Renal cortical tubules in experimental malakoplakia. Phagocytic alteration of tubular epithelium

Intrarenal injection of a crude E. coli extract (endotoxin-antigen-complex) induced malakoplakia in rats. Beside the granulation tissue the proximal tubular epithelium showed a strong phagolysosomal response — especially in two-three weeks —, thus becoming very similar to the Hansemann cells of the malakoplakia granulation tissue. This malakoplakia alteration of the epithelium if very severe sometimes led to necrosis or it was segregated inside the epithelial cells. Later on an atrophy of the tubules developed similar to the atrophy of different etiology, but the remaining cells often contained a striking number of residual bodies. It is suggested that the tubular granulated cells of megalocytic interstitial nephritis regarded as identical with renal cortical malakoplakia also have a tubular epithelial origin.