IL-18 BP Research Articles

Blood cytokines as potential predictors of the development of SARS-CoV-2 associated pneumonia in patients with stage II ESSENTIAL hypertension

The search for predictors of the severe course of COVID-19 was relevant both during the pandemic and at the present time. The aim of the study was to analyze the relationship of cytokine levels in patients with EН before SARS-CoV-2 infection with the incidence of coronavirus pneumonia. Materials and methods. From the database of 290 patients with stage II EAG who have been under observation for 8–12 years with annual blood sampling to determine cytokine levels, COVID-19 survivors were selected (mild without pneumonia and moderate to severe, pneumonia CT 1–2, CT-3). Anamnestic levels of IL-1β, IL-1α, IL-1ra, IL-18, IL-18 BP, IL-37, IL-6, sIL-6r, M-CSF, VEGF-A, IL-34 and HMGB1) in the blood serum of patients with stage II EH were analyzed (method ELISA). The analysis of the obtained results was carried out using Stat Soft Statistica 13.5. Results and discussion. Patients with EH and COVID-19 with pneumonia (CT I-II) after SARS-CoV-2 infection 2–6 months before the infectious disease had significantly higher serum levels: IL-1α (p 0.05) and a decrease in IL-37 (p 0.001). During multivariate correlation analysis, a statistically independent relationship between an increase in the incidence of viral pneumonia in patients with stage II EН was confirmed only for IL-37 with a blood level of less than 60.2 pg/ml (regression coefficient — 2.21, standard error — 0.28, t criterion — 6.12, relative risk — 2.52, criterion Walda — 7.92, p = 0.006). When studying circadian rhythms of cytokine content in blood serum in patients of the analyzed groups, calculating the strength of correlations of anamnestic evening IL-37 levels in patients with stage II EР at 19.00–20.00 with the frequency of pneumonia against the background of SARS-CoV-2 infection, it has greater specificity and sensitivity (specificity — 0.75, sensitivity — 0.82) than morning concentrations. Considering that data on circadian rhythms were obtained in a limited number of patients, further monitoring is necessary, which is carried out by our scientific group. It should be noted that patients with essential hypertension are pathogenetically heterogeneous, including in terms of cytokine regulation. The study of this area will make it possible to personalize cytokine phenotypes of the disease and develop new methods for calculating the prognosis of both cardiovascular complications and features of the course of infectious diseases.

Clinical significance of IL-18 and IL-18-binding protein in bone marrow of patients with myelodysplastic syndrome

Objective: To analyze the level and clinical significance of IL-18 and IL-18-binding protein (BP) in the bone marrow of patients with myelodysplastic syndrome (MDS) . Methods: A total of 43 newly diagnosed patients with MDS who were admitted to the Department of Hematology, Tianjin Medical University General Hospital, from July 2020 to February 2021 were randomly selected. The control group consisted of 14 patients with acute myeloid leukemia (AML) and 25 patients with iron-deficiency anemia (IDA). The levels of IL-18 and IL-18 BP in the bone marrow supernatant were measured, and their correlations with MDS severity, as well as the functionality of CD8(+) T cells and natural killer cells, was analyzed. Results: The levels of IL-18, IL-18 BP, and free IL-18 (fIL-18) in the bone marrow supernatant of patients with MDS were higher than in the IDA group. The level of fIL-18 was linearly and negatively correlated with the MDS-International Prognostic Scoring System (IPSS) score. IL-18 receptor (IL-18Rα) expression on CD8(+) T cells in the MDS group was lower than in the IDA group, and the levels of fIL-18 and IL-18Rα were positively correlated with CD8(+) T-cell function in the MDS group. Conclusion: IL-18 BP antagonizes IL-18, leading to a decrease in fIL-18 in the bone marrow microenvironment of patients with MDS, affecting CD8(+) T-cell function, which is closely related to MDS severity; therefore, it may become a new target for MDS treatment.

Изменения циркадианных ритмов уровней цитокинов в крови пациентов с эссенциальной гипертензией в постковидном периоде

In spite of a vast number of trials devoted to quantitative characteristics of the cytokine profile in patients with various diseases, no exact reference intervals are presented. It is just as important that there is a limited number of trials analyzing circadian rhythms of cytokine synthesis in patients with arterial hypertension. The purpose of the work was to analyze the characteristics of circadian rhythms of cytokines (IL18, IL18 BP, LIF, sLIFr, M-CSF, MCSFR) in patients with Grade II essential arterial hypertension, and to detect pathogenetically significant characteristics developed following Covid-19. Blood samples were taken at 7.00–8.00, 12.00–13.00, 19.00–20.00.00, 00.00–1.00 to determine the levels of IL18, IL18 BP, LIF, sLIFr, M-CSF, MCSFR in 18 patients (56 (95% CI (54–69) years) with essential arterial hypertension (EAH) within three days prior to and following Covid-19. For this, the immunoenzyme method was used. The obtained data demonstrated altered circadian expression of cytokines in the peripheral blood of patients with essential hypertension depending on whether they have EAH or not, and their additional distortion following Covid-19, which is stable in the majority of cases. It is preserved for six months as low IL18 BP (р < 0.001), and twofold increase of sLIFr and MCSF (р < 0,001) at 18.00. A significant association is determined between the circadian rhythms of sLIFr and altered systolic BP resulting in the abnormal rhythm with BP rise at night (night peaker) in patients with EAH following COVID-19. The obtained fundamental data offer prospects for new research of immunopathogenesis following COVID-19 in patients with hypertension taking into account circadian rhythms of cytokines in the blood.

Interleukin-18, Interleukin-18 Gene Polymorphisms and Interleukin18 Binding Protein in Children and Adolescents with Immune Thrombocytopenia

Background Immune thrombocytopenia (ITP) is an autoimmune illness characterized by an aberrant T cell response, which is supported by autoreactive B cell growth and differentiation. IL-18 expression has been linked to a number of autoimmune and inflammatory illnesses. IL18BP is a protein that binds IL-18 with high affinity, suggesting a potential mechanism for regulating IL-18 activity. Corticosteroids may play a significant role in reversing the IL-18- IL18BP ratio by upregulating IL18BP. Objective The aim was to study associations between IL-18 and two associated gene polymorphism sites -607 & -137 with incidence and response to therapy in patients with ITP. Patients and Methods It is a case control study conducted on children and adolescents with ITP.A total of 55 patients with different stages of ITP (25 acute, 18 persistent & 12 chronic patients) were recruited with 30 age matched healthy controls. All patients were subjected to full history and physical examination. Laboratory investigations included serial blood counts, IL-18 and IL-18BP serum levels using enzyme linked immunosorbent assay (ELISA) and IL-18 gene polymorphisms using polymerase chain reaction (PCR). Results At diagnosis the median platelet count was 16× 109/L (range 2-79) & eventually increased to a median of 90× 109/L after treatment. IL-18 level was significantly higher than that of control (P < 0.001) & even after treatment. There was no significant difference between patient and control groups regarding the studied gene polymorphism sites -607 & -137. The mean IL-18 was still significantly elevated in all stages of ITP compared to control group & as well the drop after treatment. This was also observed in IL-18 BP which increased significantly after response to steroid therapy. However, it was observed that the decline in level of IL-18 as well as increment in IL-18 BP was the least in the patients tested during the acute phase. Mean IL-18 & IL-18 BP levels show no significant relation with gender, family history of ITP, mode of treatment or genotype. Conclusion Among the studied IL-18 gene polymorphisms, no significant difference was detected among ITP patients or had a significant correlation with clinical or laboratory markers. Reversed IL-18/IL-18BP ratio is an important modulator in pathogenesis of ITP. Increasing levels of IL-18BP could have a significant role in treatment.

Interleukin 18 and IL-18 BP response to Sars-CoV-2 virus infection.

The immune response to the SARS-CoV-2 infection is crucial to the patient outcome. IL-18 is involved in the lymphocyte response to the disease and it is well established its important role in the complex developing of the host response to viral infection. This study aims at the analysis of the concentrations of IL-18, IL-18BP, INF-γ at the onset of the SARS-CoV-2 infection. The serum levels of measured interleukins were obtained through enzyme-linked immunosorbent assay. Furthermore, the free fraction of IL-18 was numerically evaluated. The enrolled patients were divided in two severity groups according to a threshold value of 300 for the ratio of arterial partial pressure of oxygen and fraction of inspired oxygen fraction and according to the parenchymal involvement as evaluated by computerized tomography at the admittance. In the group of patients with a more severe disease, a significant increase of the IL-18, INF-γ and IL-18BP levels have been observed, whereas the free IL-18 component values were almost constant. The results confirm that, at the onset of the disease, the host response keep the inflammatory cytokines in an equilibrium and support the hypothesis to adopt the IL-18BP modulation as a possible and effective therapeutic approach.

Complete genome sequence of a novel sea otterpox virus.

Members of the Poxviridae family are large, double-stranded DNA viruses that replicate in the cytoplasm of their host cells. The subfamily Chordopoxvirinae contains viruses that infect a wide range of vertebrates including marine mammals within the Balaenidae, Delphinidae, Mustelidae, Odobenidae, Otariidae, Phocidae, and Phocoenidae families. Recently, a novel poxvirus was found in a northern sea otter pup (Enhydra lutris kenyoni) that stranded in Alaska in 2009. The phylogenetic relationships of marine mammal poxviruses are not well established because of the lack of complete genome sequences. The current study sequenced the entire sea otterpox virus Enhydra lutris kenyoni (SOPV-ELK) genome using an Illumina MiSeq sequencer. The SOPV-ELK genome is the smallest poxvirus genome known at 127,879bp, is 68.7% A+Tcontent, is predicted to encode 132 proteins, and has 2546bp inverted terminal repeats at each end. Genetic and phylogenetic analyses based on the concatenated amino acid sequences of7 chorodopoxvirus core genes revealed the SOPV-ELK is 52.5-74.1% divergent from other known chordopoxviruses and is most similar to pteropoxvirus from Australia (PTPV-Aus). SOPV-ELK represents a new chordopoxvirus species and may belong to a novel genus. SOPV-ELK encodes eight unique genes. While the function of six predicted genes remains unknown, two genes appear to function as novel immune-modulators. SOPV-ELK-003 appears to encode a novel interleukin-18 binding protein (IL-18 BP), based on limited sequence and structural similarity to other poxviral IL-18 BPs. SOPV-ELK-035 appears to encode a novel tumor necrosis factor receptor-like (TNFR) protein that may be associated with the depression of the host's antiviral response. Additionally, SOPV-ELK-036 encodes a tumor necrosis factor-like apoptosis-inducing ligand (TRAIL) protein that has previously only been found in PTPV-Aus. The SOPV-ELK genome is the first mustelid poxvirus and only the second poxvirus from a marine mammal to be fully sequenced. Sequencing of the SOPV-ELK genome is an important step in unraveling the position of marine mammal poxviruses within the larger Poxviridae phylogenetic tree and provides the necessary sequence to develop molecular tools for future diagnostics and epidemiological studies.

Inhibition of IL-18 reduces renal fibrosis after ischemia-reperfusion

Acute kidney injury induced by ischemia-reperfusion injury (IRI) is a high risk factor in the progression towards chronic kidney disease, which is featured by renal interstitial fibrosis. Interleukin (IL)-18 is produced by T cells and macrophages and has been involved in the pathophysiology of IRI. However, the role of IL-18 in IRI-induced renal fibrosis is poorly understood. In the present study, we showed that interleukin (IL)-18 was significantly up-regulated after IRI stress. Mice treated with IL-18 Bp, a natural inhibitor of IL-18, presented less severe fibrotic response in the kidneys following IRI compared with vehicle-treated mice. Inhibition of IL-18 decreased myofibroblasts formation in the kidneys in response to IRI, which was associated with reduction of fibronectin and collagenⅠproteins. Moreover, inhibition of IL-18 impaired infiltration of CD3+ T cells and F4/80+ macrophages in the kidneys of mice after IRI. Treatment with IL-18 Bp reduces the levels of profibrotic molecules in the kidneys of mice following IRI. Finally, administration of IL-18 Bp impedes the transition of M2 macrophages to myofibroblasts and suppressed the accumulation of bone marrow-derived M2 macrophages. Adoptive transfer of M2 macrophages abolished the anti-fibrotic effect of IL-18 Bp. In summary, our results suggest that IL-18 plays an important role in the progression of IRI-induced renal fibrosis via modulating inflammation cells infiltration, the expression of inflammatory cytokines and chemokines, and the transition of bone marrow-derived M2 macrophages to myofibroblasts.

Brief Report: Circulating Cytokine Profiles and Antineutrophil Cytoplasmic Antibody Specificity in Patients With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

To evaluate circulating cytokine profiles in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), classified by antineutrophil cytoplasmic antibody (ANCA) specificity (proteinase 3 ANCA [PR3-ANCA] versus myeloperoxidase ANCA [MPO-ANCA]) or by clinical diagnosis (granulomatosis with polyangiitis [GPA] versus microscopic polyangiitis [MPA]). A panel of 29 cytokines was tested in 186 patients with active AAV at inclusion into the Rituximab in AAV trial. Cytokine concentrations were compared between groups within each classification system. Multivariable analyses adjusted for age, sex, and renal insufficiency were performed, with each biomarker as a dependent variable and ANCA specificity and clinical diagnosis as explanatory variables of interest. Levels of 9 circulating cytokines (interleukin-6 [IL-6], granulocyte-macrophage colony-stimulating factor [GM-CSF], IL-15, IL-18, CXCL8/IL-8, CCL-17/thymus and activation-regulated chemokine [TARC], IL-18 binding protein [IL-18 BP], soluble IL-2 receptor α [sIL-2Rα], and nerve growth factor β [NGFβ]) were significantly higher in PR3-AAV than MPO-AAV, 4 cytokines (sIL6R, soluble tumor necrosis factor receptor type II [sTNFRII], neutrophil gelatinase-associated lipocalin [NGAL], and soluble intercellular adhesion molecule 1 [sICAM-1]) were higher in MPO-AAV than in PR3-AAV, 6 cytokines (IL-6, GM-CSF, IL-15, IL-18, sIL-2Rα, and NGFβ) were higher in GPA than in MPA, and 3 cytokines (osteopontin, sTNFRII, and NGAL) were higher in MPA than in GPA (all P < 0.05). For nearly all cytokines, the difference between PR3-AAV and MPO-AAV was larger than that between GPA and MPA. The multivariate analysis showed that 8 cytokines (IL-15, IL-8, IL-18 BP, NGF-β, sICAM-1, TARC, osteopontin, andkidney injury molecule 1 (P < 0.05) distinguished patients with AAV better (lower P values and larger effect sizes) when grouped by ANCA specificity than by clinical diagnosis. Distinct cytokine profiles were identified for PR3-AAV versus MPO-AAV and for GPA versus MPA. Differences in these circulating immune mediators are more strongly associated with ANCA specificity than with clinical diagnosis, suggesting that heterogeneity in the AAV subtypes extends beyond clinical phenotypes.

Tc17 cells mediate gut GVHD via IL-22 and dysbiosis

Abstract Gut GVHD is critical for determining the outcome of allogenic hematopoietic cell transplantation (HCT). Damage of Paneth cells and loss of RegIIIg can lead to dysregulation of intestinal microbiota and gut GVHD pathogenesis. RegIIIg can be produced by Paneth cells and intestinal epithelial cells, and its secretion is augmented by IL-22. However, the circumstances leading to RegIIIg dysregulation and dysbiosis remain largely unknown. Here we show that, in a MHC-mismatched model of C57BL/6 donor to BALB/c recipient, one injection of depleting anti-CD4 effectively prevents acute gut GVHD in recipients given wild-type (WT) transplants but has no effect in recipients given IFN-g−/− transplants. Interestingly, PD-L1−/−recipients given IFN-g−/− transplants showed spontaneous recovery of the disease. Recipients given IFN-g−/− transplants showed expansion of Tc17, IL-22 but not IL-17 from Tc17 was required for the disease induction. Furthermore, host tissue PD-L1 augmented expansion of Tc17 as well as CX3CR1+ DC, CX3CR1+ DC mediate bacteria clearance and prevent bacteria translocation, at the same time, CX3CR1+ DC produce IL-18 BP, which limit Tc17 expansion through IL-18 signaling. In addition, recipients given IFN-g−/− transplants showed no damage of Paneth cells but markedly increased RegIIIg. Gut GVHD in recipients had significant reduction of Barnesiella in feces and significant increase of E. Coli and Lactobacillus. Taken together, these results indicate that 1) in the absence of donor IFN-g, host-tissue PD-L1 mediates expansion of Tc17 through IL-18 signaling and dysregulation of IL-22 functional effect; 2) Dysregualtion of IL-22 from Tc17 cell can lead to dysbiosis and gut GVHD in the absence of Paneth cell damage.

Immune cell profile of dental pulp tissue treated with zoledronic acid.

To characterize the pulp immune cell profile in the teeth of rats treated with zoledronic acid (ZA). Male Wistar rats (n=6 per group) received four intravenous infusions of ZA at doses of 0.04, 0.20 or 1.00mgkg-1 ZA or saline (control). On the 70th experimental day, they were euthanized. The first right molar was examined microscopically and submitted to toluidine blue reaction and immunohistochemical for CD68, tumour necrosis Factor (TNF)-α, interleukin (IL)-1β, inducible nitric oxide synthase (iNOS), nuclear factor kappa B (NF-kB) and IL-18 binding protein (IL-18bp). The presence of ectasic/dilated vessels and inflammatory cells was analysed, and mast cells and mononuclear CD68-positive cells were counted along with the intensity of immunostaining (0-3) for inflammatory markers in odontoblasts and nonodontoblasts pulp cells. The Kruskal-Wallis/Dunn's test (scores or quantitative data) and the chi-squared test (categorical data) were used (GraphPad Prism 5.0, P<0.05). There was no differences in the number of animals exhibiting dilated/ectasic blood vessels (P=0.242) and inflammatory cells (P=0.489) or in the number of mast cells (P=1.000). However, there was an increase in mononuclear CD68-positive cells (P=0.026), immunostaining of TNF-α (P=0.020), IL-1β (P=0.027) and iNOS (P=0.001) in odontoblasts, and IL-1β (P=0.013) in nonodontoblast pulp cells dose-dependently. NFkB (nucleus and cytoplasm) and IL-18bp did not differ between groups. ZA modified the immune cell profile in the dental pulp, increasing the number of macrophages and expression of pro-inflammatory markers independent of NFkB.

Increased IL18 mRNA levels in peripheral artery disease and its association with triglyceride and LDL cholesterol levels: a pilot study.

Peripheral artery disease (PAD) typically refers to lower limb vessel ischemia caused by atherosclerotic stenosis of lower extremity arteries. IL18 is a pleiotropic pro-inflammatory cytokine reported to function as an inflammatory biomarker in cardiovascular diseases. IL18 activity is balanced by high-affinity naturally occurring IL18-binding protein (IL18BP). This study aimed to determine whether IL18, IL18 BP mRNA levels and -137 G/C (rs187238) polymorphism, which was previously associated with IL18 gene transcriptional activity, were associated with PAD etiology. IL18, IL18BP mRNA levels from peripheral blood mononuclear cells and -137 G/C (rs187238) polymorphism were determined by quantitative real-time polymerase chain reaction (qRT-PCR) and RT-PCR, respectively, in 55 PAD patients (26 aorta-iliac, 29 femoro-popliteal) and 61 disease-free controls. IL18 mRNA levels were increased in PAD patients compared with healthy controls (p=0.09); however, did not reach a statistical significant level, also did not significantly differ between aorta-iliac and femoro-popliteal occlusive PAD subgroups (p=0.285). However, IL18BP mRNA levels were significantly lower in PAD group compared with controls (p<0.001). Genotype frequencies of rs187238 polymorphism did not significantly differ between PAD patients and controls (p=0.385). IL18 mRNA levels were significantly correlated with triglycerides and LDL cholesterol levels in PAD patients (p=0.003, p=0.014, respectively). HDL cholesterol levels were negatively correlated with IL18 mRNA levels in controls (p=0.05). This report is a preliminary study to show an association between IL18, IL18BP mRNA levels and PAD and suggests that the IL18 gene may have a significant relationship with triglyceride and LDL cholesterol levels in PAD patients.

Involvement of CX3CL1/CX3CR1 signaling in spinal long term potentiation.

The long-term potentiation (LTP) of spinal C-fiber-evoked field potentials is considered as a fundamental mechanism of central sensitization in the spinal cord. Accumulating evidence has showed the contribution of spinal microglia to spinal LTP and pathological pain. As a key signaling of neurons-microglia interactions, the involvement of CX3CL1/CX3CR1 signaling in pathological pain has also been investigated extensively. The present study examined whether CX3CL1/CX3CR1 signaling plays a role in spinal LTP. The results showed that 10-trains tetanic stimulation (100 Hz, 2s) of the sciatic nerve (TSS) produced a significant LTP of C-fiber-evoked field potentials lasting for over 3 h in the rat spinal dorsal horn. Blockade of CX3CL1/CX3CR1 signaling with an anti-CX3CR1 neutralizing antibody (CX3CR1 AB) markedly suppressed TSS-induced LTP. Exogenous CX3CL1 significantly potentiated 3-trains TSS-induced LTP in rats. Consistently, spinal LTP of C-fiber-evoked field potentials was also induced by TSS (100 Hz, 1s, 4 trains) in all C57BL/6 wild type (WT) mice. However, in CX3CR1-/- mice, TSS failed to induce LTP and behavioral hypersensitivity, confirming an essential role of CX3CR1 in spinal LTP induction. Furthermore, blockade of IL-18 or IL-23, the potential downstream factors of CX3CL1/CX3CR1 signaling, with IL-18 BP or anti-IL-23 neutralizing antibody (IL-23 AB), obviously suppressed spinal LTP in rats. These results suggest that CX3CL1/CX3CR1 signaling is involved in LTP of C-fiber-evoked field potentials in the rodent spinal dorsal horn.

The evaluation of plasma and leukocytic IL-37 expression in early inflammation in patients with acute ST-segment elevation myocardial infarction after PCI.

Objective. Acute ST-segment elevation myocardial infarction (ASTEMI) is accompanied by increased expression of inflammation and decreased expression of anti-inflammation. IL-37 was found to be involved in the atherosclerosis-related diseases and increased in acute coronary syndrome. However, the level of IL-37 in blood plasma and leukocytes from patients with ASTEMI after percutaneous coronary intervention (PCI) has not been explored. Methods. We collected peripheral venous blood from consented patients at 12 h, 24 h, and 48 h after PCI and healthy volunteers. Plasma IL-37, IL-18, IL-18-binding protein (BP), and high sensitive C reaction protein (hs-CRP) were quantified by ELISA and leukocytic IL-37 and ICAM-1 by immunoblotting. Results. Plasma IL-37, IL-18, and IL-18 BP expression decreased compared to those in healthy volunteers while hs-CRP level was high. Both leukocytic IL-37 and ICAM-1 were highest expressed at 12 h point but significantly decreased at 48 h point. Conclusion. These findings suggest L-37 does not play an important role in the systematic inflammatory response but may be involved in leukocytic inflammation in ASTEMI after PCI.

Cytokine-induced killer (CIK) cells bound with anti-CD3/anti-CD133 bispecific antibodies target CD133high cancer stem cells in vitro and in vivo

CD133 is a common marker of cancer stem cells (CSCs). We generated an anti-CD3/anti-CD133 bispecific antibody (BsAb) and bound it to the cytokine-induced killer (CIK) cells as effector cells (BsAb-CIK) to target CD133(high) CSCs. The killing of CD133(high) pancreatic (SW1990) and hepatic (Hep3B) cancer cells by the BsAb-CIK cells was significantly (p<0.05) higher than the killing by the parental CIK or by CIK cells bound with anti-CD3 (CD3-CIK) without CD133 targeting. In nude mice, the BsAb-CIK cells inhibited CD133(high) tumor growth significantly (p<0.05) more than that by CIK or CD3-CIK cells, or by the BsAb alone. BsAb-CIK cells co-cultured with CD133(high) cells produced significantly (p<0.05) higher amount of IFN-γ. Treatment with the BsAb-CIK cells significantly downregulated the expression of S100P and IL-18bp, but upregulated STAT1. The findings may help with the development of novel immunotherapies for patients with cancer containing CD133(high) CSCs by selectively targeting this cell population.

Interleukin-18 and IL-18 Binding Protein

Interleukin-18 (IL-18) is a member of the IL-1 family of cytokines. Similar to IL-1β, IL-18 is synthesized as an inactive precursor requiring processing by caspase-1 into an active cytokine but unlike IL-1β, the IL-18 precursor is constitutively present in nearly all cells in healthy humans and animals. The activity of IL-18 is balanced by the presence of a high affinity, naturally occurring IL-18 binding protein (IL-18BP). In humans, increased disease severity can be associated with an imbalance of IL-18 to IL-18BP such that the levels of free IL-18 are elevated in the circulation. Increasing number of studies have expanded the role of IL-18 in mediating inflammation in animal models of disease using the IL-18BP, IL-18-deficient mice, neutralization of IL-18, or deficiency in the IL-18 receptor alpha chain. A role for IL-18 has been implicated in several autoimmune diseases, myocardial function, emphysema, metabolic syndromes, psoriasis, inflammatory bowel disease, hemophagocytic syndromes, macrophage activation syndrome, sepsis, and acute kidney injury, although in some models of disease, IL-18 is protective. IL-18 plays a major role in the production of interferon-γ from T-cells and natural killer cells. The IL-18BP has been used safely in humans and clinical trials of IL-18BP as well as neutralizing anti-IL-18 antibodies are in clinical trials. This review updates the biology of IL-18 as well as its role in human disease.

Improving the MVA Vaccine Potential by Deleting the Viral Gene Coding for the IL-18 Binding Protein

BackgroundModified Vaccinia Ankara (MVA) is an attenuated strain of Vaccinia virus (VACV) currently employed in many clinical trials against HIV/AIDS and other diseases. MVA still retains genes involved in host immune response evasion, enabling its optimization by removing some of them. The aim of this study was to evaluate cellular immune responses (CIR) induced by an IL-18 binding protein gene (C12L) deleted vector (MVAΔC12L).Methodology/Principal FindingsBALB/c and C57BL/6 mice were immunized with different doses of MVAΔC12L or MVA wild type (MVAwt), then CIR to VACV epitopes in immunogenic proteins were evaluated in spleen and draining lymph nodes at acute and memory phases (7 and 40 days post-immunization respectively). Compared with parental MVAwt, MVAΔC12L immunization induced a significant increase of two to three-fold in CD8+ and CD4+ T-cell responses to different VACV epitopes, with increased percentage of anti-VACV cytotoxic CD8+ T-cells (CD107a/b+) during the acute phase of the response. Importantly, the immunogenicity enhancement was also observed after MVAΔC12L inoculation with different viral doses and by distinct routes (systemic and mucosal). Potentiation of MVA's CIR was also observed during the memory phase, in correlation with a higher protection against an intranasal challenge with VACV WR. Of note, we could also show a significant increase in the CIR against HIV antigens such as Env, Gag, Pol and Nef from different subtypes expressed from two recombinants of MVAΔC12L during heterologous DNA prime/MVA boost vaccination regimens.Conclusions/SignificanceThis study demonstrates the relevance of IL-18 bp contribution in the immune response evasion during MVA infection. Our findings clearly show that the deletion of the viral IL-18 bp gene is an effective approach to increase MVA vaccine efficacy, as immunogenicity improvements were observed against vector antigens and more importantly to HIV antigens.

Clinical significance of serum IL-18 and IL-18BP in patients with benign or malignant primary liver tumors

OBJECTIVE To study the relationship between the serum levels of IL-18 and IL-18BP in the development and growth of primary liver cancer, benign liver tumors and liver cirrhosis and to determine the value of serum IL-18 and IL-18BP in the diagnosis of primary liver cancer. METHODS The serum levels of IL-18 and IL-18BP in 36 patients with primary hepatic carcinoma (PHC) were detected. Eighteen patients were diagnosed with various benign liver tumors and 21 patients with cirrhosis of liver (LC), determined by using an ELISA assay. The serum levels of AFP in 36 patients with primary liver cancer were examined. The relationship among levels of serum IL-18, IL-18BP and AFP in the primary liver cancer was explored. RESULTS The sIL-18 levels in PHC were signi fi cantly lower than in control group, the benign liver tumor group and the LC group. The sIL-18BP in PHC was signi fi cantly higher than that in control group, benign liver tumor group and LC group ( P < 0.001). There was a close correlation between the levels of IL-18, IL-18BP and clinical stage in PHC: the later clinical stages had lower levels of IL-18 and higher levels of IL-18BP while the earlier clinical stages had higher levels of IL-18 and lower levels of IL-18BP. There was a negative correlation between serum levels of IL-18 and AFP in the PHC group ( r = -0.7152, n = 36, P < 0.01), and there was a positive correlation between serum levels of IL-18 BP and AFP in the patients with PHC (r = 0.6315, n = 36, P < 0.01). The IL-18and IL-18BP in the patients with various benign liver tumors or LC were significantly higher than those in control group. The differences were statistically signifi cant ( P < 0.01). CONCLUSION Serum levels of IL-18 and IL-18BP can reflect the immune function of patients with primary liver cancer, with various benign liver tumors or with LC and can also be indicative of the clinic stage of primary liver cancer. It can be used to assist in making a diagnosis and in determining the clinical stage of PHC. Detecting AFP concurrently can help make the diagnosis of primary liver cancer more precise.

Constitutive expression of IL-18 binding protein in murine testicular tissues and cells

In the present study, we examined the cellular origin and the expression levels of interleukin-18 binding protein (IL-18 BP), during normal maturation of murine testis. Immunohistochemical staining of testicular tissues from sexually mature mice, shows that testicular germ cells, at different stages of differentiation, express IL-18 BP. Leydig cells/interstitial cells and peritubular cells express higher levels of IL-18 BP, as compared to other testicular cells. The levels of IL-18 BP were similar in testicular tissues and homogenates from sexually immature and mature mice, as examined by western blot, ELISA and real time PCR analysis. Our results demonstrate, for the first time, the expression of IL-18 BP in murine testicular tissues and cells. Together with our previous studies, which showed over-expression of IL-18 in testicular tissues of immature mice as compared with mature mice, these results may indicate a role for IL-18 in testicular development, and also in the regulation of testicular functions under physiological conditions.

HLA-DRB1 ⁎04 gene polymorphisms and expressions profiles of interleukin-18 and interleukin-18 binding protein following in vitro stimulation in human peripheral blood mononuclear cells of healthy individuals and patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic arthritic condition that can lead to deformities and disabilities. Interleukin-18 (IL-18) is a proinflammatory cytokine known to play a role in the acute and chronic inflammatory phases of RA. IL-18 binding protein is the natural antagonist of IL-18 protein. We aim to identify the effect of HLA-DRB1 ⁎04 gene polymorphisms on IL-18 and IL-18BP gene expressions profiles as well as the time-course profiles following in vitro stimulation with mitogens. Peripheral blood mononuclear cells from 16 RA patients and 21 healthy controls were cultured for 1, 4, 8, 12, 24, 48 and 72 h following stimulation with either LPS or PHA. mRNA expression of IL-18 and IL 18BP were determined by quantitative real-time PCR using a comparative Ct (threshold cycle) method. IL-18 levels in supernatants were measured by enzyme-linked immunosorbent assay. Basal mRNA (4.5-fold) and protein levels of IL-18 were increased and IL-18BP mRNA expression was decreased (8-fold) in RA patients when compared to controls. Similarly, increased IL-18 levels were observed in active RA patients, whereas IL-18BP expression was increased in inactive patients. There was an increase in mRNA and protein levels of IL-18 in RA patients that peaked at 4 h and 8 h respectively following LPS stimulation. A similar profile was observed for IL-18BP; however, the expression level was higher in controls than RA patients. Persistent high production of IL-18 in RA is associated with disease progression and IL-18 BP seems to inhibit this activity.

Downregulation of Human Endometrial IL‐18 by Exogenous Ovarian Steroids

To evaluate the influence of ovarian steroids on IL-18, IL-15 and angiopoietin-2 mRNA expression in the endometrium in the mid luteal phase. We quantified IL-18/GAPDH, IL-18 BP/GAPDH, IL-15/GAPDH and angiopoietin-2/GAPDH in the endometrium by quantitative polymerase chain reaction on day 21 of the cycle. We first compared cytokines expression over two natural cycles (n = 15) then between natural and oestrogen-progestin replacement treatment (n = 18). Endometrial IL-18, IL-18 BP, IL-15 and angiopoietin-2 mRNA expression did not change over two natural cycles. Addition of exogenous hormones significantly decreased IL-18 and IL-18 BP mRNA expression but not influence IL-15 or angiopoietin-2 ratios. This was also observed with immunohistochemistry. Exogenous oestro-progestative hormones influence endometrial IL-18 system expression involved in angiogenesis and in the uterine natural killer (uNK) cell activation pathway during the implantation process.