Alterações Eritropoéticas e Leucopoéticas na Leishmaniose Visceral Canina

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The bone marrow is considered an important reservoir of parasites in sick Leishmania-infected dogs. Little is know about the process cellular genesis in bone marrow in Canine Visceral Leishmaniasis (CVL) presenting different clinical status. In this context, the aim of the present study was to evaluate leucopoiesis and erythropoiesis alterations as well as to investigate parasite load in aspirates of bone marrow dogs naturally infected by L. chagasi with different clinical status and distinct patterns of bone marrow parasite density. Herein, bone marrow (BM) smears stained by Giemsa were evaluated considering three clinical groups: asymptomatic (AD, n=50), oligosymptomatic (OD, n=44) and symptomatic (SD, n=65) compared with non-infected dogs (NID, n=28). Parasite density was performed in bone marrow and the results expressed as Leishman Donovan Units (LDU index), and classified into tertiles as low (LP, n=51), medium (MP, n=51) or high (HP, n=48) parasitism. A second group of 48 dogs (AD, n=10; OD, n= 9; SD, n= 12; NID, n= 17) was evaluated by bone marrow analysis and hemogram to investigate the association between bone marrow and periphreral blood parameters. The results obtained indicated significant differences in relation to erythropoiesis considering proerythroblasts, basophilic, polychromatic and orthochromatic erythroblasts resulting in an erythroid hypoplasia mainly in AD and SD groups. Leucopoiesis presented some alterations in infected dogs. For example, eosinophilic lineage cells number showed a significant decrease in the different clinical groups compared to NID group. However, neutrophilic lineage cells number showed alterations in the different clinical groups, such as a significant increase in the different clinical groups. Related to mononuclear cells, it was observed for lymphocytes number an increase in OD and SD groups when compared with NID group. Similar results were found for plasma cell number showing a clear tendency to a gradual increase according to the severity of the infection. By the other hand, monocytes cell number had significantly increase in OD group compared to AD group. Differential cell counts of bone marrow demonstrated an increase in the myeloid: erythroid (M:E) ratio due to the increased numbers of granulopoietic cells in the different clinical groups compared to NID group. Parasitological assessment showed higher LDU index in SD compared with AD. Moreover, our data demonstrated a positive correlation among clinical status (AD,OD,SD) and parasite density (LP,MP,HP). Assessment of the impact of parasite density on bone marrow showed similar results when the dogs were evaluated in different clinical stages such as erythroid hypoplasia, eosinophilic hypoplasia, proliferation of neutrophilic precursors cells, a significant increase in lymphocytes and plasma cells number, highlighting the high parasitism dogs group with the most significatives results. The results of second group showed that periphreral blood alterations were related to those shown by bone marrow, mainly in SD group. Indeed, SD group dogs demonstrated significant decrease in erythropoietic lineage cells number and erythrocytes, hemoglobin and hematocryt resulting in a nonregenerative anemia. Moreover, there were observed increase in neutrophils and their precursors, decrease in band eosinophils and eosinophils and significant increase in lymphocytes number in bone marrow associated to leukopenia with left shift, decrease in eosinophils, lymphocytes and monocytes number in peripheral blood. The present study showed that the clinical evolution of CVL in naturally infected dogs promotes clear alterations in the bone marrow and periphreral blood. The progression of the disease from asymptomatic to symptomatic clinical status was accompanied by intense parasitism in the bone marrow. So, the data analysed together allow to conclude that the assessment of these parameters constitute an useful and additional tool for CVL prognosis, as well as for diagnosis in two specific situations, namely: a) to clarify cases with a strong suspicion of CVL, however not confirmed by sorologic tests, by using bone marrow analysis; and b) to orientate complementary laboratory tests to investigate CVL suspicion, based on clinical and hemogram data.

ASSUNTO(S)

imunologia leishmaniose - teses. 2. cão - teses. 3. medula óssea - teses. 4.eritropoese - teses. i. universidade federal de ouro preto. instituto deciências exatas e biológicas. núcleo de pesquisas em ciências b

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