The involvement of IL-10, IL-6, IFN-gamma, TNF-alpha and TGF-beta gene polymorphisms among Turkish lung cancer patients

Several genes encoding different cytokines may play crucial roles in host susceptibility to lung cancer, since cytokine production capacity varies among individuals and depends on cytokine gene polymorphisms. The association between cytokine gene polymorphisms with primary lung carcinoma was investigated. DNA samples were obtained from a Turkish population of 44 patients with primary lung cancer, and 59 healthy control subjects. All genotyping (IFN-gamma, TGF-beta1, TNF-alpha, IL-6 and IL-10) experiments were performed using sequence-specific primers (SSP)-PCR. When compared to the healthy controls, the frequencies of high/intermediate producing genotypes of IL-10 and low producing genotype of TNF-alpha were significantly more common in the patient group. It is noteworthy that lung cancer patients with the TGF-beta T/T genotype in codon 10 had statistically longer survival compared to those having the C/C genotype (Kaplan-Meier survival function test, log rank significance = 0.014). These results suggest that IL-10, TNF-alpha and TGF-beta1 gene polymorphisms may affect host susceptibility to lung cancer and the outcome of the patients.     

Regulation of rat pulmonary artery endothelial cell transforming growth factor-beta production by IL-1 beta and tumor necrosis factor-alpha.

Recent studies suggest that transforming growth factor-beta (TGF-beta) production is up-regulated at sites of tissue injury, inflammation and repair, or fibrosis. Endothelial cells represent a potentially important in vivo source of TGF-beta; however, the identity of endogenous modulators of TGF-beta production by these cells remains unclear. To address this issue, the effects of the cytokines, IL-1 beta, and TNF-alpha on TGF-beta production by rat pulmonary artery endothelial cells were examined. Conditioned media from cells treated with 0 to 20 ng/ml IL-1 beta and/or TNF-alpha were assayed for TGF-beta activity using a mink lung epithelial cell line. The results show that rat pulmonary artery endothelial cells secreted undetectable amounts of active TGF-beta in the absence of cytokines. However, upon acidification of the conditioned media before assay, a time-dependent increase in TGF-beta activity was noted in media from both untreated and cytokine-treated cells. However, both IL-1 beta and TNF-alpha treatment caused the secretion of significantly greater amounts of TGF-beta activity than control cells, in a dose-dependent manner, with maximal response obtained at cytokine doses of greater than 10 ng/ml. At equivalent doses of cytokine tested, the magnitude of the response was significantly greater with IL-1 beta. These responses were paralleled by increases in steady state mRNA levels for TGF-beta 1. Addition of both cytokines resulted in a synergistic response. Synergism with IL-1 beta was also noted with the fibrogenic agent bleomycin. Kinetic studies indicated that a minimum of 4 h of treatment with either IL-1 beta or TNF-alpha was required for detection of significant increases in either secreted TGF-beta activity or steady state TGF-beta 1 mRNA levels. Thus, endothelial cells could play a role in various TGF-beta-dependent processes in vivo, in situations wherein IL-1 beta and/or TNF-alpha may be present at comparable concentrations.     

Quercetin's influence on exercise-induced changes in plasma cytokines and muscle and leukocyte cytokine mRNA.

Trained male cyclists (n = 40) ingested quercetin (Q; n = 20) (1,000 mg/day) or placebo (P; n = 20) supplements under randomized, double-blinded methods for 3 wk before and during a 3-day period in which subjects cycled for 3 h/day at approximately 57% maximal work rate. Blood samples were collected before and after each exercise session and assayed for plasma IL-6, IL-10, IL-1ra, IL-8, TNF-alpha, and monocyte chemoattractant protein 1, and leukocyte IL-10, IL-8, and IL-1ra mRNA. Muscle biopsies were obtained before and after the first and third exercise sessions and assayed for NF-kappaB and cyclooxygenase-2 (COX-2), IL-6, IL-8, IL-1beta, and TNF-alpha mRNA. Postexercise increases in plasma cytokines did not differ between groups, but the pattern of change over the 3-day exercise period tended to be lower in Q vs. P for IL-8 and TNF-alpha (P = 0.094 for both). mRNA increased significantly postexercise for each cytokine measured in blood leukocyte and muscle samples. Leukocyte IL-8 and IL-10 mRNA were significantly reduced in Q vs. P (interaction effects, P = 0.019 and 0.012, respectively) with no other leukocyte or muscle mRNA group differences. Muscle NF-kappaB did not increase postexercise and did not differ between Q and P. Muscle COX-2 mRNA increased significantly postexercise but did not differ between Q and P. In summary, 1 g/day quercetin supplementation by trained cyclists over a 24-day period diminished postexercise expression of leukocyte IL-8 and IL-10 mRNA, indicating that elevated plasma quercetin levels exerted some effects within the blood compartment. Quercetin did not, however, influence any of the muscle measures, including NF-kappaB content, cytokine mRNA, or COX-2 mRNA expression across a 3-day intensified exercise period.     

Influence of carbohydrate ingestion on immune changes after 2 h of intensive resistance training.

Thirty strength-trained subjects were randomized to carbohydrate (CHO) or placebo (Pla) groups and lifted weights for 2 h (10 exercises, 4 sets each, 10 repetitions, with 2- to 3-min rest intervals). Subjects received 10 ml x kg(-1) x h(-1) CHO (6%) or Pla beverages during the weight training bout. Blood, saliva, and vastus lateralis muscle biopsy samples were collected before and after exercise. Blood cell counts were determined, and plasma was analyzed for IL-6, IL-10, IL-1 receptor antagonist (IL-1ra), IL-8, and cortisol. Muscle was analyzed for glycogen content and relative gene expression of 13 cytokines (IL-1alpha, IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12p35, IL-12p40, IL-15, IFN-gamma, TNF-alpha) by use of real-time quantitative RT-PCR. Significant but modest increases were measured for plasma IL-6, IL-10, IL-1ra, and IL-8, but the pattern of increase did not differ between CHO and Pla groups. The rate of decrease in muscle glycogen content did not differ between CHO and Pla (P = 0.463). Muscle cytokine mRNA was detected preexercise for IL-1beta, IL-6, IL-15, IL-8, and TNF-alpha, and of these, IL-1beta, IL-6, IL-8, and TNF-alpha were significantly increased after the 2-h weight training bout. The increase in mRNA (fold difference from preexercise) did not differ between CHO and Pla groups. In summary, CHO vs. Pla ingestion did not alter modest increases measured for plasma IL-6, IL-10, IL-1ra, and IL-8, and muscle gene expression for IL-1beta, IL-6, IL-8, and TNF-alpha in strength-trained subjects lifting weights intensively for 2 h.     

Plasma levels of Th1 and Th2 cytokines in Ghanaian children with vaccine-modified measles

To understand the pathogenesis of vaccine-modified measles (VMM), we measured plasma levels of IFN-gamma and IL-2 (Th1 cytokines), IL-4 and IL-10 (Th2 cytokines), IL-12, TNF-alpha and TGF-beta1 in children with uncomplicated measles, who had anti-measles IgG antibodies and with a history of immunization on admission (day 0), day 14 and day 60. We compared these to levels in healthy, age-matched, immunized children. Plasma levels of IFN-gamma, IL-2 and IL-12 were significantly higher in VMM patients on day 0 compared to healthy controls (p = 0.023; p = 0.018; p = 0.001) respectively. In contrast, plasma IL-4 was lower in VMM patients on day 0 when compared to the controls (p = 0.009). Plasma levels of IL-12 remained consistently high on days 14 and 60 (p = 0.001; p = 0.04), whilst IL-10 levels fell significantly on the same days (p = 0.002; p = 0.001) respectively. Kinetically, IFN-gamma and IL-10 levels decreased consistently from day 0 to days 14 and 60 in VMM patients. In contrast, IL-4 levels increased from day 0 to day 14 and day 60. Our results therefore suggest that VMM is associated with an early up-regulation of Th1 cytokine production and a down-regulation of Th2 cytokine production. The strong Th1 response may be associated with the induction of IL-12 and memory cells, thus contributing to the early resolution of the infection and lack of complications.     

Cytokine responses differ by compartment and wasting status in patients with HIV infection and healthy controls

Inflammatory cytokines are implicated in the loss of lean tissue that occurs in patients with inflammatory and infectious diseases, including HIV infection. However, it is not known whether plasma levels or cellular production of cytokines, or their antagonists, are more closely related to lean tissue loss. We studied whether plasma cytokine analysis could substitute for PBMC production assays in studies of nutrition status and disease state, and if cytokine antagonists could offer an alternative in assessing cytokine status. We used a bout of moderately difficult exercise to perturb cytokine production in 12 adults with HIV without wasting, 10 adults with HIV wasting, and nine healthy controls. Plasma and peripheral blood mononuclear cell (PBMC) production of interleukin-1 beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), interleukin-1 receptor antagonist (IL-1ra) and soluble TNF receptor type II (sTNFrII) were measured at baseline and 2, 6, 24 and 168h following exercise. PBMC production of IL-1beta, TNF-alpha and IL-6 were all higher in the HIV-infected patients without wasting than in the controls (P<0.05) or the patients with AIDS wasting (P<0.05). Plasma concentrations of TNF-alpha and IL-6 were higher in the HIV wasted patients than in the controls (P<0.05). Both plasma and PBMC levels of sTNFrII were higher in HIV patients, regardless of wasting, than in controls. These data suggest that the PBMC cytokine compartment is more sensitive to nutritional and metabolic abnormalities than is the plasma compartment. PBMC production of IL-1beta, IL-6 and TNF-alpha best distinguish between HIV patients with and without wasting, while plasma concentrations of IL-6 and TNF-alpha are elevated in AIDS wasting, but do not reliably distinguish patients with wasting from HIV-infected patients without wasting.     

Immune responses against oxidative stress-derived antigens are associated with increased circulating tumor necrosis factor-alpha in heavy drinkers

Growing evidence indicates that pro-inflammatory cytokines play a key role in alcoholic liver disease (ALD). This study investigates whether immune response toward oxidative stress-derived antigens could be involved in promoting cytokine production in alcohol abusers. Cytokine profile and circulating IgG against human serum albumin modified by malondialdehyde (MDA-HSA) and against oxidized cardiolipin (Ox-CL) were evaluated in 59 heavy drinkers (HD) with (n=30) or without (n=29) ALD and 34 healthy controls. IgG against MDA-HSA and Ox-CL were significantly higher in HD with ALD than in HD without liver injury or healthy controls. The elevation of these antibodies was associated with higher circulating levels of IL-2 (p=0.005) and TNF-alpha (p=0.001), but not of IL-6 or IL-8. The prevalence of abnormal TNF-alpha was 5-fold higher in HD with oxidative stress-induced IgG than in those without. HD with the combined elevation of both TNF-alpha and oxidative stress-induced IgG had 11-fold (OR 10.7; 95%CI 1.2-97.2; p=0.023) greater risk of advanced ALD than those with high TNF-alpha, but no immune responses. Moreover, the combined elevation of TNF-alpha and lipid peroxidation-derived IgG was an independent predictor of ALD in HD. We propose that immune responses towards oxidative stress-derived antigen promote TNF-alpha production and contribute to liver damage in alcohol abusers.     

Indomethacin modulates circulating cytokine responses to strenuous exercise in humans

Physical stress is associated with circulating cytokinemia. However the mechanisms of cytokine regulation during such stress are not clearly defined. Non-steroidal anti-inflammatory drugs (NSAIDs), including indomethacin, are widely used in countering the effects of excessive exercise, but their impact on circulating pro- and anti-inflammatory cytokine production in healthy humans also remains unclear. This study investigated the effect of five days of oral indomethacin treatment (75 mg per day) on the serum concentrations of IL-6, IL-10, IL-12, and TNF-alpha induced by exercising healthy volunteers. The results demonstrate that indomethacin does not alter resting serum cytokine concentrations. Increased circulating levels were noted, however, for all four cytokines with exercise, but with a different time-course. During and after strenuous physical exercise, indomethacin treatment blunted serum IL-6, and augmented TNF-alpha and IL-10. These findings may have important implications for both host defense and the injuries associated with excessively vigorous exercise.     

Constitutive pro- and anti-inflammatory cytokine and growth factor response to exercise in leukocytes.

Leukocytosis following exercise is a well-described phenomenon of stress/inflammatory activation in healthy humans. We hypothesized that, despite this increase in circulating inflammatory cells, exercise would paradoxically induce expression of both pro- and anti-inflammatory cytokines and growth factors within these cells. To test this hypothesis, 11 healthy adult men, 18-30 yr old, performed a 30-min bout of heavy cycling exercise; blood sampling was at baseline, end-exercise, and 60 min into recovery. The percentage of leukocytes positive for intracellular cytokines and growth factors and mean fluorescence intensity was obtained by flow cytometry. Proinflammatory cytokines (IL-1alpha, IL-2, IFN-gamma, and TNF-alpha), a pleiotropic cytokine (IL-6), and anti-inflammatory cytokines and growth factors [IL-4, IL-10, growth hormone (GH), and IGF-I] were examined. Median fluorescence intensity was not affected by exercise; however, we found a number of significant changes (P < 0.05 by mixed linear model and modified t-test) in the numbers of circulating cells positive for particular mediators. The pattern of expression reflected both pro- and anti-inflammatory functions. In T-helper lymphocytes, TNF-alpha, but also IL-6, and IL-4 were significantly increased. In monocytes, both IFN-gamma and IL-4 increased. B-lymphocytes positive for GH and IGF-I increased significantly. GH-positive granulocytes also significantly increased. Collectively, these observations indicate that exercise primes an array of pro- and anti-inflammatory and growth factor expression within circulating leukocytes, perhaps preparing the organism to effectively respond to a variety of stressors imposed by exercise.     

Inflammatory cytokines augments TGF-beta1-induced epithelial-mesenchymal transition in A549 cells by up-regulating TbetaR-I

Epithelial-mesenchymal transition (EMT) is believed to play an important role in fibrosis and tumor invasion. EMT can be induced in vitro cell culture by various stimuli including growth factors and matrix metalloproteinases. In this study, we report that cytomix (a mixture of IL-1beta, TNF-alpha and IFN-gamma) significantly enhances TGF-beta1-induced EMT in A549 cells as evidenced by acquisition of fibroblast-like cell shape, loss of E-cadherin, and reorganization of F-actin. IL-1beta or TNF-alpha alone can also augment TGF-beta1-induced EMT. However, a combination of IL-1beta and TNF-alpha or the cytomix is more potent to induce EMT. Cytomix, but not individual cytokine of IL-1beta, TNF-alpha or IFN-gamma, significantly up-regulates expression of TGF-beta receptor type I (TbetaR-I). Suppression of TbetaR-I, Smad2 or Smad3 by siRNA partially blocks EMT induction by cytomix plus TGF-beta1, indicating cytomix augments TGF-beta1-induced EMT through enhancing TbetaR-I and Smad signaling. These results indicate that inflammatory cytokines together with TGF-beta1 may play an important role in the development of fibrosis and tumor progress via the mechanism of epithelial-mesenchymal transition.     

Ethanol induces the production of cytokines via the Ca2+, MAP kinase, HIF-1alpha, and NF-kappaB pathway

In the present study, we sought to investigate the signal transduction pathways of expression of cytokines in the ethanol-stimulated human mast cell line, HMC-1. Ethanol significantly increased the intracellular calcium level in HMC-1. Ethanol also significantly enhanced IL-6, TNF-alpha, and TGF-beta1 production compared with media control, but did not significantly affect the IL-1beta production. After 8 h of stimulation, ethanol increased mRNA and protein expression levels of TNF-alpha and TGF-beta1 in HMC-1. The increased cytokine level was significantly inhibited by BAPTA-AM, PD98059, and SB203580. These inhibitors also inhibited ethanol-induced ERK and p38 MAPK phosphorylation. Ethanol resulted in a great increase in protein levels and promoter activity driving luciferase expression of HIF-1alpha and NF-kappaB in HMC-1 cells, but it did not affect on HIF-1alpha mRNA expression. Our observations show that calcium, MAPK activation, HIF-1alpha, and NF-kappaB are necessary for ethanol-induced TNF-alpha and TGF-beta1 expression. These results may have important implications for the study of alcohol-related diseases.     

Differences in amniotic fluid and maternal serum cytokine levels in early midtrimester women without evidence of infection

The amniotic fluid cytokine profile has been shown to be indicative of various disease states, and changes may be associated with preterm labor or infection. Anti-inflammatory cytokine profiles may be essential for successful normal pregnancy. However, there are currently few normative data on the concentration of cytokines in amniotic fluids during pregnancy. The aim of this study was to provide new amniotic fluid cytokine data for future comparative studies in disease states, notably in utero viral infections, and to compare these with maternal serum levels. Amniotic fluid was obtained from 100 pregnant women undergoing elective amniocentesis at the Royal Hospital for Women, Randwick. Concentrations of 27 cytokines were simultaneously measured in amniotic fluid and a subset of matching maternal sera (n=33) using a multiplex bead-based immunoassay system (Bio-Plex, Bio-Rad). To exclude infection, nested multiplex PCR targeting 17 known congenital infectious agents were performed on all amniotic fluid and maternal serum samples, and serological testing was also performed against some of these agents. Maternal serum concentration was positively correlated with amniotic fluid levels for MIP-1beta (r=0.39, P=0.027). IL-1ra was positively correlated to maternal age (r=0.210, P=0.036), and mean IL-5 levels were significantly higher in amniotic fluids from pregnancies with male fetuses than those with female fetuses (P=0.036). Normal amniotic fluid concentrations for five cytokines (IL-6, IL-8, IP-10, MCP-1, IL-1ra) were found to be significantly elevated over maternal serum concentrations in matched pairs (P<0.05). Concentrations of 12 cytokines (eotaxin, IFN-gamma, IL-9, IL-12, IL-15, IL-17, MIP-1alpha, MIP-1beta, RANTES, TNF-alpha, VEGF, PDGF bb) were significantly elevated in maternal serum compared to paired amniotic fluid at midtrimester (P<0.05). Amniotic fluid may be more representative of the fetal cytokine profile than cytokine analysis on antenatal sera as it represents predominantly fetal urinary and respiratory secretions. This study provides new normative data for multiple cytokine levels in amniotic fluid and maternal sera at 14-16 weeks gestation, and is a valuable tool for future diagnostic and comparative studies.     

Circulating immune complexes (IC) and IC-induced levels of GM-CSF are increased in sudanese patients with acute visceral Leishmania donovani infection undergoing sodium stibogluconate treatment: implications for disease pathogenesis

Infection with Leishmania donovani is associated with IL-10 as well as with GM-CSF. Immune complexes (IC) exert important functions by stimulation of monocytes/macrophage-mediated production of pro- and anti-inflammatory cytokines in rheumatic diseases. In this investigation, we have explored IC-induced cytokine production during Leishmania infection. Sera from 43 patients with visceral leishmaniasis (VL), 17 patients with post-kala-azar dermal leishmaniasis, and 20 healthy Sudanese controls were precipitated with polyethylene glycol (PEG). The PEG precipitates were added to serum-free PBMC for 20 h,whereupon supernatant levels of IL-1beta, IL-6, IL-10, IL-1 receptor antagonist protein, TNF-alpha, TNF receptor p75, and GM-CSF were investigated using ELISA. Circulating levels of C1q-binding IC were also measured in the serum samples. PEG precipitates from Leishmania-infected patients induced significantly higher levels of GM-CSF (p = 0.0037) and IL-10 (p < 0.0001), as well as of IL-6 (p < 0.0001) and IL-1 receptor antagonist (p = 0.0238) as compared with PEG precipitates from controls. Patients with acute VL as well as VL patients receiving sodium stibogluconate treatment displayed significantly increased levels of PEG precipitate-induced GM-CSF. The induction of GM-CSF by circulating IC was especially prominent in acute VL patients receiving sodium stibogluconate treatment; ANOVA revealed significant interaction between disease activity and treatment for PEG precipitate-induced levels of GM-CSF (disease activity, p = 0.0006; treatment, p = 0.0005; interaction, p = 0.0046). Parallel associations were determined for C1q-binding immune complexes, but not for any cytokine other than GM-CSF. The importance of IC-induced GM-CSF in leishmaniasis warrants further study.     

Kinetics of cytokine profile during intraperitoneal inoculation of Japanese encephalitis virus in BALB/c mice model

Infection with Japanese encephalitis virus (JEV) is mostly asymptomatic/subclinical in 90% of the individuals. Host immune response during subclinical JEV infection is poorly understood. We assessed iNOS, IFN-gamma, TNF-alpha, IL-10 and IL-4 production in spleen, brain and sera of intraperitoneally challenged BALB/c mice by RT-PCR and ELISA along with brain histopathology at different days post inoculation (d.p.i.). In spleen of virus infected mice, expression of all cytokines including iNOS mRNA were upregulated till 5d.p.i. followed by decline. At 5d.p.i., IL-10 expression outcompeted TNF-alpha, IFN-gamma and IL-4. However, in the virus infected mice sera, IL-4 production predominated over TNF-alpha and IL-10 at 5d.p.i. Conversely, cytokines expression and iNOS mRNA remained unchanged in the brain of virus infected mice from 1 to 7d.p.i. A significant increase in the cytokine expression was observed at 11d.p.i. (P<0.05) in virus infected mice brain, with the predominance of IL-10 along with the presence of meningeal inflammation and viral RNA by histology and RT-PCR, respectively. We report a biased pattern of cytokine production in sera, brain and spleen of mice intraperitoneally challenged with JEV. IL-10 exerts neuroprotective function during JEV and regulates deleterious effects of proinflammatory cytokines; however, its mechanism needs further investigation.     

Carbohydrate ingestion influences skeletal muscle cytokine mRNA and plasma cytokine levels after a 3-h run.

Sixteen experienced marathoners ran on treadmills for 3 h at approximately 70% maximal oxygen consumption (Vo(2 max)) on two occasions while receiving 1 l/h carbohydrate (CHO) or placebo (Pla) beverages. Blood and vastus lateralis muscle biopsy samples were collected before and after exercise. Plasma was analyzed for IL-6, IL-10, IL-1 receptor agonist (IL-1ra), IL-8, cortisol, glucose, and insulin. Muscle was analyzed for glycogen content and relative gene expression of 13 cytokines by using real-time quantitative RT-PCR. Plasma glucose and insulin were higher, and cortisol, IL-6, IL-10, and IL-1ra, but not IL-8, were significantly lower postexercise in CHO vs. Pla. Change in muscle glycogen content did not differ between CHO and Pla (P = 0.246). Muscle cytokine mRNA content was detected preexercise for seven cytokines in this order (highest to lowest): IL-15, TNF-alpha, IL-8, IL-1beta, IL-12p35, IL-6, and IFN-gamma. After subjects ran for 3 h, gene expression above prerun levels was measured for five of these cytokines: IL-1beta, IL-6, and IL-8 (large increases), and IL-10 and TNF-alpha (small increases). The increase in mRNA (fold difference from preexercise) was attenuated in CHO (15.9-fold) compared with Pla (35.2-fold) for IL-6 (P = 0.071) and IL-8 (CHO, 7.8-fold; Pla, 23.3-fold; P = 0.063). CHO compared with Pla beverage ingestion attenuates the increase in plasma IL-6, IL-10, and IL-1ra and gene expression for IL-6 and IL-8 in athletes running 3 h at 70% Vo(2 max) despite no differences in muscle glycogen content.     

Elevated levels of endogenous IL-6 in systemic lupus erythematosus. A putative role in pathogenesis

Elevated spontaneous IgG production is characteristic of SLE. To identify the factors that support it, IL-6, a cytokine with an important role in the differentiation of IgG-secreting cells, was studied in SLE patients. Higher than normal levels of IL-6 were found, by a B9 assay, in sera of 63 of 70 patients (p less than 0.05). IL-6 was detected in 36 of 37 active SLE sera in higher titers (p = 0.009) than those for inactive SLE (n = 33), which were higher (p less than 0.05) than healthy controls (n = 15). IL-6 mRNA was detected in freshly isolated PBMC of 11 of 11 patients but not in normal PBMC, whereas IL-1 mRNA was detected only in patients with active disease. IL-6 activity was recovered from PBMC of four SLE patients, but not from four normal donors. By immunoperoxidase, IL-6 was detected in the cytoplasm of SLE monocytes and lymphocytes. When SLE PBMC were grown in short term cultures with no deliberate stimulation, expression of the IL-6 gene declined rapidly. Accordingly, the spontaneous production of IgG by SLE PBMC could be enhanced by exogenous IL-6. Spontaneous IgG production was diminished by 20 to 65% in the presence of neutralizing antibodies to IL-6, TNF-alpha, or IL-1. In contrast, neutralization of endogenous IL-4 increased production by approximately 40%. Anti-TNF-alpha treatment decreased IL-6 content of PBMC cultures, whereas anti-IL-4 augmented it, and exogenous IL-6 reversed anti-TNF-alpha effects on IgG production. Therefore, it is possible that the neutralization of TNF-alpha and IL-4 affected IgG production by modulating the synthesis/activity of IL-6. These results support the concept that SLE B cell hyperactivity is promoted by dysregulation of endogenous cytokines and suggest that IL-6, in particular, has an important pathogenic role.     

Systemic inflammatory priming in normal pregnancy and preeclampsia: the role of circulating syncytiotrophoblast microparticles

Systemic inflammatory responsiveness was studied in normal human pregnancy and its specific inflammatory disorder, pre-eclampsia. Compared with nonpregnancy, monocytes were primed to produce more TNF-alpha throughout normal pregnancy, more IL-12p70 in the first and second trimesters, and more IL-18 in the first trimester only. Intracellular cytokine measurements (TNF-alpha and IL12p70) showed little change by comparison. IFN-gamma production was suppressed in all three trimesters. In pre-eclampsia, IL-18 secretion was increased. Secreted but not intracellular measures of TNF-alpha and IL-12p70 were also further enhanced compared with normal pregnancy. Inhibition of IFN-gamma production was lost and involved both CD56(+) NK and CD56(-) lymphocyte subsets. We determined whether circulating syncytiotrophoblast microparticles (STBM) could contribute to these inflammatory changes. Unbound STBM could be detected in normal pregnancy by the second trimester and increased significantly in the third. They were also bound in vivo to circulating monocytes. Women with pre-eclampsia had significantly more circulating free but not cell-bound STBMs. STBMs prepared by perfusion of normal placental lobules stimulated production of inflammatory cytokines (TNF-alpha, IL12p70, and IL-18 but not IFN-gamma) when cultured with PBMCs from healthy nonpregnant women. Inflammatory priming of PBMCs during pregnancy is confirmed and is established by the first trimester. It is associated with early inhibition of IFN-gamma production. The inflammatory response is enhanced in pre-eclampsia with loss of the IFN-gamma suppression. Circulating STBMs bind to monocytes and stimulate the production of inflammatory cytokines. It is concluded that they are potential contributors to altered systemic inflammatory responsiveness in pregnancy and pre-eclampsia.     

Cytokine-mediated modulation of leptin and adiponectin secretion during in vitro adipogenesis: evidence that tumor necrosis factor-alpha- and interleukin-1beta-treated human preadipocytes are potent leptin producers

Over the last decade, compelling evidence has been presented that cytokines affect adipocyte tissue formation and function. In this study we explored the effect of pro-inflammatory (i.e. interleukin (IL)-1beta, IL-6, interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha) versus anti-inflammatory cytokines (i.e. IL-4, IL-10, and transforming growth factor (TGF)-beta1) on leptin and adiponectin secretion during in vitro human adipogenesis. Confirmative to previous reports, conversion of precursor preadipocytes into mature adipocytes was completely inhibited upon exposure to TNF-alpha, IL-1beta, IFN-gamma, or TGF-beta1. Hence, all these anti-adipogenic cytokines prevented release of adipocyte-specific adiponectin. IFN-gamma also strongly reduced leptin production (> or =85%). However, TNF-alpha, IL-1beta, and TGF-beta1 stimulated leptin production from preadipocytes in the absence of mature adipocytes (20.6+/-5.4 ng/ml, 100.8+/-18.2 ng/ml, and 5.4+/-0.4 ng/ml, respectively, compared to 6.6+/-0.8 ng/ml in control adipocyte cultures on day 21; n=4). IL-4, IL-6 and IL-10 did not, or only slightly, affect adipocyte differentiation and their hormonal secretion. In conclusion, adiponectin and leptin are both synthesized by adipocytes, whereas leptin is also produced by preadipocytes upon TNF-alpha or IL-1beta stimulation. These data suggest that preadipocytes could contribute more to total circulating leptin levels than has been previously considered, especially in diseased conditions were these pro-inflammatory factors play a prominent role.