Cell-type-specific molecular characterization of cells from circulation and kidney in IgA nephropathy with nephrotic syndrome.

Nephrotic syndrome (NS) is a relatively rare and serious presentation of IgA nephropathy (IgAN) (NS-IgAN). Previous research has suggested that the pathogenesis of NS-IgAN may involve circulating immune imbalance and kidney injury; however, this has yet to be fully elucidated. To investigate the cellular and molecular status of NS-IgAN, we performed single-cell RNA sequencing (scRNA-seq) of peripheral blood mononuclear cells (PBMCs) and kidney cells from pediatric patients diagnosed with NS-IgAN by renal biopsy. Consistently, the proportion of intermediate monocytes (IMs) in NS-IgAN patients was higher than in healthy controls. Furthermore, flow cytometry confirmed that IMs were significantly increased in pediatric patients with NS. The characteristic expression of VSIG4 and MHC class II molecules and an increase in oxidative phosphorylation may be important features of IMs in NS-IgAN. Notably, we found that the expression level of CCR2 was significantly increased in the CMs, IMs, and NCMs of patients with NS-IgAN. This may be related to kidney injury. Regulatory T cells (Tregs) are classified into two subsets of cells: Treg1 (CCR7 high, TCF7 high, and HLA-DR low) and Treg2 (CCR7 low, TCF7 low, and HLA-DR high). We found that the levels of Treg2 cells expressed significant levels of CCR4 and GATA3, which may be related to the recovery of kidney injury. The state of NS in patients was closely related to podocyte injury. The expression levels of CCL2, PRSS23, and genes related to epithelial-mesenchymal transition were significantly increased in podocytes from NS-IgAN patients. These represent key features of podocyte injury. Our analysis suggests that PTGDS is significantly downregulated following injury and may represent a new marker for podocytes. In this study, we systematically analyzed molecular events in the circulatory system and kidney tissue of pediatric patients with NS-IgAN, which provides new insights for targeted therapy in the future.

Value of the modified semiquantitative classification in predicting outcomes in children with Henoch-Schönlein purpura nephritis.

BACKGROUND: The modified semiquantitative classification (SQC) is a new pathological classification for Henoch-Schönlein purpura nephritis (HSPN), and its prognostic value with regard to the outcomes of HSPN is unclear. METHODS: We performed a retrospective review of 249 patients with biopsy-proven HSPN admitted to the Children's Hospital of Chongqing Medical University. In addition to the International Study of Kidney Disease in Children (ISKDC) classification, renal biopsy specimens were also reevaluated according to the SQC. RESULTS: During the follow-up period of 2.9 (1.0-6.9) years, 14 (5.6%) patients reached the poor outcome at the end of follow-up. The SQC activity and chronicity indexes were positively correlated with the clinical manifestations, conventional pathology grades, and 24-h urinary protein (24hUP). The difference in the areas under the curve between the total biopsy SQC scores and ISKDC classification was 0.12 (p = .001, 95% CI: 0.0485-0.192). In the receiver operating characteristic (ROC) curve analysis of 1-year, 3-year, and 5-year poor outcomes and total biopsy SQC scores, a total biopsy score ≥10 was associated with a higher risk of an adverse outcome. CONCLUSION: Our study suggests that the SQC indexes are clearly correlated with the clinical and pathological findings of HSPN. The SQC is more sensitive than ISKDC classification for the prediction of the long-term outcomes of HSPN in children.

Detection of De Novo PAX2 Variants and Phenotypes in Chinese Population: A Single-Center Study.

Background: PAX2 is a nuclear transcription factor gene that is highly conserved among species. Variants within PAX2 could result in optic nerve colobomas and kidney hypoplasia. However, little clinical and genetic information is currently available about PAX2 variants in Chinese children. Objective: This study aims to further understand the clinical manifestations and genetic characteristics of PAX2 variants in Chinese population. Methods: In this single-center retrospective study, we analyzed the clinical data of 10 children identified as carriers of PAX2 variants by gene sequencing. All the variants found in this study were analyzed using in silico prediction and American College of Medical Genetics and Genomics (ACMG) standards and guidelines. Results: The mean age for developing the first symptom in 10 unrelated children was 7.2 years old. Proteinuria and bilateral kidney dysplasia were found in every patient. Two children underwent kidney histological examination; one child showed high-intensity C1q deposition in the kidney, and the other child showed focal segmental glomerular sclerosis (FSGS). Three children had PAX2-related ocular abnormalities, including nystagmus, retinal exudation, amblyopia, microphthalmia, microcornea, and total blindness. In addition, one patient had the comorbidity of oculocutaneous albinism (OCA). Eight different PAX2 variants were found in ten patients, three of which were reported for the first time. Conclusion: We reported some patients with unique manifestations and comorbidities, and we reported three variants that have not been previously identified. The PAX2 gene is prone to spontaneous variants, and the outcome of patients is unfavorable. Because of the lack of specific therapy, genetic testing should be recommended for individuals with obvious evidence of kidney dysplasia and eye abnormalities, and kidney protective treatment should be initiated early.

Clinical features and gene variation analysis of COQ8B nephropathy: Report of seven cases.

Objective: COQ8B nephropathy is a relatively rare autosomal recessive kidney disease characterized by proteinuria and a progressive deterioration of renal function, eventually leading to end-stage renal disease (ESRD). The objective is to study the characteristics and correlation between the genotype and the clinical phenotype of COQ8B nephropathy. Methods: This is a retrospective study focusing on the clinical characteristics of seven COQ8B nephropathy patients diagnosed by gene sequencing. Basic clinical information, clinical manifestations, examinations, imaging, genomes, pathology, treatments, and prognosis of the patients were reviewed. Results: Of the seven patients, two were male children and five were female children. The median age at the disease onset was 5 years and 3 months. The initial main clinical manifestations were proteinuria and renal insufficiency. Four patients had severe proteinuria, four had focal segmental glomerulosclerosis (FSGS) diagnosed by a renal biopsy, and two had nephrocalcinosis after an ultrasound was performed on them. There were no other clinical manifestations such as neuropathy, muscle atrophy, and so on in all of them. Their gene mutations were all exon variants, which were classified as heterozygous or homozygous variants by performing family verification analysis. Compound heterozygous variants were predominant in all, and all gene variants were inherited from their parents. One novel mutation, c.1465c>t, was found in this study. This gene mutation resulted from changes in the amino acid sequence, thus leading to an abnormal protein structure. Two patients with early diagnosis of COQ8B nephropathy presented with no renal insufficiency and were treated with oral coenzyme Q10 (CoQ10), and they maintained normal renal function. For the remaining five who were treated with CoQ10 following renal insufficiency, the deterioration of renal function could not be reversed, and they progressed to ESRD within a short time (median time: 7 months). A follow-up of these patients showed normal renal function with a CoQ10 supplement. Conclusion: For unexplained proteinuria, renal insufficiency, or steroid-resistant nephrotic syndrome, gene sequencing should be considered, in addition to renal biopsy, as early as possible. Timely diagnosis of COQ8B nephropathy and early supplementation of sufficient CoQ10 can help control the progression of the disease and significantly improve the prognosis.

Clinical manifestations, prognosis, and treat-to-target assessment of pediatric lupus nephritis.

BACKGROUND: Pediatric lupus nephritis (pLN) is one of the most refractory secondary kidney diseases in childhood. The treat-to-target (T2T) strategy has become the standard treatment for systemic lupus erythematosus (SLE). This study reviewed clinical features, overall remission status, and factors affecting prognosis, to guide pLN management according to T2T strategy. METHODS: This single-center retrospective study studied 220 children diagnosed with LN from January 2012 to December 2018, with > 6-month follow-up data on 173 and complete data on 137 patients. Primary outcome was treatment failure (deterioration or no response) at the latest follow-up. RESULTS: The most common pLN manifestation was proteinuria (81.36%). Females presented more often with rash (P<0.001) and alopecia (P=0.026) than males. Class IV LN (33.33%) was the most common grade on kidney biopsy. Median follow-up was 27.20 months (IQR, 15.78-44.45 months). One-, 3-, and 5-year cumulative overall survival rates were 93.5%, 87.8%, and 86.5%, respectively. The 5-year cumulative kidney survival rate was 97.1%. Regarding initial therapy, efficacy of corticosteroids combined with immunosuppressive agents was significantly better than corticosteroids alone (P=0.010). Factors with P<0.05 in univariate analysis, including hypoalbuminemia, higher SCr at diagnosis, lower eGFR at diagnosis, anti-dsDNA positivity, heavy proteinuria, hypertension, nervous-system involvement, treatment non-compliance, and SLEDAI-2K score, were used for logistic regression analysis. Logistic regression analysis showed hypertension (OR=0.845, P=0.011), nervous-system involvement (OR=4.240, P=0.005), treatment non-compliance (OR=6.433, P=0.001), and lower estimated glomerular filtration rate at diagnosis (OR=1.020, P=0.021) affected prognosis. At end of follow-up, 34.31% achieved varying levels of remission, and 8.76% were in low disease activity state (LDAS). CONCLUSIONS: pLN usually presented with proteinuria, and class IV LN was the dominant pathology. Hypertension, nervous-system involvement, treatment non-compliance, and lower eGFR at diagnosis were independent risk factors for poor prognosis of kidney outcomes. Compared with renal remission rate and cumulative overall survival rate, the proportion of targets achieved was not ideal, suggesting T2T strategy should be used to guide pLN management. A higher resolution version of the Graphical abstract is available as Supplementary information.

Thromboelastography Detects Possible Coagulation Disturbance in Pediatric Patients with Portal Cavernoma.

BACKGROUND: Thromboelastography (TEG) allows a dynamic assessment of clot formation and dissolution that might be useful for assessing the relative contribution of the coagulation components to overall clot formation and dissolution, but it has not been fully defined in patients with portal cavernoma (PC). METHODS: We retrospectively recruited consecutive patients with PC between July 2006 and June 2016 who had no abdominal malignancy or liver cirrhosis. Blood samples were drawn on admission and were subjected to coagulation parameter assessment, including conventional coagulation tests, measurement of the circulating levels of procoagulant and anticoagulant factors, and TEG assessment. RESULTS: Compared with controls, patients with PC showed significant reductions in the serum levels of procoagulant factors and anticoagulants factors, whereas factor VIII was slightly elevated. TEG showed clot formation (α-angle), and the maximal clot strength (MA) was higher in patients with PC than in controls, indicating a hypercoagulable state. Thrombocytopenia decreased both clot formation (α-angle) and the maximal clot strength (MA) but was still significantly higher than the control. Furthermore, patients with PC had a higher level of D-dimer and LY30 than did controls, indicating the in vivo activation of coagulation and fibrinolysis. CONCLUSION: TEG analysis showed that patients with PC were in a hypercoagulable state that could be partially masked by thrombocytopenia secondary to splenomegaly and hypersplenism in these patients, which indicates that our current prophylaxis and therapy regimen could be improved.

Risk factors associated with IgA vasculitis with nephritis (Henoch-Schönlein purpura nephritis) progressing to unfavorable outcomes: A meta-analysis.

OBJECTIVE: To identify risk factors associated with unfavorable outcomes in children with IgA vasculitis with nephritis (Henoch-Schonlein purpura nephritis)(IgA-VN). METHODS: PubMed, Embase, and Web of Science databases were searched for studies, published in English through February 2019. The data were extracted to perform pooled analysis, heterogeneity testing, subgroup analysis, sensitivity analysis, and publication bias analysis. RESULTS: This meta-analysis showed that, older age at onset (WMD 1.77, 95% CI 0.35-3.18, p = 0.014), lower glomerular filtration rate (GFR; WMD -23.93, 95% CI -33.78- -14.09, p<0.0001), initial renal manifestations with nephrotic syndrome (OR 1.74, 95% CI 1.12-2.70, p = 0.013), with nephritic-nephrotic syndrome (OR 4.55, 95% CI 2.89-7.15, p<0.0001) and renal biopsy with crescentic nephritis (International Study of Kidney Disease in Children [ISKDC] grades III-V) (OR 3.85, 95% CI 2.37-6.28, p<0.0001) were significant risk factors associated with poor outcomes in IgA-VN, whereas initial clinical features with hematuria (OR 0.33, 95% CI 0.16-0.69, p = 0.003) and mild proteinuria±hematuria (OR 0.46, 95% CI 0.28-0.75, p<0.0001) were associated with progression to good outcomes. By contrast, gender, hypertension and initial renal manifestations of acute nephritic syndrome were not significantly associated with poor outcomes in IgA-VN. CONCLUSION: This meta-analysis showed that older age at onset, lower GFR, initial renal features of nephrotic syndrome and nephritic-nephrotic syndrome and renal biopsy with crescentic nephritis (ISKDC grades III-V) were predictive of poor prognosis in children with IgA-VN.

Circulating follicular T helper cells are possibly associated with low levels of serum immunoglobulin G due to impaired immunoglobulin class-switch recombination of B cells in children with primary nephrotic syndrome.

Clinically, most patients with primary nephrotic syndrome (PNS) have low serum IgG levels, which is an important factor in infection and in PNS relapse.To some extent, the mechanisms involved remain largely unknown. Here, we aimed to investigate the pathogenesis of the decreased IgG levels in PNS. Peripheral blood was collected from patients with PNS and closely age- and sex-matched healthy individuals. The frequency, phenotype and molecular function of different circulating B cell and T follicular helper cell (TFH) subsets were examined by flow cytometry. The function of the CD40/CD40 L interaction in immunoglobulin class-switch recombination (CSR) was evaluated by assessing the induction of activation-induced deaminase (AID) expression with CD40 L stimulation. We revealed an increase in the levels of circulating total plasmablasts, plasma cells and mature-naive B cells and a decrease in the levels of germinal centre-like B cells and CD19+IgG+ B cells in PNS. In addition, although the expression of CD86 on the surface of B cells and the expression of the inducible costimulator (ICOS) on the surface of TFH cells both were increased, the expression of CD40 L on the surface of TFH cells was decreased. Moreover, upon stimulation with CD40 L in vitro, the mRNA expression of AID in peripheral blood mononuclear cells (PBMCs) was decreased in patients with PNS compared with that in healthy controls. Our results indicate that the immunoglobulin CSR of B cells was partly dysfunctional and provide insights into the potential involvement of impaired TFH cell-dependent B cell responses in the pathogenesis of low IgG levels through downregulating CD40 L expression on TFH cells in PNS.

Effect of CD40/CD40L signaling on IL-10-producing regulatory B cells in Chinese children with Henoch-Schönlein purpura nephritis.

The aim of the present study was to examine the role and mechanism of interleukin-10 (IL-10)-producing regulatory B cells (B10 cells) in the pathogenesis of Henoch-Schönlein purpura nephritis (HSPN). We examined the percentage of B10 cells, CD19+CD24hiCD38hi B cells, CD19+CD24hiCD27+ B cells, Th17 cells, and T regulatory (Treg) cells within the peripheral blood mononuclear cell (PBMC) population in healthy subjects and HSP/HSPN patients. The percentage of B10 cells and CD19+CD24hiCD38hi B cells was reduced in HSPN patients and that of CD19+CD24hiCD27+ B cells was decreased only in HSPN patients with hematuria and proteinuria or massive proteinuria. The expression of IL-10 by B10 cells and their subsets was decreased in HSPN patients and returned to normal levels in HSP/HSPN patients in remission. B10 cells and their subsets negatively correlated with the Th17/Treg ratio. There was no difference in B10pro + B10 cells, Th17 cells, Treg cells, and the Th17/Treg ratio between children with HSP/HSPN and healthy controls after CD40L stimulation. On the other hand, the level of IL-10 expressed by CD19+CD40+ B cells was decreased in HSPN, and the percentage of B10pro + B10 cells and Treg cells was reduced and that of Th17 cell was increased in the presence of anti-CD40L monoclonal antibody (mAb). Thus, decreased B10 cells and CD19+CD24hiCD38hi B cells may function as an early marker of renal impairment in HSPN. The dysfunction of B10 cells may play a role in the pathogenesis of HSPN by regulating the Th17/Treg balance. Moreover, the CD40/CD40L signaling pathway may play a role in B10 cell differentiation and functional maturation.

Age- and gender-specific reference values for urine albumin/creatinine ratio in children of southwest China.

BACKGROUND: The reference value for the urine albumin/creatinine ratio (ACR) varies between races and has not been previously validated in children. We assessed the ACR reference values and the factors that affect them in a population of healthy Chinese children. METHODS: A total of 1986 healthy children (1078 males, 908 females) aged 6-19 y were enrolled. The 95th percentile of ACR was used as the normal upper limit. The associations between ACR and gender, age, body mass index (BMI), systolic blood pressure (SBP), preterm birth, intake of fruits, smoking, and geographical area were examined. RESULTS: The normal upper limit of ACR was 14.7 mg/g for male children and 19.8 mg/g for female children. The ACR value for girls was significantly higher than that for boys (P<0.001). ACR was inversely correlated with age (P<0.001) and positively correlated with BMI, SBP, and smoking (all P<0.01). CONCLUSIONS: The ACR reference value for healthy children in southwest China is approximately the same as the value for adults, but lower than that for the Western population. Age, SBP, BMI, and smoking in children influence ACR.

Ultrasound of urinary system and urinary screening in 14 256 asymptomatic children in China.

AIM: The aim of this study is to assess the characteristics of urinary system diseases and the role of the ultrasound screening and urinalysis screening for chronic kidney disease (CKD) in asymptomatic children in China. METHODS: Between September 2008 and November 2008, 14 256 children excluding those with obvious symptoms and signs were enrolled in our study. All the subjects accepted ultrasound and urinary screening. A case-control study was performed to evaluate the relative risk of having stones in those children exposed to melamine formula. RESULTS: Of the enrolled children, 6.10% (869 of 14 256) showed abnormalities, of which 409 (2.87%) were established by ultrasound, 572 (4.01%) by urinalysis and 112 (0.79%) by both ultrasound screening and urinalysis. The abnormalities included congenital anomalies of kidney and urinary tract, urinary stones and/or hydronephrosis, leucocyturia and haematuria and/or proteinuria. Children exposed to melamine formula were 5.17 times as likely to have kidney stones as children exposed to no-melamine formula (95% confidence interval, 3.28-8.14; P < 0.001); the probability of kidney stones in melamine-fed infants were 6.28 times as likely as those no melamine-fed (95% confidence interval, 3.71-10.65; P < 0.001). CONCLUSION: Ultrasonography and urinalysis could complement each other and play important roles in the early diagnosis of anomalies of the urinary system, but urinalysis is a more cost-effective screening tool for CKD in children in China. Exposure to melamine-contaminated formula associated with urinary stones, especially in infants, was significantly higher than the control group.