Change In Plasma C5a Levels After Routine Allergen Immunotherapy Correlates With Dust Mite Dosage, Changes in Wheal Size, And Rhinoconjunctivitis Symptoms

Abstract

RATIONALE: Complement split product C5a is increased in BAL fluid after segmental allergen provocation. C5a also is generated in vitro in serum in the presence of allergens. This study investigated if plasma C5a levels are altered after routine allergen immunotherapy (IT) for rhinitis/asthma.METHODS: C5a-desArg levels in plasma (ELISA) from IT subjects (n=16) were determined immediately before and 1 hr after IT. Skin reactivity to each allergen (induration) was determined at 15 min and 1 hr. Spirometry was performed before and at 1 hr. Rhinoconjunctivitis quality of life symptom scores (RQLQ, Juniper) and total serum IgE level were determined.RESULTS: Change in plasma C5a levels was found to correlate with change in total mean wheal diameter (p=0.05), total dust mite IT dose(p=0.04), and total RQLQ score (p=0.03). Change in C5a did not correlate with total IT dose or IgE.Although change in C5a levels did not correlate with spirometric parameters at 1 hr, there was a significant negative correlation between total mean wheal diameter change and change in peak flow (PEFR)(p=0.005). The mean change in wheal diameter induced by dust mite IT was negatively correlated with change in FEF25-75 (p=0.007), but not PEFR (p=0.4).CONCLUSIONS: The correlation of change in C5a levels with dust mite dosage, changes in wheal size, and symptoms scores strongly suggests that C5a is crucial in the maintenance of allergic inflammation. RATIONALE: Complement split product C5a is increased in BAL fluid after segmental allergen provocation. C5a also is generated in vitro in serum in the presence of allergens. This study investigated if plasma C5a levels are altered after routine allergen immunotherapy (IT) for rhinitis/asthma. METHODS: C5a-desArg levels in plasma (ELISA) from IT subjects (n=16) were determined immediately before and 1 hr after IT. Skin reactivity to each allergen (induration) was determined at 15 min and 1 hr. Spirometry was performed before and at 1 hr. Rhinoconjunctivitis quality of life symptom scores (RQLQ, Juniper) and total serum IgE level were determined. RESULTS: Change in plasma C5a levels was found to correlate with change in total mean wheal diameter (p=0.05), total dust mite IT dose(p=0.04), and total RQLQ score (p=0.03). Change in C5a did not correlate with total IT dose or IgE. Although change in C5a levels did not correlate with spirometric parameters at 1 hr, there was a significant negative correlation between total mean wheal diameter change and change in peak flow (PEFR)(p=0.005). The mean change in wheal diameter induced by dust mite IT was negatively correlated with change in FEF25-75 (p=0.007), but not PEFR (p=0.4). CONCLUSIONS: The correlation of change in C5a levels with dust mite dosage, changes in wheal size, and symptoms scores strongly suggests that C5a is crucial in the maintenance of allergic inflammation.