Preliminary study of anti-CD40 and ubiquitin proteasome antibodies in primary podocytopaties.

Background: Minimal change disease and focal segmental glomerulosclerosis are primary podocytopathies that are clinically presented in adults presenting with severe nephrotic syndrome. The pathogenesis of these diseases is not clear and many questions remain to be answered. A new concept about the role of changes in the antigenic determinant of podocytes and the production of anti-podocyte antibodies that cause podocyte damage is being developed. The aim of the study is to evaluate the levels of anti-CD40 and anti-ubiquitin carboxyl-terminal hydrolase L1 (anti-UCH-L1) antibodies in patients with podocytopathies in comparison with other glomerulopathies. Methods: One hundred and six patients with glomerulopathy and 11 healthy subjects took part in the study. A histological study revealed primary FSGS in 35 patients (genetic cases of FSGS and secondary FSGS in the absence of NS were excluded), 15 had MCD, 21 - MN, 13 - MPGN, 22 patients - IgA nephropathy. The effect of steroid therapy was evaluated in patients with podocytopathies (FSGS and MCD). The serum levels of anti-UCH-L1 and anti-CD40 antibodies were measured by ELISA before steroid treatment. Results: The levels of anti-UCH-L1 antibodies were significantly higher in MCD patients and anti-CD40 antibodies were higher in MCD and FSGS than in the control group and other groups of glomerulopathies. In addition, the level of anti-UCH-L1 antibodies was higher in patients with steroid-sensitive FSGS and MCD, and anti-CD40 antibodies were lower than in patients with steroid-resistant FSGS. An increase in anti-UCH-L1 antibody levels above 6.44 ng/mL may be a prognostic factor of steroid-sensitivity. The ROC curve (AUC = 0.875 [95% CI 0.718-0.999]) for response to therapy showed a sensitivity of 75% and specificity of 87.5%. Conclusion: An increase in the level of anti-UCH-L1 antibodies is specific for steroid-sensitive FSGS and MCD, while an increase in anti-CD40 antibodies - for steroid-resistant FSGS, compared with other glomerulopathies. It suggests that these antibodies could be a potential factor for differential diagnosis and treatment prognosis.

A cross-sectional study of antibodies to ubiquitin proteasome system in different glomerulopathies.

BACKGROUND: Recently, evidence has emerged that the ubiquitin system, which is involved in extracellular protein degradation, is most susceptible to damage in podocytes in cases of podocytopathies. We studied anti-ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) antibodies in glomerulopathies with proteinuria. MATERIALS AND METHODS: 71 patients with glomerulopathy and 11 healthy subjects were included in our study. 44 patients had nephrotic syndrome, and 27 did not. Serum levels of anti-UCHL1 antibodies were measured by ELISA. RESULTS: The levels of anti-UCHL1 antibodies were significantly higher in focal segmental glomerulosclerosis (FSGS) patients than in minimal change disease (MCD), IgA nephropathy, membranous nephropathy, or membranoproliferative glomerulonephritis patients and control group. The levels of UCHL1 antibodies in serum did not correlate with 24-hour proteinuria, blood pressure, glomerulosclerosis percentage, or area of tubulointerstitial fibrosis, but did correlate with serum creatinine and estimated glomerular filtration rate (eGFR). During the development of the ROC curve (AUC = 0.766 (95% CI 0.634 - 0.897)) for FSGS vs. other forms of glomerulopathies, a readjustment of the sensitivity of 75% and specificity of 61% were established. A former increase in anti-UCHL1 antibody levels above 1.93 ng/mL may be a marker of FSGS OR 3.617 (95% CI 1.051 - 12.447), p = 0.041. CONCLUSION: An increase in the level of anti-UCHL1 antibodies in the serum was noted in FSGS, which suggests that these antibodies could be a potential biomarker for FSGS patients.

Serum levels of plasminogen activator urokinase receptor and cardiotrophin-like cytokine factor 1 in patients with nephrotic syndrome.

The pathogenesis of primary focal segmental glomerulosclerosis (FSGS) and minimal change disease (MCD) remains unknown to date. Some circulating permeability factors are being discussed. This work assessed molecule candidates for permeability in serum samples of patients with nephrotic syndrome (NS). MATERIALS AND METHODS: 41 patients with chronic glomerulonephritis (CGN) were included in our study. 17 patients had FSGS, 7 patients had MCD, 5 patients had membranoproliferative glomerulonephritis (MPGN), 6 patients had IgA nephropathy, and 6 patients had membranous nephropathy (MN). The laboratory data were compared with the clinical and histological features of nephritis. Serum levels of plasminogen activator urokinase receptor (uPAR) and cardiotrophin-like cytokine factor 1 (CLCF-1)were measured by ELISA. RESULTS: The serum levels of uPAR were higher in FSGS patients before treatment than in patients with other morphological forms (MCD, IgA nephropathy, MN, and MPGN). The levels of uPAR in serum did not correlate with daily proteinuria, serum creatinine/eGFR, arterial hypertension, the number of sclerosed glomeruli, or tubulointerstitial fibrosis. No correlations were found between the levels of CLCF-1 in serum and creatinine levels/glomerular filtration rate, the percentage of sclerosed glomeruli, or the severity of tubulointerstitial fibrosis. There were no significant differences between the histological variants of nephritis. However, we found correlations between CLCF-1 levels and proteinuria and lipid levels. CONCLUSION: The data indicate an increase in the serum uPAR levels of FSGS before treatment. CLCF-1 levels in serum do not depend on histological forms of CGN, kidney function, or immunosuppressive treatment, but they correlate with proteinuria and serum lipids in patients with NS.