URINE PROTEINS AND FIBROTIC LESIONS OF RENAL COMPARTMENTS IN IMMUNE GLOMERULOPATHIES

The quantification of specific urinary  proteins in high-grade proteinuria can  be  of importance for the  evaluation of mophrological lesions, response to therapy and  prognosis.

The aim of our study was to analyze whether the urinary  excretion of high and  low molecular proteins associated with the  degree of glomerular, tubulointerstitial and  vascular fibrosis.

Patients and methods. The study included 97 patients with biopsy proven primary immune glomerulopathies: membranous nephropathy (n =22), minimal change disease (n=13), focal segmental glomerulosclerosis (n =30), IgA nephropathy (n=32). Measurements of total  protein, immunoglobulin G (IgG),  transferrin (Trf), α1-microglobulin (α1-МG), β2-microglobulin (β2-MG)  were performed by nephelometric method in morning urine samples. The results were standardized for urine creatinine (Cr) concentration.

Results. There were a correlation between proteinuria and  specific proteins: β2-MG (r=0.24, р=0.025), α1-МG (r=0.38, р<0.001), Trf (r=0.78, р<0.001), IgG (r=0.67, р<0.001), as well as the  positive correlation between high and  low molecular proteins. Low molecular proteins (β2-МG,  α1-МG)  correlated with global  glomerular sclerosis (r=0.28, р=0.010 and  r=0.21, р=0.049 respectively) while levels of proteinuria and high molecular weight proteins did not. Urinary excretion β2-microglobulin was also significantly higher in patients with moderate-to-severe tubulointerstitial and vascular fibrotic lesions.

Conclusion. β2-microglobulin was suggested to be candidate integrative biomarker of renal  fibrosis in primary glomerulopathies.

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