Vol. 9, No 1, 2002 pp. 88 - 91
UC 616.61-004 616.611 616.612
IMMUNOHISTOLOGIC KIDNEY BIOPSY STUDY
OF BALKAN ENDEMIC NEPHROPATHY
Alenka Vizjak1, Senaid Trnačević2,
Ahmet Halilbašić2, Dušan Ferluga1
1Institute of Pathology, Faculty of
Medicine, University of Ljubljana, Ljubljana, Slovenia
2Department of Nephrology and Dialysis,
University Medical Center, University of Tuzla, Tuzla, Bosnia and Herzegovina
Summary. The pathogenesis of renal histologic changes in Balkan
endemic nephropathy (BEN) is still insufficiently understood. We studied
the deposition of immune reactants in correlation with tubulo-interstitial
histologic changes and the degree of proteinuria in 50 kidney biopsies
of BEN patients and expression of collagen IV, laminin, vimentin and smooth
muscle actin in 5 biopsies. The immunofluorescence technique, using antibodies
for IgA, IgG, IgM, kappa and lambda light chains, complement components
C3, C1q and C4, fibrin/fibrinogen, and albumin, as well as the streptavidin-biotin
peroxidase technique, using antibodies for collagen IV, laminin, vimentin
and smooth muscle actin were applied. Glomerular and vascular staining
for immune reactants was mainly negative or insignificant. Deposits of
C3 along the tubular epithelium correlated with the intensity of tubulo-interstitial
changes and the degree of proteinuria. Resorptive droplets of mainly albumin
and immunoglobulin light chains in proximal tubules were less frequent
in cases with more severe tubular changes and higher proteinuria. Collagen
IV and laminin were overexpressed in interstitial capillaries and the surrounding
interstitium, occasionally associated with smooth muscle actin positive
interstitial cells. Vimentin was coexpressed in the epithelium of injured
tubuli. In conclusion, humoral immune mechanisms do not appear to play
a pathogenetic role in BEN. Interstitial sclerosis seems to result from
the overproduction of the basement membrane-related extracellular matrix
by injured and activated tubular epithelial cells and interstitial capillary
endothelial cells, as well as production of connective tissue fibers by
proliferating myofibroblasts.
Key words: Balkan endemic nephropathy, kidney biopsy, immunohistology,
pathogenesis
