Red cell traverse through thin glomerular basement membranes.
BACKGROUND
How red cells enter the urinary filtrate in most cases of hematuria of glomerular origin has remained a mystery despite the frequent ultrastructural examination of renal biopsy material.


METHODS
Serial sections of glutaraldehyde-fixed, resin-embedded material from a case of sporadic microhematuria were examined by transmission electron microscopy when the site of a red cell traversing the glomerular capillary wall was fortuitously discovered on routine examination.


RESULTS
The red cell assumed a dumbbell shape and traversed a localized gap 2.25 microm in diameter in the glomerular endothelium and basement membrane. Serial sections suggested a transcellular route. Apart from the thinning of the basement membrane (167 nm), there were no other generalized abnormalities.


CONCLUSIONS
Red cells can traverse through gaps in the glomerular capillary walls to gain access to Bowman's space. This may be the origin of glomerular hematuria in common noninflammatory forms of glomerular disease, including thin basement membrane nephropathy.
Collar
J E
JE
Department of Histopathology, Imperial College School of Medicine at St. Mary's Campus, London, England, United Kingdom.
Ladva
S
S
Cairns
T D
TD
Cattell
V
V
D000328:Adult; D001485:Basement Membrane / Q000473:pathology; D001706:Biopsy; D002196:Capillaries / Q000473:pathology / Q000648:ultrastructure; D002465:Cell Movement; D004912:Erythrocytes / Q000166:cytology* / Q000648:ultrastructure; D005260:Female; D006417:Hematuria / Q000473:pathology* / Q000503:physiopathology*; D006801:Humans; D007678:Kidney Glomerulus / Q000098:blood supply / Q000473:pathology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009394:Nephritis, Hereditary / Q000473:pathology / Q000503:physiopathology