Cimetidine-induced tubulointerstitial nephritis with both MPO-ANCA and PR3-ANCA.

We describe a 75-year-old man with tubulointerstitial nephritis (TIN) with myeloperoxidase (MPO)-antineutrophil antibody (ANCA) and proteinase-3 (PR3)-ANCA. He had a slight fever and eruption with itching after taking cimetidine (prescribed after gastrectomy for gastric cancer) and he was admitted to a nearby hospital. There, he showed proteinuria, serum creatinine (sCr) of 2.9 mg/dl, and creatinine clearance (Ccr) of 44 ml/min per 1.73 m2. His MPO-ANCA titer was 267 EU, and PR3-ANCA titer was 112 EU. Abnormal concentrations in bilateral kidneys were found by gallium scintigraphy. For these reasons, he was transferred to our hospital. Percutaneous renal biopsy was performed after admission. Severe tubular atrophy, mild interstitial fibrosis, and severe mononuclear cell infiltration of the interstitium were noted. Drug-induced renal impairment was suspected, and cimetidine administration was withdrawn. Lymphocyte stimulation tests (DLSTs) were performed. The cimetidine titer was positive, at 2,537 cpm. After the withdrawal of cimetidine, the PR3-ANCA titer was reduced gradually, and, next, the MPO-ANCA titer was also reduced. The sCr level was reduced to 1.2 mg/dl. In summary, we report herein the first case of cimetidine-induced TIN associated with both MPO-ANCA and PR3-ANCA.