Viruses and atypical bacteria in the respiratory tract of immunocompromised and immunocompetent patients with airway infection.

Respiratory tract infections (RTI) can take a serious course under immunosuppression. Data on the impact of the underlying pathogens are still controversial. Samples from the upper (n = 322) and lower RT (n = 169) were collected from 136 children and 355 adults; 225 among them have been immunocompromised patients. Exclusion criteria were presence of relevant cultivable microorganisms, C-reactive protein > 20 mg/dl, or procalcitonin > 2.0 ng/ml. Samples were tested by PCR for the presence of herpesviruses (HSV-1/-2; VZV; CMV; HHV6; EBV), adenoviruses, bocaviruses, entero-/rhinoviruses (HRV), parechoviruses, coronaviruses, influenza viruses (IV), parainfluenza viruses as well as for pneumoviruses (HMPV and RSV), and atypical bacteria (Mycoplasma pneumoniae, M.p.; Chlamydia pneumoniae, C.p.). Viral/bacterial genome equivalents were detected in more than two-thirds of specimens. Under immunosuppression, herpesviruses (EBV 30.9%/14.6%, p < 0.001; CMV 19.6%/7.9%, p < 0.001; HSV-1: 14.2%/7.1%, p = 0.012) were frequently observed, mainly through their reactivation in adults. Immunocompromised adults tended to present a higher RSV prevalence (6.4%/2.4%, p = 0.078). Immunocompetent patients were more frequently tested positive for IV (15.0%/5.8%, p = 0.001) and M.p. (6.4%/0.4%, p < 0.001), probably biased due to the influenza pandemic of 2009 and an M.p. epidemic in 2011. About 41.8% of samples were positive for a single pathogen, and among them EBV (19.9%) was most prevalent followed by HRV (18.2%) and IV (16.6%). HSV-2 and C.p. were not found. Marked seasonal effects were observed for HRV, IV, and RSV. Differences in pathogen prevalence were demonstrated between immunocompetent and immunocompromised patients. The exact contribution of some herpesviruses to the development of RTI remains unclear.

A versatile platform for activity determination of cytokines and growth factors based on the human TSLP (thymic stromal lymphopoietin) receptor.

Cytokines and growth factors are signaling proteins involved in communication processes between cells. They are involved in the control of numerous essential physiological processes such as cell proliferation, gene transcription and differentiation; therefore being in the focus of basic and applied research. Many of them are also of relevance for human diseases. When observed as potential targets for pharmacological intervention and objects of structure/function studies, it is important to measure their biological activities, optionally along with potential inhibitors, in a convenient and rational manner. Such tests are frequently laborious to set up and their establishment is complicated by the necessity to employ problematic cell types and sophisticated assays. Here we present a robust and modular activity assay system which can be adapted to virtually all ligands that signal through dimerization of membrane receptors from different families. The technique rests on fusing ligand-binding domains of specific receptors to the transmembrane and intracellular components of the thymic stromal lymphopoietin (TSLP) receptor which translates signals into readily quantifiable luciferase expression in reporter cells. We show that the activation of various hematopoietic cytokine receptors, of receptor tyrosine kinases as well as of receptors bearing serine/threonine kinase domains by their respective ligands was faithfully reflected both upon transient and stable introduction of hybrid receptor and reporter gene constructs into the murine pro-B cell line Ba/F3. Moreover, we demonstrate the suitability of this platform for the functional characterization of cytokine/growth factor receptor inhibitors.

Children undergoing cardiac surgery for complex cardiac defects show imbalance between pro- and anti-thrombotic activity.

INTRODUCTION: Cardiac surgery with cardiopulmonary bypass (CPB) is associated with the activation of inflammatory mediators that possess prothrombotic activity and could cause postoperative haemostatic disorders. This study was conducted to investigate the effect of cardiac surgery on prothrombotic activity in children undergoing cardiac surgery for complex cardiac defects. METHODS: Eighteen children (ages 3 to 163 months) undergoing univentricular palliation with total cavopulmonary connection (TCPC) (n = 10) or a biventricular repair (n = 8) for complex cardiac defects were studied. Prothrombotic activity was evaluated by measuring plasma levels of prothrombin fragment 1+2 (F1+2), thromboxane B2 (TxB2), and monocyte chemoattractant protein-1 (MCP-1). Anti-thrombotic activity was evaluated by measuring levels of tissue factor pathway inhibitor (TFPI) before, during, and after cardiac surgery. RESULTS: In all patients, cardiac surgery was associated with a significant but transient increase of F1+2, TxB2, TFPI, and MCP-1. Maximal values of F1+2, TxB2, and MCP-1 were found at the end of CPB. In contrast, maximal levels of TFPI were observed at the beginning of CPB. Concentrations of F1+2 at the end of CPB correlated negatively with the minimal oesophageal temperature during CPB. Markers of prothrombotic activity returned to preoperative values from the first postoperative day on. Early postoperative TFPI levels were significantly lower and TxB2 levels significantly higher in patients with TCPC than in those with biventricular repair. Thromboembolic events were not observed. CONCLUSION: Our data suggest that children with complex cardiac defects undergoing cardiac surgery show profound but transient imbalance between pro- and anti-thrombotic activity, which could lead to thromboembolic complications. These alterations are more important after TCPC than after biventricular repair but seem to be determined mainly by low antithrombin III.