T H 17 Cell Frequency in Peripheral Blood Is Elevated in Overweight Children without Chronic Inflammatory Diseases

• Published in: Frontiers in immunology Vol. 8; p. 1543
• Main Authors: Schindler, Theresa Isabell, Wagner, Johanna-Josophina, Goedicke-Fritz, Sybelle, Rogosch, Tobias, Coccejus, Verena, Laudenbach, Verena, Nikolaizik, Wilfried, Härtel, Christoph, Maier, Rolf Felix, Kerzel, Sebastian, Zemlin, Michael
• Format: Journal Article
• Language: English
• Published: Switzerland 2017
• Subjects: IL-17A; children; inflammation; receptor-related orphan receptor C; TH17 cells; overweight
• ISSN: 1664-3224; 1664-3224

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 T 17 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 T 17 cell frequencies. The aim of this study was to explore whether being overweight was associated with an elevated frequency of circulating T 17 cells or elevated messenger RNA (mRNA)-levels of IL-17A and RORC in children without chronic inflammatory diseases. 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. T 17 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. We found significantly elevated T 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,  = 0.0023), respectively. Moreover, T cell frequencies correlated positively with body mass index (  = 0.42,  = 0.0005, respectively). The relative mRNA expression of RORC (  = 0.013) and IL-17A (  = 0.014) were upregulated in overweight compared to non-overweight children. Childhood obesity is an independent factor that is associated with an elevated frequency of circulating T 17 cells and higher expression of RORC- and IL-17A-mRNA after stimulation with Ionomycin. This might be due to the inflammatory activity of the fat tissue. Studies on T 17 immunity should not only be adjusted for acute and chronic inflammatory diseases but also for overweight.