TH17 Cell Frequency in Peripheral Blood Is Elevated in Overweight Children without Chronic Inflammatory Diseases.

BACKGROUND: The prevalence of obesity has dramatically increased in children in the last few decades and is associated with chronic inflammatory diseases. Fat tissue produces IL-6 and TNF-α, which are stimuli for TH17 cell differentiation. These cells are characterized by expression of the transcription factor receptor-related orphan receptor C (RORC) and by IL-17A production. In murine models, obesity has been linked with elevated TH17 cell frequencies. The aim of this study was to explore whether being overweight was associated with an elevated frequency of circulating TH17 cells or elevated messenger RNA (mRNA)-levels of IL-17A and RORC in children without chronic inflammatory diseases. METHODS: We studied peripheral blood samples from 15 overweight and 50 non-overweight children without a history of autoimmune diseases, asthma, atopic dermatitis or allergic rhinoconjunctivitis. TH17 cells were quantified in Ionomycin stimulated peripheral blood mononuclear cells by flow cytometry using intracellular IL-17A staining. RORC- and IL-17A expressions were measured by real-time PCR. RESULTS: We found significantly elevated TH cell frequencies in overweight children compared then on-overweight controls with 34.7 ± 1.5% of CD3+CD4+ cells versus 25.4 ± 2.4% (mean ± SEM, p = 0.0023), respectively. Moreover, TH cell frequencies correlated positively with body mass index (r = 0.42, p = 0.0005, respectively). The relative mRNA expression of RORC (p = 0.013) and IL-17A (p = 0.014) were upregulated in overweight compared to non-overweight children. CONCLUSION: Childhood obesity is an independent factor that is associated with an elevated frequency of circulating TH17 cells and higher expression of RORC- and IL-17A-mRNA after in vitro stimulation with Ionomycin. This might be due to the inflammatory activity of the fat tissue. Studies on TH17 immunity should not only be adjusted for acute and chronic inflammatory diseases but also for overweight.

IgG4 and IgE transcripts in childhood allergic asthma reflect divergent antigen-driven selection.

The physiologic function of the "odd" Ab IgG4 remains enigmatic. IgG4 mediates immunotolerance, as, for example, during specific immunotherapy of allergies, but it mediates tissue damage in autoimmune pemphigus vulgaris and "IgG4-related disease." Approximately half of the circulating IgG4 molecules are bispecific owing to their unique ability to exchange half-molecules. Better understanding of the interrelation between IgG4 and IgE repertoires may yield insight into the pathogenesis of allergies and into potential novel therapies that modulate IgG4 responses. We aimed to compare the selective forces that forge the IgG4 and IgE repertoires in allergic asthma. Using an IgG4-specific RT-PCR, we amplified, cloned, and sequenced IgG4 H chain transcripts of PBMCs from 10 children with allergic asthma. We obtained 558 functional IgG4 sequences, of which 286 were unique. Compared with previously published unique IgE transcripts from the same blood samples, the somatic mutation rate was significantly enhanced in IgG4 transcripts (62 versus 83%; p < 0.001), whereas fewer IgG4 sequences displayed statistical evidence of Ag-driven selection (p < 0.001). On average, the hypervariable CDRH3 region was four nucleotides shorter in IgG4 than in IgE transcripts (p < 0.001). IgG4 transcripts in the circulation of children with allergic asthma reflect some characteristics of classical Ag-driven B2 immune responses but display less indication of Ag selection than do IgE transcripts. Although allergen-specific IgG4 can block IgE-mediated allergen presentation and degranulation of mast cells, key factors that influence the Ag-binding properties of the Ab differ between the overall repertoires of circulating IgG4- and IgE-expressing cells.

Impact of different types of resuscitation fluids on coagulation and continuous venovenous hemofiltration hemocompatibility in a porcine model.

Intensive therapy demanding diseases (organ failure or sepsis) are assumed to be the etiology behind a decreased biocompatibility of extracorporeal systems for renal replacement therapy (RRT). There are also potential interactions between different components of the overall therapy. Volume substitutes are known to influence hemorheology and coagulation. To define a potential net effect of volume substitutes on the hemocompatibility of an RRT, we chose an animal model without interfering pathophysiologies. According to the problem of early filter failure and coagulation disorders in critically ill patients, we focused on the hypothesized interaction between RRT and different volume substitutes with respect to blood cell counts, coagulation parameters and required heparin dose. Forty-eight pigs were assigned to four groups of fluid therapy with either normal saline (NaCl), 6%HES130kD/0.4 (HES130), 6%HES200kD/0.5 (HES200) or 4%gelatin (GEL). Six pigs of each fluid group underwent continuous venovenous hemofiltration (CVVH), the remaining six served as the control group. Anticoagulation was performed with continuous heparin infusion. CVVH was run in a recirculation-mode for 4.5 h to force hemocompatibility reactions, thereafter in a standard-mode for 2 h. During the CVVH-treatment GEL reduced platelet counts and fibrinogen concentration and additionally lowered ATIII levels. Heparin requirements did not differ between different volume substitutes or CVVH and control groups. Severe pathophysiologies are not the only reason for a reduced hemocompatibility of CVVH treatment. Interaction of a particular volume substitute with CVVH should be considered when interpreting study results and evolving new strategies.

Adverse influence of mixed acidemia on the biocompatibility of continuous veno-venous hemofiltration with respect to the lungs.

Experimental data indicate that hypercapnic adidosis has anti-inflammatory effects. These anti-inflammatory effects may even be a beneficial property in case of low tidal volume ventilation with consecutive hypercapnic acidosis. It is unclear whether these anti-inflammatory effects predominate in critically ill patients who suffer from multiple pro- and anti-inflammatory insults like extracorporeal organ support (pro-inflammatory), metabolic acidosis (pro- and anti-inflammatory), as well as hypoxia (pro-inflammatory). Eighteen pigs were randomized into three groups, mechanically ventilated and connected to a continuous veno-venous hemofiltration (CVVH) as pro-inflammatory insult. A reference group with normal acid-base state obtained normoventilation; a normoxemic acidemia group obtained normoxemic, mixed acidemia due to infusion of lactic and hyperchloremic acid and low tidal volume ventilation, and in a hypoxemic acidemia group the mixed acidemia was paralleled by hypoxemia. Lung histology including pulmonary leukocyte invasion, blood gases, blood cell counts, and hemodynamics were examined. The histological examination of the lungs of acidemic pigs showed a suppressed invasion of leukocytes and thinner alveolar walls compared with normoventilated and with hypoxemic pigs. Enhanced congestion and alveolar red blood cells (RBCs) combined with an increase of the pulmonary artery pressure were observed in acidemic pigs in comparison with the reference group. Normoxemic acidemia reduced the pro-inflammatory reaction to the CVVH and mechanical ventilation in the ventilated lung areas in the form of pulmonary leukocyte invasion. However, this did not result in reduced scores for lung injury. Instead, an increased score for criteria which represent lung injury (congestion and alveolar RBCs) was observed in acidemic pigs.