Upregulation Of Glucocorticoids Beta Receptors In Severe Rsv Bronchiolitis In Infants

Abstract

T U E S D A Y 920 Upregulation Of Glucocorticoids Beta Receptors In Severe Rsv Bronchiolitis In Infants P. V. Diaz, R. Mammani, R. A. Pinto, A. A. Gaggero, M. R. Bono, J. Guerrero, A. Goecke; Faculty of Medicine, University of Chile, Santiago, CHILE, Faculty of Science, University of Chile, Santiago, CHILE. RATIONALE: The majority of studies on glucocorticoids treatment in RSV bronchiolitis conclude there are no beneficial effects. We hypothesized that RSV infected patients may have an up-regulation of the GCR-b expression, the isoform that is unable to bind cortisol and exert an antiinflammatory action. METHODS:We studied by RT-PCR the expression of a and bGCR in the peripheral blood mononuclear cells (PBMC) obtained from 50 RSV infected infants (less than 1 year of age) of diverse clinical severity, evaluated by a modified Tal’s clinical score (15mild to 85severe). In plasma we analyzed the level of cortisol by RIA and inflammatory cytokines: IL-6, IL-8,TNF-a, IL-1b, IL-12 and IL-10 by cytometric beads assay. Statistical analysis was performed by ANOVA. RESULTS: There has found a significant up-regulation of b GCR in patients with severe illness compared to those with mild disease (p<0.001) and also to a group of healthy control (p<0.01). The a/b GCR ratio was significantly decreased in infants with severe disease (p<0.05) compared to those with mild illness and with normal controls (p<0.01). The expression of b GCR has been positively correlated with the clinical score of severity (r50.51; p<0.0006). IL-6, IL-8 and cortisol in plasma were significantly increased in severe infected infants compared with mild infected (p<0.05) and healthy controls (p<0.01). CONCLUSIONS: The decrease of the a/bGCR ratio by an up-regulation of b receptors may partly explain the insensitivity to corticoids treatments in RSV infected infants.