Induction of extraglomerular renal damage in experimental chronic serum sickness. I. Histologic and immunofluorescence findings.

Histologic and immunofluorescence studies were performed in nine rabbits after daily administration of human serum albumin at a fixed dosage for periods up to 26 weeks. All but one of the rabbits studied by immunofluorescence showed IgG, C3, and fibrinogen deposits in the renal glomeruli and in the tubules or peritubular tissues. In most cases, human serum albumin could also be identified in the deposits. In two rabbits killed at week 10, kidney pathology was minimal; in one of the rabbits killed in the early phases of the disease and in all rabbits killed after week 20, there were obvious pathologic changes affecting glomeruli, tubules, and/or interstitium. Tubulointerstitial changes were absent in only one of the rabbits killed at late stages of human serum albumin administration, in spite of evidence of tubular deposition of immune complexes. These observations suggest that tubulointerstitial damage is at least as frequent as glomerular damage during the induction of chronic serum sickness.