Pharmacologic modulation by cetirizine of some adhesion molecules expression in psoriatic skin lesions

Adhesion molecules play a major role in the pathogenesis of inflammatory skin diseases by regulating lymphocyte trafficking and homing in an inflamed area.

The expression of the lymphocyte function-associated antigen-1 (LFA-1) and of its ligand, the intercellular adhesion molecule-1 (ICAM-1) has been studied in psoriatic skin lesions of 10 patients with guttate, nummular, and palmoplantar psoriasis. In addition, the peculiar immunophenotype of infiltrating cells (CD3, CD4, CD8, CD25) and their correlation with HLA-DR expression before and after treatment with oral cetirizine, a highly selective, third generation H1-receptor antagonist has been examined using the labeled avidin biotin (LAB) system.

Cetirizine treatment modulated in vivo the expression of adhesion molecules LFA-1/CAM-1 as shown in all cases by decreased levels of their expression on keratinocytes and on dermal endothelial cells (P < 0.001). The expression of HLA-DR on keratinocytes and endothelial cells was also inhibited after treatment. The numbers of infiltrating CD3-, CD4-, CD8-positive cells were reduced, whereas there was no significant modification of CD25-positive cells within the epidermis and the dermis.

This open clinical trial suggests that cetirizine could be effective in treating psoriasis: (1) for its symptomatic control on itching; (2) for its immunopharmacologic modulation of leukocyte integrins and on the immunophenotype pattern of infiltrating and resident cells, and (3) for contributing to the clearing of the lesions clinically.