Abstract
The fine structural alterations of the glomeruli and interstitium were studied in two human renal allografts associated with the episode of an early acute rejection. Specimens were obtained immediately after the renal transplantation, during acute rejection and after successful treatment of a rejection crisis.
Kidney tissues taken immediately after transplantation showed no significant changes except mild edema in the interstitium.
During acute rejection, both endothelial and epithelial cells of the glomeruli were proliferated. Amorphous materials were accumulated subendothelially at the basement membrane of the glomerulus.
The thickening and tortuousness of the basement membranes were frequently observed. Mesangial cells were also hypertrophied with increased amount of mesangial matrix. Edema as well as infiltration of lymphoid cells and plasma cells were the prominent features in the interstitium. Capillaries were also affected.
The vascular and interstitial changes will be the cause of renal ischemia, which in turn contribute to the clinical manifestation of the acute rejection.
Rejection crisis were successfully treated by decapsulation, irradiation and immunosuppressive agents. Renal function recovered in both cases. At this time, cell infiltrations were less prominent. Vascular lesions, however, persisted both in glomeruli and interstitium. Even the advanced lesions of the basement membrane were appreciated in some glomerular tufts.
Vascular alterations at the time of clinical regression seem to be irreversible and insidiously progressed by current therapy. Persistence and progression of these alterations will finally result in deterioration of the renal function.
