title: Serum interleukin-5 levels are elevated in mild and moderate persistent asthma irrespective of regular inhaled glucocorticoid therapy.
abstract: 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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Internal Medicine, Faculty of Medicine and Health Sciences, Al Ain, UAE. jjoseph@uaeu.ac.ae
authors.forename: Jose
authors.initials: J
authors.lastname: Joseph
authors.forename: Sheela
authors.initials: S
authors.lastname: Benedict
authors.forename: Wassef
authors.initials: W
authors.lastname: Safa
authors.forename: Maries
authors.initials: M
authors.lastname: Joseph