DETACHED PODOCYTES IN HUMAN ATUBULAR GLOMERULI IN CHRONIC ALLOGRAFT NEPHROPATHY

 

RJ Barnetsonl, IW Gibson2 , GBM Lindop1

1 Department of Pathology, Western Infirmary, Glasgow, UK

2 Department of Pathology, University of Manitoba, Canada

 

BACKGROUND:

Podocyte loss is believed to be an early change in irreversible glomerular injury in many glomerulopathies. Microscopy of atubular glomeruli in chronic allograft nephropathy (CAN) shows detached, rounded cells within Bowman's space which are believed to be of podocytic origin, but their immunophenotype has not been previously studied in CAN.

 

AIMS:

To describe the light microscopy, ultrastructure and immunophenotype of detached podocytes and to distinguish them from other cells in Bowman's space.

 

MATERIALS AND METHODS:

We studied serial sections of 2 nephrectomies and routine sections from a transplant nephrectomy, and needle biopsies from native and transplant kidneys. We studied the immunophenotype of the detached cells in Bowman's space using immunocytochemistry antibody markers for podocytes (synaptopodin, GLEPP, vimentin and WT-1 protein), for macrophages (CD68) and for lymphocytes (CD 3, 20 and 45). Glomeruli from two cases containing abundant detached cells were also sampled for electron microscopy (EM).

 

RESULTS:

Detached rounded cells within Bowmanís space of atubular glomerular cysts consisted mostely of podocytic cells, with a smaller number of macrophages and lymphocytes.The podocyte markers confirmed podocytic differentiation, and also demonstrated the presence of parietal podocytes lining much of the Bowmanís capsule of atubular glomerular cysts.By light microscopy, the detached podocytes had reniform nuclei and eosinophilic cytoplasm.By EM, the cells showed cytoplasmic ultrastructure similar to other podocytes, but lacked processes and pedicels.

 

 

CONCLUSIONS:

Detached podocytes are recognisable by light microscopy, EM and immunostaining. Histological recognition of these cells could be important in renal allograft biopsy interpretation, helping in the identification of atubular glomerular cysts in CAN.

 

 

Details of authors:

 

1.Dr. Robert J. Barnetson

Specialist Registrar

Department of Pathology

Western Infirmary

GLASGOW

United Kingdom

Tel:+44 141 211 2473

Email:rjb@mailbox.co.za

 

Dr George B M Lindop

Consultant Histopathologist

Department of Pathology Western Infirmary

GLASGOW

United Kingdom

Tel:+44 141 211 2473

Email:gb11s@clinmed.gla.ac.uk

 

Dr. Ian Gibson

Associate Professor

Department of Pathology

MS4-Thorlakson Building

Health Science Centre

820 Sherbrook Street

WINNIPEG, R3A 1R9

Manitoba

Canada

Email:igibson@exchange.hsc.mb.ca