Acute interstitial nephritis (AIN) and uveitis of unknown etiology developed in a 15-year-old girl. Symptoms and urinary abnormalities improved spontaneously but moderate renal dysfunction and anterior uveitis persisted. A repeat biopsy performed 2 years later showed focal tubulointerstitial changes, while bone marrow examination revealed granulomas. Simultaneously, antineutrophil cytoplasmic antibodies (ANCA) were detected, and decreases in T cell population and lymphocyte function were found. These immunological abnormalities normalized in parallel with clinical improvement with corticosteroid therapy, strongly suggesting that in some patients autoimmune disorders contribute to the pathogenesis of the disease.