| dc.description.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.
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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
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prevention of allergic and autoimmune diseases needs further consideration but is
a promising field both in human and veterinary medicine. | en |
