Abstract: Impairment of the response of HIV-specific CD8(+) T cells, in spite of the high frequency of occurrence of these cells even in the advanced phase of HIV-1 infection, has been demonstrated. It is also known that new antiretroviral treatments are able to reduce the viral load and partially repair the immunological damage caused by HIV-1, but it is not clear whether the extent of these changes affects the functional profile of HIV-specific CD8(+) T cells. We evaluated, in HIV-1(+) patients undergoing antiretroviral therapy, the HIV-specific CD8(+) subset distribution and their functional capacity as intracellular expression of IFN-gamma, TNF-alpha, and perforin after PMA stimulation. Our results indicate that HIV-1(+)-treated individuals show distributions of HIV-specific CD8 subsets similar to nontreated patients, while the frequency of HIV-specific CD8 cells expressing IFN-gamma and perforin after stimulation is lower in HAART-treated patients. This indicates that HAART, which controls viral replication, may impair the HIV-specific CD8(+) response.

Abstract: Our group has previously reported that a significantly larger proportion of peripheral monocytes from human immunodeficiency virus type 1 (HIV-1) seropositive individuals receiving highly active antiretroviral therapy (HAART) express HLA-G1 and also that one of the HAART components, the nucleoside reverse transcriptase inhibitors (NRTIs), may be involved in this effect. Because protease inhibitors (PIs) are another component of HAART that are administered with NRTIs, the aim of this work was to determine whether or not PIs are also involved in the HLA-G1 changes previously observed in treated HIV-1 positive patients. CD14(+) cells expressing HLA-G1 were therefore measured in 7 HIV-1 positive patients whose initial HAART was changed to a protease inhibitor-only regime due to drug toxicity and/or virologic resistance. Our results indicate that PIs do not appear to be implicated in the rise of HLA-G1 expression on CD14(+) cells from HIV-1 infected individuals receiving HAART, while we further confirm that NRTIs are involved in the surface induction of HLA-G1.

Abstract: The aim of this study was to further determine the immediate influence, over a 12-h period, after the initiation of daily immunosuppressive treatment on the serum levels of sHLA-G in heart transplant patients during the post-transplant period (1 month). It was found that there are two patterns of patients in term of the changes observed in their levels of sHLA-G in response to the immunosuppressive treatment. One group (group A) showed no changes on sHLA-G while the other group (group B) a significant rise in sHLA-G levels was observed at 2 to 4 h post dose. Interestingly, it was observed that the patients in group B have better prognosis of acceptance of the heart graft than those of group A. On the other hand it was found that the patients with high levels of sHLA-G (77.3+/-34.8 ng/ml) in pre-transplant sera have a better prognosis of acceptance of the heart graft than those with low sHLA-G levels (9.7+/-7.1 ng/ml). In conclusion, both the intensity of changes of sHLA-G levels induced by immunosuppression and basal levels in pre-transplant could be used in the monitoring of the immunosuppression as well as the heart transplant evolution.

Abstract: In order to better understand the possible beneficial effects of intermittent IL-2 treatment as complement of antiretroviral therapy in HIV-1+ patients, we have measured the levels of RANTES in the supernatants and the CD25 expression in cultured PBMCs obtained from HIV-1+ individuals in presence of IL-2. The results showed a significant increases in RANTES production and in the expression of CD25+ in the cultures with IL-2 of PBMC obtained from HIV-1+ patients with a detectable viral load in comparison with both, HIV-1+ patients with no detectable viral loads and with healthy individuals. These results suggest that therapeutic IL-2 administered in addition to highly active anti-retroviral therapy (HAART) may contribute to increase the effect of this therapy by rising both RANTES production and CD25 expression only in HIV-1+ patients with detectable viral loads.

Abstract: Tumour necrosis factor-alpha (TNF-alpha) mediates hepatocyte cell death by D-galactosamine (D-GalN) and its protection by prostaglandin E(1) (PGE(1)). The activation of immune system plays an important role in the development of liver injury. TNF-alpha and PGE(1) regulate the activity and cytokine release of different inflammatory cells. The present study was undertaken to determine if the noxious or hepatic protective properties of TNF-alpha during D-GalN-induced liver injury was related to an alteration by PGE(1) of the immunoregulatory activity of TNF-alpha. The role of TNF-alpha was assessed by anti-TNF-alpha antibodies to D-GalN-treated rats in the presence or absence of PGE(1). D-GalN enhanced the percentage of monocytes and T lymphocytes in the total peripheral blood mononuclear cells (PBMCs). D-GalN enhanced the activation degree of monocytes, but reduced that of T lymphocytes. D-GalN also enhanced TNF-alpha, IL-1alpha, IL-6 and IFN-gamma concentrations in blood. Anti-TNF-alpha antibodies abolished all immunological changes and greatly reduced liver damage induced by D-GalN. The protection by PGE(1) against D-GalN liver injury was associated with an increase in TNF-alpha concentration and a reduction of IL-1alpha and IL-6. These changes were associated with a reduction of monocyte activation degree and a recovery of that of T lymphocytes. Although anti-TNF-alpha antibodies abolished the protection by PGE(1) against D-GalN-liver injury, they did not essentially counteract the effect of the prostanoid in all immunological parameters studied. The present study showed that the protection against D-GalN liver damage by PGE(1) or anti-TNF-alpha was associated with similar effects on the inflammatory parameters studied. Nevertheless, the abolishment of liver protection by PGE(1) with anti-TNF-alpha in D-GalN-treated rats in the presence of a protective cytokine profile suggests that the release of TNF-alpha induced by PGE(1) pre-administration was exerting a direct protective effect on hepatocytes against D-GalN injury. Consequently, the effect of PGE(1) on inflammatory parameters studied during liver injury was unrelated to TNF-alpha.

Abstract: BACKGROUND: Tumour necrosis factor-alpha (TNF-5) has been shown to exacerbate or protect against liver injury in different experimental models. In a previous study, we observed that enhancement of TNF-alpha expression in hepatocytes by prostaglandin E1 (PGE1) pre-administration induced iNOS expression and cytoprotection against experimental liver injury in rats. Nevertheless, the reduction of TNF-alpha bioactivity by anti-TNF-alpha antibodies also reduced liver injury by D-GalN. The purpose of the present study was to evaluate whether protection by PGE1 or anti-TNF-alpha was related to a common effect on the membrane-bound TNF-alpha receptor expression. METHODS: Liver injury was induced in male Wistar rats by intraperitoneal injection of D-galactosamine (D-GalN) (1 g/kg). PGE1 or anti-TNF-alpha was administered at 30 or 60 min before D-GalN, respectively. Liver injury was evaluated by alanine aminotransferase (ALT) activity in serum and histological examination in liver sections. TNF-alpha was determined by ELISA in serum. The expression of TNF-alpha receptor type 1 (TNF-R1) and TNF-alpha receptor type 2 (TNF-R2) in hepatocytes was assessed by immunohistochemistry and immunoprecipitation + Western-blot analysis. RESULTS: PGE1 or anti-TNF-alpha reduced liver injury induced by D-GalN. Although PGE1 enhanced and anti-TNF-alpha reduced TNF-alpha concentration in serum, both protective treatments reduced the expression of TNF-R1 in hepatocytes. TNF-R2 was not detected in our experimental conditions. CONCLUSIONS: Our study showed that reduction of liver injury by PGE1 or anti-TNF-alpha antibodies was related to a reduction of TNF-R1 expression in hepatocytes.

Abstract: The aim of this work is to analyze if the highly active antiretroviral therapy (HAART) has any effect in the number of peripheral monocytes expressing the tolerogenic molecule human leukocyte antigen G (HLA-G) in HIV-1 infected individuals. In this sense, expression of HLA-G was measured by flow cytometry on peripheral monocytes from HIV-1 antiretroviral-receiving and antiretroviral naïve patients and in HIV-1 patients at different times after the antiretroviral treatments were removed. It was found an increment of monocytes expressing HLA-G in HIV-1 infected individuals receiving HAART, whereas monocytes from untreated HIV-1 patients did not change. When the HLA-G was measured on monocytes after antiretroviral treatment was removed, the number of peripheral monocytes expressing HLA-G was progressively decreasing. These data suggest that antiretroviral therapy is able to induce the expression of the tolerogenic molecule HLA-G on peripheral monocytes from HIV-1 seropositive individuals.

Abstract: OBJECTIVE: To study the expression of HLA-G on peripheral blood mononuclear cells (PBMC) from HIV-1-infected individuals in order to determine whether this molecule is induced as a consequence of HIV-1 infection. DESIGN: A total of 23 HIV-positive individuals in different stages of the disease were studied. METHODS: Flow cytometric analysis and Western blot were used to measure HLA-G expression on PBMC obtained from HIV-positive and control individuals. RESULTS: Most of the monocytes obtained from HIV-1-infected individuals express HLA-G, whereas only a very low proportion of monocytes from healthy individuals express this molecule. When T lymphocytes from HIV-1 infections were studied, it was found that 30% of them express HLA-G, whereas only 1% were HLA-G-positive in healthy individuals. HLA-G expression was also confirmed by Western blot using specific anti-HLA-G monoclonal antibodies. CONCLUSION: The synthesis of HLA-G is increased in monocytes and certain T lymphocytes from HIV-1-infected individuals.

Abstract: BACKGROUND/AIMS: Prolonged acute-phase response and increase of cytokines have been associated with higher mortality and surgical complications. This study investigated the status of cytokines and acute-phase response markers in patients with obstructive jaundice. METHODOLOGY: Forty-one patients were investigated. Endotoxin, tumor necrosis factor-alpha, interleukin-6, nitric oxide, C-reactive protein, liver enzymes, albumin and percentage of weight loss were determined at admission. RESULTS: Endotoxin, interleukin-6 and C-reactive protein were significantly elevated in both benign and malignant obstructive jaundice. Increased plasma levels of tumor necrosis factor-alpha were only detected in malignant tumors (68 vs. 24 pg/mL; P < 0.001). Patients with positive acute-phase response (C-reactive protein > mean + 2 SD of controls) had greater weight loss (P = 0.02), endotoxin (P = 0.03) and interleukin-6 plasma levels (P = 0.05) than those with no inflammatory response. Prolonged biliary obstruction (> 10 days) was associated with higher weight loss (P = 0.04), tumor necrosis factor-alpha (P = 0.003) and interleukin-6 (P = 0.05) plasma levels. CONCLUSIONS: A prolonged high-grade biliary tract obstruction prompted an increase in endotoxin levels, associated with a positive acute-phase response and cytokine elevation.

Abstract: Patients with obstructive jaundice (OJ) that requires surgery often have malnutrition associated with increased perioperative morbidity. This study investigated the factors influencing nutritional derangements in these patients. A series of 46 OJ patients were investigated prospectively (28 malignant tumors, 18 benign obstructions). A nutritional risk index of < 83.5 was used to define protein-calorie malnutrition. Liver function, cholecystokinin (CCK), tumor necrosis factor-alpha (TNFalpha), and endotoxin levels were determined. A multivariate analysis was performed, and an obstructive jaundice malnutrition index (OJMI) was obtained. Altogether, 22 (48%) OJ patients had malnutrition (33% with benign obstructions, 57% with malignant disease). Malnourished patients had higher serum bilirubin levels (258 +/- 120 vs. 154 +/- 62 mmol/L; p = 0.005), longer duration of jaundice (16 +/- 9 vs. 9 +/- 5 days; p = 0.03), and higher plasma levels of CCK (4.0 +/- 1.3 vs. 1.7 +/- 1.0 pmol/L; p = 0.005), alanine aminotransferase (ALT) (226 +/- 209 vs. 187 +/- 161 UI/L; p = 0.01), endotoxin (15 +/- 10 vs. 6.5 +/- 7.0 EU/L; p = 0.007), and TNFalpha (69 +/- 82 vs. 23 +/- 15 pg/ml; p = 0.008) than those without malnutrition. However, only serum bilirubin, CCK, ALT, and patient age were predictors for malnutrition by multivariate analysis. Malnutrition might be expected (95% confidence interval) in patients older than 68 years with increased bilirubin (> 290 mmol/L) and ALT (> 210 UI/L) levels that corresponded with an OJMI > 55. It was concluded that nutritional alterations in patients with obstructive jaundice were determined by the intensity of the biliary obstruction correlated with increased plasma CCK levels as well as with liver dysfunction and patient age.

Abstract: BACKGROUND: Prostaglandin E1 (PGE1) treatment of humans and rodents during acute hepatic failure ameliorates different parameters of hepatic dysfunction. PURPOSE: To investigate whether prevention of acute liver injury induced by D-galactosamine (D-GalN) with preadministration of PGE1 is correlated with a change in the concentration of two proinflammatory cytokines, as tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1alpha, and/or nitrite+nitrate (NOx), as nitric oxide-related end products in serum. RESULTS: D-GalN significantly increased alanine aminotransferase (ALT) and TNF-alpha concentration in serum 5 and 10 mins, respectively, after treatment compared with the control group (P< or =0.05). D-GalN did not change the IL-1alpha concentration at any time during the study. Preadministration of PGE1 to D-GalN-treated rats significantly reduced the ALT content and increased significantly the TNF-alpha concentration in serum 1, 2.5, 5 and 10 mins after D-GalN treatment compared with the D-GalN group (P< or =0.05). Nitric oxide was not involved in either the toxic effect due to D-GalN or the protection observed with PGE1 against D-GalN toxicity. CONCLUSIONS: Acute liver injury induced by D-GalN is correlated with an increased TNF-alpha release. Preadministration of PGE1 to D-GalN-treated rats exerted a priming effect on inflammatory cells to release enhanced levels of TNF-alpha but not IL-1alpha. These findings indicate that stimulation of TNF-alpha release may be involved in the acute D-GalN-induced liver injury and also in PGE1 protection from hepatotoxicity in clinical and experimental studies.

Abstract: BACKGROUND: Tumour necrosis factor alpha (TNF-alpha) and nitric oxide modulate damage in several experimental models of liver injury. We have previously shown that protection against D-galactosamine (D-GalN) induced liver injury by prostaglandin E(1) (PGE(1)) was accompanied by an increase in TNF-alpha and nitrite/nitrate in serum. AIMS: The aim of the present study was to evaluate the role of TNF-alpha and nitric oxide during protection by PGE(1) of liver damage induced by D-GalN. METHODS: Liver injury was induced in male Wistar rats by intraperitoneal injection of 1 g/kg of D-GalN. PGE(1) was administered 30 minutes before D-GalN. Inducible nitric oxide synthase (iNOS) was inhibited by methylisothiourea (MT), and TNF-alpha concentration in serum was lowered by administration of anti-TNF-alpha antibodies. Liver injury was evaluated by alanine aminotransferase activity in serum, and histological examination and DNA fragmentation in liver. TNF-alpha and nitrite/nitrate concentrations were determined in serum. Expression of TNF-alpha and iNOS was also assessed in liver sections. RESULTS: PGE(1) decreased liver injury and increased TNF-alpha and nitrite/nitrate concentrations in serum of rats treated with D-GalN. PGE(1) protection was related to enhanced expression of TNF-alpha and iNOS in hepatocytes. Administration of anti-TNF-alpha antibodies or MT blocked the protection by PGE(1) of liver injury induced by D-GalN. CONCLUSIONS: This study suggests that prior administration of PGE(1) to D-GalN treated animals enhanced expression of TNF-alpha and iNOS in hepatocytes, and that this was causally related to protection by PGE(1) against D-GalN induced liver injury.

Abstract: Prostaglandin E1 has hepatoprotective properties in several clinical and experimental models of liver dysfunction. Hepatotoxicity induced by D-galactosamine (D-GalN) is a suitable animal model of human acute hepatic failure. The aim of the study was to investigate if prostaglandin E1 (PGE1) protection against hepatic D-GalN-induced apoptosis was related to tumour necrosis factor-alpha (TNF-alpha) content in serum. This cytokine is associated with in vitro apoptosis and general inflammatory disorders. In this study, PGE1 was administered 30 min before D-GalN to rats. In other experiments, several doses of TNF-alpha were administered 15min after PGE1 to D-Ga1N-treated rats. Several parameters related to apoptosis and necrosis were measured by flow cytometry, gel electrophoresis, biochemical analysis, and optical and electron microscopy. Tumour necrosis factor-alpha was quantified by competitive enzyme-linked immunosorbent assay (ELISA). PGE1 by itself did not modify the cell cycle of hepatocytes and liver toxicity, but increased TNF-alpha in serum in comparison with the control group. D-Galactosamine increased the percentage of hepatocytes in apoptosis and in the S phase of the cell cycle, and decreased those in G0/G1. Such an increase of hepatocytes in apoptosis was correlated with a higher number of apoptotic bodies and DNA fragmentation in liver than control samples. Also, D-GalN increased alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase and TNF-alpha in serum compared with the control group. Pre-administration of PGE1 to D-GalN-treated rats reduced all the parameters of apoptosis and necrosis in liver, and increased additionallyTNF-alpha content in serum. In those experiments where low doses of TNF-alpha were administered to PGE1 and D-GalN-treated rats an inverse relationship appeared between TNF-alpha and ALT content in serum. In conclusion, the protective effects of PGE1 on D-GalN-induced apoptosis may be linked to its capacity to modulate cell division and/or its immunomodulatory activity. In this sense, our experimental results suggest that TNF-alpha could be involved in protection or exacerbation of liver damage in relation to the pathophysiological status of the liver.