Significance of glomerular fibrinogen deposition in children with Henoch-Schönlein purpura nephritis

Erythrocyte Glutathione S-Transferase Activity as a Sensitive Marker of Kidney Function Impairment in Children with IgA Vasculitis

IgA vasculitis (IgAV) is the most common childhood vasculitis. The main cause of morbidity and mortality in children with IgAV is nephritis (IgAVN), but the risk of its development, severity, and chronicity remain unclear. Erythrocyte glutathione S-transferase (e-GST) activity has been previously detected as a sensitive marker of kidney function impairment in several diseases. We spectrophotometrically assessed and correlated e-GST activity between 55 IgAV patients without nephritis (IgAVwN), 42 IgAVN patients, and 52 healthy controls. At disease onset, e-GST activity was significantly higher in IgAVN patients (median (interquartile range)) (5.7 U/gHb (4.4-7.5)) than in IgAVwN patients (3.1 U/gHb (2.2-4.2); p < 0.001), and controls (3.1 U/gHb (1.9-4.2); p < 0.001). Therewithal, there were no differences between the IgAVwN patients and controls (p = 0.837). e-GST activity was also significantly higher in the IgAVN patients than in the IgAVwN patients after 3 months (5.0 U/gHb (4.2-6.2) vs. 3.3 U/gHb (2.3-4.1); p < 0.001) and 6 months (4.2 U/gHb (3.2-5.8) vs. 3.3 U/gHb (2.1-4.1); p < 0.001) since the disease onset. Consistent correlations between e-GST activity and serum creatinine, estimated glomerular filtration rate (eGFR), and proteinuria levels were not detected. In conclusion, increased e-GST activity can serve as a subtle indicator of kidney function impairment in children with IgAV.

[Urinary protein and renal pathological features in children with immunoglobulin A vasculitis with nephritis and hypercoagulability]

OBJECTIVES

To study the association of hypercoagulability with urinary protein and renal pathological damage in children with immunoglobulin A vasculitis with nephritis (IgAVN).

METHODS

Based on the results of coagulation function, 349 children with IgAVN were divided into a hypercoagulability group consisting of 52 children and a non-hypercoagulability group consisting of 297 children. Urinary protein and renal pathological features were compared between the two groups, and the factors influencing the formation of hypercoagulability in children with IgAVN were analyzed.

RESULTS

Compared with the non-hypercoagulability group, the hypercoagulability group had significantly higher levels of urinary erythrocyte count, 24-hour urinary protein, urinary protein/creatinine, urinary immunoglobulin G/creatinine, and urinary N-acetyl-β-D-glucosaminidase (P<0.05). The hypercoagulability group also had a significantly higher proportion of children with a renal pathological grade of III-IV, diffuse mesangial proliferation, capillary endothelial cell proliferation, or >25% crescent formation (P<0.05). The multivariate logistic regression analysis showed that capillary endothelial cell proliferation and glomerular crescent formation >25% were associated with the formation of hypercoagulability in children with IgAVN (P<0.05).

CONCLUSIONS

The renal injury in IgAVN children with hypercoagulability is more severe, with greater than 25% crescent formation and increased proliferation of glomerular endothelial cells being important contributing factors that exacerbate the hypercoagulable state in IgAVN.

Characteristics of renal pathology and coagulation function in IgA nephropathy and IgA vasculitis associated nephritis

BACKGROUND

The objective of this study is to investigate the clinical and pathological differences between patients with IgA nephropathy (IgAN) and IgA vasculitis associated nephritis (IgAVN).

METHODS

A total of 253 patients with IgAN and 71 patients with IgAVN were retrospectively included in the study, and clinical and laboratory data were collected and analysed.

RESULTS

Compared with IgAVN group, months from onset to kidney biopsy were significantly prolonged in IgAN patients because of the lack of obvious symptoms such as rash, abdominal symptoms, and joint pain (13.5 ± 26.6 vs. 10.2 ± 31.6 months, P = 0.007), and the levels of serum creatinine (92.3 ± 94.7 vs. 68.9 ± 69.2 µmol/L, P = 0.015) was higher and eGFR (99.1 ± 35.2 vs. 123.4 ± 41.8 mL/min/1.73m2, P < 0.001) was lower in IgAN group. The pathological results revealed that patients with IgAN have a greater degree of chronic kidney injury compared to patients with IgAVN. In addition, the levels of plasma D-Dimers (1415.92 ± 1774.69 vs. 496.78 ± 711.91 ng/mL, P < 0.001) and fibrinogen degradation products (FDP) (3.92 ± 4.73 vs. 1.63 ± 2.46 µg/mL, P = 0.001) were significantly higher in IgAVN patients than in IgAN patients. The deposition of fibrinogen in the renal tissues was more severe and the cumulative partial remission rate was higher in patients with IgAVN as compared to those with IgAN (P = 0.001).

CONCLUSIONS

In comparison, IgAN patients had poorer renal function, whereas IgAVN patients had more severe coagulation abnormalities. These findings provide a basis for the differentiation of the two diseases at an early stage.

Comparative proteomic analysis of glomerular proteins in IgA nephropathy and IgA vasculitis with nephritis

BACKGROUND

IgA nephropathy (IgAN) and IgA vasculitis with nephritis (IgAVN) are related glomerular diseases characterized by marked similarities in immunological and histological findings. We herein performed a comparative proteomic analysis of glomerular proteins in IgAN and IgAVN.

METHODS

We used renal biopsy specimens from 6 IgAN patients without nephrotic syndrome (NS) (IgAN-I subgroup), 6 IgAN patients with NS (IgAN-II subgroup), 6 IgAVN patients with 0-8.0% of glomeruli with crescent formation (IgAVN-I subgroup), 6 IgAVN patients with 21.2-44.8% of glomeruli with crescent formation (IgAVN-II subgroup), 9 IgAVN patients without NS (IgAVN-III subgroup), 3 IgAVN patients with NS (IgAN-IV subgroup), and 5 control cases. Proteins were extracted from laser microdissected glomeruli and analyzed using mass spectrometry. The relative abundance of proteins was compared between groups. An immunohistochemical validation study was also performed.

RESULTS

More than 850 proteins with high confidence were identified. A principal component analysis revealed a clear separation between IgAN and IgAVN patients and control cases. In further analyses, 546 proteins that were matched with ≥ 2 peptides were selected. The levels of immunoglobulins (IgA, IgG, and IgM), complements (C3, C4A, C5, and C9), complement factor H-related proteins (CFHR) 1 and 5, vitronectin, fibrinogen chains, and transforming growth factor-β inducible gene-h3 were higher (> 2.6 fold) in the IgAN and IgAVN subgroups than in the control group, whereas hornerin levels were lower (< 0.3 fold). Furthermore, C9 and CFHR1 levels were significantly higher in the IgAN group than in the IgAVN group. The abundance of some podocyte-associated proteins and glomerular basement membrane (GBM) proteins was significantly less in the IgAN-II subgroup than in the IgAN-I subgroup as well as in the IgAVN-IV subgroup than in the IgAVN-III subgroup. Among the IgAN and IgAVN subgroups, talin 1 was not detected in the IgAN-II subgroup. This result was supported by immunohistochemical findings.

CONCLUSIONS

The present results suggest shared molecular mechanisms for glomerular injury in IgAN and IgAVN, except for enhanced glomerular complement activation in IgAN. Differences in the protein abundance of podocyte-associated and GBM proteins between IgAN and IgAVN patients with and without NS may be associated with the severity of proteinuria.

A simple nomogram for assessing the risk of IgA vasculitis nephritis in IgA vasculitis Asian pediatric patients

A nomogram for assessing the risk of IgA vasculitis nephritis (originally termed Henoch–Schönlein purpura nephritis, HSPN) in IgA vasculitis (originally termed Henoch–Schönlein purpura, HSP) pediatric patients can effectively improve early diagnosis and prognosis of IgA vasculitis nephritis. However, currently, no nomogram is available. 246 IgA vasculitis and 142 IgA vasculitis nephritis Asian pediatric patients confirmed by renal biopsy were enrolled. Univariate and multivariate logistic regressions were performed to identify the independent risk factors and construct a series of predictive models. The receiver operating characteristic curve, calibration plot, decision curve analysis, net reclassification index and integrated discrimination index were used to screen the best model. Stratification analysis was applied to optimize model’s clinical utility. An external validation set was introduced to verify the predictive efficiency. The final predictive model was converted to nomogram for visual use. We identified age, duration of rash (Dor), D-dimer and IgG as independent risk factors and constructed four models as follows: AIDD (Age + IgG + Dor + D-dimer), AIDi (Age + IgG + D-dimer), AIDo (Age + IgG + Dor) and ADD (Age + Dor + D-dimer), which achieved the receiver operator characteristic curve (AUROC) of 0.931, 0.920, 0.856 and 0.907, respectively. Finally, AIDi model with an AUROC of 0.956 and 0.897 in internal and external validating sets was proposed as a novel predictive model. In stratification analysis by gender and histological grade, the AUROC of AIDi was 0.949 in female, 0.926 in male, 0.933 in mild histological grades and 0.939 in severe histological grades, respectively. AIDi nomogram is an effective and visual tool for assessing the risk of nephritis in IgA vasculitis Asian pediatric patients, regardless of IgA vasculitis nephritis histological grades and gender.

Clinical effect of combined western medicine and traditional Chinese medicine on children with Henoch-Schönlein purpura nephritis

OBJECTIVE

To investigate the efficacy of combined Chinese and western medicine in the treatment of children with Henoch-Schönlein purpura nephritis (HSPN) and its effects on immune function, interleukin (IL)-16, and IL-18 expressione.

METHODS

The clinical data of 91 children with HSPN were retrospectively collected and divided into two groups according to the treatment regimen. Group A (n=45) was treated only with western medicine, while group B (n=46) was treated with combined Chinese and western medicine. The clinical efficacy, traditional Chinese medicine (TCM) syndrome points before and after treatment, immune function indices, urinary indices, levels of IL-16 and IL-18, and the recurrence rate were compared between the two groups.

RESULTS

The total effective rate was 95.65% in group B, higher than 75.56% in group A (P<0.05). The TCM scores after treatment in group B was lower than that in group A (P<0.05). The levels of immunoglobulin IgA and IgM after treatment were lower while IgG levels were higher in group B than those in group A (P<0.05); Urinary microalbumin, urinary beta₂ microglobulin, 24 h urine protein elimination, and red blood cells (RBC) in the urine were lower in group B after treatment than in group A (P<0.05). The serum levels of IL-16 and IL-18 in group B were lower than those in group A after treatment (P<0.05). The recurrence rate was 4.35% in group B, lower than 26.67% in group A (P<0.05).

CONCLUSION

Combined regimen of western and Chinese medicine in children showed significant efficacy on improving immune function and reducing recurrence rate and IL-16 and IL-18 levels in patients with HSPN.

A cross-sectional analysis of clinicopathologic similarities and differences between Henoch-Schönlein purpura nephritis and IgA nephropathy

Introduction

Recent studies noted that Henoch-Schönlein purpura nephritis (HSPN) and IgA nephropathy (IgAN) share the feature of galactose-deficient IgA1 (Gd-IgA1)-oriented pathogenesis, although there are distinct clinical differences. We aimed to clarify the clinicopathologic differences between these 2 diseases.

Methods

We cross-sectionally analyzed adult patients with HSPN (n = 24) or IgAN (n = 56) who underwent renal biopsy (RB) between 2008 and 2018 at Showa University Hospital. Serum Gd-IgA1 (s-Gd-IgA1) levels at the time of RB were compared among study groups using enzyme-linked immunosorbent assay (ELISA) with anti-human Gd-IgA1-specific monoclonal antibody (KM55). We also immunohistochemically stained paraffin-embedded sections for glomerular Gd-IgA1 (g-Gd-IgA1)-deposition using KM55. Serum inflammatory cytokines were measured using ELISA.

Results

Glomerular endothelial injury with subendothelial IgA deposition was significant in patients with HSPN. Serum IL-8, MCP-1, TNF-α, and IL-6 levels were significantly higher in patients with HSPN than IgAN. Levels of s-Gd-IgA1 were comparable among patients with HSPN and IgAN, and a similar degree of g-Gd-IgA1-deposition was detected in both diseases. Furthermore, g-Gd-IgA1-deposition was evident in patients with histopathologically advanced HSPN or IgAN. In HSPN, significant positive correlations between s-Gd-IgA1 levels and crescent formation or IL-6 elevation were confirmed, and g-Gd-IgA1 intensity showed a significant positive correlation with MCP-1 and a tendency to positively correlate with IL-8. Meanwhile, patients with IgAN showed no correlation between inflammatory cytokines and both-Gd-IgA1. Moreover, most g-Gd-IgA1-positive areas were not double stained with CD31 in HSPN.

Conclusions

Although assessing both-Gd-IgA1 alone was insufficient to distinguish between HSPN and IgAN, patients with HSPN showed considerable glomerular capillaritis with subendothelial IgA deposition and significant elevation of serum inflammatory cytokines. Furthermore, such glomerular subendothelial IgA deposition might not contain Gd-IgA1, and factors associated with Gd-IgA1 were inconsistent among these 2 diseases. Thus, developmental mechanisms for IgAN might not apply to HSPN completely, and these 2 diseases still have different aspects.