concanavalin-a and Airway-Obstruction

Nocturnal airway obstruction occurs frequently in childhood asthma and results from increased airway inflammation. Lymphocytes are believed to be key effector cells of airway wall inflammation, releasing pro-inflammatory mediators and cytokines. A previous study showed that hydrocortisone infusion, an effective anti-inflammatory treatment, improves nocturnal and daytime FEV(1) values. This study in 16 children with moderate asthma was designed to assess whether there exists day and night differences in IL-4, IL-5, IL-8, and IFN-gamma production of concanavaline A stimulated peripheral blood mononuclear cells. Furthermore, we investigated whether substitution of low serum cortisol levels with intravenous hydrocortisone would affect those parameters. Saline (as a placebo) or hydrocortisone (30 microg/m(2) body surface area/24 h) was intravenously administered in a randomized, double blind, cross-over design. Measurements under saline or hydrocortisone infusions were separated by 1 wk. At 04:00 and 16:00 hours 10 ml blood was taken for determination of peripheral blood mononuclear cell isolation and stimulation, and an eosinophil count. Hydrocortisone infusion significantly reduced the nocturnal fall in FEV(1). Median values of IFNgamma, IL-4, IL-5, and IL-8 produced by peripheral blood mononuclear cells did not significantly differ at 04:00 and 16:00 hours, both with saline and hydrocortisone infusion. Our results suggest that FEV(1) improvement is not due to suppression of circulating peripheral blood mononuclear cell activation. We hypothesize that it is rather due to its effect on local lung tissue epithelial and/or fibroblasts thereby reducing airway inflammation and vascular leakage.

Topics: Adolescent; Airway Obstruction; Anti-Inflammatory Agents; Asthma; Child; Circadian Rhythm; Concanavalin A; Cross-Over Studies; Cytokines; Double-Blind Method; Female; Forced Expiratory Volume; Humans; Hydrocortisone; Infusions, Intravenous; Interferon-gamma; Interleukin-4; Interleukin-5; Interleukin-8; Leukocytes, Mononuclear; Male; Time Factors