The natural history of untreated focal allograft rejection in liver transplant recipients.

Focal rejection involves less than 20% of portal tracts in liver allograft biopsy results. The clinical significance of "focal" rejection on protocol liver biopsy results is unknown. The purpose of this study was to prospectively determine the incidence of clinically significant rejection in patients with focal rejection after orthotopic liver transplantation. Biopsy specimens from 165 consecutive transplantations in 149 patients were analyzed. After protocol biopsy specimens were obtained, patients with focal or mild rejection were observed. Fifty of 583 (8.6%) protocol biopsy results in 41 patients showed focal or mild rejection. None were treated on the basis of this histological finding. Six patients subsequently developed abnormal liver function tests and required treatment with additional immunosuppression. We conclude that focal or mild rejection is a relatively common finding on protocol liver biopsy results and only rarely progresses to a clinically significant problem. Patients with this finding can safely be observed without treatment.