Objective: Platelets play a role in the pathogenesis of inflammation beside hemostasis. Mean platelet volume (MPV) is used as a biomarker of platelet activation. Although the platelet`s role in the pathogenesis of allergic diseases is well known, the MPV value is still controversial in allergic diseases. The objective is to observe the changes of the MPV value in patients with allergic diseases and patients receiving subcutaneous venom and aeroallergen immunotherapy (SCIT).

Materials and Methods: Patients who are followed by our pediatric allergy and immunology clinic were enrolled in the study. The study group included patients with atopic dermatitis, food allergy, chronic urticaria, allergic rhinitis, asthma and obese asthmatics. The control group consisted of age- and gender-matched and otherwise healthy children. The value of MPV was recorded and compared to the control group`s value. The value of MPV was evaluated at the beginning and at the second year of SCIT.

Results: Study subgroups included patients with atopic dermatitis (n:132), food allergy (n:47), allergic rhinitis (n:48), chronic urticaria (n:102 ), asthma (n:22), and obese asthmatics (n:31). The value of MPV was not statistically different between the patient and control groups. The severity of atopic dermatitis, autoimmunity of chronic urticaria and presence of obesity in asthmatic patients did not influence the value of MPV. The beginning and the second year median (IQR) MPV levels of the patients receiving SCIT were 7.5 (7.1-8.1) fl and 8.6 (7.6-9.2) fl respectively in the aeroallergen immunotherapy (IT) group, and 7.9 (7.2-8.4) fl and 8.8 (8.3-9.3) fl respectively in the venom immunotherapy (VIT) group (p<0.001).

Conclusion: This study has shown that MPV changes significantly over the years in SCIT.