THE EFFECT OF LORATADINE ON ACTIVATED CELLS OF THE NASAL-MUCOSA IN PATIENTS WITH ALLERGIC RHINITIS

The effect of loratadine on the numbers of activated cells - cells exp ressing interleukin-2 receptors(IL-2R), HLA-DR antigens and proliferat ing cell nuclear antigen (PCNA) - in the nasal mucosa was studied in 4 8 patients with allergic rhinitis. Patients were treated with either l oratadine (10 mg) or placebo for 1 month. At the end of treatment, a s ignificant decrease in the symptom scores was noted in both groups of patients. However, the clinical score was significantly lower in the l oratadine group compared to the placebo group. At the end of treatment , the numbers of IL-2R+, HLA-DR+ and PCNA+ cells were significantly de creased only in the group on loratadine. An almost significant correla tion was also observed between the numbers of IL-2R+ cells and symptom s in the loratadine group. Our results show that loratadine exerts its beneficial effect possibly by inhibiting both the action of histamine and immune activation.