Effect of specific immunotherapy versus loratadine on serum adhesion molecules.

Objective: To evaluate comparatively the effect on serum ICAM-1 and VCAM-1 values of specific immunotherapy versus loratadine in the treatment of allergic rhinitis.

Population: 65 patients with mild to moderate House Dust Mite allergic rhinitis.

Methods: Patients were divided into three groups, according to patients' preference: a control group with patients receiving only rescue therapy (antihistamines and/or nasal cromoglycate when needed); an antihistamine group with patients receiving daily loratadine 10 mg (and nasal cromoglycate as rescue therapy); an immunotherapy group with patients receiving subcutaneous house dust mite specific immunotherapy (and antihistamines or nasal cromoglycate when needed). In all groups we measured soluble ICAM-1 and VCAM-1 serum levels before the start of the study period and at the end of the study period. The duration of the study was one year for the control group and for the immunotherapy group. In patients taking daily antihistamines we measured serum adhesion molecules one month after the beginning of the therapy. We used Student's T test for statistical analysis.

Results: Patients in the control group didn't have significant variations in serum ICAM-1 (p = 0.239) or VCAM-1 (p = 0.38) levels. Patients receiving loratadine showed significant decreases in serum VCAM-1 levels (p = 0.0012) but not in serum ICAM-1 levels (p = 0.224). Patients receiving immunotherapy also showed a similar pattern, with significant decreases in serum VCAM-1 levels (p = 0.012) but not in serum ICAM-1 levels (p = 0.254).

Conclusions: Specific house dust mite immunotherapy and regular daily loratadine therapy are able to lower significantly serum levels of soluble VCAM-1. However, this effect, which can be interpreted as an anti-inflammatory action, is not applied to soluble ICAM-1 levels, which raises the possibility of a differential action of these therapies on the mechanisms of allergic inflammation. Patients on rescue medication alone did not show any significant differences in these parameters.