Ondrej Beran

Evaluation of potential biomarkers for the discrimination of bacterial and viral infections

PurposeTimely knowledge of the bacterial etiology and localization of infection are important for empirical antibiotic therapy. Thus, the goal of this study was to evaluate routinely used biomarkers together with novel laboratory parameters in the diagnosis of infection.MethodsIn this prospective study, 54 adult patients with bacterial infections admitted to the Department of Infectious Diseases were included. For comparison, 27 patients with viral infections were enrolled. In these patients, white blood cell (WBC) counts, differential blood counts, serum levels of procalcitonin (PCT), IL-1β, IL-6, IL-8, IL-10, IL-12, TNF-α, IFN-γ, soluble CD14 (sCD14), heparin-binding protein (HBP), cortisol (Cort), and monocyte surface expression of TLR2, TLR4, HLA-DR, and CD14 were analyzed. Also, these biomarkers were evaluated in 21 patients with acute community-acquired bacterial pneumonia (CABP), as well as in 21 patients with pyelonephritis and urosepsis.ResultsThe highest sensitivity and specificity (expressed as the area under the curve [AUC]) for bacterial infection were observed in serum concentration of PCT (0.952), neutrophil and lymphocyte counts (0.852 and 0.841, respectively), and serum levels of HBP (0.837), IL-6 (0.830), and Cort (0.817). In addition, the serum levels of IFN-γ and Cort were significantly higher and IL-8 levels were lower in CABP when compared to pyelonephritis or urosepsis.ConclusionsFrom the novel potential biomarkers, only PCT demonstrated superiority over the routine parameters in the differentiation of bacterial from viral infections. However, some of the novel parameters should be further evaluated in larger and better characterized cohorts of patients in order to find their clinical applications.

Sequential analysis of biomarkers in cerebrospinal fluid and serum during invasive meningococcal disease

The aim of the present study was to determine the profile of different inflammatory molecules in serum and cerebrospinal fluid (CSF) during invasive meningococcal disease (IMD). Their relationship with IMD severity was also assessed. A cohort of 12 patients with IMD was investigated. Paired serum and CSF samples were obtained at the time of diagnostic and follow-up lumbar puncture and were examined using Luminex® analysis. IMD severity correlated with serum interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1ra) on admission. Furthermore, the CSF levels of IL-1β, IL-1ra, IL-6, IL-8, macrophage inflammatory protein-1β (MIP-1β), and monocyte chemoattractant protein-1 (MCP-1) were significantly higher than their respective serum levels. The strongest correlations were found between serum concentrations of IL-1β and IL-1ra, IL-6, IL-8, and MIP-1β, whereas the strongest correlations in CSF were found between endotoxin and IL-8, IL-17, MIP-1β, and MCP-1. As was expected, the concentrations of inflammatory molecules in both serum and CSF significantly decreased after antibiotic treatment. With regard to kinetics, a severe course of IMD correlated positively with rapid declines of CSF IL-6 and cortisol levels. Sequential multiple analyses revealed patterns of inflammatory responses that were associated with the severity of IMD, as well as with the compartmentalization and kinetics of the immune reaction.

Antiretroviral Treatment of HIV Infection Does Not Influence HIVSpecific Immunity but Has an Impact on Non-Specific Immune Activation

HIV-specific and non-specific immune responses are crucial in the immunopathogenesis of HIV infection. Therefore, the objective of our study was to analyse the frequency and functional status of HIV-specific CD8+ T cells and the expression of non-specific activation markers on CD8+ T cells in HIV+ patients, and to assess the effects of combined antiretroviral treatment (cART). We examined 28 HIV+ patients, including 13 patients not receiving therapy and 15 patients on cART therapy using ELISpot assay and flow cytometry with intracellular and MHC tetramer staining. MHC tetramers detected HIV-specific CD8+ T cells in 6 HIV+ patients on cART and in 7 untreated individuals; the ELISpot method detected these cells in 5 untreated HIV+ individuals only. Reduced intracellular IFN-γ and IL-2 production by HIV-specific CD8+ T cells was detected in both treated and untreated HIV+ patients, and multifunctional CD8+ T cells simultaneously producing these cytokines were not found in any patient. In contrary to these findings, the percentage of CD8+ T cells expressing CD38 and HLA-DR was significantly higher in untreated patients as compared to HIV+ patients on cART. Together, these results suggest that the alterations of HIV-specific immunity are not influenced by the therapy of HIV infection; whereas, the non-specific chronic immune activation is down-regulated by cART.

Neisseria meningitidis strains from patients with invasive meningococcal disease differ in stimulation of cytokine production

Cytokine production was determinedin vitro after stimulation with three differentNeisseria meningitidis (NM) strains. Virulent NM B strain isolated from a patient with mild course of invasive meningococcal disease (IMD) elicited higher cytokine production than NM B and NM C hypervirulent strains isolated from patients with moderate and fatal course of IMD, respectively. Endotoxin concentration afterin vitro stimulation correlated with cytokine production: the highest endotoxin levels were observed with virulent NM B strain. Serum cytokines and endotoxin levels showed an opposite trend. These results suggest that inflammatory response during IMD is predominantly influenced by host factors.

Kinetics of immune parameters in a patient with sepsis caused by Streptococcus pyogenes treated with activated protein C.

We report a case of streptococcal sepsis treated with recombinant human activated protein C (rhAPC). High plasma IL-6 and cortisol levels at baseline significantly decreased 24 h following the infusion of rhAPC. This decrease was accompanied by a rise of circulating lymphocyte subsets. Our observation may be due to immunomodulatory properties of rhAPC.

The Effect of Latent Toxoplasma gondii Infection on the Immune Response in HIV-Infected Patients

A relationship between latent toxoplasmosis and the immune system during HIV disease is poorly understood. Therefore, the aim of this follow-up study was to characterize immunological parameters in HIV-infected patients with latent toxoplasmosis and noninfected individuals. A total of 101 HIV-infected patients were enrolled in the study. The patients were classified into two groups based on anti-Toxoplasma gondii antibodies: a group of 55 toxoplasma-positive persons (TP) and a group of 46 toxoplasma-negative persons (TN). Absolute counts of several lymphocyte subsets decreased in the TP group, namely, T cells (p = 0.007), B cells (p = 0.002), NK cells (p = 0.009), CD4 T cells (p = 0.028), and CD8 T cells (p = 0.004). On the other hand, the percentage of CD8 T cells expressing CD38 and HLA-DR significantly increased during the follow-up in the TP group (p = 0.003, p = 0.042, resp.) as well as the intensity of CD38 and HLA-DR expression (MFI) on CD8 T cells (p = 0.001, p = 0.057, resp.). In the TN group, analysis of the kinetics of immunological parameters revealed no significant changes over time. In conclusion, the results suggest that latent T. gondii infection modulates the immune response during HIV infection.

Different cytokine production and toll-like receptor expression induced by heat-killed invasive and carrier strains of Neisseria meningitidis

Neisseria meningitidis may cause severe invasive disease. The carriage state of the pathogen is common, and the reasons underlying why the infection becomes invasive are not fully understood. The aim of this study was to compare the differences between invasive and carrier strains in the activation of innate immunity. The monocyte expression of TLR2, TLR4, CD14, and HLA‐DR, cytokine production, and the granulocyte oxidative burst were analyzed after in vitro stimulation by heat‐killed invasive (n = 14) and carrier (n = 9) strains of N. meningitidis. The expression of the cell surface markers in monocytes, the oxidative burst, and cytokine concentrations were measured using flow cytometry. Carrier strains stimulated a higher production of inflammatory cytokines and oxidative burst in granulocytes than invasive strains (all p < 0.001), whereas invasive strains significantly up‐regulated TLR2, TLR4 (p < 0.001), and CD14 (p < 0.01) expression on monocytes. Conversely, the monocyte expression of HLA‐DR was higher after the stimulation by carrier strains (p < 0.05) in comparison to invasive strains. The LPS inhibitor polymyxin B abolished the differences between the strains. Our findings indicate different immunostimulatory potencies of invasive strains of N. meningitidis compared with carrier strains.

Toxic Shock Syndrome and Persistent Immune Activation in an HIVPositive Patient

The case of an HIV-positive treatment-naive male with toxic shock syndrome (TSS) is presented herein. The course of TSS was favorable; however, the patient had extremely high plasma levels of MCP-1 and CD38 and HLA-DR expression on CD8+ T cells during the acute illness. Furthermore, the numbers of CD8+ T cells were reduced and CD4+ T cells remained stable during acute illness in comparison to baseline values. MCP-1 and HLA-DR gradually decreased, but they were still elevated after a month, whereas the number of circulating CD8+ T cells increased more than fivefold. CD38 expression remained stable during this period. A further decrease in CD38, HLA-DR and MCP-1 was noted five months after the initiation of antiretroviral therapy.