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