Peripheral small vessel involvement in chronic nephritides.

Small cutaneous vessels, obtained by ear lobe biopsies, were studied in 14 patients with various chronic nephritides and in 10 normal controls. The capillaries in the group of patients with nephritis were found to undergo two main changes: thickening of the adventitia reticularis and perivascular cellular infiltration in an inverse ratio. This infiltration was seen to be made up of mononuclear cells and an increased number of mast cells in various stages of degranulation. Changes in the basement membrane as seen by electron microscopy are not constant. All of the above changes were absent in the controls and are similar to what has been described in previous studies in both experimental and spontaneous pathologic conditions, such as experimental hypertension, diabetes mellitus, scleroderma, rheumatoid arthritis, etc. Small vessel involvement in chronic nephritides could be part of a process of diffuse microvascular damage that includes the kidneys or it may be related to hypertension or to the biochemical changes which follow uremic and pre-uremic states.