Temporal trends of circulating nitric oxide and pro-inflammatory cytokine responses ex vivo in intra-abdominal sepsis: results from a cohort study.

OBJECTIVE AND DESIGN: To evaluate the association of pro-inflammatory mediators with organ dysfunction and adverse outcome in intra-abdominal sepsis patients. SUBJECTS: Twenty-one patients admitted to the Intensive Care Unit (ICU) were prospectively included in the study. Only patients with surgical diagnosis of intra-abdominal sepsis were enrolled. RESULTS: Tumor necrosis factor-α (TNFα) and interleukin (IL)-6 produced ex vivo were significantly lower in non-survivors on admission (p = 0.021) and day 2 (p = 0.013), respectively. Nitric oxide (NO(x)) levels were significantly higher in non-survivors from the onset of sepsis and until day 4 after diagnosis (p < 0.05). Circulating lymphocyte counts were lower in non-survivors after admission over time, but there was no association with impaired cytokine production in this group of patients during the entire follow-up. All non-survivors developed nosocomial pneumonia concomitantly with multiple organ dysfunction and septic shock. There was a significant correlation between nitric oxide (NO(x)) concentrations and the sequential organ failure assessment (SOFA) score at day 2 (r = 0.598, p = 0.009), and ICU stay (r = 0.605, p = 0.006). Continuously high NO(x) levels correlated with organ failure. The pro-inflammatory mediators TNFα, IL-6 and NO(x), and also the Simplified Acute Physiology Score II (SAPS-II), discriminate survivors from non-survivors. According to logistic regression models, although these parameters are independently associated with the outcome, they do not improve the predictive power of the SAPS-II score for mortality risk. CONCLUSIONS: Disturbances in inflammatory responses and increase in NO(x) generation seem to characterize early intra-abdominal sepsis, in which immune suppression is associated with an increased susceptibility to nosocomial infections. Sequential NO(x) determinations could be a useful approach for improving the management of patients with intra-abdominal sepsis.

Induction of IgA and sustained deficiency of cell proliferative response in chronic hepatitis C.

AIM: In the present study, antibody and peripheral blood mononuclear cells (PBMC) proliferative responses against hepatitis C virus (HCV) antigens were evaluated in HCV chronically infected patients. METHODS: Paired serum and PBMC samples were taken six months apart from 34 individuals, either treated or not, and tested by enzyme-linked immunosorbent assay (ELISA) and carboxyfluorescein succinimidyl ester staining. RESULTS: Over 70% of the patients showed specific IgG and IgM against capsid, E1 and NS3, while HVR-1 was recognized by half of the patients. An increase in the levels of the anti-capsid IgM (P = 0.027) and IgG (P = 0.0006) was observed in six-month samples, compared to baseline. Similarly, a significantly higher percent of patients had detectable IgA reactivity to capsid (P = 0.017) and NS3 (P = 0.005) after six months, compared to baseline. Particularly, IgA against structural antigens positively correlated with hepatic damage (P = 0.036). IgG subclasses evaluation against capsid and NS3 revealed a positive recognition mediated by IgG1 in more than 80% of the individuals. On the contrary, less than 30% of the patients showed a positive proliferative response either of CD4+ or CD8+ T cells, being the capsid poorly recognized. CONCLUSION: These results confirm that while the cellular immune response is narrow and weak, a broad and vigorous humoral response occurs in HCV chronic infection. The observed correlation between IgA and hepatic damage may have diagnostic significance, although it warrants further confirmation.

Induction of IgA and sustained deficiency of cell proliferative response in chronic hepatitis C

AIM: In the present study, antibody and peripheral blood mononuclear cells (PBMC) proliferative responses against hepatitis C virus (HCV) antigens were evaluated in HCV chronically infected patients. METHODS: Paired serum and PBMC samples were taken six months apart from 34 individuals, either treated or not, and tested by enzyme-linked immunosorbent assay (ELISA) and carboxyfluorescein succinimidyl ester staining.RESULTS: Over 70% of the patients showed specific IgG and IgM against capsid, E1 and NS3, while HVR-1 was recognized by half of the patients. An increase in the levels of the anti-capsid IgM (P = 0.027) and IgG (P = 0.0006) was observed in six-month samples, compared to baseline. Similarly, a significantly higher percent of patients had detectable IgA reactivity to capsid (P = 0.017) and NS3 (P = 0.005) after six months, compared to baseline. Particularly, IgA against structural antigens positively correlated with hepatic damage (P = 0.036). IgG subclasses evaluation against capsid and NS3 revealed a positive recognition mediated by IgG1 in more than 80% of the individuals. On the contrary, less than 30% of the patients showed a positive proliferative response either of CD4+ or CD8+ T cells, being the capsid poorly recognized.CONCLUSION: These results confirm that while the cellular immune response is narrow and weak, a broad and vigorous humoral response occurs in HCV chronic infection. The observed correlation between IgA and hepatic damage may have diagnostic significance, although it warrants further confirmation(AU)

Inhibition of LPS-responses by synthetic peptides derived from LBP associates with the ability of the peptides to block LBP-LPS interaction.

The ability of LPS-binding protein (LBP) to greatly potentiate cell responses to lipopolysaccharide (LPS) may largely contribute to LPS toxicity in sepsis. The study of agents with the capacity to block the interaction between LBP and LPS might improve the understanding of the role of LBP in Gram-negative infections as well as offering new therapeutic tools for septic disorders. Here we confirm the ability of synthetic peptides comprising the human LBP amino acid region 86-108 to interfere with the LBP-LPS interaction. The analysis of selected alanine mutants of a blocking peptide corresponding to the LBP region 86-99 suggests the importance of peptide amphipathicity for the inhibitory activity. The potency of the native peptide and a selected analogue at inhibiting in vitro and in vivo LPS-induced responses was associated with their relative activity in blocking LBP-LPS interaction. It was remarkable that these peptides were at least 500-fold more active in vivo than in vitro. Also, the inhibitory activity of peptides LBP86-99 and LBPK95A seems to be independent of LBP concentrations, a behavior that may be relevant for the potential use of these peptides in septic disorders where LBP serum concentrations are considerably elevated.