CHANGES IN NASAL SPECIFIC IGE TO MITES AFTER PERIODS OF ALLERGEN EXPOSURE-AVOIDANCE - A COMPARISON WITH SERUM LEVELS

Variations of serum and nasal specific IgE to Dermatophagoides pterony ssinus (Der p) during alternate periods of antigen avoidance-exposure have been evaluated with an open design in a group of allergic childre n with asthma and rhinitis at the residential house Istituto Pio XII ( Misurina, BL, Italy), at 1756 m, in the Italian Dolomites. A method ba sed on direct incubation of allergen coupled substrate on the nasal mu cosa has been employed to evaluate the levels of nasal IgE. Serum spec ific IgE decreased respectively from (median) 117-89.3 kU/1 (P < 0.001 ) during an initial period of 3 months of allergen avoidance and from 88.2 to 78.4 kU/1 (P < 0.0002) during a subsequent period of allergen avoidance. No significant increase in serum specific IgE was, in contr ast, observed during two periods, 22 and 9 days, of antigen exposure, changing respectively from 89.3 to 88.2 and from 78.4 to 89.1 kU/1. In contrast, nasal IgE has been significantly influenced by the alternat e periods of antigen exposure-avoidance, showing a decrease from 19.75 to 4.01 kU/1 (P < 0.0001) after the initial period of avoidance, foll owed by an increase to 9.95 kU/1 (P < 0.0001) after 22 days of exposur e. A significant decrease to a value of 2.37 kU/1 (P < 0.0001) was als o observed during the subsequent period of avoidance, followed again b y an increase to 7.87 kU/1 (P < 0.002) after 9 days of exposure. The e valuation of the kinetics of changes in nasal specific IgE revealed a significant decrease (P < 0.01) as soon as antigen avoidance was imple mented for 3 days. Nasal specific IgE, therefore, appears to be a more sensitive index of antigen exposure-avoidance than serum IgE levels.