Acute tubulointerstitial nephritis in children: clinical, morphologic, and lectin studies. A report of the Southwest Pediatric Nephrology Study Group.

Clinical histories and renal biopsies were reviewed in 12 children with acute tubulointerstitial nephritis, which was drug related in eight, idiopathic in one, and multifactorial in three. Presentation with rashes and hypertension was most common in patients with drug-associated nephritis. Eosinophils, which were present in the majority of the renal biopsies, did not distinguish between drug-related and non-drug-related disease. The majority of the children had a good outcome irrespective of the insulting agent. Frequent tubular basement membrane breaks were identified in seven of the biopsies but were not associated with a poor outcome. Proximal tubule brush border thinning, demonstrated by periodic acid-Schiff and Tetragonolobus lotus staining, paralleled the severity of acute renal failure. Lectin and immunohistochemical techniques to identify proximal tubules (Tetragonolobus lotus), thick ascending limb of Henle (anti-Tamm-Horsfall protein antibodies), and collecting ducts (Arachis hypogaea) allowed better delineation of sites of inflammation and injury, showed collecting tubules to be involved in all cases, and demonstrated that small atrophic tubules were able to maintain the ability to stain with the appropriate lectin/antibody. It is proposed that studies using these techniques may better identify the nephron sites involved in a variety of renal diseases involving tubular segments.