Cell-Mediated Glomerulonephritis Without Immune Complexes in Native Kidney Biopsies: A Report of 7 Cases

We report 7 native kidney biopsies with diffuse endocapillary hypercellularity without immune deposits, affecting 5 women and 2 men aged 52-85 years. All patients had acute kidney injury, and 4 had nephrotic-range proteinuria. Comorbidities included breast cancer in 2, pancreatitis in 1, and para-aortic lymphadenopathy and bilateral carpal tunnel syndrome in 1. Kidney biopsies were characterized by predominant T-cell and CD68-positive macrophage infiltration in glomerular capillaries without deposits. Coexisting lesions included small cellular crescents in 5, mild peritubular capillaritis in 1, mononuclear cell intimal arteritis in 1, acute tubulointerstitial nephritis in 4, and mild arteriolosclerosis in 1. During the mean follow-up duration of 24.8 months, 4 patients showed partial or complete initial remission in response to immunosuppression. However, 2 deteriorated when prednisone was rapidly tapered (1 of them achieved subsequent remission with increased prednisone). Three patients developed kidney failure. We propose that this unusual pattern of injury is mediated by abnormal cell-mediated immune response. The underlying causes and pathogenesis of this cell-mediated glomerulonephritis will require further study.