Immune mechanisms in alcoholic liver disease

Growing evidence indicates that inflammatory reactions play an important role in the pathogenesis of alcoholic liver disease (ALD). The implication of immunity in fueling chronic inflammation in ALD has emerged from clinical and experimental evidence showing the recruitment and the activation of lymphocytes in the inflammatory infiltrates of ALD and has received further support by the recent demonstration of a role of Th17 lymphocytes in alcoholic hepatitis. Nonetheless, the mechanisms by which alcohol triggers adaptive immune responses are still incompletely characterized. Patients with advanced ALD show a high prevalence of circulating IgG and T-lymphocytes towards epitopes derived from protein modification by hydroxyethyl free radicals (HER) and end-products of lipid peroxidation. In both chronic alcohol-fed rats and heavy drinkers the elevation of IgG against lipid peroxidation-derived antigens is associated with an increased production of pro-inflammatory cytokines/chemokines and with the severity of histological signs of liver inflammation. Moreover, CYP2E1-alkylation by HER favors the development of anti-CYP2E1 auto-antibodies in a sub-set of ALD patients. Altogether, these results suggest that allo- and auto-immune reactions triggered by oxidative stress might contribute to fuel chronic hepatic inflammation during the progression of ALD.     

Interplay between oxidative stress and immunity in the progression of alcohol-mediated liver injury

Inflammation is recognized increasingly as having an important role in the pathogenesis of alcoholic liver disease (ALD). Nonetheless, the mechanisms by which alcohol maintains hepatic inflammation are still characterized incompletely. Several studies have demonstrated that ethanol-induced oxidative stress promotes immune responses in ALD by stimulating both humoral and cellular reactions against liver proteins adducted to hydroxyethyl free radicals and several lipid peroxidation products. Moreover, ALD patients have autoantibodies targeting cytochrome P4502E1 and oxidized phospholipids. In both chronic alcohol-fed rats and heavy drinkers, the elevation of IgG against lipid peroxidation-derived antigens is associated with tumor necrosis factor-alpha production and the severity of liver inflammation. On this basis, we propose that allo- and autoimmune reactions associated with oxidative stress might contribute to fueling hepatic inflammation in ALD.     

Zinc prevention and treatment of alcoholic liver disease

Alcoholic liver disease (ALD) is associated with decreases in zinc (Zn) and its major binding protein, metallothionein (MT), in the liver. Studies using animal models have shown that Zn supplementation prevents alcohol-induced liver injury under both acute and chronic alcohol exposure conditions. There are hepatic and extrahepatic actions of Zn in the prevention of alcoholic liver injury. Zn supplementation attenuates ethanol-induced hepatic Zn depletion and suppresses ethanol-elevated cytochrome P450 2E1 (CYP2E1) activity, but increases the activity of alcohol dehydrogenase in the liver; an action that is likely responsible for Zn suppression of alcohol-induced oxidative stress. Zn also enhances glutathione-related antioxidant capacity in the liver. At the cellular level, Zn inhibits alcohol-induced hepatic apoptosis partially through suppression of the Fas/FasL-mediated pathway. Zn supplementation preserves intestinal integrity and prevents endotoxemia, leading to inhibition of endotoxin-induced tumor necrosis factor-alpha (TNF-alpha) production in the liver. Zn also directly inhibits the signaling pathway involved in endotoxin-induced TNF-alpha production. These hepatic and extrahepatic effects of Zn are independent of MT. However, low levels of MT in the liver sensitize the organ to alcohol-induced injury, and elevation of MT enhances the endogenous Zn reservoir and makes Zn available when oxidative stress is imposed. Zn has a high potential to be developed as an effective agent in the prevention and treatment of ALD.     

Free radical mechanisms in immune reactions associated with alcoholic liver disease.

Immune reactions toward the liver have been implicated in the pathogenesis of alcoholic liver disease (ALD), however the antigens involved are still poorly characterized. The contribution of free radical mechanisms to the immune reactions associated with ALD first emerged from the observation that the binding of hydroxyethyl free radicals (HER) to hepatic proteins, including cytochrome P4502E1 (CYP2E1), stimulates the production of specific antibodies in both alcohol-fed rats and alcoholic patients. We have subsequently observed that ALD patients have increased titers of antibodies directed against protein adducts with different lipid peroxidation products and antigens derived from the combination of malonildialdehyde and acetaldehyde. Free radical mechanisms can also contribute in promoting the autoimmune reactions often associated with ALD. Indeed, we have observed that antiphospholipid antibodies present in more than 50% of ALD patients recognize oxidized cardiolipin complexed with beta2-glycoprotein 1. Furthermore, a strict association between anti-HER IgG and the development of autoantibodies against CYP2E1 indicates that CYP2E1 modification by HER might promote anti-CYP2E1 autoreactivity in subjects with alcoholic cirrhosis. Altogether, these observations suggest the importance of ethanol-induced oxidative stress in stimulating immune reactions towards both liver allo-and self-antigens.     

Methylenedioxymethamphetamine (MDMA; Ecstasy) suppresses IL-1beta and TNF-alpha secretion following an in vivo lipopolysaccharide challenge

In this study we examined the effects of methylenedioxymethamphetamine (MDMA) administration on responsiveness to an in vivo immune challenge with lipopolysaccharide (LPS; 100 microg/kg; i.p.). LPS produced an increase in circulating IL-1beta and TNF-alpha in control animals. MDMA (20 mg/kg; i.p.) significantly impaired LPS-induced IL-1beta and TNF-alpha secretion. The suppressive effect of MDMA on IL-1beta secretion was transient and returned to control levels within 3 hours of administration. In contrast, the MDMA-induced suppression of TNF-alpha secretion was evident for up to 12 hours following administration. In a second study we examined the effect of co-administration of MDMA (5, 10 and 20 mg/kg; i.p.) on LPS-induced IL-1beta and TNF-alpha secretion, and demonstrated that all three doses potently suppressed LPS-induced TNF-alpha secretion, but only MDMA 10 and 20 mg/kg suppressed LPS-induced IL-1beta secretion. In addition, serum MDMA concentrations displayed a dose-dependent increase, with the concentrations achieved following administration of 5 and 10 mg/kg being in the range reported in human MDMA abusers. In order to examine the possibility that the suppressive effect of MDMA on IL-1beta and TNF-alpha could be due to a direct effect of the drug on immune cells, the effect of in vitro exposure to MDMA on IL-1beta and TNF-alpha production in LPS-stimulated diluted whole blood was evaluated. However IL-1beta or TNF-alpha production were not altered by in vitro exposure to MDMA. In conclusion, these data demonstrate that acute MDMA administration impairs IL-1beta and TNF-alpha secretion following an in vivo LPS challenge, and that TNF-alpha is more sensitive to the suppressive effects of MDMA than is IL-1beta. However the suppressive effect of MDMA on IL-1beta and TNF-alpha could not be attributed to a direct effect on immune cells. The relevance of these findings to MDMA-induced immunomodulation is discussed.     

Oxidative mechanisms in the pathogenesis of alcoholic liver disease

Although the capacity of ethanol to induce oxidative stress in the liver is well established, the mechanisms by which oxidative damage contributes to the pathogenesis of alcoholic liver disease (ALD) is still incompletely understood. Recent reports have implicated oxidative mechanisms in the onset of alcoholic steatosis and in the formation of Mallory's bodies. Moreover, by inducing mitochondrial alterations, oxidative stress promotes hepatocyte necrosis and contributes to alcohol-induced sensitization of hepatocyte to the pro-apoptotic action of TNF-alpha. Oxidative mechanisms play also a role in the progression of liver fibrosis by triggering the release of pro-fibrotic cytokines and activating collagen gene expression in hepatic stellate cells. Finally, immune responses towards antigens originating from the reactions of lipid peroxidation products with hepatic proteins might represent one of the mechanisms that contribute to perpetuate chronic hepatic inflammation in ALD. Altogether these observations give a rationale to the possible clinical application of antioxidants in the therapy of ALD.     

IL-12 elispot assays to detect and enumerate IL-12 secreting cells

The cytokine IL-12 promotes Th(1)type immune responses and plays a key role in immune regulation. The complex nature of IL-12 hampered its detection without use of stimulants that might give less relevant information. To detect circulating IL-12 p40, we developed enzyme-linked immunospot (ELISPOT) assays that allow enumeration of IL-12 p40 secreting cells without prior in vitro stimulation of the cells. In parallel, intracellular staining of IL-12 p40 by flow cytometry was performed to compare the two methods. IL-12 p40 secreting cells were detected in healthy subjects at a mean number of 103+/-155 per 10(5)blood mononuclear cells (MNC). Numbers of IL-12 p40 secreting blood MNC correlated with IL-12 p40 positive blood MNC detected by flow cytometry. Bacterial endotoxins and the inflammatory cytokines TNF-alpha and IFN-gamma control IL-12 production by antigen presenting cells. Utilizing IL-12 p40 ELISPOT assays, we could confirm occurrence of elevated numbers of IL-12 p40 secreting blood MNC after stimulation with TNF-alpha, IFN-gamma, LPS, LPS+TNF-alpha or LPS+IFN-gamma, compared to cultures without stimulant. Due to its central role in inflammation and autoimmunity, IL-12 is an attractive target for immunotherapy. IL-12 p40 ELISPOT assays represent a sensitive, specific and reliable tool for investigating the role of IL-12 in both health and disease.     

Monocyte cytokine secretion in patients with pulmonary tuberculosis differs from that of healthy infected subjects and correlates with clinical manifestations

Cell-mediated immunity, leading to Mycobacterium tuberculosis (Mtb)-constraining granuloma formation, is the major component of host defense against tuberculosis and is regulated by the balance of cytokines secreted mostly by mononuclear phagocytes and lymphocytes. To better understand the role of monocytes in the regulation of the immune response against pulmonary tuberculosis, we examined IL-10, IL-12 and TNF-alpha release by monocytes from healthy purified protein derivative (PPD) reactors and pulmonary tuberculosis patients with or without systemic reactions (e.g., fever, weight loss, asthenia). Our study shows that, probably as a result of in vivo priming by circulating antigens, monocytes from patients, especially those with systemic manifestations, have a biased ex vivo cytokine secretion, with high IL-10 and TNF-alpha but low IL-12, in contrast with PPD reactors. Higher spontaneous IL-10 and TNF-alpha release persisted when monocytes were co-cultured with autologous lymphocytes. Challenge of patients' monocytes with a virulent Mtb strain led to a further enhancement of IL-10 and TNF-alpha, but not of IL-12. When lymphocytes were added to these cultures, IL-10 and TNF-alpha elevation persisted and, in the patients with a systemic reaction, both IL-12 and IFN-gamma were significantly reduced compared to PPD reactors. Intragroup comparisons revealed that in the patients with systemic reactions, the lymphocyte-monocyte interaction resulted in a positive feedback for IL-10 secretion, while in the patients without systemic reaction and PPD reactors, the feedback was positive for IL-12 secretion. Thus, in tuberculosis, there appears to exist a relationship between the immunological findings and the distinct clinical manifestations.     

Chronic viral hepatitis and iron affect the plasma levels of LIGHT--a new member of the TNF superfamily in uraemic haemodialyzed patients

LIGHT (lymphotoxin-like inducible protein that competes with glycoprotein D for binding herpesvirus entry mediator on T cells) is a recently identified of the tumor necrosis factor alpha (TNF-alpha) ligand superfamily. We wanted to establish whether the presence of chronic viral hepatitis could be implicated in enhanced inflammation as well as the elevation of plasma LIGHT levels in haemodialyzed (HD) patients. The plasma levels of LIGHT, high sensitivity C-reactive protein (hs CRP) and TNF-alpha were measured in HD patients with hepatitis in comparison to subjects without hepatitis and to healthy volunteers. The values of hs CRP and TNF-alpha were significantly elevated in HD patients when compared to the controls. TNF-alpha levels were significantly higher in the hepatitis-positive relative to the hepatitis-negative group (p <0.01). LIGHT levels were significantly decreased in hepatitis-negative patients as compared to controls (p <0.001) and hepatitis-positive group (p < 0.01). Both LIGHT and TNF-alpha were directly associated with the presence of hepatitis. Multiple stepwise regression analysis identified increased iron levels as the only independent variable significantly associated with increased LIGHT (beta=0.475, p=0.003). These results suggest the presence of chronic viral hepatitis and iron levels are novel determinants of the increased LIGHT in the plasma of HD patients.     

Noncoding RNAs in alcoholic liver disease

Alcoholic liver disease (ALD) is a complex process with high morbitity and can cause liver dysfunction, which contains a wide spectrum of hepatic lesions, including steatohepatitis, fibrosis, cirrhosis, and eventually hepatocellular carcinoma. To date, the molecular mechanisms for ALD have not been fully explored and an effective therapy is still missing. Overwhelming evidence shows dysregulation of noncoding RNAs (ncRNAs), particularly microRNAs (miRNAs), is correlated with etiopathogenesis and progress of ALD including hepatocyte damage, disrupted lipid metabolism, aggressive inflammatory responses, oxidative stress, programmed cell death, fibrosis, and epigenetic changes induced by alcohol. For example, circulating miRNA-122 is a marker of hepatocyte damage, and miRNA-155 is a potential marker of inflammation, indicating their diagnosis therapeutic potential in ALD. In addition, roles for long noncoding RNAs (lncRNAs) and circular RNAs in ALD are being uncovered. Further, circulating ncRNAs and exosome-derived ncRNAs have attracted more attention lately, suggesting a role in the prevention and treatment of ALD. This review covers the roles of ncRNAs in ALD, and the potential uses as markers for diagnosis and therapeutic options.     

Genetic determinants of ethanol-induced liver damage

BACKGROUND: Although a clear correlation exists between cumulative alcohol intake and liver disease, only some of the alcohol abusers develop signs of ethanol-induced liver damage. To identify some of the genetic variations predisposing persons to alcoholic liver disease (ALD), a genetic study was performed in heavy drinkers from the cohort of the Dionysis study, a survey aimed at evaluating liver disease in the open population of two towns in Northern Italy (6917 individuals). MATERIALS AND METHODS: 158 heavy drinkers (approximately 85% of all heavy drinkers in the population; daily alcohol intake > 120 g in males and >60 g in females) were investigated by the analysis of nine polymorphic regions, mapping in exons III and IX of the alcohol-dehydrogenase (ADH)-2 gene, in exon VIII of the ADH3 gene, in intron VI, in the promoter region of the cytochrome P4502E1 (CYP2E1) gene, and in the promoter region of the tumor necrosis factor-alpha gene. RESULTS: Heavy drinkers with or without ALD significantly differed for the distribution of alleles of the cytochrome P4502E1 (CYP2E1) and alcohol-dehydrogenase-3 (ADH-3) genes. In one town, allele C2 in the promoter region of the CYP2E1 gene had a frequency of 0.06 in healthy heavy drinkers, of 0.19 in heavy drinkers with ALD (p = 0.012), and of 0.33 in heavy drinkers with cirrhosis (p = 0.033). In the other town, whose inhabitants have different genetic derivation, a prominent association between ALD and homozygosity for allele ADH3*2 of ADH3 was found, with a prevalence of 0.31 in heavy drinkers with ALD and of 0.07 in healthy heavy drinkers controls (p = 0.004). CONCLUSIONS. Both heterozygosity for allele C2 of CYP2E1 and homozygosity for allele ADH3*2 of ADH3 are independent risk factors for ALD in alcohol abusers. The relative contribution of these genotypes to ALD is dependent on their frequency in the population. Overall, heavy drinkers lacking either of these two genotypes are 3.2 and 4.3 times more protected from developing ALD and cirrhosis respectively.     

The relationship between serum cytokine levels with obesity and obstructive sleep apnea syndrome

Inflammatory cytokines such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) may have a direct effect on glucose and lipid metabolism. On the other hand, it is known that IL-6 and TNF-alpha are important pro-inflammatory cytokines in the pathogenesis of atherosclerosis. The goal of present study was to test whether sleep apnea contributes to the previously reported increases of IL-6 and TNF-alpha independent of obesity. Forty-three obese (body mass index, BMI>27 kg/m2) men with newly diagnosed obstructive sleep apnea syndrome (OSAS) (apnea-hypopnea index, AHI> or =5) and age- and BMI-matched 22 obese nonapneic male controls (AHI<5) were enrolled in this study. To confirm the diagnosis, all patients underwent standard polysomnography in the sleep disorders center. Serum samples were taken at 08:00 h in the morning after overnight fasting. Serum IL-6 and TNF-alpha levels were found significantly higher in OSAS patients than in controls (p=0.002, p=0.03). Serum IL-6 and TNF-alpha levels were significantly correlated with AHI in OSAS patients (r=0.03, p=0.046 and r=0.36, p=0.016). There was no significant correlation between serum IL-6, TNF-alpha levels and AHI in controls. Serum IL-6 and TNF-alpha levels were not correlated with BMI both in OSAS patients and controls. In conclusion, circulating IL-6 and TNF-alpha levels in patients with OSAS, as independent of BMI are significantly higher than levels in controls and there is a positive relationship between previously mentioned cytokines' levels and the severity of OSAS. According to these results, the link between cardiovascular morbidity and OSAS may be explained by the coexistence of other cardiovascular risk factors such as circulating IL-6 and TNF-alpha levels.     

Non-invasive oxidative stress markers for liver fibrosis development in the evolution of toxic hepatitis

Oxidative stress is related to the liver fibrosis, anticipating the hepatic stellate cells' (HSC) activation. Our aim was to correlate oxidative stress markers with the histological liver alterations in order to identify predictive, noninvasive parameters of fibrosis progression in the evolution of toxic hepatitis.CCl4 in sunflower oil was administered to rats intragastrically, twice a week. After 2, 3, 4 and 8 weeks of treatment, plasma levels of malondialdehyde (MDA), protein carbonyls (PC), hydrogen donor capacity (HD), sulfhydryl groups (SH), and glutathione (GSH) were measured and histological examination of the liver slides was performed. Dynamics of histological disorders was assessed by The Knodell score. Significant elevation of inflammation grade was obtained after the second week of the experiment only (p=0.001), while fibrosis started to become significant (p=0.001) after 1 month of CCl4 administration. Between plasma MDA and liver fibrosis development a good correlation was obtained (r=0.877, p=0.05). Correlation between PC dynamics and liver alterations was marginally significant for inflammation grade (r=0.756, p=0.138). HD evolution revealed a marginally inverse correlation with inflammation grade (r=-0.794, p=0.108). No correlations could be established for other parameters with either inflammation grade or fibrosis stage.Our study shows that MDA elevation offers the best prediction potential for fibrosis, while marginal prediction fiability could be attributed to high levels of plasma PC and low levels of HD.     

Serum cytokines of the 20 Krad-irradiated S. mansoni cercariae vaccinated, primary and superinfected Cercopethicus aethiops aethiops

Appropriate animal models are necessary to better understand the immune response in schistosomiasis. Schistosoma mansoni infection was established using irradiated cercariae in Cercopithecus aethiops aethiops (Grivet monkey) to describe immune responses of the serum cytokines, IL-4, IL-10, IL-12, IFN- gamma, and TNF-alpha. Intraperitoneal irradiated cercariae immunization on three occasions resulted in some differences of cytokine production. In primary infection, IL-4 was significantly raised (p=0.03) in the immunized monkeys, and there was an insignificant increase (p>0.05) in IL-10. However, ova excretion did not influence the cytokines, except in the controls where both IL-4 and IL-10 were significantly increased (p<0.05). In the controls, IL-12 and INF-gamma levels were lower after ova excretion, but the inflammatory TNF-alpha increased (p=0.049) and these findings can be associated with more liver pathogenesis in the group. Thus, this work has indicated the potential importance of anti-schistosome vaccine studies on the grivet monkeys.     

Reduced glucocorticoid sensitivity of monocyte interleukin-6 release in male employees with high plasma levels of tumor necrosis factor-alpha

Cytokine production by monocytes plays a key role in atherosclerosis. In vitro, preincubation of whole blood with tumor necrosis factor (TNF)-alpha regulates interleukin (IL)-6 release from monocytes stimulated with lipopolysaccharide (LPS). We investigated whether plasma levels of TNF-alpha would also relate to LPS-stimulated monocyte IL-6 production and the inhibitory effect of a glucocorticoid on this process. 224 middle-aged men were assigned to three groups according to tertiles of plasma levels of TNF-alpha. Subjects in the highest tertile (high TNF-alpha, n = 75) were compared to those in the lowest (low TNF-alpha, n = 74) and medium tertile (medium TNF-alpha, n = 75), respectively. In vitro monocyte IL-6 release following lipopolysaccharide (LPS)-stimulation was assessed with and without coincubation with incremental doses of dexamethasone. Monocyte glucocorticoid sensitivity was defined as the dexamethasone concentration inhibiting IL-6 release by 50%. Subjects with high TNF-alpha showed more IL-6 release after LPS-stimulation than those with low TNF-alpha (p =.011). Monocyte glucocorticoid sensitivity was lower in subjects with high levels of TNF-alpha than in subjects with low (p =.014) and with medium (p =.044) levels of TNF-alpha. Results held significance when a set of classic cardiovascular risk factors was controlled for. Our findings suggest that elevated plasma levels of TNF-alpha might enhance LPS-stimulated IL-6 release from circulating monocytes. Such a mechanism might contribute to exaggerated monocyte cytokine release in vivo to any LPS-like danger signal such as related to an infection or cellular stress thereby promoting atherosclerosis.     

Prognostic Significance of the Systemic Inflammatory and Immune Balance in Alcoholic Liver Disease with a Focus on Gender-Related Differences

Objectives

Mechanisms of immune regulation in alcoholic liver disease (ALD) are still unclear. The aim of our study was to determine an impact of Th17 / regulatory T (Treg) cells balance and its corresponding cytokine profile on the ALD outcome. Possible gender-related differences in the alcohol-induced inflammatory response were also assessed.

Materials and Methods

147 patients with ALD were prospectively recruited, assigned to subgroups based on their gender, severity of liver dysfunction and presence of ALD complications at admission, and followed for 90 days. Peripheral blood frequencies of Th17 and Treg cells together with IL-1beta, IL-6, IL-17A, IL-23, and TGF-beta1 levels were investigated. Flow cytometry was used to identify T cell phenotype and immunoenzymatic ELISAs for the corresponding cytokine concentrations assessment. Multivariable logistic regression was applied in order to select independent predictors of advanced liver dysfunction and the disease complications.

Results

IL-17A, IL-1beta, IL-6 levels were significantly increased, while TGF-beta1 decreased in ALD patients. The imbalance with significantly higher Th17 and lower Treg frequencies was observed in non-survivors. IL-6 and TGF-beta1 levels differed in relation to patient gender in ALD group. Concentrations of IL-6 were associated with the severity of liver dysfunction, development of ALD complications, and turned out to be the only independent immune predictor of 90-day survival in the study cohort.

Conclusions

We conclude that IL-6 revealed the highest diagnostic and prognostic potential among studied biomarkers and was related to the fatal ALD course. Gender-related differences in immune regulation might influence the susceptibility to alcohol-associated liver injury.     

Early cytokine responses after percutaneous magnetic resonance imaging guided laser thermoablation of malignant liver tumors

An early systemic response induced by magnetic resonance imaging (MRI)-guided interstitial percutaneous laser thermoablation was analyzed in 13 consecutive patients with malignant liver tumors by serum interleukin (IL)-1beta, IL-6, IL-10, tumor necrosis factor (TNF)-alpha, its receptor TNFRI, and C-reactive protein (CRP) levels up to 72h after the procedures. Only IL-6 (p=0.033) and TNFRI (p<0.001) increased statistically significantly after ablation, while the TNF-alpha, IL-1 beta, and IL-10 levels remained unchanged. The peak median CRP response was 92mg/l. There was a dose-dependent correlation between the energy used and the maximum CRP values (tau=0.68, p=0.013). MRI-guided laser thermoablation induced an early systemic inflammatory reaction with statistically significantly elevated IL-6, TNFRI, and CRP levels but not TNF-alpha or IL-10 levels and without procedure-related complications, favoring this procedure as a safe therapeutic alternative for well-selected patients with liver tumors.     

The effects of peritoneal dialysis and hemodialysis on serum tumor necrosis factor-alpha, interleukin-6, interleukin-10 and C-reactive-protein levels

BACKGROUND: Markers of an acute phase reaction, such as C-reactive protein (CRP) or tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6, are predictive for cardiovascular morbidity and mortality in normal subjects and in chronic renal failure patients. In this study, we aimed to investigate serum TNF-alpha, IL-6, IL-10 and CRP levels in continuous ambulatory peritoneal dialysis (CAPD) and hemodialysis (HD) patients. MATERIALS AND METHODS: Serum levels of TNF-alpha, IL-6, IL-10 and CRP levels were measured in 30 patients who were just diagnosed with end-stage renal failure and treated, with 16 CAPD (nine female, seven male) and 14 HD (eight female, six male) patients, before CAPD or HD treatment and after 3 months from the beginning of CAPD or HD in patients with no clinical signs of infection. The control groups were 20 healthy persons of similar age and sex. Serum levels of TNF-alpha, IL-6, IL-10 and CRP were measured by enzyme-linked immunosorbent assay in stable CAPD and HD patients and in healthy persons. RESULTS: The mean serum levels of TNF-alpha, IL-6, IL-10 and CRP showed no significant differences between the CAPD and HD patients for the beginning values and the third month of treatment. However, serum TNF-alpha, IL-6, IL-10 and CRP levels were higher than the control group in the CAPD and HD patients regarding the beginning values and the third month of treatment (p < 0.001). CONCLUSIONS: CAPD and HD of the renal replacement therapy have no effects on serum CRP and cytokines.     

IL-12 is required for antibody-mediated protective immunity against blood-stage Plasmodium chabaudi AS malaria infection in mice.

In this study, we investigated the role of endogenous IL-12 in protective immunity against blood-stage P. chabaudi AS malaria using IL-12 p40 gene knockout (KO) and wild-type (WT) C57BL/6 mice. Following infection, KO mice developed significantly higher levels of primary parasitemia than WT mice and were unable to rapidly resolve primary infection and control challenge infection. Infected KO mice had severely impaired IFN-gamma production in vivo and in vitro by NK cells and splenocytes compared with WT mice. Production of TNF-alpha and IL-4 was not compromised in infected KO mice. KO mice produced significantly lower levels of Th1-dependent IgG2a and IgG3 but a higher level of Th2-dependent IgG1 than WT mice during primary and challenge infections. Treatment of KO mice with murine rIL-12 during the early stage of primary infection corrected the altered IgG2a, IgG3, and IgG1 responses and restored the ability to rapidly resolve primary and control challenge infections. Transfer of immune serum from WT mice to P. chabaudi AS-infected susceptible A/J mice completely protected the recipients, whereas immune serum from KO mice did not, as evidenced by high levels of parasitemia and 100% mortality in recipient mice. Furthermore, depletion of IgG2a from WT immune serum significantly reduced the protective effect of the serum while IgG1 depletion had no significant effect. Taken together, these results demonstrate the protective role of a Th1-immune response during both acute and chronic phases of blood-stage malaria and extend the immunoregulatory role of IL-12 to Ab-mediated immunity against Plasmodium parasites.