Eosinophiliával járó betegségek a kisállatpraxisban

Abstract

Eosinophil granulocytes having multiple and complex task within the body are the target of many investigations. They are produced in the bone marrow during myelopoesis, stimulated by IL-5, IL-3, and the granulocyte-macrophage colonising factor. In the blood smears they can be easily recognised due to their eosinophilic granules and bisegmentated nucleoli. Their size is approximately 10 micrometers, their number in physiological conditions is 0.01-1.25 G/l (2-5% of the white blood cells). The main function of the eosinophils is the deffence against parasites and in the hypersensitivity reactions. They reach their target cells and immuncomplexes by their direct phagocytic activity or by the enzymes stored in the granulumes (major basic protein, eosinophil cationic protein, eosinophil derived neurotoxin, eosinophil peroxidase, etc.). In the same time increased activity of these factors have strong tissue damaging effect. Because of these reason, processes accompanied by eosinophilia and infiltration with eosinophils (hypereosinophilic syndrome, eosinophilic gastroenteritis, eosinophilic meningoencehpalomyelitis, etc.). can induce severe conditions, even can take deadly course. The number of eosinophils moderately increase in the peripheral blood in case of parasitic infections and hypersensibility reactions, mainly due to the increased IL-5 activity (reactive eosinophilia). Parasites with larval migration or arthropoda can induce severe eosinophilia: Dirofilaria immitis (eosinophil number 1-13.4G/l), Leischmaniasis (eosinophil number 6 G/l), and Sarcocystis infection (eosinophil number 6.3 G/l), pulmonary parasitism (eosinophil number: 1.4-2.8 G/l), Sarcoptes infection 3.4 G/l), Pneumonyssoides nasal mites, which is not present in Hungary (4.1 G/l). In our study comprising 49 cases when in the same time blood cell count and faecal parasatic results were awailable, there was no statistical significance between blood eosinophilia (expressed eiher in relative percentage or absolute count) and positive results of blood faecal parasitic (intestinal nematodes or protozoa) examination. From 15 dogs with eosinophilia, 20% of the dogs was positive on faecal parasitic examination, while 8.8 % of the non-eosinophilic dogs had positive result. 45 Variable eosinophilic response can be seen related to allergic reaction. Generally, recurrent antigen induce more accentuated eosnophilic response in the blood. The presence of a parasitic infection and hypersensitivity reaction in the same time can induce strong eosinophilic reaction (eg. flea allergy 3.3 G/l) Severe eosinophilia is present in eosinophilic leukemia, which is due to the expansion of eosinophil granulocytes in the bone marrow (clonal eosinophilia). Idiopathic causes of eosinophilia can occure in generalised (Hypereosinophilic Syndrome, HES; with eosinophil cell count up to 50 G/l), or localized form (Eosinophilic Meningoencephalomyelitis, Eosinophilic Gastroenteritis, Pulmonary Infiltrates with eosinophilia-syndrome, Eosinophilic Myositis). Their exact cause is unknown, but hypersensitivity reaction may lay in the background. Hypereosinophilic states can cause severe tissue damage, so their treatment is necessary. Treatment consists in administration of glucocorticoids, chemoterapeutic drugs and alpha interferon. In human HES cases abberant immunphenotype of T-lymphocyte lines were found, which causes eosinophilia trough IL-5 production. In the literature an increased case of hypereosinophilic cases is described in rotweillers. Eosinophilia is also reported in neoplasia (T-cell lymphoma, mastocytoma, certain types of carcinomas), endocrine diseases (Addison-disease, hyperthyreosis in cats), inflammatory conditions (panostitis, osteomyelitis) and infectious diseases (Cryptococcosis). Studies are conducted to reveal the common immunological background of the allergic and parasitic diseases, in order to find a possible treatment for allergic conditions. In people suffering from asthma and Crohn disease research on therapy with intestinal parasites (Schistosoma mansoni, Trichuris suis) is conducted and promising results were published. In animal models the immunomodulant effect of helmintic therapy was proven and the beneficial effect of parasite therapy was also suggested. Altough results yet are conflicting; in some experiments helmint therapy increased the hypersensitivity reaction, while in others the immunomodulant activity was dependent on the gender of the applied parasite. Altough experimental infection with Trichuris and Uncinara in canine atopic dermatitis seemed to have a positive effect, statistically significant effect of treatment can not been shown. The role of helmint therapy in the 46 prevention of allergic and autoimmune diseases needs further consideration but is a promising field both in human and veterinary medicine.