ORIGINAL ARTICLE

Ezrin—a useful factor in the prognosis of nephrotic syndrome in children: an immunohistochemical approach

D Ostalska-Nowicka¹, J Zachwieja¹, M Nowicki², E Kaczmarek³, A Siwinska¹ and M Witt⁴

¹ Department of Pediatric Cardiology and Nephrology, Poznan University of Medical Sciences, Poznan, Poland
² Department of Histology and Embryology, Poznan University of Medical Sciences
³ Department of Clinical Pathomorphology, Poznan University of Medical Sciences
⁴ Department of Anatomy, University of Technology, Dresden Medical School, Dresden, Germany

Correspondence to:
Correspondence to:
D Ostalska-Nowicka
Department of Pediatric Cardiology and Nephrology, Poznan University of Medical Sciences, ul. Szpitalna 27/33, 60–572 Poznan, Poland; dostalska{at}interia.pl

Background: Minimal change disease (MCD) and diffuse mesangial proliferation (DMP) are the most common pathomorphological forms of nephrotic syndrome glomerulopathies in children. The clinical course of DMP can be characterised by either DMP-sensitivity (DMP-S) or DMP-resistance (DMP-R) to steroids, resulting in an unfavourable course of the glomerulopathy. Although the clinical processes of DMP-S and DMP-R are initially identical, resistance to steroids may be foreseen by the immunohistochemical expression of cytoskeleton-associated proteins in podocytes.

Aims: To estimate the immunohistochemical expression of ezrin in children with MCD, DMP and focal segmental glomerulosclerosis (FSGS) and to evaluate its usefulness in predicting resistance to steroids.

Materials and methods: Renal biopsy specimens of patients with MCD (n = 15), DMP (n = 16) and FSGS (n = 6) were taken. The control tissue consisted of normal-appearing cortex taken from kidneys resected for localised neoplasms (n = 6). The indirect immunohistochemical protocol for the use of a monoclonal antibody directed against ezrin was used.

Results: The immunohistochemical expression of ezrin in cases progressively reduced from MCD to DMP-S to DMP-R to FSGS. Except for DMP-R and FSGS (p>0.05), the difference in ezrin expression in podocytes was significant.

Conclusion: Ezrin can be a potent marker of podocyte injury (podocytopathy) and may help in the histological qualification of MCD, DMP and FSGS. The increased permeability of the filtration barrier in steroid-resistant and proteinuric glomerulopathies may be a consequence of subcellular changes in podocyte-associated proteins following decreased expression of ezrin.

Abbreviations: DMP, diffuse mesangial proliferation; DMP-R, diffuse mesangial proliferation-resistance; DMP-S, diffuse mesangial proliferation-sensitivity; FSGS, focal segmental glomerulosclerosis; INS, idiopathic nephrotic syndrome; MCD, minimal change disease

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