MINIMAL PERSISTENT INFLAMMATION IS PRESENT AT MUCOSAL LEVEL IN PATIENTS WITH ASYMPTOMATIC RHINITIS AND MITE ALLERGY

The natural exposure to house dust mites causes sensitization in genet ically susceptible patients. Persistent exposure of sensitized patient s causes chronic inflammation, and consequently, hyperreactivity, thus promoting the development of clinical features. Recently, intercellul ar adhesion molecule-1 (ICAM-1)/CD54 expression on epithelial cells tr iggered by allergen has been demonstrated and related to the inflammat ion caused by the allergic reaction. Therefore we evaluated the possib le presence of inflammation (i.e., inflammatory cell infiltrate and IC AM-1/CD54 expression on epithelium) at conjunctival and nasal levels i n patients with asymptomatic allergic rhinitis caused by mites, in the ir relatives living in the same environment, and in healthy volunteers . In addition the possible relationship between inflammation and house dust mite allergen exposure was evaluated Conjunctival and nasal scra pings of allergic subjects enrolled in the study showed many inflammat ory cells. A mild ICAM-1/CD54 expression on conjunctival and nasal epi thelium was detectable in allergic subjects, whereas relatives and hea lthy volunteers showed few inflammatory cells and no ICAM-1/CD54 expre ssion on epithelial cells. A detectable level of house dust mite, suff icient to cause sensitization, was found in all houses. This study dem onstrates a minimal persistent inflammation at conjunctival and nasal levels constantly detectable in patients without symptoms who are sens itized to mires and continuously exposed to the natural allergens.