Serial Manifestation of Acute Kidney Injury and Nephrotic Syndrome in a Patient with TAFRO Syndrome

Abstract

A 76-year-old woman suddenly developed anasarca and a fever, and an examination revealed thrombocytopenia, reticulin fibrosis, and acute kidney injury, yielding the diagnosis of thrombocytopenia, anasarca, fever, reticulin fibrosis, organomegaly (TAFRO) syndrome. Renal replacement therapy and steroid treatment were soon started. Her proteinuria was minor at first; however, once the kidney function improved, nephrotic syndrome occurred. A kidney biopsy showed membranoproliferative glomerulonephritis-like glomerulopathy with massive macrophage infiltration. Although kidney dysfunction is often observed in TAFRO syndrome patients, its detailed mechanism is unclear. This case suggests that TAFRO syndrome involves both acute kidney injury with minor proteinuria and nephrotic syndrome, and these disorders can develop serially in the same patient.

Keywords: TAFRO syndrome; acute kidney injury; membranoproliferative glomerulonephritis-like glomerulopathy; nephrotic syndrome.

Figure 1.

Hyperplastic bone marrow in a patient with TAFRO syndrome (A, Hematoxylin and Eosin staining) accompanied by reticulin fibrosis (B, silver stain). (C) Immunoperoxidase staining for CD42b shows an increased number of megakaryocytes (original magnification, A, B, C, 100×). (D) The patient’s clinical course shows that steroid treatment resulted in an improved kidney function, increased platelet count (Plt), and decreased body weight (BW), waist size, and levels of inflammatory markers including C-reactive protein (CRP), interleukin (IL) -6, and vascular endothelial growth factor (VEGF). In contrast, urine protein (U-pro) increased after steroid therapy was started. Day X is the admission day. CHDF: Continuous hemodiafiltration, HD: hemodialysis, KBx: kidney biopsy, S-Cr: serum creatinine

Figure 2.

Histological features of a kidney biopsy in a patient with TAFRO syndrome. (A) Lobulation of a glomerulus and mesangial proliferation can be seen in light microscopy sections (periodic acid-Schiff stain). (B) The glomerular capillary walls show focal double contouring (periodic acid-methenamine-silver stain). (C) Immunoperoxidase staining for CD68 (Nichirei Biosciences, Tokyo, Japan) shows many intraglomerular macrophages. (D) Double immunofluorescence staining for neutrophils (neutrophil elastase; Calbiochem, San Diego, USA) labeled with Alexa Fluor 488 (Thermo Fisher Scientific, Waltham, USA; green) and macrophages (CD68; Agilent, Santa Clara, USA) labeled with Alexa Fluor 594 (Thermo Fisher Scientific; red) shows massive macrophage infiltration within the tubulointerstitial area. The neutrophil infiltration is unremarkable. (E) Immunoperoxidase staining for CD34 (Agilent) shows prominently decreased CD34 immunoreactivity in some glomerular endothelial cells (arrows). Effacement of the podocyte foot processes (arrowheads) and mesangial interposition (Mes, F), expansion of the subendothelial space (asterisk, G), and infiltration of macrophages (MP, H) are shown in electron microscopy sections. There were no electron-dense deposits present (original magnification, A, B, C, 100×, D, 66×, E, 25×).