Significance of interstitial lesions as the early indicator for acute vascular rejection in human renal allografts

To evaluate the relevance between interstitial lesions and acute vascular r ejection of renal allograft, we examined 129 renal allograft biopsy samples obtained from 60 transplant patients within 90 d post-transplantation. Pla sma cells. eosinophils and polymorphonuclear cells (PMNs) in the cortical i nterstitium were counted, respectively, and the number of each cells per 10 fields at a magnification of 200 x was calculated. Then, the existence of interstitial edema was judged. We categorized 129 biopsy specimens into spe cimens before (Pre), on (R) and after acute rejection (Post). An increased number of eosinophils (mean +/- SE; 15.4 +/- 9.2 per 10 fields) was observe d in R rather than in Pre (0.6 +/- 0.3, p < 0.05). The increasing number of plasma cells depends on a time course following the onset of acute rejecti on. The number is significantly larger in acute vascular rejection (4.3 +/- 1.1) than in non-vascular rejection (1.3 +/- 0.4, p < 0.01). In living don or transplants, the number of PMNs in patients before vascular rejection (m edian, 16.7 per 10 fields; range, 5.0-20.0 per 10 fields) was significantly larger than in normal or borderline patients (2.2; 0.0-36.7, p < 0.01). Th e incidence of interstitial edema in patients before vascular rejection (55 .6%) was significantly higher than in normal or borderline patients (8.0%, p < 0.01). This study suggested that acute vascular rejection is relevant t o interstitial lesions, such as for a plasma cell, eosinophil and PMN infil trate, and edema. Also, these lesions seem to be the indicator of acute vas cular rejection. These findings may contribute to the refinement of histolo gical diagnosis of acute vascular rejection.