Chronic interstitial nephritis. Its occurrence with oxalosis and anti-tubular basement membrane antibodies after jejunoileal bypass.

A 38-year-old woman suffered rapid onset of renal failure between 11 and 15 months after undergoing a jejunoileal bypass for morbid obesity. Microscopic examination of renal biopsy specimens revealed oxalosis and severe tubulointerstitial nephritis. Immunofluorescence microscopy disclosed linear staining of tubular basement membranes with antisera to IgG and C3, which suggests antitubular basement membrane disease, a side effect not previously recognized with jejunoileal bypass. Possible mechanisms leading to the formation of these antibodies include (1) oxalate damage to renal tubules with release of tubular basement membrane antigens, and (2) bacterial overgrowth in the bypass segment, with mucosal damage and release of intestinal mucosal antigens that share antigenetic determinants with renal proximal tubules. Anti-tubular basement membrane disease may be an additional mechanism that produces or enhances renal damage in patients with jejunoileal bypass.