Obesity and metabolic syndrome are shown to be related to changes in the immune system, both at the cellular and humoral levels. Indeed, higher T lymphocyte counts have been associated with greater body mass index (BMI)( Reference Zaldivar, McMurray and Nemet 1 ), and total leukocyte count is positively correlated with markers of metabolic syndrome( Reference Wu, Hsiao and Lin 2 ). The aim of this study was to detect possible interactions between risk of metabolic syndrome and immunological biomarkers. To this end, relationships between immunological markers and BMI, total cholesterol, HDL-c and LDL-c, triglycerides (TGs) and C-reactive protein (CRP), were evaluated in a sample of obese children (7–10.9 y, n=58) and adolescents (11–16 y, n=132) from Granada, Córdoba and Zaragoza (the PRONAOS study). Among the immunological markers, CD19 (B cells), CD3 (T cells), CD4 (helper T cells), CD8 (cytotoxic T cells), CD45RA (naïve cells) and CD45RO (memory cells) were analyzed by flow cytometry and serum immunoglobulin levels (IgA, IgG2, IgG3, IgG4, total IgG, IgE and IgM) by Cytometric Bead Array (Becton Dickinson) and C-reactive protein (CRP) by nephelometry. Spearman correlation test was used to analyze associations between these variables. BMI showed a positive correlation with CRP, in both children and adolescents. Only in children, BMI was positively associated with CD4+CD45RO+ levels and negatively with CD4+CD45RA+ and total CD4+. TGs were positively associated with absolute counts and percentages of B cells (CD19+) in the whole population, and with CD3+CD45RA+ in adolescents. In addition, TGs showed a significant correlation with IgE, which was positive in children and negative in adolescents. Total cholesterol showed a positive association with CD3+CD8+ and negative with total CD3+ in children, while LDL-c was positively correlated with CD4+CD45RO+. In conclusion, our results show that the immune system might suffer from an age-related adaptation with regard to the metabolic syndrome risk observed in these obese children and adolescents. Therefore, these immunological markers could be used as potential biomarkers for obesity and related metabolic alterations in children and adolescents in further studies.
This work was supported by PROYECTO CENIT-PRONAOS (PRONAOS Study, CDTI 2008 1114 and Biosearch.