Abnormal distribution of anionic sites in the glomerular basement membranein glomerulonephritis of dogs infected with Dirofilaria immitis

Ultrastructural alteration of anionic sites (ASs) in the glomerular basemen t membrane (GBM) was studied in glomerulonephritis characterized by linear capillary Ige deposition in four dogs infected with Dirofilaria immitis and two normal control dogs using polyethyleneimine. ASs were identified as sm all dense particles distributed regularly in the lamina rara externa (LRE), but there were no ASs in the lamina densa (LD) of the GEM of the control d ogs. In the glomeruli of the infected dogs, ASs were distributed regularly or irregularly in the thickened LD. ASs were in addition localized over the characteristic continuous bands of subendothelial dense deposits. The numb er of ASs of the LRE increased in all four infected cases as compared to th e controls (p<0.01).