Spontaneous swine glomerulonephritis in littermates from a leukemic sow.

Spontaneous glomerulonephritis was found in seven six-month-old littermates from a leukemic sow. Light microscopy of the glomerular lesions showed proliferation of the mesangial cells and increase of the mesangial matrix with deposition of homogeneous materials. All glomeruli were affected, but the severity of the lesions varied among pigs. The glomerular capillary walls had local and segmental changes such as thickening and/or irregularity. Electron microscopy revealed dense deposits in the mesangial, paramesangial, subendothelial, subepithelial, and intramembranous areas. The mesangial and paramesangial deposits were most characteristic and prominent. In five of seven pigs, the clusters of extracellular spherical microparticles with a diameter ranging from 25 to 60 nm were observed in the subepithelial, intramembranous, subendothelial, and mesangial areas. No conspicuous lesions were noted in other organs.