Minimal Change Disease In Relapse Research Articles

The utility of urinary CD80 as a diagnostic marker in patients with renal diseases

CD80, which regulates T cell activation, may provide a differential diagnostic marker between minimal change disease (MCD) and other renal diseases, including focal segmental glomerular sclerosis (FSGS). However, recent reports show contrasting results. Therefore, we evaluated the utility of urinary CD80 as a diagnostic biomarker. We collected 65 urine samples from 55 patients with MCD (n = 31), FSGS (n = 4), inherited nephrotic syndrome (n = 4), Alport syndrome (n = 5) and other glomerular diseases (n = 11), and control samples (n = 30). We measured urinary CD80 levels by ELISA. Urinary CD80 (ng/gCr) (median, interquartile range) levels were significantly higher in patients with MCD in relapse (91.5, 31.1–356.0), FSGS (376.2, 62.7–1916.0), and inherited nephrotic syndrome (220.1, 62.9–865.3), than in patients with MCD in remission (29.5, 21.7–52.8) (p < 0.05). Elevation of urinary CD80 was observed, even in patients with inherited nephrotic syndrome unrelated to T cell activation. Additionally, urinary CD80 was positively correlated with urinary protein levels. Our results suggest that urinary CD80 is unreliable as a differential diagnostic marker between MCD in relapse and FSGS or inherited kidney diseases. Increased urinary CD80 excretion was present in all patients with active kidney disease.

Minimal change disease: a dysregulation of the podocyte CD80-CTLA-4 axis?

Minimal Change Disease (MCD) is associated with CD80 expression in podocytes and elevated urinary CD80 excretion during active renal disease. We have evaluated the urinary excretion of CTLA-4 and CD80 during different stages of the nephrotic syndrome in patients with MCD to test the hypothesis that persistent increased urinary CD80 excretion in patients with MCD in relapse is due to an ineffectual CTLA-4 response of the host to curtail the activation of CD80. Thirty-two children with biopsy-proven MCD were studied during relapse and/or remission. Eleven healthy subjects served as controls. Urinary CD80 excretion was significantly increased in MCD patients in relapse relative to that in MCD patients in remission (p < 0.001) and controls (p < 0.001). Although urinary CTLA-4 excretion was higher in MCD patients in relapse than in MCD patients in remission (p = 0.01) and controls (p = 0.03), no significant correlation was observed between urinary CD80 excretion and urinary CTLA-4 level in MCD patients at the time of relapse (p = 0.06). At the time of remission, CD80 had decreased significantly in all patients, but CTLA-4 levels either decreased or remained unchanged in all but five patients, and no correlation was observed between urinary CD80 excretion and CTLA-4 level (p = 0.7). Urinary CTLA-4 levels do not correlate with urinary CD80 excretion, suggesting the possibility that the CTLA4 response may be suboptimal in this disease during relapse.

CD80 and suPAR in patients with minimal change disease and focal segmental glomerulosclerosis: diagnostic and pathogenic significance

Minimal change disease (MCD) is characterized by increased urinary excretion of CD80, whereas focal segmental glomerulosclerosis (FSGS) is associated with increased serum soluble urokinase-type plasminogen activator receptor (suPAR). The aim of the study was to assess whether the simultaneous measurement of urinary CD80 and serum suPAR helps differentiate MCD and FSGS. Urine and sera were collected from patients with MCD in relapse or in remission, from FSGS patients with nephrotic syndrome, and from healthy individuals. CD80 and suPAR were measured by ELISA. Urinary CD80 was significantly increased in MCD patients in relapse compared with those in remission and with FSGS patients and control individuals. Serum suPAR levels were significantly higher in patients with FSGS when compared with MCD patients in relapse. Urinary suPAR showed a positive correlation with proteinuria in MCD in relapse and FSGS patients, whereas urinary CD80 correlated with proteinuria only in MCD patients in relapse. Urinary CD80 is elevated in MCD patients in relapse compared with FSGS patients. In contrast, serum suPAR is significantly elevated in FSGS patients. The consistent pattern of these two biomarkers in MCD and FSGS suggests that these two conditions represent different entities rather than a continuum spectrum of one disease.

Serum from minimal change patients in relapse increases CD80 expression in cultured podocytes

Minimal change disease (MCD) is the most common cause of nephrotic syndrome in children and is associated with the expression of CD80 in podocytes and the increased excretion of CD80 in urine. We hypothesized that serum from patients with MCD might stimulate CD80 expression in cultured podocytes. Sera and peripheral blood mononuclear cells (PBMCs) were collected from subjects with MCD in relapse and remission and from normal controls. Immortalized human podocytes were incubated with culture media containing patient sera or supernatants from patient and control PBMC cultures. CD80 expression was measured by quantitative PCR and western blot analysis. Sera collected from patients with MCD in relapse, but not in remission, significantly increased CD80 expression (mean ± standard deviation: 1.8 ± 0.7 vs. 0.8 ± 0.2; p < 0.004) and CD80 protein secretion by podocytes (p < 0.05 between relapse and normal controls). No such CD80 increase was observed when podocytes were incubated with supernatants of PBMC cultures from patients in relapse. Sera from MCD patients in relapse, but not in remission, stimulated CD80 expression in cultured podocytes. Identifying this factor in sera could provide insights into the pathogenesis of this disorder. No role in CD80 expression by podocytes was found for cytokines released by PBMCs.

Urinary monocyte chemoattractant protein-1 excretion in children with glomerular proteinuria

The aim of the study was to examine the urinary levels and clinical significance of monocyte chemoattractant protein-1 (uMCP-1) in children according to histological diagnosis and degree of proteinuria. Group I comprised 20 children with idiopathic nephrotic syndrome (INS), examined twice (A, during INS relapse; and B, after proteinuria subsided). Group II comprised 17 children with persistent proteinuria due to focal segmental glomerulosclerosis (FSGS). Group III included 12 children with immunoglobulin A nephropathy (IgAN). The control group (C) contained 22 healthy children. uMCP-1 was determined by enzyme-linked immunosorbent assay and expressed in pg/ml. The median uMCP-1/creatinine ratio (uMCP-1/cr) in children with minimal change disease in relapse (IA) was significantly higher than in controls (p < 0.05), but when controlling for cyclosporine A (CsA) treatment the median uMCP-1 in children with INS, who were not treated with CsA, was 12.01 pg/mg cr (range 1.82-261.56 pg/mg cr) and did not differ from healthy controls. In examination IB the uMCP-1/cr concentration decreased and did not differ from healthy controls (p > 0.05). Children from groups II and III also had higher uMCP-1/cr levels than groups I and C (p < 0.01). uMCP-1/cr positively correlated with serum total cholesterol, low-density lipoprotein and protein/creatinine ratio in relapse (IA), and with serum cholesterol level in group B. A positive correlation between uMCP-1/cr and protein/creatinine ratio was also confirmed in groups II and III. Increased uMCP-1 was found in children with IgAN and FSGS correlated with proteinuria. A slight increase in uMCP-1 in children with INS was probably associated with CsA treatment.

Urinary CD80 is elevated in minimal change disease but not in focal segmental glomerulosclerosis

Controversy exists as to whether minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS) represent different diseases or are manifestations within the same disease spectrum. Urinary excretion of CD80 (also known as B7.1) is elevated in patients with MCD and hence we tested whether urinary CD80 excretion might distinguish between patients with MCD from those with FSGS. Urinary CD80 was measured in 17 patients with biopsy-proven MCD and 22 with proven FSGS using a commercially available enzyme-linked immunosorbent assay and its molecular size determined by western blot analysis. A significant increase in urinary CD80, normalized to urinary creatinine, was found in patients with MCD in relapse compared to those in remission or those with FSGS. No significant differences were seen when CD80 urinary excretion from MCD patients in remission were compared to those with FSGS. In seven of eight MCD patients in relapse, CD80 was found in glomeruli by immunohistochemical analysis of their biopsy specimen. No CD80 was found in glomeruli of two patients with FSGS and another MCD patient in remission. Thus, our study supports the hypothesis that MCD and FSGS represent two different diseases rather than a continuum of one disease. Urinary CD80 excretion may be a useful marker to differentiate between MCD and FSGS.

Urinary CD80 Excretion Increases in Idiopathic Minimal-Change Disease

CD80 is expressed on all antigen-presenting cells and is present on podocytes in a number of experimental models of nephrotic syndrome. We tested whether urinary soluble CD80 increased with idiopathic minimal-change disease (MCD). We collected urine and serum samples from patients with MCD in relapse and in remission, patients with nephrotic syndrome resulting from other glomerular diseases (FSGS, membranoproliferative glomerulonephritis, IgA nephropathy, and membranous nephropathy), patients with systemic lupus erythematosus, and normal control subjects. Urinary concentrations of soluble CD80 in patients with relapsed MCD were significantly higher compared with those observed in patients with MCD in remission, other glomerular diseases, and systemic lupus erythematosus with and without proteinuria and healthy control subjects. Urinary concentrations of soluble CTLA-4, which is a negative regulator of CD80, were not statistically different in patients with relapsed MCD compared with those in remission. The urinary soluble CD80/CTLA-4 ratio was >100-fold higher in patients with relapsed MCD compared with those in remission (P < 0.008). In contrast, serum concentrations of soluble CD80 and CTLA-4 did not distinguish patients with MCD in relapse and in remission. In conclusion, urinary soluble CD80 is elevated in idiopathic MCD, which could be relevant to both diagnosis and pathogenesis.

Altered activity of plasma hemopexin in patients with minimal change disease in relapse

Since an active isoform of plasma hemopexin (Hx) has been proposed to be a potential effector molecule in minimal change disease (MCD), we tested plasma and urine samples from subjects with MCD in relapse (n = 18) or in remission (n = 23) (after treatment with prednisolone) for presence or activity of Hx. For comparison, plasma or urine from proteinuric subjects with focal and segmental glomerulosclerosis (FSGS, n = 11), membranoproliferative glomerulonephritis (MPGN, n = 9), IgA nephropathy (n = 5) or healthy control donors (n = 10), were incorporated into the study. Electrophoresis and Western blotting methods were used for evaluation of the Hx status, whereas protease activity of Hx was tested upon kidney tissue in vitro according to standard methods. The results show (1) a decreased mean titer of plasma Hx exclusively in MCD relapse subjects as compared with MCD in remission (0.21+/-0.14 mg/ml vs 0.44+/-0.06 mg/ml; p < 0.01). Mean Hx titers in other proteinuric subjects ranged from 0.38+/-0.05 mg/ml to 0.40+/- 0.06 mg/ml, whereas, the mean titer of healthy controls was 0.59+/-0.03 mg Hx/ml; (2) an increased Hx activity (expressed in arbitrary units) exclusively in plasma from MCD relapse subjects (3.3+/-0.72 vs 1.16+/-0.56, MCD remission; p < 0.01); (3) different Western blot patterns in MCD relapse vs remission plasma; (4) reduced stainability or virtual absence of the 80-kD Hx band in blots of urine from MCD relapse in contrast to urine samples from other proteinuric subjects with FSGS, MPGN, or IgA nephropathy. It is concluded that Hx in MCD relapse subjects may exist in an altered isoform, showing enhanced protease activity as compared with subjects in remission, subjects with other forms of primary glomerulopathy, or healthy control individuals.

Is 100KF an isoform of hemopexin? Immunochemical characterization of the vasoactive plasma factor 100KF.

The human vasoactive plasma factor 100KF has been proposed to play a role in minimal change disease in relapse. Since preliminary data suggested similarity between 100KF and the human plasma glycoprotein hemopexin (Hx), this study was conducted to compare 100KF with purified Hx for sequence homology, immunostaining properties in Western and dot-blot assays, ability to affect glomerular ecto-ATPase and glomerular polyanions in vitro, as well as their glomerular permeability increasing effect following alternate perfusion into the rat kidney ex vivo. 100KF was purified from normal pooled plasma according to standard chromatographic techniques, and from the same batch Hx was prepared using affinity chromatography. A second batch of Hx was prepared directly from human serum according to a standard protocol. (For comparison, additional Hx samples obtained from other centers were also included in the study.) The results show: (1) 100% homology of 100KF with plasma Hx after internal sequence analysis; (2) positive staining of the eluate with both monoclonal and polyclonal anti-Hx IgG as well as anti-100KF IgG in dot-blot assays, and similar bands on Western blotting using the same antibodies; (3) affection of glomerular polyanions and glomerular ecto-ATPase after incubation of kidney tissue with either 100KF or Hx (1.5 respectively 1.0 mg/ml; 1.0 h, 37 degrees C), as detected by computerized histochemical quantification; and (4) significant enhancement of urinary protein leakage after Hx perfusion followed by diluted rat serum into the rat kidney ex vivo (Hx: 210.65+/-49.79 microg protein leakage per min versus heat-inactivated Hx control: 112.2+/-49.18 microg per min [both n = 6]). From these data and from the observation that both Hx and 100KF activity can be inhibited by serine protease inhibitors but not by broad spectrum collagenase inhibitors, it is concluded that Hx may be closely related or identical to the active moiety of 100KF.