Background: Eosinophil granulocytes and eosinophilic granule proteins are deposited in the skin lesions of AD patients. Increased Th2 activity in the acute phase of AD is associated with IL-5 expression and results in enhanced eosinophilopoiesis, eosinophilic activation, and chemotaxis.
Material and methods: Thirty AD patients attending the Allergic Diseases Diagnostic Center and hospitalized in the Department of Dermatology were examined. Two control groups were included: 30 patients suffering from chronic urticaria and 30 healthy individuals without any symptoms of allergic diseases. Laboratory tests included the number of eosinophils expressed as a percentage of a differential white blood cell count, the absolute number of eosinophils in mm(3) (Carpentier's eosin method), and an evaluation of antigen-specific IgE (asIgE) in serum using fluoroenzyme immunoassay (CAP System FEIA, Pharmacia).
Results: The number of eosinophils/mm3 in the peripheral blood was 290.0 +/- 205.7 in AD patients, and 113.3 +/- 93.7 and 153.3 +/- 113.7 in the two control groups; the difference was statistically significant. Patients with severe AD had higher eosinophilia than patients with mild to moderate AD, but the difference was not significant. In AD patients with positive SPT tests and detectable specific IgE in serum, and also in patients with symptoms of other atopic diseases, the peripheral blood eosinophilia was more prominent compared to patients with negative SPTs and without symptoms of other atopic diseases.
Conclusion: The results point to the role of eosinophils in etiopathogenesis of AD. Peripheral blood eosinophilia could serve as a diagnostic parameter in differentiating allergic AD from non-allergic AD.