| Abstract | Cilj ovog rada bio je pobliže opisati patofiziologiju leukemija i limfoma više vrsta životinja,
uz naglasak na pse i mačke.
Patofiziologija leukemija i limfoma u životinja nije dovoljno razjašnjena i treba dodatnu
sistematizaciju i klasifikaciju, uz dodatne animalne modele i istraživanja kako bi se rasvijetlile
mnoge nepoznanice od etiologije do mehanizma nastanka bolesti.
Pojava hematoloških neoplazija vezana je uz stanični ciklus i njegovu kontrolu te se javlja
zbog grešaka u istom u kombinaciji sa specifičnim obilježjima tumorskih stanica što rezultira
brojnim mutacijama i nekontroliranim diobama jednom zdravih i funkcionalnih stanica.
Limfom i leukemija različite su bolesti, čija je osnovna razlika da se leukemija primarno
javlja u koštanoj srži i krvi te zahvaća, više ili manje, sve krvne loze. Limfom zahvaća isključivo
limfocite te se javlja u pojedinim organima i to najčešće u onima koji čine osnovu imunosnog
odgovora, gdje je prisutna najveća koncentracija limfocita.
Limfom, koji potječe od stanica imunološkog sustava – limfocita, može biti T ili B
staničnog podrijetla, a osim toga može se razlikovati prema svojoj anatomskoj lokaciji,
imunofenotipu, histološkoj građi i biološkom ponašanju. Klinički oblici su brojni, a incidencija
navedenih razlikuje se od vrste do vrste, gdje je u pasa najčešća varijanta multicentričnog
oblika. Kod mačaka je to limfom gastrointestinalnog trakta uz što je sama pojava bolesti često
u svezi s pozitivnim nalazom FeLV-a. U farmskih životinja jedini značaj pridodaje se
enzootskoj leukozi goveda čiji je uzročnik retrovirus roda Deltaretrovirus i pogađa govedo,
ovce i koze. Patogeneza enzootske leukoze goveda se odvija na način da se virusna DNK
integrira u DNK stanice domaćina pomoću enzima reverzne transkriptaze, a primarno inficira
B-stanice i uzrokuje perzistentnu limfocitozu. Bolest zahvaća samo odrasle jedinke i većina ih
u pravilu ne razvija kliničke znakove, a suzbija se prema „Naredbi o mjerama zaštite zdravlja
životinja od zaraznih i nametničkih bolesti i njihovom financiranju u 2021. godini“.
Leukemiju obilježava proliferacija malignih hematopoetskih stanica, koje su svojim
porijeklom iz koštane srži i javlja se u svih domaćih životinja i to rjeđe od limfoma. Dijeli se
na akutnu ili kroničnu i limfatičku (limfocitnu/limfoblastnu) ili mijeloičnu pa tako razlikujemo
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akutnu limfoblastičnu leukemiju (ALL), akutnu mijeloblastičnu leukemiju (AML), kroničnu
limfocitnu leukemiju (CLL) i kroničnu mijeloičnu leukemiju (CML).
Akutna limfoblastična leukemija pokazuje malu staničnu diferencijaciju, a dominantna
stanična populacija su blasti i/ili prolimfociti, dok je akutna mijeloblastična leukemija ona kod
kojih je prisutna leukocitoza, uz veći broj cirkulirajućih atipičnih blasta te su stanice
diferencirane u granulocitne, monocitne, eritrocitne i megakariocitne stanične linije. Kod pasa
je zabilježeno veća incidencija akutne mijeloblastične leukemije, a u mačaka akutne
limfoblastične leukemija te je ona, kao i kod limfoma, često u korelaciji s infekcijom mačjim
virusom leukemije.
Kronična leukemija može biti limfatična ili mijeloična, koje imaju svoje podtipske
varijante. O njima nije poznato puno i javljaju se rjeđe nego akutne, a studije pokazuju da
pogađaju pse i mačke starije životne dobi. U mačaka se oba tipa javljaju u populaciji izuzetno
rijetko, dok je kod pasa ipak zabilježena nešto češća pojava kronične limfocitne leukemije nego
one mijeloičnog porijekla. Kronična limfocitna leukemija se očituje kao perzistentna periferna
limfocitoza, a limfociti su morfološki zreli i perzistiraju u organizmu dulje od tri mjeseca.
Kronična mijeloična leukemija (CML) uključuje nekoliko podtipova - kroničnu mijeloičnu ili
granulocitnu, kroničnu monocitnu i kroničnu mijelomonocitnu leukemiju, a klinički se očituje
gotovo identično kao i kronična limfocitna leukemija. |
| Abstract (english) | The aim of this paper was to describe the details of the pathophysiology of leukemias and
lymphomas of several animal species, with emphasis on dogs and cats.
The pathophysiology of leukemias and lymphomas in animals is not sufficiently elucidated
and needs additional systematization and classification, with additional animal models and
research in order to resolve many of today’s unknowns, from etiology to the mechanisms of the
two diseases.
The occurrence of hematological neoplasms is related to the cell cycle and its control and
occurs due to errors in it. Precisely this, in combination with specific characteristics of tumorous
cells, results in numerous mutations and uncontrolled divisions of once before healthy and
functional cells.
The main difference between leukemia and lymphoma is that leukemia occurs primarily in
the bone marrow and blood affecting almost all cell lineage. Lymphoma affects only
lymphocytes, and it occurs in certain organs. It is most often seen in organs which have the
highest concentration of lymphocytes - those that form the basis of the immune response.
Lymphoma, which originates from cells of the immune system - lymphocytes, can by its
cellular origin be of T or B type, and in addition may differ according to its anatomical location,
immunophenotype, histological structure and biological behavior. Clinical forms are numerous,
and the incidence of these varies from species to species, where in dogs the most common
variant is the multicentric form. In cats, it is a lymphoma of the gastrointestinal tract, and the
onset of the disease is often associated with a positive FeLV test. The most important disease
variant in farm animals is the enzootic bovine leukosis, which is caused by a retrovirus of the
genus Deltaretrovirus and it affects cattle, sheep, and goats. The pathogenesis of enzootic
bovine leukosis starts when viral DNA integrates into the DNA of the host cell by reverse
transcriptase enzyme, and it primarily infects B cells and causes persistent lymphocytosis. The
disease affects only adult bovine and most of them do not usually show clinical signs. This
disease is controlled by the law according to the "Order on measures to protect animal health
from infectious and parasitic diseases and their financing in 2021."
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Leukemia is characterized by the proliferation of malignant hematopoietic cells, which
originate from the bone marrow. It occurs in all domestic animals, and it is less frequent than
lymphoma. It is classified into acute or chronic, and lymphoid (lymphocytic/lymphoblastic) or
myeloid, by which we differentiate main types: acute lymphoblastic leukemia (ALL), acute
myeloblastic leukemia (AML), chronic lymphocytic leukemia (CLL) and chronic myeloid
leukemia (CML).
Acute lymphoblastic leukemia shows a little of cell differentiation, and the dominant cell
population are blasts and/or prolymphocytes. On the other hand, acute myeloblastic leukemia
is the one where leukocytosis is present, with a number of circulating atypical blasts and cells
are differentiated into granulocyte, monocyte, erythrocyte, and megakaryocyte cell lineage. In
dogs, it has been reported a higher incidence of acute myeloblastic leukemia, whereas in cats
acute lymphoblastic leukemia is more common, and it is often correlated with feline leukemia
virus infection.
Chronic leukemia can also be lymphoid or myeloid, and those have their own subtypes.
There is not much known about it, and it occurs less frequently than the acute one, but studies
show that it affects older dogs and cats. In cats, both types are extremely rare in the population,
whereas in dogs, chronic lymphoid leukemia is somewhat more common than the one of
myeloid origin. Chronic lymphoid leukemia manifests as persistent peripheral lymphocytosis
where lymphocytes are morphologically mature and persist in the body for more than three
months. Chronic myeloid leukemia (CML) includes several subtypes - chronic myeloid or
granulocytic, chronic monocytic and chronic myelomonocytic leukemia, and it is clinically
almost identical to chronic lymphocytic leukemia. |
