Kidney transplant biopsies in the diagnosis and management of acute rejection reactions.
In 68 consecutive renal transplant biopsies, histopathologic changes and clinical status of the graft  recipient, both at the time of biopsy as well as one month later, were evaluated by independent observers. Nine histologic features were graded semiquantitatively (scale, 0 to 4): glomerular endothelial swelling, proliferation, exudation and necrosis; interstitial edema and infiltrate: vascular endothelial edema, infiltration and necrosis. The total score for each biopsy was termed the acute rejection index (ARI). The validity of the ARI as a means of evaluation rejection reactions was established by correlating the ARI with a second, overall histopathologic categorization. Clinical status at the time of biopsy was classified by retrospective analysis of all clinical data except the biopsy. The mean ARI of patients with an acute clinical rejection was significantly higher than those of patients with just a chronic clinical rejection or no clinical rejection. The utility of the biopsy in predicting the response of the graft recipient to therapy was evaluated in those 46 patients in whom an acute rejection was diagnosed clinically and in whom a full and complete course of therapy for the acute clinical rejection was given. Of the 28 patients whom the pathologist predicted would response to therapy, 27 did show substantial improvement of their renal function up to one month following institution of treatment. Of the 18 patients whom the pathologist predicted would not respond to therapy, 15 had no clinical response. The data suggest that the transplant biopsy is helpful in 1) establishing the diagnosis of an acute rejection and 2) indicating whether or not the graft recipient will respond to standard immunosuppressive treatment for an acute rejection,
D000208:Acute Disease; D001707:Biopsy, Needle; D006084:Graft Rejection; D006801:Humans; D007668:Kidney / Q000473:pathology; D016030:Kidney Transplantation; D013997:Time Factors; D014184:Transplantation, Homologous