Interstitial nephritis in human kala-azar.

Little is known about renal alterations in kala-azar. The renal histopathology of 21 patients admitted to hospital in São Paulo, Brazil, during the period 1960 through 1981 who either died or had a renal biopsy (two cases) is presented. All the specimens showed oedema and diffuse interstitial inflammatory infiltrate of lymphocytes and plasma cells with more compact foci of cells in some areas. In general, glomeruli did not show any important alterations. These aspects were interpreted as acute interstitial nephritis aetiologically related to later phase kala-azar. This interstitial alteration does not usually seem to determine any clinical manifestations. However, it seems that moderate and severe cortical intersitial damage contribute to the onset of renal insufficiency when severe clinical complications occur. The precise mechanisms of this lesion need further investigation since the aetiological agents have not been seen causing the damage locally.