Circulating soluble RAGE and cell surface RAGE on peripheral blood mononuclear cells in healthy children

Background: The receptor for advanced glycation end products (RAGE) has a critical role in the pathogenesis of inflammation. In healthy children, its basal expression on the peripheral blood mononuclear cell (PBMC) and the basal circulating soluble RAGE (sRAGE) levels are unknown. The aim of this study was to describe both. Methods: This is a monocentric, observational and descriptive study of samples obtained from healthy children. The RAGE expression on PBMC was analyzed using flow cytometry. The sRAGE values were determined with a specific sandwich enzyme-linked immunosorbent assay (ELISA) kit, later the relation between cellular RAGE and sRAGE was described. Results: Forty-three children were included. The median sRAGE level was 849.0 +/- 579.0 pg/mL. The RAGE mean fluorescence intensity (MFI) was 1382 +/- 506 in monocytes and 792 +/- 506 in lymphocytes. There were no differences between genders. A negative correlation was found between sRAGE and RAGE MFI in lymphocytes (r = -0.3; p = 0.04). Conclusions: We describe for the first time the RAGE surface levels on PBMC in children. It showed a negative correlation with sRAGE. The sRAGE circulating level is lower than the sRAGE level described in adult population or non-healthy children. Our findings should be confirmed in order to apply them as reference values for future investigations.