Immunological studies in Balkan Endemic Nephropathy

To re-examine serum complement and immunoglobulin levels in patients with Balkan Endemic Nephropathy (BEN) in the early stage of the disease; to study autoantibodies (anti-thyroid, anti-smooth muscle, anti-mitochondrial, anti-parietal, anti-nuclear, and anti-DNA) in these patients; and, finally, to re-asses the immunohistology in kidney biopsies from BEN patients. A review of the immunological studies in BEN will be presented.

Forty-five BEN patients in the early stage of disease, from the South Morava Region, were included in this study. Fifty-five apparently healthy controls, matched for age and sex, from the neighbouring control villages were selected. Serum complement and immunoglobulin levels were determined by the Immunochemistry system of Beckman. Auto-antibodies were detected in the sera by the indirect fluorescence method or by radio-immunoassay (anti-single stranded DNA). Immunofluorescent microscopy was used for kidney samples treated with FITC conjugated antisera for IgG, IgM, IgA, C3, C1q, C4 and fibrin/fibrinogen.

Serum C3 was decreased in the sera of patients with BEN compared to healthy controls (p < 0.001), serum IgM was also decreased (p < 0.05). Anti-thyroid antibodies were detected in 5/45 BEN patients, anti-parietal in 7/45 patients and ANA in 2 BEN patients. No anti-smooth muscle, anti-mitochondrial, or anti-DNA antibodies were detected in any BEN patient. Immunofluorescent studies of 10 kidney biopsy specimens showed rare, unspecific, focal, mesangial deposits of C3 and IgM in some glomeruli, and rare deposits, mostly of C3, in tubuli and extraglomerular vessels.

Humoral immune mechanisms do not appear to play a pathogenetic role in BEN. A few studies on cell-mediated immunity in BEN were performed, and further studies are needed on patients in the early stage of the disease.