[Recurrence of the original disease in the transplanted kidney].

Recurrence of the original disease in the transplanted kidney is observed in 5.6%-9.3% of the patients. However, the clinical significance of recurrence is often minor. Diagnosis is easy in diseases with specific renal lesions, e.g., in dense deposit disease and IgA-nephropathy, but may be difficult if such a marker is missing. Recurrence is of special clinical importance in the following conditions: Membranoproliferative GN type I (in 33%, often severe) and type II (= dense deposit disease, recurrence in 90%, often minor), focal segmental glomerulosclerosis (in 48% of patients with a rapid course (less than 3 years) and in 12% of patients with a longer duration of the original disease; often severe), membranous nephropathy (recurrence rather rare, but often serious), and primary hyperoxaluria (in 100%). Mesangial IgA deposits recur in half of the patients with IgA-nephropathy and anaphylactoid purpura, but clinical findings are often minimal. Recurrence in anti-GBM-nephritis and SLE is rare. The study of recurrence may contribute to a better understanding of many renal diseases.