Serum interleukin-5 levels are elevated in mild and moderate persistent asthma irrespective of regular inhaled glucocorticoid therapy

BACKGROUND: Interleukin-5 (IL-5) is thought to play a pivotal role in the pathogenesis of asthma. High levels of circulating IL-5 have been documented in acute asthma. However, serum IL-5 levels in mild to moderate asthmatics and the influence of regular use of inhaled glucocorticoids, is not known. METHODS: Fifty-six asthmatics and 56 age and sex matched controls were recruited prospectively from an outpatient department. Information on asthma severity and treatment was gathered by a questionnaire. Serum IL-5, total IgE and specific IgE levels were measured in a blinded fashion. RESULTS: There were 32 atopic and 24 non-atopic mild-to-moderate asthmatics. The median serum IL-5 levels in atopic asthmatics (9.5 pg/ml) and in non-atopic asthmatics (8.1 pg/ml) were significantly higher than in normal controls (4.4 pg/ml, both p < 0.003). However, median serum IL-5 levels in atopic and non-atopic asthmatics were not significantly different. The median serum IL-5 level was insignificantly higher in fourteen moderate persistent asthmatics (10.6 pg/ml) compared to forty-two mild persistent asthmatics (7.3 pg/ml) (p = 0.13). The median serum IL-5 levels in asthmatics using regular inhaled steroids (7.8 pg/ml) was not significantly different from those not using inhaled steroids (10.2 pg/ml). Furthermore, serum total IgE levels and eosinophil counts were not significantly different in those using versus those not using inhaled glucocorticoids. CONCLUSION: Serum IL-5 levels are elevated in mild and moderate persistent atopic and non-atopic asthmatics. Regular use of inhaled glucocorticoids may not abrogate the systemic Th2 type of inflammatory response in mild-moderate persistent asthma

Effect of oral glucocorticoid treatment on serum inflammatory markers in acute asthma

BACKGROUND Acute asthma is associated with elevated serum concentrations of products of activated T cells and eosinophils.AIMS To compare the changes in concentrations of these products with disease severity and changes in lung function following oral prednisolone treatment.METHODS Twenty patients (mean age 8.7 years) were recruited on admission with acute asthma to a district general hospital. Disease severity was recorded before and after treatment with oral prednisolone using a validated pulmonary index score. Serum concentrations of interleukin (IL)-4, IL-5, soluble (s)CD25 (soluble IL-2 receptor), using a specific enzyme linked immunosorbent assay, and eosinophil cationic protein (ECP), using radioimmunoassay, were measured concomitantly. Non-asthmatic children (n = 6, mean age 9.2 years) undergoing elective surgery were recruited as controls, and serum samples were obtained on one occasion without treatment. Main outcome measures were changes in serum concentrations of cytokines and ECP, clinical asthma severity score, and peak expiratory flow rate.RESULTS As expected, oral glucocorticoid treatment in the children with asthma was associated with clinical improvement and also with significant reductions in serum concentrations of IL-5 (mean 5.59 to 2.19 pg/ml, p = 0.0001), sCD25 (mean 2236 to 1772 pg/ml, p = 0.002), and ECP (mean 54.3 to 33.1 pg/ml, p = 0.0001). Serum IL-4 concentrations, in most patients and all the controls, remained below the sensitivity of the assay. However, serum concentrations of IL-5, sCD25, and ECP remained significantly higher than in controls, even after treatment with oral glucocorticoids (p = 0.03).CONCLUSIONS These data suggest that T cell mediated inflammation may persist in childhood asthma despite apparent clinical remission associated with conventional doses of prednisolone. The long term consequences of persistent inflammation after an apparently treated acute attack of asthma require clarification. Clinical assessment and pulmonary function are inadequate surrogates for airway inflammation