Renal involvement in canine leishmaniasis: a morphological and immunohistochemical study / Envolvimento renal na leishmaniose canina: estudo morfológico e imunoistoquímico

IgG and IgM deposits in kidneys of dogs with visceral leishmaniasis (VL) were studied in 25 symptomatic dogs (case) and 15 asymptomatic dogs (control) by an immunohistochemical method. All tested dogs were positive for VL by polymerase chain reaction, enzyme-linked immunosorbent assay, and indirect immunofluorescence test. Kidney fragments were submitted to immunohistochemical reaction. Many morphological patterns of distribution of subendothelial granules were identified for IgG and IgM in glomerular capillaries: global, segmental, diffuse, or focal. Intensity of immunohistochemical reaction to IgG was not significantly different when comparing the symptomatic and the asymptomatic animal groups by Fisher's exact test. IgM reactions were significantly different between groups (P<0.01). Deposits of IgM on mesangial cells and in inflammatory interstitial infiltrate were rarely seen, although IgG reactions were frequent at these sites. This study concluded that immunohistochemical reactions for IgM were more intense than those observed for IgG in canine VL, and these reactions were characterized by distribution of subendothelial granules in glomerular capillaries.

Caracterizou-se a deposição de IgG e IgM em rins de cães com leishmaniose visceral (LV) pelo uso da técnica imunoistoquímica. Foram estudados rins de 25 cães sintomáticos (caso) e de 15 cães assintomáticos (controle). Todos os animais foram positivos para leishmaniose pela reação em cadeia da polimerase, pelo ELISA e pela imunofluorescência indireta. Fragmentos renais foram submetidos à reação imunoistoquímica. Diversos padrões morfológicos de distribuição de grânulos subendoteliais de IgG e IgM foram identificados nos capilares glomerulares: global, segmentar, difuso ou focal. A intensidade da reação imunoistoquímica da IgG, medida pelo teste exato de Fisher não diferiu entre os grupos sintomáticos e assintomáticos e a intensidade de reação da IgM foi diferente entre os grupos (P<0,01). Depósitos de IgM nas células mesangiais e no infiltrado inflamatório raramente foram visualizados, no entanto as reações IgG foram freqüentemente visualizadas nesses locais. Concluiu-se que as reações de IgM foram mais intensas que as reações de IgG na LV canina e caracterizam-se pela distribuição de grânulos subendoteliais nos capilares glomerulares.

Polymerase chain reaction in detecting Leishmania sp in symptomatic and asymptomatic seropositive dogs

In human and canine renal histological studies of visceral leishmaniasis (VL), the etiological agent is rarely found in situ. The objective of this study was to evaluate PCR in identifying the etiological agent in spleen, liver, lymph node, and kidneys of VL-seropositive dogs. Twenty-five symptomatic (case group) and 15 asymptomatic (control group) VL-seropositive dogs of different breeds, sexes, and ages from Teresina, Piauí State, Brazil, were used. Serologic diagnosis was made by enzyme-linked immunosorbent assay and indirect immunofluorescence test. Animals were subjected to euthanasia and necropsy. Renal fragments were immersed in buffered formaldehyde solution. Spleen, liver, lymph node, and kidney samples were collected and frozen at -70ºC until DNA extraction. After dehydration and diaphanization, renal fragments were infiltrated and embedded in paraffin, cut at 3 mm, and stained with hematoxylin-eosin (HE). DNA amplification used an automatic thermocycler with specific Leishmania primers. All case-group dogs and 2 controls showed positive results in spleen, liver, or lymph node PCRs. There was a significant difference by Fisher exact test. In symptomatic seropositive dogs, renal histopathological evaluation showed one animal (4%) with amastigote forms of Leishmania in inflammatory infiltrate, and kidney PCRs detected Leishmania DNA in eight animals (32%). The conclusion was that PCR is more precise than the conventional histopathology in detecting the Leishmania parasite in kidney

Renal involvement in visceral leishmaniasis dogs

Visceral leishmaniasis (VL) is a zoonosis that affects both animals and man. Dogs are the etiological agent’s main reservoir. The aim of this study was to evaluate the clinical laboratory aspects and renal histopathology of VL dogs. Thirty-four symptomatic (case) and 17 asymptomatic (control) VL seropositive dogs of different breeds, sexes, and ages from Teresina, Piauí State, Brazil, were used. Diagnosis was confirmed by enzyme-linked immunosorbent assay and indirect immunofluorescence test. Clinical and laboratory tests included blood cell count and renal function analysis (urea and creatinine). Animals were subjected to euthanasia and necropsy. Renal fragments were prepared by the usual histological techniques and stained with hematoxylin-eosin and periodic acid-Schiff. Physical examination showed that lymph node hypertrophy (85.29%) and skin lesions (35.29%) were frequent in the case group. Anemia was found in 55.88% of the case and in 11.76% of the control group. There was a significant difference between groups by Fisher’s exact test. Two case-group dogs showed azotemia. Renal histopathological evaluation showed that 61.76% case and 17.65% control-group dogs had membranoproliferative glomerulonephritis. Mesangial proliferative glomerulonephritis was seen in 32.35% case and 64.70% control-group animals. There was a significant difference for both types of glomerulonephritis between groups. Amastigote forms of Leishmania were found in the renal parenchyma, in the inflammatory infiltrate of one case-group dog. We concluded that, in canine VL, regardless of the clinical signs at physical examination, the kidneys are frequently compromised