ENGLISH VERSION

ZESZYT 365

Selected parameters of a systemic immune response in dogs 
with atopic dermatitis and their suitability for diagnosis and therapy
zeszyt 365, ss. 122

Atopic dermatitis (AD) in dogs is an chronic, recurrent disease resulting from a genetic predisposition to the development of the body’s hypersensitivity to environmental allergens. In the course of AD intensive pruritus as well as characteristic localisation and clinical features of the skin lesions are observed. This disease is incurable, and therefore it requires a regular lifelong treatment. In the course of medical proceeding there is a need to make the correct diagnosis and to choose the symptomatic treatment most appropriate for canine patient. Treatment proceedings should be adapted to each patient and monitored depending on the sevetity of the disease. For this purpose a number of available methods are used to objectively assess the status of the immune system as well as the organic and systemic changes in dog with AD.

The purpose of the study was the assessment of selected parameters of the immune response in dogs with AD and in healthy individuals in terms of the usefulness of these indicators for the diagnosis and monitoring of both the course of disease and the efficacy of the applied symptomatic treatment with the use of antibiotics, glucocorticosteroid, ciclosporine and pentoxifylline. The comparative analysis of the immunological indices in dogs with AD also allowed the determination of the effect of these medicines on the immune response profile.

The study was performed on dogs with AD of different breeds aged 1–3 years. The control group was constisted of healthy dogs. In the first stage of the research the bacterial skin infections (pyoderma) in dogs with AD were treated with cefalexin in a dose of 30 mg/kg bw. daily, orally for 2–4 weeks. After the elimination of secondary dermatoses the dogs with simple AD (pruritic erythematous stage) were receiving oral prednisone (0.5 mg/kg bw. daily) or ciclosporine (5 mg/kg bw. daily) for 4 weeks. In canine patients without remission after 4 weeks of antipruritic and anti-inflammatory therapy further treatment was applied using pentoxifylline (10 mg/kg bw. daily) for another 4 weeks. During the antire treatment period, in intervals of two weeks, the percentage of blood leukocytes subpopulations was evaluated by flow cytometry method with the use of antibodies directed against surface molecules CD3, CD4, CD8, CD21, CD11b, CD11/18 and MHC class II. In addition, serum concentration of IL-10 and the the phagocytal activity and intracellular killing ablity of bloog leukocytes were determined. At the same time hematological and biochemical blood and urine examinations were performed.

In dogs with AD complicated secondary pyoderma, the significantly greater percentage of T lymphocytes containing CD8, CD11b, CD11/18 molecules and B lymphocytes containing CD21 molecule were observed in peripheral blood as well as IL-10 serum concentration in comparison for healthy dogs. The significant augmentation of phagocytic cells percentage, capable of intracellular killing – which is an indicator of their metabolic activity – was discovered regardless of the degree of AD severity in dogs. However no significant differences related to granulocytes and monocytes percentage, containing CD11b, CD11/18 and MHC class II molecules, were observed in the peripheral blood of dogs with AD or in healthy dogs. On the other hand, in dogs with AD, after the antibiotic treatment, the expression of MHC class II molecules was low as well as the decrease of T lymphocytes CD3 and B lymphocytes CD21 was significant in comparison with that in healthy individuals.

Prednisone used in the treatment of AD caused immunosuppressive action in short time, witch was manifested by a significant decreasein the percentage of lymphocytes containing MHC class II as well as CD3, CD4, CD21, CD11b and CD11/18 molecules, whereas CD8 lymphocytes level was constant. The decrease persisted for two weeks after cessation of symptomatic treatment. Ciclosporine in turn, applied in dogs with AD demonstrated immune modulating properties, consisting in the increase in CD3, CD4, CD8 and CD21 lymphocytes percentage, decrease in CD11b and CD11/18 lymphocytes, at the constant share of MHC class II molecules. The immune modulating influence of cyclosporine was observed 2 weeks after the medicine discontinuation. However, in dogs with AD, first treated with ciclosporine or prednisone, but next treated with pentoxifylline the significant decrease in CD3, CD4 lymphocytes and CD11/18 leukocytes percentage, at constant percentage of CD21 lymphocytes were observed.

The immune response profile in dogs with AD is dependent on degree of the disease severity. The dogs with AD complicated by secondary pyoderma show a significantly higher percentage of MHC II molecules, CD8, CD11b, CD11/18 T lymphocytes, CD21 B lymphocytes and IL-10 serum concentration in comparison with healthy individuals, which indicates an important role of humoral mechanisms of the immune response effector phase in the pathogenesis of this disease. However in dogs with uncomplicated AD, the immune response profile depends on the applied anti-pruritic and anti-inflammatory treatment.