A case of infection-related glomerulonephritis with massive eosinophilic infiltration
.

Infection-related glomerulonephritis (IRGN) is rarely complicated with eosinophil infiltration into the glomerulus. Here we report a case of eosinophilic proliferative glomerulonephritis related with infection. A 70-year-old man with respiratory symptoms displayed hypereosinophilia, hypocomplementemia, impaired renal function, and nephrotic syndrome. Renal biopsy revealed endocapillary proliferative glomerulonephritis with immunostaining for immunoglobulin G and complement 3, and subepithelial hump-like electron-dense deposits, thus fulfilling the criteria for IRGN. Immunostaining for the nephritis-associated plasmin receptor (NAPlr) in the glomerulus confirmed the diagnosis of IRGN. Of note, eosinophils infiltrated into the glomerular subendothelial spaces, renal tubules, peritubular capillaries, and the interstitium in the kidney as well as in the alveolar walls and pulmonary arteries in the lung. Corticosteroid therapy rapidly improved hypereosinophilia as well as respiratory symptoms and renal function. Urinary protein exertion was decreased, and serum level of complement and albumin was increased. These findings suggest that eosinophil infiltration might play a prominent role in respiratory and renal disorders. Severe endothelial damage of glomeruli and tubulointerstitial nephritis, caused by eosinophil-rich inflammation, might significantly contribute to exacerbation of renal insufficiency.
.