Mesangiolysis associated with severe glomerular endocapillary proliferation of CD57 large granular lymphocytes

A 54-year-old man developed renal failure, with renal biopsy findings of diffuse mesangiolysis with severe endocapillary proliferation. Immunohistochemical studies revealed that CD3-CD56-CD57+ large granular lymphocytes were present predominantly within glomerular tufts. Intercellular adhesion molecule-1 was more preferentially expressed in the glomerular endothelial cells with severe endocapillary proliferation as compared to those without endocapillary proliferation. These findings suggest that CD57+ large granular lymphocytes caused glomerular endothelial injury by a cell-mediated cytolytic mechanism, resulting in the development of mesangiolysis and microaneurysm formation.