Conversion of glomerular histology from a mesangiopathic to a membranopathic pattern in serum sickness nephritis with prolonged sensitization.

In order to examine the effect of prolonged sensitization on glomerular injury, serum sickness nephritis was induced in Fischer rats by administration of egg albumin (EA). Animals were divided into A, B and C groups with 4-week, 6-week and 8-week sensitization, respectively. The experimental results were as follows: Both group A (4 weeks) and group B (6 weeks) showed mesangial immune complex deposition with proliferation (mesangiopathic pattern), but in the latter both the size and the amount of the deposits were larger than those in the former; while group C (8 weeks) demonstrated predominant distribution of deposition along the capillary walls (membranopathic pattern). It is suggested that such conversion of deposition from mesangiopathic to membranopathic pattern after prolonged repeated sensitization may be the result of the change of the host immune response to antigen, and/or the character of the antibody.