IgA triggers tumor necrosis factor alpha secretion by monocytes: a study in normal subjects and patients with alcoholic cirrhosis

Under endotoxin-free conditions, peripheral blood mononuclear cells and purified monocytes isolated from healthy control subjects and patients with alcoholic cirrhosis disclose elevated tumor necrosis factor alpha messenger RNA level and produce tumor necrosis factor alpha in response to stimulation by either soluble polymeric IgA or monomeric IgA bound to the surface of culture dishes but not by soluble monomeric IgA. Polymeric IgA induces tumor necrosis factor alpha secretion in a dose-dependent fashion. These results suggest that cross-linking of Fc alpha receptors on human monocytes induces the messenger RNA accumulation and the secretion of the cytotoxic and immunoregulatory cytokine tumor necrosis factor alpha. Furthermore, it is shown that lipopolysaccharide-induced tumor necrosis factor alpha secretion by peripheral blood mononuclear cells is synergistically enhanced in the presence of solid phase monomeric IgA but not in the presence of either soluble monomeric or polymeric IgA. Although increased lipopolysaccharide-induced tumor necrosis factor alpha secretion is observed at baseline in alcoholic cirrhotic patients, this synergism is also expressed in this group of patients. These observations could be of pathophysiological relevance in alcoholic cirrhosis because monomeric IgA deposits along the liver sinusoids and increased serum levels of polymeric IgA are common even in the early stages of this disease.     

Enhanced production of interleukin-1 and tumor necrosis factor alpha by cultured peripheral blood monocytes from patients with scleroderma

Cultured peripheral blood mononuclear cells from 20 patients with scleroderma were shown to produce high levels of interleukin-1 alpha, interleukin-1 beta, and tumor necrosis factor alpha. There were positive correlations between the production of these 3 molecules. Purified monocytes from these patients produced much more tumor necrosis factor alpha than did those from normal subjects, even without lipopolysaccharide stimulation. These results show the hyperactivity of monocytes from scleroderma patients.     

Increased tumor necrosis factor production by monocytes in alcoholic hepatitis

Tumor necrosis factor is a cytokine that mediates many of the biologic actions of endotoxin. Recent studies have shown that tumor necrosis factor administration may cause liver injury and that tumor necrosis factor may mediate the lethality of the hepatotoxin galactosamine. One of the most potent inducers of tumor necrosis factor production is endotoxin. Because patients with alcoholic liver disease frequently have endotoxemia and because many of the clinical manifestations of alcoholic hepatitis are known biologic actions of tumor necrosis factor, we thought it would be important to evaluate tumor necrosis factor activity in patients with alcoholic hepatitis. Basal and lipopolysaccharide-stimulated tumor necrosis factor release from peripheral blood monocytes, a major source of tumor necrosis factor production, was determined in 16 patients with alcoholic hepatitis and 16 healthy volunteers. Eight of 16 alcoholic hepatitis patients and only two of 16 healthy volunteers had detectable spontaneous tumor necrosis factor activity (p less than 0.05). After lipopolysaccharide stimulation, mean monocyte tumor necrosis factor release from alcoholic hepatitis patients was significantly increased to over twice that of healthy controls (25.3 +/- 3.7 vs. 10.9 +/- 2.4 units per ml, p less than 0.005). We conclude that monocytes from alcoholic hepatitis patients have significantly increased spontaneous and lipopolysaccharide-stimulated tumor necrosis factor release compared to monocytes from healthy volunteers. We suggest that some of the metabolic abnormalities and possibly some of the liver injury of alcoholic hepatitis may be due to enhanced tumor necrosis factor production.     

Tumor necrosis factor alpha production by peripheral blood mononuclear cells of patients with chronic liver disease

We investigated the production of tumor necrosis factor alpha by peripheral blood mononuclear cells of patients with chronic liver disease and its association with hepatitis activity. Tumor necrosis factor alpha production was measured with an enzyme-linked immunosorbent assay. Tumor necrosis factor alpha production by peripheral blood mononuclear cells stimulated with recombinant gamma-interferon of patients with chronic active hepatitis (5.8 +/- 4.0 units per ml, p less than 0.05) and patients with cirrhosis (4.1 +/- 2.1 units per ml, p less than 0.05) was significantly increased when compared with controls (2.5 +/- 1.6 units per ml). Tumor necrosis factor alpha production by peripheral blood mononuclear cells stimulated with a combination of recombinant gamma-interferon and recombinant interleukin 2 of patients with chronic persistent hepatitis (5.8 +/- 3.8 units per ml, p less than 0.05), patients with chronic active hepatitis (8.9 +/- 3.0 units per ml, p less than 0.001) and patients with cirrhosis (6.7 +/- 3.2 units per ml, p less than 0.05) was significantly increased in comparison with controls (3.3 +/- 1.8 units per ml). Tumor necrosis factor alpha production of patients with chronic active hepatitis was significantly higher than that of patients with chronic persistent hepatitis (p less than 0.05). There was a significant correlation (r = 0.5699, p less than 0.005) between tumor necrosis factor alpha production and histologic activity index in patients with chronic persistent hepatitis or chronic active hepatitis. These findings show that tumor necrosis factor alpha production is increased in chronic liver disease and that the increased tumor necrosis factor alpha production is related to hepatitis activity.     

Impaired lipopolysaccharide-inducible tumor necrosis factor production in vitro by peripheral blood monocytes of patients with viral hepatitis

We investigated lipopolysaccharide-induced tumor necrosis factor production in vitro by peripheral blood monocytes from patients with various liver diseases. Tumor necrosis factor production was found to be significantly reduced in patients with chronic hepatitis B (n = 17; 135 +/- 30 pg tumor necrosis factor/ml; mean +/- S.E.M.) and patients with chronic non-A, non-B hepatitis (n = 15; 212 +/- 22 pg tumor necrosis factor/ml) compared with healthy control individuals (n = 47; 411 +/- 40 pg tumor necrosis factor/ml; p less than 0.0005 and p less than 0.01, respectively). This reduced tumor necrosis factor production was not only seen with an optimal stimulating concentration of lipopolysaccharide (100 ng/ml) but also with suboptimal concentrations (0.1 ng/ml). In contrast to patients with chronic viral hepatitis, monocytes from patients with alcohol-induced cirrhosis (n = 26; 444 +/- 49 pg tumor necrosis factor/ml), primary biliary cirrhosis (n = 7; 412 +/- 81 pg tumor necrosis factor/ml) and alcohol-induced fatty liver changes (n = 5; 401 +/- 62 pg tumor necrosis factor/ml) produced normal amounts of tumor necrosis factor when stimulated with an optimal concentration of lipopolysaccharide. Lipopolysaccharide (0.1 ng lipopolysaccharide/ml)-stimulated peripheral blood monocytes of patients with chronic hepatitis B (n = 15; 102 +/- 32 pg/ml) or non-A, non-B hepatitis (n = 13; 97+/- 16 pg/ml) could not be induced to produce more tumor necrosis factor either when prestimulated with gamma-interferon (170 +/- 45 pg/ml and 149 +/- 32 pg/ml, respectively), a lymphokine known to activate monocytes, or with the cyclooxygenase inhibitor indomethacin to reduce the suppressive effect of prostaglandin E2 (148 +/- 40 pg/ml and 153 +/- 45 pg/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Blood neutrophil functions and cytokine release in severe alcoholic hepatitis: effect of corticosteroids

BACKGROUND/AIMS: Several observations point to an important role of interactions between polymorphonuclear neutrophils and cytokines in severe alcoholic hepatitis. The polymorphonuclear neutrophil activation status and the local and systemic pro- and anti-inflammatory cytokine responses were quantified. The effect of corticosteroids, widely used in this setting, was evaluated using these parameters. METHODS: We studied blood polymorphonuclear neutrophil functions in terms of L-selectin and beta2-integrin expression, H2O2 production and IL-8 and tumor necrosis factor alpha synthesis capacity. We also measured IL-8, tumor necrosis factor alpha and IL-10 plasma and liver tissue levels. Fifteen patients with alcoholic hepatitis were compared to 15 patients with alcoholic cirrhosis without alcoholic hepatitis, and to 10 healthy volunteers. The impact of a 28-day course of corticosteroids on blood neutrophils activation status and cytokine levels was evaluated in patients with alcoholic hepatitis. RESULTS: Blood polymorphonuclear neutrophils were activated, as shown by increased H2O2 production (48+/-6 vs 29+/-6 MFI in healthy controls), and decreased L-selectin expression (300+/-61 vs 449+/-59 in healthy controls). Upon stimulation, polymorphonuclear neutrophils synthesized large amounts of IL-8 (21.7+/-9.2 ng/ml vs 8.8+/-10 ng/ml in healthy controls) and tumor necrosis factor alpha (524+/-132 pg/ml vs 79+/-144 pg/ml in healthy controls). Tumor necrosis factor alpha and IL-8 plasma and tissue levels were markedly increased as IL-10 was barely detectable in alcoholic hepatitis patients, compared to cirrhotic patients and healthy controls. During steroid therapy, plasma levels of the pro-inflammatory cytokine IL-8 fell as early as day 14, while levels of the anti-inflammatory cytokine IL-10 increased on day 21. Finally, polymorphonuclear neutrophil functions returned to normal after treatment. CONCLUSION: Severe alcoholic hepatitis appears to be associated with polymorphonuclear neutrophil activation and an imbalance between pro- and anti-inflammatory cytokines; during steroid therapy a normalization of these parameters was observed.     

Effect of flurbiprofen on cytokine production by human monocytes and U-937 and THP-1 cell lines.

Possible effects of nonsteroidal antiinflammatory drugs (NSAID) on inflammatory mediators other than arachidonic acid metabolites which might contribute to the antiinflammatory effects of these drugs have not been fully explored. We investigated the effects of an NSAID, flurbiprofen, on production of the cytokines tumor necrosis factor alpha (TNF alpha), interleukin 1 beta (IL-1 beta) and interleukin 6 (IL-6) by human peripheral blood monocytes and by the human cell lines U-937 and THP-1. Cytokine production was induced by 1 microgram/ml bacterial lipopolysaccharide (LPS) in both monocytes and cell lines, and cytokine levels in supernatants were measured by enzyme immunoassay. In monocytes, IL-6 was the major product while in both cell lines, TNF alpha was the major product. Flurbiprofen caused moderate inhibition of IL-1 beta and TNF alpha production by stimulated monocytes, but did not affect IL-6 production. In contrast, flurbiprofen completely abolished IL-6 production by both cell lines and substantially inhibited IL-1 beta and TNF alpha production. These observations raise the possibility that inhibition of cytokine production by flurbiprofen may contribute to the antiinflammatory properties of this drug.     

酒精性肝硬化患者体外单核细胞肿瘤坏死因子及其受体的表达

为调查酒精性肝硬化（ＡＣ）患者周围血单核细胞肿瘤坏死因子（ＴＮＦα）和可溶性肿瘤坏死因子受体（ｓＴＮＦＲ）自然表达和是否通过内毒素脂多糖（ＬＰＳ）或酒精刺激后表达增强，用酶联免疫吸附试验（ＥＬＩＳＡ）对其进行了定量测定。结果示ＡＣ组ＴＮＦα和ｓＴＮＦＲｐ５５、ｐ７５自然表达较正常组增强。经ＬＰＳ刺激后ＴＮＦα、ｓＴＮＦＲｐ５５、ｐ７５的表达不论在ＡＣ组还是健康组均较自发性表达增加，但ＡＣ组较正常组明显增高，Ｐ值分别＜０．０５，＜０．０１，＜０．０５。经酒精刺激后不论ＡＣ组还是正常组ＴＮＦα、ｓＴＮＦＲｐ５５的表达与自发性表达无差异，虽然ｓＴＮＦＲｐ７５的表达较正常组增高，但这种差异在自发性表达中已显示出来。这些结果提示ＡＣ组血清中ＴＮＦα和ｓＴＮＦＲ水平升高与体内单核细胞活化有关，它的活化受其内毒素影响，酒精对其活化未显示直接作用。持续性ＴＮＦα和ｓＴＮＦＲ水平增高是促进ＡＣ发生和发展的重要因素。     

Coordinated antiinflammatory effects of interleukin 4: interleukin 4 suppresses interleukin 1 production but up-regulates gene expression and synthesis of interleukin 1 receptor antagonist.

Interleukin 1 receptor antagonist (IL-1ra), a naturally occurring polypeptide with amino acid sequence homology to interleukin 1 alpha (IL-1 alpha) and interleukin 1 beta (IL-1 beta), prevents Escherichia coli-induced shock and death. Both IL-1 and IL-1ra are produced by monocytes stimulated with lipopolysaccharide (LPS). Because interleukin 4 (IL-4) suppresses IL-1 production, we investigated whether IL-4 modulated IL-1ra synthesis in LPS-stimulated human peripheral blood mononuclear cells. IL-1 beta and IL-1ra were measured by specific RIAs. IL-4 alone (0.01-100 ng/ml) did not stimulate IL-1 beta synthesis but rather induced IL-1ra (4.82 +/- 0.94 ng/ml). LPS induced synthesis of both IL-1 beta (6.67 +/- 1.06 ng/ml) and IL-1ra (10.77 +/- 2.79 ng/ml). IL-4 suppressed LPS-induced IL-1 beta mRNA accumulation and synthesis. However, IL-4 acted synergistically with LPS in inducing IL-1ra. IL-4 enhanced LPS-induced IL-1ra mRNA accumulation 4-fold and IL-1ra protein synthesis nearly 2-fold. Moreover, IL-1ra mRNA levels were maximal after 6 hr of exposure to LPS but peaked within the first 3 hr in the presence of IL-4. IL-4 added as late as 12 hr after LPS stimulation still enhanced IL-1ra synthesis. In human peripheral blood mononuclear cells stimulated with IL-1 alpha, IL-4 markedly suppressed IL-1 beta production but enhanced IL-1ra synthesis greater than 2-fold. Because IL-4 favors synthesis of the natural antagonist IL-1ra over synthesis of the agonist IL-1, IL-4 may exert potent antiinflammatory effects on host responses to Gram-negative infections.     

Soluble interleukin 2 receptor in acute viral hepatitis and chronic liver disease

Serum levels of soluble interleukin 2 receptor were determined in patients with acute viral hepatitis and patients with various chronic liver diseases. In addition, the ability of peripheral blood mononuclear cells of patients with alcoholic cirrhosis to generate soluble interleukin 2 receptor following mitogenic stimulation was studied in vitro. Serum soluble interleukin 2 receptor concentrations in all patients with acute viral hepatitis were found to be significantly elevated (1,319 +/- 527 units per ml) during the first week after onset of disease, as compared to healthy control individuals (375 +/- 102 units per ml; p less than 0.0005) and declined toward normal levels during the course of the illness. Similarly, patients suffering from chronic liver disease such as alcoholic liver cirrhosis (1,172 +/- 507 units per ml), primary biliary cirrhosis (619 +/- 190 units per ml) or chronic active HBsAg+ hepatitis (941 +/- 357 units per ml) showed increased serum soluble interleukin 2 receptor concentrations (p less than 0.0005 vs. controls, respectively). In vitro mitogen stimulation of peripheral mononuclear cells derived from patients with alcoholic cirrhosis resulted in a soluble interleukin 2 receptor production not different from that seen in healthy individuals, suggesting that elevated soluble interleukin 2 receptor serum levels seen in this disease are not the result of an increased synthesis by circulating lymphocytes. Due to the ability of soluble interleukin 2 receptor to bind free interleukin 2--thus making it a potential immunoregulatory molecule--its high serum levels could explain some of the immunologic abnormalities observed in acute and chronic liver disease.     

Endotoxin clearance and its relation to hepatic and renal disturbances in rats with liver cirrhosis

BACKGROUND/AIMS: Little is known about endotoxin clearance and secretion of cytokines from macrophages in liver cirrhosis. The aims of this study were to investigate the relationship of endotoxin clearance and release of tumor necrosis factor alpha by various macrophages to hepatic and renal disturbances in liver cirrhosis. Methods: Male Sprague-Dawley rats were given 0.04% thioacetamide orally for 6 or 12 months. The organ distribution of infused [3H]-endotoxin (10 microg/kg b.w.) was analyzed at 30 min or at 24 h. Uptake of [3H]-endotoxin and secretion of tumor necrosis factor alpha by Kupffer cells, splenic macrophages and peripheral blood monocytes (1 x 10(4) cells/ml) from cirrhotic and control rats were determined. RESULTS: In cirrhotic rats, more endotoxin was left in the body and more endotoxin accumulated in the spleen and kidney, and thus was related to elevation of serum total bilirubin, aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, creatinine and tumor necrosis factor alpha. Endotoxin uptake and tumor necrosis factor alpha release by the Kupffer cells were decreased and those by the splenic macrophages and peripheral blood monocytes were increased in cirrhotic rats. CONCLUSIONS: In liver cirrhosis, impaired clearance of endotoxin together with increased secretion of tumor necrosis factor alpha by extrahepatic macrophages may play an important role in the progression of hepatic and renal disturbances.     

Production of cytokines by peripheral blood monocytes/macrophages infected with human immunodeficiency virus type 1 (HIV-1)

The study of monocyte/macrophage functions after human immunodeficiency virus type 1 (HIV-1) infection may help in understanding the pathogenesis of AIDS. The production of four cytokines, tumor necrosis factor alpha (TNF alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6), and granulocyte-macrophage colony-stimulating factor (GM-CSF), by peripheral blood monocytes/macrophages was evaluated after in vitro infection with HIV-1. HIV-1 infection of these monocytes/macrophages did not result in release of any of these cytokines. Similarly, treatment of uninfected cells with purified recombinant HIV-1 envelope protein did not result in cytokine production. After stimulation with endotoxin or endotoxin plus interferon-gamma, HIV-1-infected monocytes/macrophages produced amounts of TNF alpha, IL-6, GM-CSF, and IL-1 beta comparable to that of uninfected cells. HIV-1 infection does not appear to induce or alter cytokine production by mononuclear phagocytes, which retain the capacity to produce these cytokines after endotoxin stimulation.     

The role of monocyte-derived hemopoietic growth factors in the regulation of myeloproliferation in juvenile chronic myelogenous leukemia

Juvenile chronic myelogenous leukemia (JCML) is a rare pediatric malignancy characterized by marked hepatosplenomegaly, leukocytosis with prominent monocytosis, elevated fetal hemoglobin, no Philadelphia chromosome, and generally a poor prognosis. In vitro, JCML peripheral blood granulocyte-macrophage progenitors (granulocyte-macrophage colony-forming units, CFU-GM) demonstrate the unique characteristic of "spontaneous" proliferation at very low cell densities in the absence of exogenous growth factors. The "spontaneous" CFU-GM proliferation can be abolished by prior adherent cell (monocyte) depletion, suggesting a paracrine mode of cellular proliferation. Although previous studies using a [3H]thymidine ([3H]TdR) incorporation assay suggested an important role for granulocyte-macrophage colony-stimulating factor (GM-CSF) in JCML, many non-growth factor-related reasons for [3H]TdR incorporation and the relatively low level of inhibition of [3H]TdR uptake left those conclusions open to question. Therefore, we performed clonal CFU-GM assays, which more specifically reflect cytokine effects on CFU-GM, using JCML peripheral blood mononuclear cells (PBMNC) and neutralizing antibodies against GM-CSF, granulocyte colony-stimulating factor (G-CSF), macrophage colony-stimulating (M-CSF), interleukin 3 (IL-3), interleukin 1 alpha (IL-1 alpha), interleukin 1 beta (IL-1 beta), interleukin 4 (IL-4), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF alpha), and interferon gamma (IFN gamma). Cultures containing anti-GM-CSF alone inhibited "spontaneous" JCML CFU-GM by 87% +/- 9% (mean +/- standard error of the mean [SEM]). No other anti-cytokine antibody produced a significant inhibition of CFU-GM growth. Various combinations of antibodies, excluding anti-GM-CSF, failed to demonstrate any synergistic inhibitory effects upon CFU-GM. Because this apparent paracrine cellular stimulation could be due to excessive cytokine production, by monocytes or other accessory cells, we examined cytokine levels in conditioned media from various JCML cell populations using enzyme-linked immunosorbent assays (ELISAs). Monocytes from only a minority of JCML patients produced higher than normal quantities of GM-CSF, G-CSF, IL-1 beta, IL-6, and/or TNF alpha, but no obvious pattern could be discerned. Further, only 7 of 15 JCML monocyte-conditioned media (MCM) had elevated GM-CSF, and 6 of 15 JCML patients had normal levels of all nine cytokines tested. The monocyte depletion experiments and the inhibition experiments with anti-cytokine antibodies taken together demonstrate clearly that the "spontaneous" growth of JCML CFU-GM in vitro critically depends on at least one monocyte-derived growth factor, GM-CSF.(ABSTRACT TRUNCATED AT 400 WORDS)     

Blunted anti-inflammatory response to adenosine in alcoholic cirrhosis.

BACKGROUND/AIM: Adenosine is an endogenous nucleoside that is released under metabolically unfavourable circumstances such as ischaemia or infection. It exerts potent anti-inflammatory effects by decreasing tumour necrosis factor release and costimulating interleukin-10 production by human monocytes. The aim of this study was to assess the cytokine response to adenosine in whole blood cultures from alcoholic cirrhotic patients. METHODS: Whole blood from 17 patients and 17 healthy controls stimulated with lipopolysaccharide was cultured in the presence of adenosine at different concentrations and, in some experiments, with the adenosine deaminase inhibitor deoxycoformycin. Peripheral blood mononuclear cell response was compared to whole blood, and plasma adenosine deaminase activity was measured. RESULTS: Adenosine (100 microM) significantly inhibited TNF release and increased IL-10 production in whole blood cultures from controls stimulated with lipopolysaccharide, but not from cirrhotic patients. However, the response to adenosine was restored in peripheral mononuclear cells of patients in the absence of autologous plasma. To test the hypothesis that plasma adenosine deaminase, which was increased in the patients' plasma, was actually involved in this blunted response to adenosine in alcoholic cirrhosis, we performed adenosine dose-response experiments and pharmacologically blocked adenosine deaminase activity with deoxycoformycin. In both kinds of experiment, adenosine-induced inhibition of TNF release could be restored in alcoholic cirrhotic patients. CONCLUSIONS: These data indicate that increased circulating adenosine deaminase activity blunts the anti-inflammatory properties of adenosine in alcoholic cirrhotic patients.     

Plasma Tumor Necrosis Factor α Predicts Decreased Long-Term Survival in Severe Alcoholic Hepatitis

Plasma tumor necrosis factor alpha (TNF alpha), interleukin 1 alpha (IL-1 alpha), and interleukin 1 beta (IL-1 beta) were measured in plasma samples obtained from 23 patients with severe alcoholic hepatitis on admission and after 30 days of hospitalization. Over a 2-year follow-up period, 14 patients died at a mean time of 8 months following discharge. The presence of elevated plasma TNF alpha either at admission or discharge from the hospital was associated with death in 82% (14/17) of patients. By contrast absence of elevated plasma TNF alpha was associated with survival in 100% (6/6). The difference in survival with and without detectable plasma TNF alpha was significant at p = 0.0022. Plasma TNF alpha was not elevated in alcoholic patients without clinically apparent liver disease, with alcoholic cirrhosis, or in nonalcoholic healthy controls. Plasma IL-1 alpha was also significantly increased in alcoholic hepatitis whereas IL-1 beta was not. Neither IL-1 alpha nor beta was correlated with outcome in the alcoholic hepatitis group. It is concluded that the presence of elevated plasma TNF alpha is a significant predictor of decreased long-term survival in patients with severe alcoholic hepatitis.     

Interleukin 1 beta and tumour necrosis factor alpha stimulate the release of gonadotropin-releasing hormone and interleukin 6 by primary cultured rat hypothalamic cells

The abilities of recombinant human interleukin 1 beta and tumour necrosis factor alpha to induce release of GnRH and interleukin 6 from primary culture of rat hypothalamic cells were examined. The effect of estradiol on the release of interleukin 6 by these cells was also tested. Both interleukin 1 beta and tumour necrosis factor alpha caused significant stimulation of GnRH secretion from the hypothalamic cells within 5 min. The hypothalamic cells secreted interleukin 6 spontaneously, and their secretion over 24 h was stimulated dose-dependently by interleukin 1 beta, tumour necrosis factor alpha and estradiol. These results suggest that interleukin 1 beta and tumour necrosis factor alpha stimulate the secretions of GnRH and interleukin 6 in the hypothalamus, and that these cytokines may be involved in the mechanism of GnRH secretion in the hypothalamus.     

Circulating tumor necrosis factor, interleukin-1 and interleukin-6 concentrations in chronic alcoholic patients

Although altered cytokine homeostasis has been implicated in the pathogenesis of alcoholic liver disease, the relationship between cytokines and metabolic consequences of alcoholic liver disease is unknown. We, therefore, sought to correlate circulating concentrations of tumor necrosis factor-alpha, interleukin-1 and interleukin-6 to clinical and biochemical parameters of liver disease in chronic alcoholic patients. We used an enzyme-linked immunosorbent assay to measure plasma tumor necrosis factor and interleukin-1 and a bioassay to measure serum interleukin-6 in three groups of alcoholic men as follows: (a) actively drinking alcoholic men without evidence of chronic liver disease, (b) nondrinking alcoholic men with stable cirrhosis and (c) patients with acute alcoholic hepatitis. Mean cytokine concentrations were elevated in cirrhotic patients and alcoholic hepatitis patients compared with controls and alcoholic patients without liver disease. Tumor necrosis factor-alpha and interleukin-1 alpha concentrations remained elevated for up to 6 mo after diagnosis of alcoholic hepatitis, whereas interleukin-6 normalized in parallel with clinical recovery. Concentrations of all three cytokines were correlated with biochemical parameters of liver injury and hepatic protein synthesis plus serum immunoglobulin concentrations. We could not demonstrate a relationship between cytokine concentrations and peripheral endotoxemia. Percentages of peripheral blood monocytes that reacted with monoclonal antibodies to CD25 (interleukin-2 receptor) and human lymphocyte antigen-DR were similar for alcoholic patients and controls. These data suggest that tumor necrosis factor-alpha and interleukin-1 alpha are related to some of the metabolic consequences of both acute and chronic alcohol-induced liver disease, whereas interleukin-6 is related to abnormalities seen in acute liver injury.     

Human T-cell leukemia virus type I infection of monocytes and microglial cells in primary human cultures.

The pathogenesis of progressive spastic paraparesis [HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP)], a serious consequence of human T-cell leukemia virus type I (HTLV-I) infection, is unclear. T and B lymphocytes can be naturally infected by HTLV-I, but the susceptibility to HTLV-I infection of other cell types that could contribute to the pathogenesis of HAM/TSP has not been determined. We found that a human monocyte cell line (THP-1), primary human peripheral blood monocytes, and isolated microglial cells but not astrocytes or oligodendroglial cells derived from adult human brain were infected by HTLV-I in vitro. Infection with HTLV-I enhanced the secretion of interleukin 6 in human microglial cell-enriched cultures but did not stimulate the release of interleukin 1 from monocytes or microglial cells. Tumor necrosis factor alpha production was stimulated by HTLV-I infection of monocytes and microglial cells and could be enhanced by suboptimal amounts of lipopolysaccharide. Since both tumor necrosis factor alpha and interleukin 6 have been implicated in inflammatory demyelination and gliosis, our findings suggest that human microglial cells and monocytes infected with and activated by HTLV-I could play a role in the pathogenesis of HAM/TSP.     

Preactivated peripheral blood monocytes in patients with essential hypertension.

The purpose of this study was to investigate the possible involvement of human peripheral blood monocytes in the pathology of hypertensive disease. We determined the in vitro secretion patterns of proinflammatory cytokines obtained from isolated peripheral monocytes from normal controls and from hypertensive patients either after in vitro stimulation with angiotensin II (Ang II) with or without preincubation with an Ang II type 1 receptor antagonist (losartan) or after stimulation with lipopolysaccharide. Blood samples were obtained from 22 patients with essential hypertension (before any drug administration or after interruption of antihypertensive therapy) and from 24 normotensive healthy individuals used as a control group. Peripheral blood monocytes were isolated by density gradient centrifugation and plastic adherence. The state of monocyte activity was determined by the capacity to secrete tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), and interleukin-6, (IL-6) either spontaneously or after stimulation. Cytokine concentrations were determined in culture supernatants by specific ELISA. Proinflammatory cytokine levels were assessed by semiquantitative reverse transcribed polymerase chain reaction. After stimulation with Ang II, the IL-1beta secretion of peripheral blood monocytes was significantly increased in hypertensive patients versus healthy individuals (P<0.05). In contrast, in monocytes preincubated with losartan before exposure to Ang II, IL-1beta secretion was diminished in both groups to comparable levels. The secretion of IL-1beta and TNF-alpha was significantly increased in peripheral blood monocytes from hypertensive patients versus healthy individuals after stimulation with lipopolysaccharide (TNF-alpha, P<0.02; IL-1beta, P<0.05). Upregulation of IL-1beta and TNF-alpha secretion in peripheral blood monocytes from hypertensive patients was also seen at the RNA level. Our results indicate preactivated peripheral blood monocytes in hypertensive patients. Ang II may be directly involved in the process of monocyte activation.