AB 82. Specific nasal challenge induces late phase reactions in asthmatics sensitive to Alternaria
Background: Specific challenges provide a better understanding of the underlying inflammatory mechanisms in asthma. The aim of this study was to evaluate the immediate and late phase asthmatic response after specific nasal challenge (SNC) in asthmatic patients sensitive to Alternaria.
Patients and methods: The study population consisted of 15 adult patients with mild, allergic asthma sensitive to Alternaria and two control groups: (I) 8 patients with mild, allergic asthma non-attributed to Alternaria and (II) 7 healthy controls. Two nasal challenge tests were performed, one with normal saline (placebo) and another with Alternaria antigen (SNC) at two different days. FEV1, exhaled nitric oxide (FeNO) and nasal nitric oxide (nNO) were measured at 18 time points, during the 12-hour time period following nasal provocation tests.
Results: No immediate reactions were recorded in terms of FEV1, FeNO and nNO both in patients and controls. Significant changes in FEV1 (decline >20% from baseline), in FeNO (increase >50% from baseline) and in nNO (increase >50% from baseline) were recorded in 10 patients (66.7%), in 12 (80%) and in 10 (66.7%) patients out of the 15 asthmatics sensitive to Alternaria respectively. In the above 15 patients the mean decline in FEV1 was 26.02±2.38%, the mean increase in FeNO was 113.69±24.07% and the mean increase in nNO was 91.53±19.90%. The lowest values of FEV1 were measured 9.30±1.77 hours after SNC, the highest values of FeNO were measured 10.00±1.53 hours and the highest values of nNO were measured 11.90±0.32 hours after SNC (P<0.001 compared to both control groups for all three parameters). Strong negative correlation between mean % changes in FEV1 and in FeNO for all 15 patients at the same time point was observed after SNC (R=-0.947, P<0.001).
Conclusions: SNC induces late phase asthmatic reactions in terms of airway obstruction and inflammation in asthmatics sensitive to Alternaria.
