Nivolumab-induced acute granulomatous tubulointerstitial nephritis in a patient with gastric cancer

We here report a case of nivolumab-induced acute granulomatous tubulointerstitial nephritis in a patient with gastric cancer. A 68-year-old woman with recurrent gastric cancer developed acute kidney injury associated with kidney enlargement and urinary leukocytes after 38 cycles of nivolumab treatment. A diagnosis of acute granulomatous tubulointerstitial nephritis was made based on kidney biopsy findings. Immunohistochemistry revealed expression of programmed cell death–ligand 1 (PD-L1) in degenerated epithelial cells of collecting tubules. Among infiltrating immune cells, aggregation of T cells was more extensive than that of B cells, with CD4⁺ T cells outnumbering CD8⁺ T cells, consistent with the relative numbers of these cells in the circulation. Treatment with methylprednisolone (1.0 mg/kg daily) led to a rapid improvement in renal function and reduction in the number of circulating CD4⁺ T cells. Prompt administration of high-dose corticosteroid is thus recommended after diagnosis of this adverse event of nivolumab treatment by kidney biopsy.