conditions, such as rheumatoid arthritis, systemic lupus erythematosus, primary Sjogren's syndrome, ankylosing spondylitis, type 2 diabetes, Graves' disease, and hepatic cell carcinoma. Our understanding of this molecule is quite restricted due to its novelty. However, because of its inflammatory characteristics, there is a high probability that it contributes to a variety of inflammatory disease complications. The aim of the present review is to highlight all available data on the importance of assessing IL-40 levels in human diseases up to now, which could be used as a diagnostic biomarker for the onset or progression of numerous inflammatory diseases.

A novel intergenic variant, rs2004339 A/G, of the gene encoding interleukin-40, C17orf99, is associated with risk of rheumatoid arthritis in Iraqi women

Interleukin-40 (IL-40) is a novel cytokine encoded by the chromosome 17 open reading frame 99 (C17orf99) gene. Recent studies have shown that IL-40 levels are significantly up-regulated in patients with rheumatoid arthritis (RA). However, the association of genetic variants of the C17orf99 gene with the risk of RA has not been investigated. In this case-control study, two intergenic variants, rs2004339 A/G and rs2310998 G/A, were genotyped for the first time in 120 Iraqi women with RA (30 newly diagnosed [ND] and 90 medicated [MD; treated with the tumor necrosis inhibitor etanercept plus methotrexate]) and 110 control women using TaqMan 5'-allele discrimination method. Serum IL-40 levels were also determined using an enzyme-linked immunosorbent assay kit. Multinomial logistic regression analysis was used to analyze rs2004339 and rs2310998 under five genetic models (allele, recessive, dominant, over-dominant, and co-dominant). Results revealed that the mutant A allele (allele model) and the homozygous AA genotype (co-dominant model) of rs2004339 were significantly associated with an increased risk of RA (odds ratio [OR] = 3.37 and 7.44, respectively; corrected probability [pc] < 0.001), while rs2310998 showed no association with RA risk. When comparing the allele and genotype frequencies of rs2004339 and rs2310998 between ND and MD patients, there were no statistically significant differences. Haplotype analysis of the two variants (in the order rs2004339-rs2310998) revealed that haplotypes A-A (OR = 1.72; pc = 0.024) and A-G (OR = 2.85; pc < 0.001) were associated with an increased risk of RA. IL-40 levels (median and interquartile range) were significantly elevated in RA patients compared to controls (29.3 [15.5-41.5] vs. 12.6 [7.4-18.8] pg/mL; p < 0.001). IL-40 levels were not influence by disease duration or disease activity, but the rs2310998 genotypes had an effect; IL-40 levels were significantly higher in women with the AA genotype than in women with the GG genotype (20.1 [12.9-37.1] vs. 15.8 [8.3-22.6] pg/mL; p = 0.006). Regarding medication, IL-40 tended to show elevated levels in ND cases compared to MD cases but without a significant difference. In conclusion, the mutant A allele and the mutant-type AA genotype of the intergenic variant rs2004339 were associated with an increased risk of RA among Iraqi women. Serum IL-40 levels were also elevated in patients, particularly ND patients, and were positively affected by the mutant-type AA genotype. Accordingly, the role of IL-40 in the pathogenesis of RA has been indicated.

Cytokines and their role as immunotherapeutics and vaccine Adjuvants: The emerging concepts

Cytokines are a protein family comprising interleukins, lymphokines, chemokines, monokines and interferons. They are significant constituents of the immune system, and they act in accordance with specific cytokine inhibiting compounds and receptors for the regulation of immune responses. Cytokine studies have resulted in the establishment of newer therapies which are being utilized for the treatment of several malignant diseases. The advancement of these therapies has occurred from two distinct strategies. The first strategy involves administrating the recombinant and purified cytokines, and the second strategy involves administrating the therapeutics which inhibits harmful effects of endogenous and overexpressed cytokines. Colony stimulating factors and interferons are two exemplary therapeutics of cytokines. An important effect of cytokine receptor antagonist is that they can serve as anti-inflammatory agents by altering the treatments of inflammation disorder, therefore inhibiting the effects of tumour necrosis factor. In this article, we have highlighted the research behind the establishment of cytokines as therapeutics and vaccine adjuvants, their role of immunotolerance, and their limitations.

New pro-inflammatory cytokine IL-40 is produced by activated neutrophils and plays a role in the early stages of seropositive rheumatoid arthritis

OBJECTIVE

Interleukin (IL)-40 is a new cytokine related to immune system function and malignancies. Recently, an association of IL-40 with rheumatoid arthritis (RA) and externalisation of neutrophil extracellular traps (NETosis) was found. As neutrophils are implicated in RA development, we investigated IL-40 in early stages of RA (ERA).

METHODS

IL-40 was determined in serum of treatment naïve patients with ERA at baseline (n=60) and 3 months after initiation of conventional therapy and in healthy controls (HC; n=60). Levels of IL-40, cytokines and NETosis markers were measured by ELISA. NETosis was visualised by immunofluorescence. In vitro experiments were performed on peripheral blood neutrophils from ERA patients (n=14). Cell-free DNA was analysed in serum and supernatants.

RESULTS

Serum IL-40 was elevated in ERA compared with HC (p<0.0001) and normalised after 3 months of therapy (p<0.0001). Baseline serum IL-40 correlated with rheumatoid factor (IgM) (p<0.01), anti-cyclic citrullinated peptide (p<0.01) autoantibodies and NETosis markers (proteinase 3; neutrophil elastase (NE); myeloperoxidase) (p<0.0001). Levels of NE significantly decreased after therapy (p<0.01) and correlated with the decrease of serum IL-40 (p<0.05). In vitro, neutrophils enhanced IL-40 secretion following NETosis induction (p<0.001) or after exposure to IL-1β, IL-8 (p<0.05), tumour necrosis factor or lipopolysaccharide (p<0.01). Recombinant IL-40 up-regulated IL-1β, IL-6 and IL-8 (p<0.05 for all) in vitro.

CONCLUSION

We showed that IL-40 is significantly up-regulated in seropositive ERA and decreases after conventional therapy. Moreover, neutrophils are an important source of IL-40 in RA, and its release is potentiated by cytokines and NETosis. Thus, IL-40 may play a role in ERA.

Possible role for IL-40 and IL-40-producing cells in the lymphocytic infiltrated salivary glands of patients with primary Sjögren's syndrome

OBJECTIVES

Aim of this study was to investigate the expression of interleukin (IL)-40, a new cytokine associated with B cells homoeostasis and immune response, in primary Sjögren syndrome (pSS) and in pSS-associated lymphomas.

METHODS

29 patients with pSS and 24 controls were enrolled. Minor salivary gland (MSG) biopsies from patients, controls and parotid gland biopsies from pSS-associated lymphoma were obtained. Quantitative gene expression analysis by TaqMan real-time PCR and immunohistochemistry for IL-40 were performed on MSG. MSG cellular sources of IL-40 were determined by flow-cytometry and immunofluorescence. Serum concentration of IL-40 was assessed by ELISA and cellular sources of IL-40 were determined by flow-cytometry. An in vitro assay with recombinant IL-40 (rIL-40) was performed to detect the effect on cytokine production from peripheral blood mononuclear cells (PBMCs).

RESULTS

IL-40 was significantly increased in the lymphocytic infiltrated MSG of patients with pSS and correlated with focus score and with IL-4 and transforming growth factor-β expression. In addition, IL-40 was increased in the serum of pSS and its levels correlated with the EULAR Sjögren's Syndrome Disease Activity Index score. B cells from patients were shown to be the major source of IL-40 at both tissue and peripheral level. PBMCs from patients, exposed to rIL-40 in vitro, released proinflammatory cytokines, specifically interferon-γ from B cells and T-CD8⁺ and tumour necrosis factor-α and IL-17 from both T-CD4⁺ and T-CD8⁺. IL-40 expression in parotid glands of pSS-associated lymphomas was also increased. Moreover, IL-40-driven NETosis was evidenced in neutrophils obtained from pSS.

CONCLUSION

Our results suggest that IL-40 may play a role in pSS pathogenesis and pSS-associated lymphomas.

A novel signature of interleukins 36α, 37, 38, 39 and 40 in ankylosing spondylitis

The current study examined five cytokines, three belong to interleukin (IL)-1 family (IL-36α, IL-37 and IL-38), one belongs to IL-12 family (IL-39) and one has not been assigned to a family (IL-40), in the serum of 110 male patients with ankylosing spondylitis (AS) and 103 male controls. Studies regarding these cytokines in AS are very limited. Therefore, the significance of IL-36α, IL-37, IL-38, IL-39 and IL-40 as biomarkers of AS was evaluated. Cytokine levels were measured using enzyme-linked immunosorbent assay kits. Results revealed that serum levels (median and interquartile range) of IL-36α (90.7; 53.7-166.2 vs 39.7; 31.3-59.2 pg/mL; probability [p] < 0.001), IL-37 (161.3; 62.8-236.6 vs 58.4; 46.8-80.7 ng/mL; p < 0.001), IL-38 (135.8; 78.2-213.5 vs 65.8; 51.1-87.1 pg/mL; p < 0.001), IL-39 (57.7; 34.1-92.3 vs 29.1; 19.3-58.6 ng/L; p < 0.001) and IL-40 (3.89; 2.99-6.19 vs 2.10; 1.75-2.68 ng/L; p < 0.001) were significantly higher in AS patients than in controls. Besides, they were of value in distinguishing between AS patients and controls as evidenced by the receiver operating characteristic curve analysis: area under the curve = 0.797 (IL-36α), 0.75 (IL-37), 0.797 (IL-38), 0.728 (IL-39) and 0.886 (IL-40). Some of these cytokines were significantly correlated, but no correlation with AS activity was found. In conclusion, the levels of IL-36α, IL-37, IL-38, IL-39 and IL-40 were up-regulated in the serum of AS patients regardless of age, age at disease onset, disease duration, disease activity or HLA-B27.

Interleukin-40 is a promising biomarker associated with type 2 diabetes mellitus risk

Interleukin (IL)-40 is a recently identified cytokine with a proposed role in the pathogenesis of inflammatory diseases. Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by low-grade inflammation. Therefore, it can be suggested that IL-40 may be involved in the pathogenesis of T2DM, but this topic has not been explored. The current study evaluated the potential of IL-40 as a biomarker for T2DM. Serum IL-40 levels were determined in 106 patients with T2DM and 109 healthy controls using an enzyme-linked immunosorbent assay kit. Median (interquartile range) IL-40 levels were significantly higher in patients than in controls (2.82 [2.58-3.25] vs. 1.22 [0.93-1.42] ng/L; probability [p] < 0.001). When IL-40 levels were stratified according to age, gender, disease duration, body mass index, diabetic neuropathy, fasting plasma glucose or glycated hemoglobin, no significant differences were found in each stratum. Receiver operating characteristic curve analysis showed that IL-40 was an excellent predictor in discriminating between T2DM patients and controls (area under the curve = 0.989; 95% confidence interval = 0.973-1.00; p < 0.001). Age- and gender-adjusted multinomial logistic regression analysis estimated an odds ratio of 53.36 (95% confidence interval = 12.52-227.45; p < 0.001) for IL-40 in T2DM. IL-40 level was negatively correlated with age (correlation coefficient = -0.274; p = 0.005) and onset age (correlation coefficient = -0.203; p = 0.037). In conclusion, IL-40 was up-regulated in the serum of T2DM patients, and can be considered as a reliable biomarker in distinguishing patients with T2DM from healthy controls.

Biological Role, Mechanism of Action and the Importance of Interleukins in Kidney Diseases

Each year, the number of patients who are diagnosed with kidney disease too late is increasing, which leads to permanent renal failure. This growing problem affects people of every age, sex and origin, and its full etiopathogenesis is not fully understood, although the involvement of genetic susceptibility, infections, immune disorders or high blood pressure is suggested. Difficulties in making a correct and quick diagnosis are caused by the lack of research on early molecular markers, as well as educational and preventive activities among the public, which leads to the late detection of kidney diseases. An important role in the homeostasis and disease progression, including kidney diseases, is attributed to interleukins, which perform several biological functions and interact with other cells and tissues of the body. The aim of this article was to systematize the knowledge about the biological functions performed by interleukins in humans and their involvement in kidney diseases development. In our work, we took into account the role of interleukins in acute and chronic kidney disease and kidney transplantation.