Background Since dogs frequently develop allergic diseases, similar to those in humans, dogs represent a possible animal model for allergy in humans. In human atopic dermatitis (AD), CC chemokine receptor 4 (CCR4) has been shown to play an important role in the development of allergic inflammation of AD; however, the association between allergic reaction and CCR4 is not well understood in dogs.
Objective To examine CCR4 expression in peripheral blood CD4+ cells in dogs that had AD and were experimentally sensitized with Japanese cedar pollen.
Materials and methods Peripheral blood mononuclear cells (PBMCs) were isolated from 17 dogs with AD. The proportion of CCR4+ cells in peripheral blood CD4+ cells (CCR4/CD4) was evaluated by flow cytometry and compared with that in 10 healthy dogs. Similarly, in dogs that were experimentally sensitized to Japanese cedar pollen antigen, the proportion of CCR4/CD4 was examined pre- and post-sensitization.
Results The proportion of CCR4/CD4 in dogs with AD was 40.3±3.3%, which was significantly higher than that in normal dogs (23.6±4.3%) (P<0.01). In the experimentally sensitized dogs, the proportion of CCR4/CD4 was 25.4±2.6% at pre-sensitization and it was significantly increased (29.8±2.9%) at post-sensitization (P<0.01).
Conclusion The proportion of CCR4+ cells in peripheral blood CD4+ cells was measured in dogs with allergic conditions. The present findings indicate that CCR4+ cells may be involved in the pathogenesis of allergy in dogs as in humans.