Relationship Between Immunoglobulin Deposition and Early Lesions of Progressive Glomerulonephropathy in Young Common Marmosets

Morphological analyses of nephrin expression in progressive glomerulonephropathy of common marmosets

In this study, we focused on nephrin, one of the key molecules within the slit diaphragm of podocytes, as although there have been reports on its expression in humans and rats, their presence in common marmosets has not been reported. We investigated nephrin expression and changes in glomeruli, depending on the development of spontaneous progressive glomerulonephropathy in common marmosets. Nineteen common marmosets at two to ten years of age were evaluated. The kidney was examined by microscopy with hematoxylin and eosin and immunohistochemical staining for nephrin. The lesions were classified into three grades according to a renal lesion grading system reported previously. The nephrin-positive area was measured by morphometric analysis, and the nephrin-positive ratio was calculated. Nephrin expression was observed along the glomerular capillary loop in a continuous linear pattern in renal lesion grades 0 to 2 and either discontinuous linear or coarse granular pattern in grade 3. Nephrin expression tended to decrease significantly depending on the grade of renal lesions. Alteration in nephrin expression has been suggested to play an important role in the progression of renal lesions.

Establishment of a novel nomogram for the clinically diagnostic prediction of minimal change disease, -a common cause of nephrotic syndrome

Background

Minimal change disease (MCD) is one of the major causes of nephrotic syndrome (NS). A confirmed MCD diagnosis mainly depends on renal biopsy at present, which is an invasive procedure with many potential risks. The overall incidence of complications caused by renal biopsy procedures has been reported as approximately 11 and 6.6% outside and within China, respectively. Unfortunately, there is currently no noninvasive procedure or practical classification method for distinguishing MCD from other primary glomerular diseases available.

Method

A total of 1009 adult patients who underwent renal biopsy between January 2017 and November 2019 were enrolled in this study. Twenty-five parameters extracted from patient demographics, clinical manifestations, and laboratory test results were statistically analysed. LASSO regression analysis was further performed on these parameters. The parameters with the highest area under the curve (AUC) were selected and used to establish a logistic diagnostic prediction model.

Results

Of the 25 parameters, 14 parameters were significantly different (P < 0.05). MCD patients were mostly younger (36 (22, 55) vs. 41 (28.75, 53)) and male (59% vs. 52%) and had lower levels of diastolic blood pressure (DBP) (79 (71, 85.5) vs. 80 (74, 89)) and IgG (5.42 (3.17, 6.36) vs. 9.38 (6.79, 12.02)) and higher levels of IgM (1.44 (0.96, 1.88) vs. 1.03 (0.71, 1.45)) and IgE (160 (46.7, 982) vs. 47.3 (19, 126)) than those in the non-MCD group. Using the LASSO model, we established a classifier for adults based on four parameters: DBP and the serum levels of IgG, IgM, IgE. We were able to clinically classify adult patients with NS into MCD and non-MCD using this model. The validation accuracy of the logistic regression model was 0.88. A nomogram based on these four classifiers was developed for clinical use that could predict the probability of MCD in adult patients with NS.

Conclusions

A LASSO model can be used to distinguish MCD from other primary glomerular diseases in adult patients with NS. Combining the model and the nomogram potentially provides a novel and valuable approach for nephrologists to diagnose MCD, avoiding the complications caused by renal biopsy.

The Clinical Impact of Glomerular Immunoglobulin M Deposition in Patients with Type 2 Diabetic Nephropathy

BACKGROUND

Glomerular immunoglobulin M (IgM) deposition is common in diabetic kidney disease. The clinical implication of IgM deposition in the renal tissues of type 2 diabetes mellitus patients with biopsy-proven diabetic nephropathy remains unclear.

MATERIALS AND METHODS

One hundred thirty-two patients with type 2 diabetes and biopsy-proven pure diabetic nephropathy were enrolled retrospectively. Clinicopathological features and renal outcomes were compared between patients with and without glomerular capillary IgM deposition. A Cox proportional hazards model was employed to identify the risk factors associated with renal survival.

RESULTS

Fifty-two patients had positive linear glomerular capillary IgM staining. Patients with glomerular capillary IgM deposition presented with heavier proteinuria, and lower serum albumin. During 35.5 (12, 107) months of follow-up, patients with glomerular tuft IgM deposition had shorter renal survival than those with negative IgM deposition (39 [23.74, 54.26] versus (vs.) 64 [45.82, 82.18] months, P = 0.01). Patients with glomerular complement 1q (C1q) deposition showed worse renal survival than those lacking glomerular C1q deposition (36 [23.82, 48.18] vs. 60 [50.27, 69.74] months, P = 0.001). Worse renal outcome was observed in patients with glomerular C3 deposition than in those without glomerular C3 deposition (37 [22.43, 51.56] vs. 63 [51.75, 74.25] months, P = 0.001). Multivariate Cox proportional analysis demonstrated that combined glomerular capillary IgM and C1q deposition was an independent predictor of end-stage renal disease (hazard ratio 3.75, 95% CI[ 1.68,8.35], P = 0.001).

CONCLUSIONS

Patients with diabetic nephropathy and combined glomerular capillary IgM and C1q deposition had unfavorable renal outcome, which indicates that IgM derived from B cells might be involved in diabetic kidney injury.

A pilot and comparative study between pathological and serological levels of immunoglobulin and complement among three kinds of primary glomerulonephritis

Background

Immunoglobulin A nephropathy (IgAN), membranous nephropathy (MN) and minimal-change disease (MCD) are three common types of glomerulonephritis in China. Pathological diagnosis based on renal biopsy is the criterion and the golden standard for diagnosing the sub-types of primary or secondary glomerulonephritis. Immunoglobulin and complements might be used in the differential diagnosis of glomerulonephritis without renal biopsies. However, the relationship between IF intensities of immune proteins and the corresponding serum levels remained unclear, and seldom studies combine histopathological examination results and blood tests together for a predictive purpose. This study was considered as a pilot study for integrating histopathological indicators into serum parameters for exploring the relationship of IF intensity and serum values of immunoglobulin and complement, and for screening and investigating effective indicators inIgAN, MN and MCD.

Methods

Renal tissue immunofluorescence (IF) intensity grades and serum levels of immunoglobulin and complements (IgG, IgA, IgM, C3 and C4) were retrospectively analyzed in 236 cases with IgAN, MN or MCD. IF grades were grouped as negative (−), positive (+) or strong positive (++) with both high and low magnification of microscope. Other serum indicators such as urea nitrogen (BUN), creatinine (Crea) and estimated glomerular filtration rate (eGFR) were also evaluated among the groups.

Results

There were difference in IgA, IgG and C3 IF intensity grades among IgAN, MN and MCD groups (p = 9.82E-43, 4.60E-39, 7.45E-15, respectively). Serum values of BUN, Crea, eGFR, IgG, IgA, IgM and C4 showed difference in three groups (BUN: p = 0.045, Crea: p = 3.45E-5, eGFR: p = 0.005, IgG: p = 1.68E-14, IgA: p = 9.14E-9, IgM: p = 0.014, C4: p = 0.026). eGFR had the trend to decrease with enhanced IgA IF positive grades (p = 8.99E-4); Crea had trends to decrease with both enhanced IgA and IgG IF intensity grades (p = 2.06E-6, 2.94E-5, respectively). In all subjects, serum IgA levels was inversely correlated with eGFR(r = − 0.216, p = 0.001) and correlated with Crea levels(r = 0.189, p = 0.004); serum IgG and Crea showed no correlation which were discordance with inverse correlation of IgG IF grade and Crea(r = 0.058,p = 0.379). IgG serum level was inverse correlated with its IF grades (p = 3.54E-5, p = 7.08E-6, respectively); C3 serum levels had significantly difference between Neg and positive (+) group (p = 0.0003). IgA serum level was positive correlated with its IF grades (Neg-(+): p = 0.0001; (+)-(++): p = 0.022; Neg-(++): p = 2.01E-10). After matching comparison among C3 groups, C3 Neg. group and C3 ++ group had difference (*p = 0.017). C4 had all negative IF expression in all pathological groups. In IgAN subjects, there were statistical differences of serum C3 levels between its pathological Neg and positive (+) group(p = 0.026), and serum IgA levels showed difference between IgA pathological positive(+) and (++)(p = 0.007). In MN subjects, sIgG levels showed difference between IgG pathological IF grade positive (+) and (++)(p = 0.044); serum C3 levels showed difference between C3 pathological IF grade Neg and positive(+)(p = 0.005); and serum IgA levels showed difference between Neg and positive(+)(p = 0.040). In IgAN, eGFR showed serum IgA levels had significant differences among groups (p = 0.007) and had increasing trend with enhanced its IF grades(P_trend = 0.016). There were also difference between IgG group Neg and positive (+) (p = 0.005, P_trend = 0.007) in IgAN. In MN, serum IgG levels had significant differences among IF groups (p = 0.034) and had decreasing trend with its enhanced IF grades (P_trend = 0.014). Serum C3 concentrations also were found distinctive among IF groups (p = 0.016) and had in inverse correlation with its enhanced IF grades (P_trend = 0.004).

Discussion

Our research cross contrasts several immunoprotein IF intensities and relevant serum levels in three kinds of primary glomerular nephritis, and finally acquired helpful results for understanding the relationships between pathological presentation and serological presentation of immunoproteins in kidney diseases. Furthermore, this pilot study is offering a possible method for the analysis of combination of pathology and serology.

Conclusion

Different pathological types of nephritis presented different expression patterns of immunoglobulin and complement, especially IgA and IgG, which suggested different pathogenesis involved in the development of IgAN and MN. Furthermore, either in tissue or in serum, increased IgA level was closely related with renal function in all of the patients.

Electronic supplementary material

The online version of this article (10.1186/s12865-018-0254-z) contains supplementary material, which is available to authorized users.