Serum IL-18 levels in patients with type 1 diabetes: Relations to metabolic control and microvascular complications

Serum levels of interleukin-18 in diabetic retinopathy patients: A meta-analysis

PURPOSE

To assess the relationship between plasma interleukin-18 (IL-18) levels and the risk of diabetic retinopathy (DR).

MATERIALS AND METHODS

PubMed, Embase, Web of science, and Cochrane were reviewed systemically from inception to August 2022. Searches were performed using a combined term that included all spellings of "diabetic retinopathy," and "interleukin-18". Eligible studies were retrospective studies reporting changes in IL-18 levels between the DR group and the control group. The healthy controls had no identifiable DR disease. Pooled outcomes were reported as standard mean difference (SMD) with 95% confidence intervals (CI) with a random-effects model. Heterogeneity was assessed using the I2 statistics, and it was considered significant if I2 > 75%. Publication bias was evaluated using funnel plots and Begg's and Egger's tests. A meta-analysis was conducted using STATA 12.0 (StataCorp LLC, College Station, TX, USA).

RESULTS

7 studies and four countries incorporated 160 cases, and 119 controls were incorporated in this meta-analysis. When comparing subjects without DR, those with DR tended to have higher serum IL-18 levels (SMD = 3.41, 95% CI = 1.84-4.97). Publication bias indicated that no publication bias existed in the study.

CONCLUSIONS

Elevated circulating IL-18 levels may be one of the significant risk factors positively correlated with the development of DR. Future studies should clarify the mechanism behind this trend.

Sustained low-grade inflammation in young participants with childhood onset type 1 diabetes: The Norwegian atherosclerosis and childhood diabetes (ACD) study

BACKGROUND AND AIMS

Persons with type 1 diabetes (T1D) have increased mortality from cardiovascular disease. Early inflammation is important in the development of atherosclerosis. We aimed to evaluate the extent of inflammation and difference in mean over a five-year period in young persons with T1D compared to healthy controls.

METHODS

The Norwegian Atherosclerosis and Childhood Diabetes (ACD) study is a prospective population-based cohort study on atherosclerosis development in childhood-onset T1D compared to healthy controls, with follow-ups every fifth year. The original study cohort consisted of 314 children with T1D on intensive insulin treatment and 120 healthy controls of similar age. Circulating levels of VCAM-1, TNA-α, P-selectin, E-selectin, CRP, IL-6, IL-18, MCP-1, MMP-9 and TIMP-1 were measured by ELISAs at baseline and at the five-year follow-up.

RESULTS

The group with T1D had mean age 13.7 (SD = 2.8) years, disease duration 5.6 (SD = 3.4) years and HbA1c 68 (SD = 13.1) mmol/mol at baseline. Levels of almost all inflammatory markers were significantly increased in the group with T1D compared to controls, and significant mean-difference between the two groups over the five-year period was observed in four markers: IL-18, P-selectin, E-selectin and TIMP-1.

CONCLUSIONS

The early low-grade inflammation present in young individuals with T1D five years after diagnosis is sustained at ten-year disease duration, with moderate changes for most markers of inflammation over time. The evolving inflammatory profile indicates an accelerated chain of events in the progression of early atheromatosis in T1D.

Neutrophils and their role in the aetiopathogenesis of type 1 and type 2 diabetes

Multiple and complex aetiological processes underlie diabetes mellitus, which invariably result in the development of hyperglycaemia. Although there are two prevalent distinct forms of the disease, that is, type 1 and type 2 diabetes, accumulating evidence indicates that these syndromes share more aetiopathological mechanisms than originally thought. This compels a rethinking of the approaches to prevent and treat the different manifestations of what eventually becomes a hyperglycaemic state. This review aims to address the involvement of neutrophils, the most abundant type of granulocytes involved in the initiation of the acute phase of inflammation, in the aetiopathogenesis of diabetes mellitus, with a focus on type 1 and type 2 diabetes. We review the evidence that neutrophils are the first leucocytes to react to and accumulate inside target tissues of diabetes, such as the pancreas and insulin-sensitive tissues. We then review available data on the role of neutrophils and their functional alteration, with a focus on NETosis, in the progression towards clinical disease. Finally, we review potential approaches as secondary and adjunctive treatments to limit neutrophil-mediated damage in the prevention of the progression of subclinical disease to clinical hyperglycaemia.

Association between IL-18 and IL-6 gene polymorphisms and the risk of T1D in Egyptian children

Purpose

To test the involvement between IL-18 and IL-6 genetic polymorphisms and susceptibility to Type 1 diabetes (T1D).

Methods

Single nucleotide polymorphisms (SNPs) at positions -607A/C and - 137G/C in IL-18 promoter region were examined by sequence specific primers-polymerase chain reaction (SSP-PCR) and position -174G/C in promoter region of IL-6 gene which analyzed by Mutagenically Separated PCR (MS-PCR) in 104 T1D participants and 114 controls.

Results

IL-18 -137GC and -137CC genotypes and -137C allele were significantly decreased in T1D subjects (P < 0.05), while -137GG genotype was insignificantly increased as compared to controls. A significant decrease was detected in haplotype -137C/-607C frequency in T1D participants compared with controls (OR = 0.04, P < 0.001). There was significant association between IL-18 -607 of (CC, AC and AA genotypes) in age at diagnosis, glycated hemoglobin (HbA1c) and higher body mass index (BMI) (P < 0.05).

Conclusion

This study demonstrated that IL-18 gene promoter polymorphisms might be associated with susceptibility to T1D in Egyptian children. Individuals carrying CC genotype at position -137 of IL-18 promoter may be at a low risk of T1D progression. Additionally, the susceptible combination of IL-18 and IL-6 cytokine genes associated with T1D highlight their risk toward the disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40200-021-00763-w.

NLRP1 variant M1184V decreases inflammasome activation in the context of DPP9 inhibition and asthma severity

Background

NLRP1 is an innate immune sensor that can form cytoplasmic inflammasome complexes. Polymorphisms in NLRP1 are linked to asthma; however, there is currently no functional or mechanistic explanation for this.

Objective

We sought to clarify the role of NLRP1 in asthma pathogenesis.

Methods

Results from the GALA II cohort study were used to identify a link between NLRP1 and asthma in Mexican Americans. In vitro and in vivo models for NLRP1 activation were applied to investigate the role of this inflammasome in asthma at the molecular level.

Results

We document the association of an NLRP1 haplotype with asthma for which the single nucleotide polymorphism rs11651270 (M1184V) individually is the most significant. Surprisingly, M1184V increases NLRP1 activation in the context of N-terminal destabilization, but decreases NLRP1 activation on dipeptidyl peptidase 9 inhibition. In vitro studies demonstrate that M1184V increases binding to dipeptidyl peptidase 9, which can account for its inhibitory role in this context. In addition, in vivo data from a mouse model of airway inflammation reveal a protective role for NLRP1 inflammasome activation reducing eosinophilia in this setting.

Conclusions

Linking our in vitro and in vivo results, we found that the NLRP1 variant M1184V reduces inflammasome activation in the context of dipeptidyl peptidase 9 inhibition and could thereby increase asthma severity. Our studies may have implications for the treatment of asthma in patients carrying this variant of NLRP1.

Limited impact of impaired awareness of hypoglycaemia and severe hypoglycaemia on the inflammatory profile of people with type 1 diabetes

AIM

To investigate whether a history of severe hypoglycaemia (SH) or the associated presence of impaired awareness of hypoglycaemia (IAH) is characterized by a pro-inflammatory profile in people with type 1 diabetes.

RESEARCH DESIGN AND METHODS

We measured circulating inflammatory markers and pro- and anti-inflammatory cytokine production after ex vivo stimulation of peripheral blood mononuclear cells (PBMCs) in a well-characterized cohort of individuals with type 1 diabetes (n = 239) and in people without diabetes (n = 56). Data were corrected for confounders by using multivariate linear regression models.

RESULTS

People with type 1 diabetes had higher circulating concentrations of high-sensitivity C-reactive protein (hs-CRP; 0.91 [0.36-2.25] vs. 0.52 [0.20-0.98] pg/mL, P < 0.001 and interleukin-18-binding protein (IL-18BP; 1746 [1304-2112] vs. 1381 [1191-1807] pg/mL; P = 0.001) than those without diabetes. In multivariate analysis, only higher hs-CRP concentrations persisted. Neither circulating immune cells nor ex vivo cytokine levels produced by PBMCs in response to an extensive panel of stimuli differed in groups defined by awareness state or a history of SH, apart from elevated IL-18BP in people with, versus those without, history of SH (1524 [1227-1903] vs. 1913 [1459-2408] pg/mL; P < 0.001).

CONCLUSIONS

IAH or history of SH in people with type 1 diabetes was not associated with altered inflammatory profiles, arguing against chronically elevated inflammatory activity mediating the increased cardiovascular risk associated with hypoglycaemia. The finding of higher circulating concentrations of IL-18BP in individuals with a history of SH requires further investigation.

Higher levels of IL-18 in patients with prediabetes compared to obese normoglycaemic controls

Background: Overweight and obesity are linked to low-grade chronic inflammation that can impair normal insulin function and induce insulin resistance. The aim of this study was to compare IL-18 levels between patients with prediabetes and obese normoglycaemic controls.Patients and methods: In this study, we included 131 patients with mean age 54.9 ± 9.1 years, divided into two groups - group 1 with obesity without glycaemic disturbances (n = 66) and group 2 with prediabetes (n = 65). IL-18 was measured using enzyme-linked immunosorbent assay (ELISA) method.Results: Patients with prediabetes had significantly higher levels of IL-18 compared to obese controls (304.0 ± 220.4 vs. 233.6 ± 103.6 pg/l, p=.029). When patients with prediabetes were divided into IFG only, IGT only and IFG + IGT the highest levels of IL-18 were found in IGT only patients.Conclusions: Patients with prediabetes have higher levels of IL18 compared to obese normoglycemic controls.

New Insights into the Mechanisms of Pyroptosis and Implications for Diabetic Kidney Disease

Pyroptosis is one special type of lytic programmed cell death, featured in cell swelling, rupture, secretion of cell contents and remarkable proinflammation effect. In the process of pyroptosis, danger signalling and cellular events are detected by inflammasome, activating caspases and cleaving Gasdermin D (GSDMD), along with the secretion of IL-18 and IL-1β. Pyroptosis can be divided into canonical pathway and non-canonical pathway, and NLRP3 inflammasome is the most important initiator. Diabetic kidney disease (DKD) is one of the most serious microvascular complications in diabetes. Current evidence reported the stimulatory role of hyperglycaemia-induced cellular stress in renal cell pyroptosis, and different signalling pathways have been shown to regulate pyroptosis initiation. Additionally, the inflammation and cellular injury caused by pyroptosis are tightly implicated in DKD progression, aggravating renal fibrosis, glomerular sclerosis and tubular injury. Some registered hypoglycaemia agents exert suppressive activity in pyroptosis regulation pathway. Latest studies also reported some potential approaches to target the pyroptosis pathway, which effectively inhibits renal cell pyroptosis and alleviates DKD in in vivo or in vitro models. Therefore, comprehensively compiling the information associated with pyroptosis regulation in DKD is the main aim of this review, and we try to provide new insights for researchers to dig out more potential therapies of DKD.

Confirmation and Identification of Biomarkers Implicating Environmental Triggers in the Pathogenesis of Type 1 Diabetes

Multiple environmental triggers have been proposed to explain the increased incidence of type 1 diabetes (T1D). These include viral infections, microbiome disturbances, metabolic disorders, and vitamin D deficiency. Here, we used ELISA to examine blood plasma from juvenile T1D subjects and age-matched controls for the abundance of several circulating factors relevant to these hypotheses. We screened plasma for sCD14, mannose binding lectin (MBL), lipopolysaccharide binding protein (LBP), c-reactive protein (CRP), fatty acid binding protein 2 (FABP2), human growth hormone, leptin, total adiponectin, high molecular weight (HMW) adiponectin, total IgG, total IgA, total IgM, endotoxin core antibodies (EndoCAbs), 25(OH) vitamin D, vitamin D binding protein, IL-7, IL-10, IFN-γ, TNF-α, IL-17A, IL-18, and IL-18BPa. Subjects also were tested for prevalence of antibodies targeting adenovirus, parainfluenza 1/2/3, Coxsackievirus, cytomegalovirus, Epstein-Barr virus viral capsid antigen (EBV VCA), herpes simplex virus 1, and Saccharomyces cerevisiae. Finally, all subjects were screened for presence and abundance of autoantibodies targeting islet cell cytoplasmic proteins (ICA), glutamate decarboxylase 2 (GAD65), zinc transporter 8 (ZNT8), insulinoma antigen 2 (IA-2), tissue transglutaminase, and thyroid peroxidase, while β cell function was gauged by measuring c-peptide levels. We observed few differences between control and T1D subjects. Of these, we found elevated sCD14, IL-18BPa, and FABP2, and reduced total IgM. Female T1D subjects were notably elevated in CRP levels compared to control, while males were similar. T1D subjects also had significantly lower prevalence of EBV VCA antibodies compared to control. Lastly, we observed that c-peptide levels were significantly correlated with leptin levels among controls, but this relationship was not significant among T1D subjects. Alternatively, adiponectin levels were significantly correlated with c-peptide levels among T1D subjects, while controls showed no relationship between these two factors. Among T1D subjects, the highest c-peptide levels were associated with the lowest adiponectin levels, an indication of insulin resistance. In total, from our examination we found limited data that strongly support any of the hypotheses investigated. Rather, we observed an indication of unexplained monocyte/macrophage activation in T1D subjects judging from elevated levels of sCD14 and IL-18BPa. These observations were partnered with unique associations between adipokines and c-peptide levels among T1D subjects.

Gingival crevicular fluid levels of interleukin-18 and tumor necrosis factor-alpha in type 1 diabetic children with gingivitis

OBJECTIVE

This study aimed to evaluate the levels of interleukin-18 and tumor necrosis factor-alpha in gingival crevicular fluid of diabetic children with gingivitis.

METHODOLOGY

Eighty-eight children (44 with type 1 diabetes mellitus and 44 systemically healthy) were recruited for the study. The children were divided into four subgroups based on their periodontal and systemic condition: (1) systemically and periodontally healthy children (H), (2) systemically healthy children with gingivitis (G), (3) periodontally healthy children with T1DM (T1DM + H), and (4) children with T1DM and gingivitis (T1DM + G). The plaque index, gingival index, probing pocket depth, and GCF volume were recorded. The IL-18 and TNF-α levels in GCF were determined by ELISA.

RESULTS

The clinical periodontal parameters, GCF IL-18 level, and TNF-α level were similar between diabetic and systemically healthy children (p > 0.05). The gingivitis subgroups had a significantly higher GI, PI, PPD, GCF volume, and TNF-α total amounts than the H subgroups (p < 0.0001). The IL-18 concentrations in the gingivitis subgroups were significantly lower than in the periodontally healthy subgroups.

CONCLUSIONS

In diabetic children with good metabolic control, T1DM did not affect the GCF levels of IL-18 and TNF-α in the presence of gingivitis. However, increased GCF TNF-α levels in children with gingivitis confirm that TNF-α is closely related to gingival inflammation.

CLINICAL RELEVANCE

Type 1 diabetes mellitus is not associated with GCF interleukin-18 and tumor necrosis factor-alpha levels in children with gingivitis.

Innate inflammation drives NK cell activation to impair Treg activity

IL-12 and IL-18 synergize to promote T_H1 responses and have been implicated as accelerators of autoimmune pathogenesis in type 1 diabetes (T1D). We investigated the influence of these cytokines on immune cells involved in human T1D progression: natural killer (NK) cells, regulatory T cells (Tregs), and cytotoxic T lymphocytes (CTL). NK cells from T1D patients exhibited higher surface CD226 versus controls and lower CD25 compared to first-degree relatives and controls. Changes in NK cell phenotype towards terminal differentiation were associated with cytomegalovirus (CMV) seropositivity, while possession of IL18RAP, IFIH1, and IL2RA T1D-risk variants impacted NK cell activation as evaluated by immuno-expression quantitative trait loci (eQTL) analyses. IL-12 and IL-18 stimulated NK cells from healthy donors exhibited enhanced specific killing of myelogenous K562 target cells. Moreover, activated NK cells increased expression of NKG2A, NKG2D, CD226, TIGIT and CD25, which enabled competition for IL-2 upon co-culture with Tregs, resulting in Treg downregulation of FOXP3, production of IFNγ, and loss of suppressive function. We generated islet-autoreactive CTL "avatars", which upon exposure to IL-12 and IL-18, upregulated IFNγ and Granzyme-B leading to increased lymphocytotoxicity of a human β-cell line in vitro. These results support a model for T1D pathogenesis wherein IL-12 and IL-18 synergistically enhance CTL and NK cell cytotoxic activity and disrupt immunoregulation by Tregs.

IL-1 Family Members Mediate Cell Death, Inflammation and Angiogenesis in Retinal Degenerative Diseases

Inflammation underpins and contributes to the pathogenesis of many retinal degenerative diseases. The recruitment and activation of both resident microglia and recruited macrophages, as well as the production of cytokines, are key contributing factors for progressive cell death in these diseases. In particular, the interleukin 1 (IL-1) family consisting of both pro- and anti-inflammatory cytokines has been shown to be pivotal in the mediation of innate immunity and contribute directly to a number of retinal degenerations, including Age-Related Macular Degeneration (AMD), diabetic retinopathy, retinitis pigmentosa, glaucoma, and retinopathy of prematurity (ROP). In this review, we will discuss the role of IL-1 family members and inflammasome signaling in retinal degenerative diseases, piecing together their contribution to retinal disease pathology, and identifying areas of research expansion required to further elucidate their function in the retina.

Interleukin-18 and diabetic nephropathy: A review

The inflammatory response has an important role in the pathophysiology of diabetic nephropathy that is contributed to by inflammatory mediators such as interleukin-1 (IL-1), IL-6, IL-18, tumor necrosis factor-α, and macrophage chemotactic protein-1; however, the role of IL-18 seems to be more specific than other cytokines in the inflammatory process. IL-18 is expressed in renal tissue and is upregulated by several stimuli including hyperglycemia. The expression/urinary level of IL-18 is positively correlated with the progression of diabetic nephropathy and the urinary albumin excretion rate. In this review, we have focused on the molecular pathways modulating the relationship between IL-18 and diabetic nephropathy.

Interleukin-18 serum level is elevated in type 2 diabetes and latent autoimmune diabetes

BACKGROUND

Interleukin-18 (IL-18) is an inflammatory cytokine found to be elevated in obesity, metabolic syndrome and type 2 diabetes (T2D) as a part of the chronic low-grade inflammatory process in these states. The aim of the study was to evaluate the interleukin level in patients with latent autoimmune diabetes of the adults (LADA) in comparison to that in T2D subjects.

MATERIALS AND METHODS

IL-18 was analyzed through enzyme-linked immunosorbent assay in 76 participants with T2D and 24 with LADA and 14 control subjects. Evaluation was also carried out in body mass index (BMI)- and glycemic control-matched diabetic patients.

RESULTS

The serum concentration of IL-18 was higher in patients with T2D (389.04 ± 203.44 pg/mL) and LADA (327.04 ± 144.48 pg/mL) than that in control subjects (219.88 ± 91.03 pg/mL), P < 0.05. However, it was not significantly different between both diabetic groups (P = 0.255) despite higher IL-6 (4.78 ± 5.84 vs 1.79 ± 0.96 pg/mL, P < 0.001) and hs-CRP (2.60 ± 1.70 vs 1.29 ± 1.20 mg/L, P = 0.002) level in T2D patients. The results were persistent in BMI-matched subjects with diabetes (IL-18 = 403.48 ± 226.32 vs 329.30 ± 146.30 pg/mL, respectively for T2D and LADA, P = 0.391). The correlations in T2D group concerning HDL cholesterol (r = -0.377, P = 0.001), postprandial glucose (r = 0.244, P = 0.043), IL-6 (r = 0.398, P < 0.001) and hs-CRP (r = 0.427, P = 0.001) were not confirmed in LADA and control subjects.

CONCLUSION

The IL-18 serum level was higher in T2D and LADA than that in control subjects, but did not differ between both diabetic groups, even when they were BMI matched. Correlations with lipid, glycemic and inflammatory parameters were present in T2D only.

Per os colchicine administration in cholesterol fed rabbits: Triglycerides lowering effects without affecting atherosclerosis progress

BACKGROUND

Atherosclerosis is a chronic inflammatory disease that is promoted, among others, by pro-inflammatory cytokines such as IL-1β and IL-18 produced by NLRP 3 inflammasome. Development of atherosclerotic lesions is also affected by leptin. Furthermore, inflammasome's action is interfered with other inflammatory diseases, like diabetes. On the other hand, colchicine is reported to act as anti-inflammatory agent inhibiting inflammasome's action and stabilizing atherosclerotic lesions. The purpose of this study is to investigate the effect of per os colchicine on the de novo formation of atherosclerotic lesions and on the levels of IL-18, leptin and insulin in cholesterol-fed rabbits.

METHODS

Twenty-three male, 2 months old New Zealand White rabbits, were seperated in 3 groups and were fed with different types of diet for 7 weeks: standard, cholesterol 1% w/w and cholesterol 1% w/w plus colchicine 2 mg/kg body weight. Blood was collected for biochemical measurements and conduction of ELISA for leptin, IL-18 and insulin. Histologic examination of stained with eosin and hematoxylin aorta specimens was performed. Aortic intimal thickness was evaluated using image analysis. The statistical analysis included non-parametric tests: a) paired-sample Wilcoxon test, b) Spearman correlation coefficient and c) Kruscal-Wallis test.

RESULTS

Triglerycide levels were decreased in cholesterol plus colchicine group in the end of the experiment (p < 0.05), whereas the cholesterol group had increased levels. No statistical differences were observed in the levels of IL-18, leptin and insulin between groups. Likewise, there was neither any correlation between IL-18, leptin and intima thickness nor between IL-18 and glucose and between leptin and weight. In cholesterol and colchicine group there was a strong positive correlation between IL-18 and insulin levels in the 4th week (r s = .66, n = 10, p < 0.05), whereas in the 7th week this correlation became strong negative (r s = -.86, n = 10, p < 0.05). Finally, intima thickness in the ascending and thoracic aorta of the cholesterol and colchicine group was significantly greater than that of the other groups (p < 0.05).

CONCLUSIONS

Per os administration of colchicine did not influence atherosclerosis progression in cholesterol-fed rabbits, levels of IL-18, insulin and leptin. We encountered the attenuating role of colchicine on TG levels.

The Four-Way Stop Sign: Viruses, 12-Lipoxygenase, Islets, and Natural Killer Cells in Type 1 Diabetes Progression

Natural killer (NK) cells represent an important effector arm against viral infection, and mounting evidence suggests that viral infection plays a role in the development of type 1 diabetes (T1D) in at least a portion of patients. NK cells recognize their target cells through a delicate balance of inhibitory and stimulatory receptors on their surface. If unbalanced, NK cells have great potential to wreak havoc in the pancreas due to the beta cell expression of the as-yet-defined NKp46 ligand through interactions with the activating NKp46 receptor found on the surface of most NK cells. Blocking interactions between NKp46 and its ligand protects mice from STZ-induced diabetes, but differential expression non-diabetic and diabetic donor samples have not been tested. Additional studies have shown that peripheral blood NK cells from human T1D patients have altered phenotypes that reduce the lytic and functional ability of the NK cells. Investigations of humanT1D pancreas tissues have indicated that the presence of NK cells may be beneficial despite their infrequent detection. In non-obese diabetic (NOD) mice, we have noted that NK cells express high levels of the proinflammatory mediator 12/15-lipoxygenase (12/15-LO), and decreased levels of stimulatory receptors. Conversely, NK cells of 12/15-LO deficient NOD mice, which are protected from diabetes development, express significantly higher levels of stimulatory receptors. Furthermore, the human NK92 cell line expresses the ALOX12 protein [human 12-lipoxygenase (12-LO), related to mouse 12/15-LO] via Western blotting. Human 12-LO is upregulated in the pancreas of both T1D and T2D human donors with insulin-containing islets, showing a link between 12-LO expression and diabetes progression. Therefore, our hypothesis is that NK cells in those susceptible to developing T1D are unable to function properly during viral infections of pancreatic beta cells due to increased 12-LO expression and activation, which contributes to increased interferon-gamma production and an imbalance in activating and inhibitory NK cell receptors, and may contribute to downstream autoimmune T cell responses. The work presented here outlines evidence from our lab, as well as published literature, supporting our hypothesis, including novel data.

Cytokines of the IL-1 family: recognized targets in chronic inflammation underrated in organ transplantations

Interleukin 1 (IL-1) family is a group of cytokines with multiple local and systemic effects, which regulates both innate and adaptive immune responses. Generally, most IL-1 family cytokines express prevailing pro-inflammatory activities (IL-1α, IL-1β, IL-18, IL-33, IL-36 α, β, γ), whereas others are anti-inflammatory (IL-1Ra (IL-1 receptor antagonist), IL-36Ra, IL-38, IL-37). In addition to their immunomodulatory roles, some of them are also involved in the physiological modulation of homeostatic processes and directly affect mRNA transcription. IL-1 family cytokines bind to specific receptors composed of a ligand-binding chain and an accessory chain. The pro-inflammatory effects of IL-1 family cytokines are regulated on the level of transcription, enzymatic processing of precursors, release of soluble antagonists, and expression of decoy receptors. Members of the IL-1 family regulate the recruitment and activation of effector cells involved in innate and adaptive immunity, but they are also involved in the pathogenesis of chronic disorders, including inflammatory bowel disease, rheumatoid arthritis, and various autoimmune and autoinflammatory diseases. There are only limited data regarding the role of IL-1 cytokines in transplantation. In recent years, targeted therapeutics affecting IL-1 have been used in multiple clinical studies. In addition to the recombinant IL-1Ra, anakinra (highly effective in autoinflammatory diseases and tested for other chronic diseases), the monoclonal antibodies canakinumab, gevokizumab, and rilonacept (a long-acting IL-1 receptor fusion protein) provide further options to block IL-1 activity. Furthermore, new inhibitors of IL-18 (GSK 1070806, ABT-325, rIL-18BP (IL-18 binding protein)) and IL-33 (CNTO-7160) are presently under clinical studies and other molecules are being developed to target IL-1 family cytokines.

The role of IL-18 in type 1 diabetic nephropathy: The problem and future treatment

Diabetic vascular complication is a leading cause of diabetic nephropathy, a progressive increase in urinary albumin excretion coupled with elevated blood pressure leading to declined glomerular filtration and eventually end stage renal failure. There is growing evidence that activated inflammation is contributing factor to the pathogenesis of diabetic nephropathy. Meanwhile, IL-18, a member of the IL-1 family of inflammatory cytokines, is involved in the development and progression of diabetic nephropathy. However, the benefits derived from the current therapeutics for diabetic nephropathy strategies still provide imperfect protection against renal progression. This imperfection points to the need for newer therapeutic agents that have potential to affect primary mechanisms contributing to the pathogenesis of diabetic nephropathy. Therefore, the recognition of IL-18 as significant pathogenic mediators in diabetic nephropathy leaves open the possibility of new potential therapeutic targets.

The Role of Markers of Low-Grade Inflammation for the Early Time Course of Glycemic Control, Glucose Disappearance Rate, and β-Cell Function in Recently Diagnosed Type 1 and Type 2 Diabetes

OBJECTIVE

Inflammatory processes are involved in the progression of insulin resistance and β-cell dysfunction in individuals with prediabetes and contribute to the development of diabetes. We hypothesized that higher levels of biomarkers of low-grade inflammation are associated with the early progression of recently diagnosed diabetes.

RESEARCH DESIGN AND METHODS

Within the prospective German Diabetes Study, patients with recently diagnosed type 1 (n = 42) and type 2 (n = 94) diabetes underwent detailed metabolic characterization within the first year after diagnosis and 2 years thereafter. Associations between changes in markers of low-grade inflammation with changes in glycemic control, β-cell function, and glucose disappearance rate were assessed using multivariable linear regression analysis. Associations were adjusted for age, sex, BMI, smoking status, and 2-year changes in BMI, smoking status, and glucose-lowering medication.

RESULTS

Patients with type 1 and type 2 diabetes exhibited good glucometabolic control at baseline (mean HbA1c 7.08 ± 1.58% [54 ± 17 mmol/mol] and 6.43 ± 0.98% [47 ± 11 mmol/mol], respectively) and 2 years thereafter (mean HbA1c 7.03 ± 1.20% [53 ± 13 mmol/mol] and 6.62 ± 1.14% [49 ± 13], respectively). Two-year increases of high-sensitivity C-reactive protein, soluble E-selectin (sE-selectin), and soluble intercellular adhesion molecule-1 in type 2 diabetes and of IL-18 in type 1 diabetes were associated with 2-year increases of HbA1c. Additionally, 2-year increases of sE-selectin were associated with 2-year decreases of prehepatic β-cell function in type 2 diabetes (all P < 0.05).

CONCLUSIONS

These data indicate that with the clinical onset of diabetes, low-grade inflammation relates to worsening of glycemia and that endothelial activation may contribute to decreasing β-cell function.

Elevated levels of serum IL-12 and IL-18 are associated with lower frequencies of CD4(+)CD25 (high)FOXP3 (+) regulatory t cells in young patients with type 1 diabetes

Type 1 diabetes is thought to involve chronic inflammation, which is manifested by the activation and expression of different inflammatory mediators. IL-12 and IL-18 are two cytokines that have been shown to exert strong proinflammatory activity and have been implicated in the pathogenesis of type 1 diabetes in mice and humans. The overproduction of proinflammatory mediators is controlled by specialized T cell subset, namely regulatory T cells that express FOXP3 transcription factor. Since IL-12 and IL-18 mediate inflammatory response and Tregs exhibit anti-inflammatory potential, we aimed to examine their reciprocal relationship in patients with type 1 diabetes. The study group consisted of 47 children diagnosed with type 1 diabetes and 28 healthy individuals. Serum levels of IL-12 and IL-18 were measured by ELISA, and the peripheral blood CD4⁺CD25^high FOXP3⁺ regulatory T cell frequencies were analyzed by flow cytometry. Patients with type 1 diabetes had a decreased percentage of circulating CD4⁺CD25^highFOXP3⁺ Tregs in comparison to their healthy counterparts. In addition, they produced more IL-12 and IL-18 than children from the control group. Concentrations of these cytokines positively correlated with one another, as well as with CRP and HbA1c. Moreover, the negative association between IL-12, IL-18, CRP serum levels, and the frequency of regulatory CD4⁺CD25^highFOXP3⁺ Tregs was observed. IL-12 and IL-18 may have direct or indirect impact on regulatory T cell subset, which may contribute to their reduced frequency in peripheral blood of patients with type 1 diabetes mellitus.

Noncoding RNAs, cytokines, and inflammation-related diseases

Chronic inflammation is involved in the onset and development of many diseases, including obesity, atherosclerosis, type 2 diabetes, osteoarthritis, autoimmune and degenerative diseases, asthma, periodontitis, and cirrhosis. The inflammation process is mediated by chemokines, cytokines, and different inflammatory cells. Although the molecules and mechanisms that regulate this primary defense mechanism are not fully understood, recent findings offer a putative role of noncoding RNAs, especially microRNAs (miRNAs), in the progression and management of the inflammatory response. These noncoding RNAs are crucial for the stability and maintenance of gene expression patterns that characterize some cell types, tissues, and biologic responses. Several miRNAs, such as miR-126, miR-132, miR-146, miR-155, and miR-221, have emerged as important transcriptional regulators of some inflammation-related mediators. Additionally, little is known about the involvement of long noncoding RNAs, long intergenic noncoding RNAs, and circular RNAs in inflammation-mediated processes and the homeostatic imbalance associated with metabolic disorders. These noncoding RNAs are emerging as biomarkers with diagnosis value, in prognosis protocols, or in the personalized treatment of inflammation-related alterations. In this context, this review summarizes findings in the field, highlighting those noncoding RNAs that regulate inflammation, with emphasis on recognized mediators such as TNF-α, IL-1, IL-6, IL-18, intercellular adhesion molecule 1, VCAM-1, and plasminogen activator inhibitor 1. The down-regulation or antagonism of the noncoding RNAs and the administration of exogenous miRNAs could be, in the near future, a promising therapeutic strategy in the treatment of inflammation-related diseases.

Altered CD161 bright CD8+ mucosal associated invariant T (MAIT)-like cell dynamics and increased differentiation states among juvenile type 1 diabetics

Type 1A diabetes (T1D) is believed to be caused by immune-mediated destruction of β-cells, but the immunological basis for T1D remains controversial. Microbial diversity promotes the maturation and activation of certain immune subsets, including CD161^bright CD8⁺ mucosal associated invariant T (MAIT) cells, and alterations in gut mucosal responses have been reported in type 1 diabetics (T1Ds). We analyzed T cell populations in peripheral blood leukocytes from juvenile T1Ds and healthy controls. We found that proportion and absolute number of MAIT cells were similar between T1Ds and controls. Furthermore, while MAIT cell proportions increased with age among healthy controls, this trend was not observed among long-standing T1Ds. Additionally, the CD27- MAIT cell subset is significantly increased in T1Ds and positively correlated with HbA1c levels. However, after T1Ds are stratified by age, the younger group has significantly increased proportions of CD27- MAIT cells compared to age-matched controls, and this proportional increase appears to be independent of HbA1c levels. Finally, we analyzed function of the CD27- MAIT cells and observed that IL-17A production is increased in CD27- compared to CD27⁺ MAIT cells. Overall, our data reveal disparate MAIT cell dynamics between T1Ds and controls, as well as signs of increased MAIT cell activation in T1Ds. These changes may be linked to hyperglycemia and increased mucosal challenge among T1Ds.

Increased expression of IL-18 in the serum and islets of type 1 diabetics

Type 1 diabetes (T1D) is a chronic disease characterized by autoimmune-mediated destruction of pancreatic insulin-producing beta cells. Interleukin (IL)-18 is a pro-inflammatory cytokine implicated in the pathogenesis of a number of inflammatory diseases. Here, we analyzed IL-18 levels in the plasma of juveniles with T1D. Compared to control subjects, IL-18 levels were significantly elevated in patients with T1D. On the other hand, levels of IL-18 binding protein (IL-18BP) and IL-37, two negative regulators of IL-18 function, remained unchanged when comparing T1D to control samples. Notably, however, although IL-18BP levels were not elevated, IL-18 and IL-18BP were found to be positively correlated in type 1 diabetics. Even so, free, unbound IL-18 remained significantly increased in diabetic patients. Additionally, correlation studies also revealed that IL-18 and IL-18BP are positively correlated with HbA1c levels in T1D patients, suggesting a potential link between IL-18 and metabolic control in these patients. Finally, we observed a significant increase in IL-18 protein expression within human pancreatic islet specimens collected from type 1 diabetics. These results further expand our knowledge of the role of IL-18 in T1D, may give insight into common pathogenic mechanisms associated with metabolic control in both T1D and T2D, and suggest that targeting this cytokine may improve therapeutic outcomes for T1D patients.

High serum concentration of interleukin-18 in diabetic patients with foot ulcers

BACKGROUND

It is well known that interleukin-18 (IL-18) plays a key role in the inflammatory process. However, there are limited data on the role IL-18 plays with diabetic foot ulcers, an acute and complex inflammatory situation. Therefore, we aimed to evaluate serum IL-18 levels of diabetic patients with foot ulcers.

METHODS

Twenty diabetic patients with acute foot ulcers, 21 diabetic patients without a history of foot ulcers, and 21 healthy volunteers were enrolled in our study. Circulating levels of IL-18, and other biochemical markers are parameters of inflammation and were measured in all three groups.

RESULTS

Diabetic patients both with and without foot ulcers had high IL-18 concentrations (P < 0.001 and P = 0.020, respectively) when compared with the nondiabetic volunteers. Those with foot ulcers had higher levels of IL-18 level (P < 0.001), high-sensitivity C-reactive protein (hsCRP) (P = 0.001), and erythrocyte sedimentation rate (ESR) (P < 0.001) than those without foot ulcers.

CONCLUSIONS

We found that serum IL-18 concentrations were elevated in diabetic patients with acute diabetic foot ulcers. However, these findings do not indicate whether the IL-18 elevation is a cause or a result of the diabetic foot ulceration. Further studies are needed to show the role of IL-18 in the course of these ulcers.

Cytokine networking of innate immunity cells: a potential target of therapy

Innate immune cells, particularly macrophages and epithelial cells, play a key role in multiple layers of immune responses. Alarmins and pro-inflammatory cytokines from the IL (interleukin)-1 and TNF (tumour necrosis factor) families initiate the cascade of events by inducing chemokine release from bystander cells and by the up-regulation of adhesion molecules required for transendothelial trafficking of immune cells. Furthermore, innate cytokines produced by dendritic cells, macrophages, epithelial cells and innate lymphoid cells seem to play a critical role in polarization of helper T-cell cytokine profiles into specific subsets of Th1/Th2/Th17 effector cells or regulatory T-cells. Lastly, the innate immune system down-regulates effector mechanisms and restores homoeostasis in injured tissue via cytokines from the IL-10 and TGF (transforming growth factor) families mainly released from macrophages, preferentially the M2 subset, which have a capacity to induce regulatory T-cells, inhibit the production of pro-inflammatory cytokines and induce healing of the tissue by regulating extracellular matrix protein deposition and angiogenesis. Cytokines produced by innate immune cells represent an attractive target for therapeutic intervention, and multiple molecules are currently being tested clinically in patients with inflammatory bowel disease, rheumatoid arthritis, systemic diseases, autoinflammatory syndromes, fibrosing processes or malignancies. In addition to the already widely used blockers of TNFα and the tested inhibitors of IL-1 and IL-6, multiple therapeutic molecules are currently in clinical trials targeting TNF-related molecules [APRIL (a proliferation-inducing ligand) and BAFF (B-cell-activating factor belonging to the TNF family)], chemokine receptors, IL-17, TGFβ and other cytokines.

IL-18 in inflammatory and autoimmune disease

Inflammation serves as the first line of defense in response to tissue injury, guiding the immune system to ensure preservation of the host. The inflammatory response can be divided into a quick initial phase mediated mainly by innate immune cells including neutrophils and macrophages, followed by a late phase that is dominated by lymphocytes. Early in the new millennium, a key component of the inflammatory reaction was discovered with the identification of a number of cytosolic sensor proteins (Nod-like receptors) that assembled into a common structure, the 'inflammasome'. This structure includes an enzyme, caspase-1, which upon activation cleaves pro-forms of cytokines leading to subsequent release of active IL-1 and IL-18. This review focuses on the role of IL-18 in inflammatory responses with emphasis on autoimmune diseases.

Leptin enhances the secretion of interleukin (IL)-18, but not IL-1β, from human monocytes via activation of caspase-1

Circulating levels of leptin are elevated in type-2 diabetes mellitus (T2DM) and leptin plays a role in immune responses. Elevated circulating IL-18 levels are associated with clinical complications of T2DM. IL-18 regulates cytokine secretion and the function of a number of immune cells including T-cells, neutrophils and macrophages and as such has a key role in immunity and inflammation. Pro-inflammatory monocytes exhibiting elevated cytokine secretion are closely associated with inflammation in T2DM, however, little is known about the role of leptin in modifying monocyte IL-18 secretion. We therefore aimed to investigate the effect of leptin on IL-18 secretion by monocytes. We report herein that leptin increases IL-18 secretion in THP-1 and primary human monocytes but has no effect on IL-18mRNA. Leptin and LPS signalling in monocytes occurs by overlapping but distinct pathways. Thus, in contrast to a strong stimulation by LPS, leptin has no effect on IL-1βmRNA levels or IL-1β secretion. In addition, LPS stimulates the secretion of IL-6 but leptin did not whereas both treatments up regulate IL-8 secretion from the same cells. Although leptin (and LPS) has a synergistic effect with exogenous ATP on IL-18 secretion in both THP-1 and primary monocytes, experiments involving ATP assays and pharmacological inhibition of ATP signalling failed to provide any evidence that endogenous ATP secreted by leptin-stimulated monocytes was responsible for enhancement of monocyte IL-18 secretion by leptin. Analysis of the action of caspase-1 revealed that leptin up regulates caspase-1 activity and the effect of leptin on IL-18 release is prevented by caspase-1 inhibitor (Ac-YVAD-cmk). These data suggest that leptin activates IL-18 processing rather than IL-18 transcription. In conclusion, leptin enhances IL-18 secretion via modulation of the caspase-1 inflammasome function and acts synergistically with ATP in this regard. This process may contribute to aberrant immune responses in T2DM and other conditions of hyperleptinemia.

Detection of expression of IL-18 and its binding protein in Egyptian pediatric immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is an autoimmune disorder, characterized by dysfunctional cellular immunity including the presence of activated platelet specific autoreactive T cells that recognize and respond to autologous platelet antigens. Autoreactive T cells drive the generation of platelet reactive autoantibodies by B cells as well as T-cytotoxic cell-mediated lysis of platelets. Interleukin-18 (IL-18) is a mediator of T helper type 1 cell responses synergistically with IL-12 that initiate and promote host defense and inflammation. IL-18 has a specific binding protein (IL-18BP) which belongs to the immunoglobulin superfamily. In the present study, serum level and messenger RNA( mRNA) expression of IL-18 as well as IL-18BP mRNA expression were measured in peripheral blood mononuclear cells (PBMNCs) of 100 Egyptian pediatric patients with ITP (70 acute and 30 chronic). In addition to this, we recruited 80 healthy volunteers in order to investigate the possible association between the imbalance of IL-18 and IL-18 BP expressions and the pathogenesis of ITP. IL-18 serum level and mRNA expression were not elevated in cases more than in the control group, but IL-18 mRNA was higher in chronic cases when compared to the acute ones (p=0.031) and there was a good negative correlation between the platelet count and serum IL-18. IL-18 BP m-RNA was slightly elevated in cases more than in the control group (95% Confidence interval=1.15-2.01). Our results were not supportive for previous findings of elevated IL18/BP mRNA ratio in ITP patients. This could be referred to the fact that autoimmune diseases are complex genetic disorders, therefore further studies on polymorphisms affecting IL-18 gene expression as well as kinetics of IL-18 expression are required to evaluate the role of interleukin 18 and its binding protein in the pathogenesis of ITP.

Polymorphisms in the IL-18 and IL-12B genes and their association with the clinical outcome in Croatian patients with Type 1 diabetes

Genetic variants of IL-18 and IL-12B may be important in immunoregulatory abnormalities, observed in the patients with Type 1 diabetes mellitus (T1DM), that contribute to individual differences in response to a treatment. Therefore, we examined the significance of IL-18-137G/C, IL-18-607C/A, and IL-12B A/C polymorphisms in Croatians (187 patients, 236 controls), not only as factors that contribute to susceptibility to T1DM, but also as determinants of the clinical presentation of disease. The polymorphism screening has been performed using PCR sequence-specific primers (IL-18) or PCR-RFLP (IL-12B) approach. Results were evaluated by GraphPad Prism and Sigma Stat 3.5, Arlequin software and calculator for Hardy-Weinberg equilibrium. The genotype, allele and haplotype distribution were not statistically different between the patients and control subjects. The clinical parameter analysis revealed that patients with minor alleles at each locus, IL-18-137C/-607A, were significantly younger at T1DM onset than carriers of major alleles, IL-18-137G/-607C (20 vs 23.5 years). Moreover, the concomitant presence of minor alleles not only of IL-18 but also of IL-12B, is associated with the risk of disease progression even at younger age. These patients developed diabetes at 16 years of age, what is significantly earlier (p=0.044) compared to 25.5 years of age in patients with common alleles IL-18-137G/-607C/IL-12B A. Furthermore, combined genotype analysis of IL-18 and IL-12B has pointed out that patients with CC/AA/AA genotype have the worst glucose control based on HbA1c (8.7%, range 6.8-13.1%). In conclusion, susceptibility to T1DM in Croatians is not strongly associated with IL-18-137/-607 and IL-12B polymorphisms. These SNPs are associated with the higher risk of earlier disease development and might be implicated in the effectiveness of glycemic control.

Novel identified receptors on mast cells

Mast cells (MC) are major participants in the allergic reaction. In addition they possess immunomodulatory roles in the innate and adaptive immune reactions. Their functions are modulated through a number of activating and inhibitory receptors expressed on their surface. This review deals with some of the most recently described receptors, their expression patterns, ligand(s), signal transduction mechanisms, possible cross-talk with other receptors and, last but not least, regulatory functions that the MC can perform based on their receptor expression in health or in disease. Where the receptor role on MC is still not clear, evidences from other hematopoietic cells expressing them is provided as a possible insight for their function on MC. Suggested strategies to modulate these receptors’ activity for the purpose of therapeutic intervention are also discussed.

Young patients with both type 1 diabetes mellitus and asthma have a unique IL-12 and IL-18 secretory pattern

BACKGROUND

The expression of the regulatory cytokines interleukin (IL)-12 and IL-18 in patients with both Th1- and Th2-mediated diseases, type 1 diabetes mellitus (T1DM) and asthma, is unknown.

OBJECTIVE

To investigate the in vivo and in vitro IL-12 and IL-18 secretion patterns in patients with both T1DM and asthma.

METHODS

Peripheral blood mononuclear cells (PBMC) were collected from 44 patients. Mean age 19.4 ± 4.7 yr (10.5-28 yr), divided into four paired groups: T1DM and asthma, asthma only, T1DM only, and healthy controls. T-cell proliferative response was assessed. IL-12 and IL-18 serum levels and expression by PBMC following in vitro stimulation by lipopolysaccharide (LPS) were determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Patients with T1DM and asthma had higher serum levels of both IL-12 and IL-18 compared to controls: 146.2 ± 69.2 and 109.7 ± 34.6 pg/mL, p = 0.038 and 436.1 ± 117.9, 320.2 ± 99.1 pg/mL, p = 0.028, respectively. Stimulated IL-12 secretion was significantly lower in these patients compared to those with one disease only: 809 ± 426.4, 2111.6 ± 2214.3, 3188.1 ± 2692.9 pg/mL and after 48 h: 956.3 ± 489.3, 2429.8 ± 2394.6, 3874.5 ± 2820.3 pg/mL, respectively, p < 0.03 for all. The IL-18/IL-12 serum ratio was also significantly higher in patients with both diseases compared to those with asthma only, p = 0.017.

CONCLUSION

Patients with both T1DM and asthma display a different pattern of IL-12 and IL-18 expression compared to patients with one disease only and controls.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

Relationship between oxidative stress and inflammatory cytokines in diabetic nephropathy

The prevalence of diabetes has dramatically increased worldwide due to the vast increase in the obesity rate. Diabetic nephropathy is one of the major complications of type 1 and type 2 diabetes and it is currently the leading cause of end-stage renal disease. Hyperglycemia is the driving force for the development of diabetic nephropathy. It is well known that hyperglycemia increases the production of free radicals resulting in oxidative stress. While increases in oxidative stress have been shown to contribute to the development and progression of diabetic nephropathy, the mechanisms by which this occurs are still being investigated. Historically, diabetes was not thought to be an immune disease; however, there is increasing evidence supporting a role for inflammation in type 1 and type 2 diabetes. Inflammatory cells, cytokines, and profibrotic growth factors including transforming growth factor-β (TGF-β), monocyte chemoattractant protein-1 (MCP-1), connective tissue growth factor (CTGF), tumor necrosis factor-α (TNF-α), interleukin-1 (IL-1), interleukin-6 (IL-6), interleukin-18 (IL-18), and cell adhesion molecules (CAMs) have all been implicated in the pathogenesis of diabetic nephropathy via increased vascular inflammation and fibrosis. The stimulus for the increase in inflammation in diabetes is still under investigation; however, reactive oxygen species are a primary candidate. Thus, targeting oxidative stress-inflammatory cytokine signaling could improve therapeutic options for diabetic nephropathy. The current review will focus on understanding the relationship between oxidative stress and inflammatory cytokines in diabetic nephropathy to help elucidate the question of which comes first in the progression of diabetic nephropathy, oxidative stress, or inflammation.

Association of polymorphisms in the IL-18 and IL-12 genes with susceptibility to Type 1 diabetes in Turkish patients

BACKGROUND

Recent studies have indicated that polymorphisms of the interleukin-18 (IL-18) and interleukin- 12 (IL-12) genes are associated with the development of Type 1 diabetes mellitus (T1DM) in some populations, but not all.

AIM

The present study was designed to examine the roles of polymorphisms in the IL-18 promoter and IL-12p40 with respect to susceptibility to T1DM in Turkish patients.

SUBJECTS AND METHODS

Ninety-one patients with T1DM and 87 unrelated healthy subjects were included in the study. The IL-18 polymorphisms at positions -607 and -137 were detected by a sequence-specific PCR method. The single nucleotide polymorphism in the IL-12p40 3' untranslated region (3'-UTR) at position +1188 was analyzed by the PCR-restriction fragment length polymorphism (RFPL) method.

RESULTS

The allelic and genotypic frequencies of the IL-18 and IL-12p40 polymorphisms did not differ significantly between subjects with T1DM and the controls (p>0.05). However, diabetic patients with the -137 (CC) genotype showed a younger onset age compared to patients with the -137 (GG) genotype (p=0.02). In addition, patients with the -607 (CC) genotype had higher levels of glycated hemoglobin (HbA1c) than patients with the -607 (AC) genotype (p=0.004). Furthermore, patients with the IL-12p40 (AC) genotype had higher HbA(1c) levels than patients with the IL-12p40 (AA) genotype (p=0.01).

CONCLUSIONS

The results of the present study show that the IL- 18 and IL-12p40 polymorphisms may have some effect on the onset age and deterioration of glycemic control in Turkish patients with T1DM.

High expression of the ectonucleotidase CD39 on T cells from the inflamed site identifies two distinct populations, one regulatory and one memory T cell population

The ectonucleotidase CD39 has recently been described as being highly expressed on regulatory Foxp3(+) CD4 T cells. Through hydrolysis of proinflammatory extracellular ATP, CD39 activity represents a newly described mechanism of regulatory T cell action. We report a novel population of human CD4 T cells that express CD39 yet are Foxp3 negative. These cells produce the proinflammatory cytokines IFN-gamma and IL-17 and fail to suppress proliferation; however, they still have high ATP hydrolysis activity. In the inflammatory site in human juvenile idiopathic arthritis, the CD39(+)Foxp3(-) population is greatly increased compared with peripheral blood of patients or healthy controls. We also show that cells expressing the AMPase CD73 are less frequent in the joint than in blood. To our knowledge, this is the first study to describe and characterize CD39 function on CD4 T cells from the target site in a human autoinflammatory condition. Our data suggest that in human CD4(+) T cells from the inflamed site, CD39 can be highly expressed on two populations, one regulatory and the other of a memory phenotype.

Perinatal systemic inflammatory response syndrome and retinopathy of prematurity

Fetal and neonatal inflammation is associated with several morbidities of prematurity. Its relationship to retinopathy of prematurity (ROP) has not been investigated. Our objective was to determine the relationship between cytokine levels and ROP in the first 3 postnatal wks. Data for this study were derived from the NICHD Cytokine Study. Dried blood spots (DBS) were obtained from infants <1000 g on days 0-1, 3 +/- 1, 7 +/- 2, 14 +/- 3, and 21 +/- 3. Infants were classified into three groups-no, mild, and severe ROP. Multiplex Luminex assay was used to quantify 20 cytokines. Temporal profiles of cytokines were evaluated using mixed-effects models after controlling for covariates. Of 1074 infants enrolled, 890 were examined for ROP and 877 included in the analysis. ROP was associated with several clinical characteristics on unadjusted analyses. Eight cytokines remained significantly different across ROP groups in adjusted analyses. IL-6 and IL-17 showed significant effects in early time periods (D0-3); TGF-beta, brain-derived neurotrophic factor (BDNF), and regulated on activation, normal T cell expressed and secreted (RANTES) in later time periods (D7-21) and IL-18, C-reactive protein (CRP), and neurotrophin-4 (NT-4) in both early and later time periods. We conclude that perinatal inflammation may be involved in the pathogenesis of ROP.