Objective: Recent pathophysiologic research demonstrated the crucial role p
layed by adhesion molecules in recruiting and activating inflammatory cells
during allergic reaction.
Data Sources: Intracellular adhesion molecule (ICAM-1) expression on nasal
epithelial cells is involved in two main pathogenetic phenomena. The first
is to allow leukocyte infiltration of respiratory mucosa, since they expres
s LFA1 and Mad, which are ligands of ICAM-1. This point is very important,
because it has been demonstrated that patients with mite allergy tie, conti
nuously exposed to allergen) present a minimal persistent inflammation (MPI
) both at nasal and conjunctival levels. This inflammation is characterized
by the presence of leukocyte infiltration and ICAM-1 expression on epithel
ial cells and by a relationship between specific and nonspecific hyperreact
ivity in the absence of clinical symptoms. The second is that ICAM-1 is als
o the main receptor of the human rhinoviruses. This fact may partially expl
ain the relationship among allergy, viral infections, and asthma attacks.
Study Selection: Different studies have been performed to demonstrate the p
ossible effects on the different clinical aspects of MPI exerted by an anti
allergic drug.
Results: It has been demonstrated that cetirizine is able to reduce ICAM-1
expression on nasal epithelial cells and conjunctival nonspecific hyperreac
tivity in asthmatic asymptomatic children with MPI.
Conclusions: The therapeutical strategy of mite allergy should be targeted
to treat minimal persistent inflammation.