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Dirofilariasis. IV. Glomerulonephropathy induced by Dirofilaria immitis infection
Abstract:
The kidneys of dogs chronically infected with Dirofilaria immitis were studied by light, electron, and immunofluorescent microscopy. The glomeruli of dogs with high microfilaremia showed a moderately increased mesangium and thickened glomerular basement membrane. There was a deposition of electron-dense particles which were continuously distributed in the lamina rara interna and lamina densa of the glomerular basement membrane. Immunofluorescent microscopy showed intense IgG deposits in a uniform linear pattern along the glomerular basement membrane. This linear deposition of IgG appeared to correspond to continuous distribution of electron-dense particles in the basement membrane. Microfilariae present in the glomerular capillary lumens were connected with the capillary endothelial cells by narrow cytoplasmic bands. The interaction of the worm's internal substances with the glomerular capillaries through these cytoplasmic bands may deposit worm antigen on the glomerular capillary wall before antigen-antibody interaction takes place. These findings suggest that the glomerulopathy seen in dogs infected with D. immitis is caused by the in situ formation of immune complexes in the glomerular basement membrane.
Insights
Canine kidney disease in dogs with heartworm (Dirofilaria immitis) infection is caused by immune complexes forming in the glomerular basement membrane. This study reveals IgG deposits and electron-dense particles in affected glomeruli.
Area of Science:
- Veterinary Pathology
- Immunology
- Nephrology
Background:
- Chronic Dirofilaria immitis infection in dogs can lead to kidney damage.
- Glomerulopathy is a recognized complication in canine heartworm disease.
Purpose of the Study:
- To investigate the pathological changes in the kidneys of dogs with chronic Dirofilaria immitis infection.
- To elucidate the immunopathogenesis of glomerulopathy associated with heartworm disease.
Main Methods:
- Light, electron, and immunofluorescent microscopy were used to examine kidney tissues.
- Analysis focused on glomerular structure, basement membrane, and immune deposits.
Main Results:
- Dogs with high microfilaremia exhibited mesangial expansion and thickened glomerular basement membranes.
- Electron microscopy revealed electron-dense particle deposition within the glomerular basement membrane.
- Immunofluorescence showed linear IgG deposits along the glomerular basement membrane, correlating with electron-dense particles.
Conclusions:
- The findings suggest glomerulopathy in Dirofilaria immitis-infected dogs results from in situ immune complex formation.
- Interaction between microfilariae and glomerular capillaries may initiate antigen deposition, leading to immune-mediated kidney damage.