12751
document
A single nasal allergen challenge increases induced sputum inflammatory markers in non-asthmatic subjects with seasonal allergic rhinitis : correlation with plasma interleukin-5 . BACKGROUND Seasonal allergic rhinitis ( SAR ) is a risk factor for asthma in affected individuals . Nasal allergic inflammation enhances bone-marrow eosinophil production , mainly via IL-5 , and rhinitis patients have increased airway inflammation during the pollen season . OBJECTIVE To assess the impact of nasal allergy on sputum inflammatory markers . METHODS In an open-labelled , randomized , placebo-controlled cross-over study with 16 non-asthmatic SAR patients ( median age 25 years , 56 % males ) , the effect of a single nasal allergen challenge performed out of season on induced sputum inflammatory parameters was evaluated . SAR patients were identified by history , skin-prick test and specific IgE . All patients had normal lung function/bronchial hyper-responsiveness out of season and a negative asthma/wheezing history . Sputum cells and supernatant levels of ECP , sICAM , IL-5 and IL-10 , and plasma levels of IL-5 and ECP , were measured before and 24 h after nasal allergen challenge . After a washout period of at least 4 weeks , the procedure was repeated with placebo challenge ( diluent ) . RESULTS Nasal allergen challenge led to an increase in sputum ECP ( pre = 60 +/- 12 , post = 212 +/- 63 micro g/L , P = 0.02 vs. placebo ) , and sICAM ( 4.8 +/- 2.7 to 6.5 +/- 2.9 ng/mL , P = 0.02 vs. placebo ) , whereas IL-10 decreased after provocation ( 44 +/- 11 to 29 +/- 6 pg/mL , P = 0.06 vs. placebo ) . Sputum IL-5 was undetectable in all patients . The absolute number of blood and sputum eosinophils did not change significantly after allergen or placebo challenge ( P > 0.07 , both comparisons ) . Plasma levels of IL-5 increased after allergen challenge ( 8.7 +/- 2.9 to 14.5 +/- 3.9 pg/mL , P = 0.001 ) , and the increase in plasma IL-5 was positively correlated with the rise in sputum ECP in a subgroup of 'responders ' ( n = 12 , r = 0.71 , P = 0.01 ) . CONCLUSIONS A single nasal allergen challenge in SAR patients increased markers of allergic inflammation in the lower respiratory tract , possibly via pronounced activation of inflammatory cells through circulating immediate-type reaction cytokines like IL-5 . These findings may provide additional explanatory data for the high susceptibility of SAR patients to incident asthma .
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Intervention_Pharmacological
single nasal allergen challenge
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Intervention_Control
placebo-controlled
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Intervention_Pharmacological
single nasal allergen challenge
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Intervention_Pharmacological
single nasal allergen challenge
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Outcome_Physical
sputum inflammatory markers
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Outcome_Physical
sputum inflammatory markers
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Outcome_Physical
sputum inflammatory
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Outcome_Physical
Sputum cells and supernatant levels of ECP
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Outcome_Physical
sICAM
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Outcome_Physical
IL-5 and IL-10
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Outcome_Physical
plasma levels of IL-5 and ECP
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Outcome_Physical
sputum ECP
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Outcome_Physical
sICAM
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Outcome_Physical
IL-10
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Outcome_Physical
Sputum IL-5
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Outcome_Physical
blood and sputum eosinophils
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Outcome_Physical
Plasma levels of IL-5
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Outcome_Physical
sputum ECP
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Outcome_Physical
allergic inflammation
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Participant_Condition
non-asthmatic subjects with seasonal allergic rhinitis :
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Participant_Condition
risk factor for asthma in affected individuals .
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Participant_Sample-size
16
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Participant_Sample-size
56 %