The transcriptomic profile of peripheral blood nuclear cells in dogs with atopy dermatitis

The aim of the study was to identify genes which are differentially expressed in the blood of dogs with canine atopic dermatitis (AD) in comparison to healthy control dogs. Diagnosis of AD was based on compatible history and clinical signs determined using Willemse and Prélaud diagnostic criteria, completed by Favrot criteria as follows: pruritus sine material, indoor lifestyle and the exclusion of other causes of pruritus ongoing for at least one year. Clinical diagnosis of atopic dermatitis was confirmed by serological allergy testing (IDEXX allergic panel test) and intradermal skin testing (Artuvetrin test set, Netherlands). In order to avoid the role of food antigens as a cause of the skin condition elimination diets was used for 6–8 weeks. No anti-inflammatory drugs were given for at least 3 weeks prior examination with serological test, intradermal test and blood collection. All dogs, which were classified to the investigated group had positive reactions in serological allergy testing and intradermal skin testing. Twenty eight two-color microarrays were performed, one for each patient ( 8 from healthy dogs and 20 microarrays with samples from AD dogs ). RNA from healthy dogs and dogs with AD was hybridized to Agilent two color microarrays with a common reference. The common reference comprised a pool of equal amounts of RNA from 13 healthy dogs which did not take part in the experiment.