Clinical significance of renal allograft biopsies with ''borderline changes,'' as defined in the Banff Schema

Background. The Banff Schema suggests the term ''borderline changes'' for biopsies showing changes insufficient for a diagnosis of mild acute rejection, The appropriate clinical management for patients showing such changes on biopsy is controversial. Methods. We reviewed the clinical course and response to antirejection therapy of 24 patients with borderline changes, and compared our findings with those obtained from 14 patients with mild acute rejection, Patients were classified as showing-complete response, partial response, or no response to antirejection treatment, depending on whether the posttreatment fall in serum creatinine was > 70%, 30-70%, or < 30% of the pretreatment rise, respectively. Renal allograft biopsies were systematically evaluated in accordance with the Banff schema, Results. Complete response to antirejection therapy was seen in 15/24 (63%), partial response-in 3/24 (13%), and nonresponse in 6/24 (25%) patients with borderline change. Compared with patients showing complete response, nonresponse was associated with higher scores of acute tubular necrosis and chronic allograft nephropathy (P < 0.05). By comparison, 12/14 (86%) cases of mild acute rejection showed complete response to antirejection therapy (P = 0.25 vs. patients with borderline change), and lack of response was associated with a higher score for chronic allograft nephropathy. Conclusion. When biopsies are done in the cont est of renal allograft dysfunction, borderline changes frequently require increased immunosuppression, These findings should not be extrapolated to protocol biopsies performed in the setting of stable graft function.