[Granulomatous interstitial nephritis in a patient with Behçet's disease treated with infliximab]

The patient is a 41-year-old man diagnosed with uveitis in 2004. Although the patient was positive for HLA-B51, the primary disease could not be identified, and oral administration of prednisolone (PSL) was initiated. A subsequent gradual decrease in the PSL dose was accompanied by the development of recurrent spasmodic chorioretinopathy and hypopyon. In November 2007, the patient was diagnosed with Behçet's disease based on the findings of erythema nodosum, acneiform eruption, and oral aphtha. In order to control the ocular symptoms, infliximab was administered. However, the patient's renal function began to deteriorate in November 2011, and he was transferred to our department after 6 months. At that time, his creatinine level was 8.56 mg/dL. Renal biopsy examination revealed granulomatous interstitial nephritis. Moreover, only infliximab yielded a positive result in a drug-induced lymphocyte stimulation test (DLST). Following initiation of PSL administration at 60 mg/day, his renal function improved. His creatinine level remained constant at approximately 3 mg/dL. In the present case, Behçet's disease, sarcoidosis, and infection were excluded as the underlying disease causing granulomatous interstitial nephritis. Moreover, infliximab is reportedly involved in the development of granulomas. Recent reports have stated that administration of TNF-alpha inhibitors occasionally results in the development of granulomas in the lungs and skin, and sometimes, in the kidneys as well. When renal dysfunction occurs in patients receiving TNF-alpha inhibitors, we believe that it is essential to include adverse events associated with TNF-alpha inhibitors in the differential diagnoses.