Symptomless acute renal transplant rejections. Occurrence six months or more after transplantation.

A total of 22 cases of acute rejection episodes occurring six months to five years after renal transplantation were retrospectively reviewed for the presence of fever, graft tenderness, increase in blood pressure, declining urine output, falling urine sodium level, change in WBC count, and patient's response to antirejection therapy. A total of 13 episodes were not associated with any of these symptoms or signs of an acute rejection episode; seven episodes were associated with an increase in blood pressure alone and only two episodes were associated with fever. Nineteen rejection episodes were confirmed by biopsy. In 16 of these late-rejection episodes, the patient had complete or partial response to therapy. Acute rejection episodes can occur months to years after transplantation; patients are typically asymptomatic; many patients do respond to therapy; and biopsy is often helpful in establishing the diagnosis.