Genome-Wide Association Study in Acute Tubulointerstitial Nephritis.

SIGNIFICANCE STATEMENT: Polymorphisms of HLA genes may confer susceptibility to acute tubulointerstitial nephritis (ATIN), but small sample sizes and candidate gene design have hindered their investigation. The first genome-wide association study of ATIN identified two significant loci, risk haplotype DRB1*14-DQA1*0101-DQB1*0503 (DR14 serotype) and protective haplotype DRB1*1501-DQA1*0102-DQB1*0602 (DR15 serotype), with amino acid position 60 in the peptide-binding groove P10 of HLA-DR ß 1 key. Risk alleles were shared among different causes of ATIN and HLA genotypes associated with kidney injury and immune therapy response. HLA alleles showed the strongest association. The findings suggest that a genetically conferred risk of immune dysregulation is part of the pathogenesis of ATIN. BACKGROUND: Acute tubulointerstitial nephritis (ATIN) is a rare immune-related disease, accounting for approximately 10% of patients with unexplained AKI. Previous elucidation of the relationship between genetic factors that contribute to its pathogenesis was hampered because of small sample sizes and candidate gene design. METHODS: We undertook the first two-stage genome-wide association study and meta-analysis involving 544 kidney biopsy-defined patients with ATIN and 2346 controls of Chinese ancestry. We conducted statistical fine-mapping analysis, provided functional annotations of significant variants, estimated single nucleotide polymorphism (SNP)-based heritability, and checked genotype and subphenotype correlations. RESULTS: Two genome-wide significant loci, rs35087390 of HLA-DQA1 ( P =3.01×10 -39 ) on 6p21.32 and rs2417771 of PLEKHA5 on 12p12.3 ( P =2.14×10 -8 ), emerged from the analysis. HLA imputation using two reference panels suggested that HLA-DRB1*14 mainly drives the HLA risk association . HLA-DRB1 residue 60 belonging to pocket P10 was the key amino acid position. The SNP-based heritability estimates with and without the HLA locus were 20.43% and 10.35%, respectively. Different clinical subphenotypes (drug-related or tubulointerstitial nephritis and uveitis syndrome) seemed to share the same risk alleles. However, the HLA risk genotype was associated with disease severity and response rate to immunosuppressive therapy. CONCLUSIONS: We identified two candidate genome regions associated with susceptibility to ATIN. The findings suggest that a genetically conferred risk of immune dysregulation is involved in the pathogenesis of ATIN.

Light-chain proximal tubulopathy: a retrospective study from a single Chinese nephrology referral center.

Background: Light-chain proximal tubulopathy (LCPT) is a rare disease characterized by the accumulation of monoclonal light chains within proximal tubular cells. This study aimed to investigate the clinical characteristics of LCPT from a single Chinese nephrology referral center.Methods: Patients with kidney biopsy-proven isolated LCPT between 2016 and 2022 at Peking University First Hospital were retrospectively included. Clinical data, kidney pathological type, treatment, and prognosis were analyzed.Results: Nineteen patients were enrolled, the mean age at diagnosis was 57 ± 11 and the sex ratio was 6/13 (female/male). Mean proteinuria was 2.44 ± 1.89 g/24 hr and the mean estimated glomerular filtration rate (eGFR) at the point of biopsy was 59.640 ± 27.449 ml/min/1.73 m2. κ-restriction (84%) was dominant among LCPTs. An abnormal free light chain ratio was observed in 86% of the patients. Proximal tubulopathy with cytoplasmic inclusions accounted for the majority (53%), followed by tubulopathy associated with interstitial inflammation reaction (26%), proximal tubulopathy without cytoplasmic inclusions (16%), and proximal tubulopathy with lysosomal indigestion/constipation (5%). One patient presented with acute kidney injury and 16 patients presented with chronic kidney disease. Regarding follow-up, patients received bortezomib-based or R-CHOP chemotherapy or supportive treatment only. The mean follow-up time was 22 ± 16 months, and the mean eGFR was 63.098 ± 27.439 ml/min/1.73 m2 at the end of follow-up. These patients showed improved or stable kidney function.Conclusions: This is the first case series report of LCPT in four different pathological types in northern China. Clone-targeted chemotherapy may help preserve the kidney function in these patients.

A modified renal risk score for Chinese patients with antineutrophil cytoplasmic antibody-associated vasculitis.

BACKGROUND: The renal risk score (RRS) is a useful tool to predict end-stage renal disease (ESRD) in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The current study aimed to validate the predictive performance of RRS and to further modify this model in Chinese AAV patients. METHODS: Two hundred and seventy-two patients diagnosed with AAV confirmed by renal biopsies were retrospectively enrolled from a single center. The RRS was calculated based on 3 categorical variables, i.e., the proportion of normal glomeruli, the proportion of interstitial fibrosis and tubular atrophy (IF/TA), and eGFR at biopsy, classifying these patients into low-, medium-, and high-risk groups. In addition, a modified model was developed based on the RRS and was further validated in another independent cohort of 117 AAV patients. The predictive performance of each model was evaluated according to discrimination and calibration. RESULTS: Patients were classified by the RRS into low- (26.5%), medium- (46.7%), and high-risk (26.8%) groups, with 120-month renal survival rates of 93.3%, 57.2%, and 18.4%, respectively (P < 0.001). The RRS showed good discrimination but less satisfactory calibration. Therefore, a modified model with improved discrimination and calibration was developed in Chinese AAV patients, with eGFR, proportion of normal glomeruli (both as continuous variables), and IF/TA (< 25%, 25-50%, > 50%) included. Internal and external validation of the modified model were performed. Finally, an online risk prediction tool was developed based on the modified model. CONCLUSIONS: The RRS was an independent predictor of ESRD of AAV patients. The modified model could predict the probability of ESRD for AAV patients with improved performance in Chinese AAV patients.

Pathological and clinical characteristics of late-onset oligomeganephronia based on a histomorphometric study.

BACKGROUND: Late-onset oligomeganephronia (OMN) is a rare chronic kidney disease and has no quantitative criteria for diagnosis yet. The current study aimed to explore its clinicopathological features by histomorphometric analysis. METHODS: We retrospectively re-reviewed all patients with enlarged and sparse glomeruli by light microscopy at Peking University First Hospital from 2012 to 2021, excluding those with any factor known to contribute to similar changes. Age- and sex-matched patients with thin basement membrane nephropathy were selected as control to establish the cut-off values for glomerulomegaly and rarity. Late-onset OMN cases were then confirmed and the clinicopathological characteristics were summarized. RESULTS: Mean diameter and density of cortical glomeruli in control was 156.53 ± 27.50 µm and 4.07 ± 0.63 /mm2, giving a lower limit of 211.53 µm for glomerulomegaly and an upper of 2.81 /mm2 for rarity. Seven adults of three females and four males were finally diagnosed as late-onset OMN with a mean age of 26.57 years. They showed mild to moderate proteinuria and/or renal dysfunction at biopsy with the mean proteinuria, serum creatinine (Scr) level, and estimated glomerular filtration rate of 0.50 g/d (0.10-0.95 g/d), 140.9 µmol/L (95.1-227.1 µmol/L), and 58.7 mL/min/1.73m2 (21.3-98.0 mL/min/1.73m2), respectively. Four patients (57.1%) had normal Scr at diagnosis. Six patients with available data showed renal tubular injury with increased urinary microalbumin in all, elevated N-acetyl-ß-glucosaminidase in two, and elevated α1 microglobulin in five. Kidney size was normal or slightly reduced. The mean density and glomerular diameter of the seven cases was 0.86 mm2 (0.55-1.41 /mm2) and 229.73 µm (211.88-260.66 µm). Segmental glomerular sclerosis was observed in six (85.7%) with four (66.7%) of perihilar type. Proximal tubule dilation was observed in all, focal to diffuse, lining with enlarged epithelial cells. The mean foot process width was 634.02 nm, wider than 472.54 nm of the control (P = 0.0002). CONCLUSION: Late-onset OMN should be considered a special entity with relatively slow clinical progress characterized by hypertrophy of the sparsely distributed nephron.

Primary membranous nephropathy in two siblings with one combined with anti-glomerular basement membrane disease: a case report.

BACKGROUND: The phospholipase A2 receptor (PLA2R) associated with membranous nephropathy (MN) is an organ-specific autoimmune disease associated with PLA2R and human leukocyte antigen (HLA) genes. Familial PLA2R-related MN is rarely reported. The combination of anti-GBM disease and MN has been well documented, though the mechanism behind it remains unclear. CASE PRESENTATION: We describe two siblings diagnosed with pathology-confirmed PLA2R-related MN 1 year apart. And one of the two siblings developed an anti-GBM disease. The high-resolution HLA typing showed identical alleles in both siblings, specifically heterozygotes of DRB1*15:01/*03:01. CONCLUSION: We describe a familial case of PLA2R-related MN supporting the role of genetic factors that HLA-DRB1*15:01 and DRB1*03:01 predispose patients in the development of PLA2R-related MN in the Han Chinese population. The combination of MN and anti-GBM disease may also partially be associated with the same susceptible HLA allele DRB1*15:01.

Clinical value of the renal pathologic scoring system in complement-mediated thrombotic microangiopathy.

OBJECTIVES: This study was initiated to establish a renal thrombotic microangiopathy (TMA) scoring system based on clinical needs and investigate its predictive value for patients' long-term outcomes. METHODS: Kidney biopsy-proven Complement-mediated TMA (C-TMA) patients from January 2000 to December 2017 in Peking University First Hospital were retrospectively studied. Both acute and chronic TMA-related lesions, including 15 pathologic indices, were semiquantitatively scored. The interobserver and intraobserver reproducibility and correlation between the pathologic indices and clinical parameters were analyzed. Furthermore, the patients were divided into 2 groups by dialysis use at baseline, and the association of these pathologic indices with their prognostic outcomes was assessed between the two groups. RESULTS: Ninety-two patients with renal biopsy-proven C-TMA were enrolled. All fifteen included pathology indices showed good or moderate interobserver and intraobserver reproducibility and correlated well with several clinical parameters. Several clinicopathological indices were worse in the dialysis group than in the nondialysis group, such as serum creatinine, hemoglobin, platelet count, and estimated glomerular filtration rate. Moreover, morphologic features in the dialysis group presented with more severe vascular lesions. Interstitial fibrosis and chronic tubulointerstitial lesions were related to a trend of high risk of continuous dialysis in the dialysis group. Based on univariate and multivariable Cox regression analysis, more severe glomerular lesions, including glomerular mesangiolysis, glomerular basement membrane double contours and glomerular mesangial proliferation, were identified as risk factors predicting worse prognosis. CONCLUSIONS: Our renal C-TMA semiquantitative scoring system is reliable with good reproducibility and prognostic value in clinical practice, which needs further validation.

Recognizing the true face of noninfectious cryoglobulinemic glomerulonephritis.

Cryoglobulinemia encompasses a group of diseases with circulating aberrant Igs, which can cause systemic cryoglobulinemic vasculitis, including cryoglobulinemic glomerulonephritis. The complexities of different types and changing etiologies of cryoglobulinemias determine its heterogeneous clinical manifestations and diagnostic difficulties. In this issue of Kidney International, Javaugue et al. have emphasized the diagnostic points of cryoglobulinemic glomerulonephritis and hematological disorders as the major culprits of noninfectious cryoglobulinemic glomerulonephritis in a large cohort.

Myeloma cast nephropathy with diffuse amyloid casts without systemic amyloidosis: two cases report.

BACKGROUND: Multiple myeloma (MM) is a plasma-cell derived hematologic malignant disease. The malignant proliferating plasma cells secrete massive monoclonal immunoglobulins which lead to various pathologic types of renal injury. Myeloma cast nephropathy (MCN) is the most common histopathologic lesion with the worst renal prognosis. Rarely, the free light chains in the protein casts can form amyloid fibrils. Here, we reported two rare cases of MCN with diffuse amyloid casts. CASE PRESENTATION: Case 1: A 54-year-old Chinese man presented with a 4-year history of multiple myeloma, proteinuria and hematuria. He had monoclonal IgAλ plus free λ spike in both serum and urine. He had been on chemotherapy for 4 years and maintained normal serum creatinine until 11 months ago. Then, his renal function deteriorated and he went on hemodialysis 4 months before admission. Renal biopsy showed diffuse amyloid casts in the tubular lumens, without any obvious amyloid deposits in other kidney compartments or signs of extra-renal amyloidosis. The amyloid fibrils formed around mononuclear cells which were CD68 negative. According to the morphology and location, these mononuclear cells were considered as tubular epithelial cells. The patient was maintained on chemotherapy and hemodialysis. He died 8 months after renal biopsy. Case 2: A 58-year-old Chinese man presented with a one-and-a-half-year history of proteinuria and slowly rising serum creatinine. He had monoclonal IgDλ spike in both serum and urine. Amyloid casts were observed in the tubular lumens and mononuclear cells could be identified in the center of some casts. There were no amyloid deposits in other kidney compartments and no sign of systemic amyloidosis. The patient also had fine granular deposits along the tubular basement membrane with λ linear staining along tubular basement membrane suggesting light chain deposition disease. He was treated with bortezomib-based chemotherapy followed by lenalidomide-based chemotherapy and achieved very good partial remission (VGPR). After 27 months of follow-up, the patient still showed no signs of systemic amyloidosis. CONCLUSIONS: These 2 cases of MCN with diffuse amyloid casts have different histopathologic characteristics from the usual myeloma casts and tubular epithelial cells might play important roles in the pathogenesis.

C3 glomerulonephritis associated with monoclonal gammopathy: a retrospective case series study from a single institute in China.

OBJECTIVE: To investigate the demographic and clinicopathological features and renal outcomes of Chinese patients with C3 glomerulonephritis in the setting of monoclonal gammopathy. METHODS: Patients with renal biopsy-proven C3 glomerulonephritis and detectable serum and/or urine monoclonal immunoglobulin from 2006 to 2018 in Peking University First Hospital were included, their clinical data, renal pathology type, treatment, and prognosis were collected and analyzed. RESULTS: Nineteen patients were enrolled, accounting for 24% of C3GN patients in the study period. The mean age of onset was 55 years old and the gender ratio was 4/15 (female/male). The mean eGFR at biopsy was 49.55 ± 29.81 ml/min/1.73m2. The prominent clinical manifestations included nephrotic syndrome (58%), anemia (68%), microscopic hematuria and leukocyturia (58%), and hypocomplementemia (13, 68%). The IgG was the most common isotype of monoclonal Ig on immunofixation electrophoresis. Kidney biopsies revealed a relatively prominent MPGN pattern. Only two patients had direct evidence of monocle immunoglobulins acting as C3GN pathogenic factors. Two patients had concurrent TMA-like renal injuries. The median renal survival was 12 and 15 months, respectively in patients receiving conservative therapy and immunosuppressant therapy, without statistical significance. The efficacy of clone-targeted therapy needed further investigation. Plasma exchange therapy only improved one patient's renal outcome. CONCLUSIONS: This is the first case series report of C3GN combined with monoclonal Ig in northern China. The renal prognosis of these patients is poor, and immunosuppressant therapies show no advantage over supportive therapy in renal prognosis, while the benefit of clone-targeted chemotherapy is still requiring investigation.

A Validation of the 2018 Revision of International Society of Nephrology/Renal Pathology Society Classification for Lupus Nephritis: A Cohort Study from China.

BACKGROUND: A revision of the International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification for lupus nephritis has been published in 2018. The current study aimed to verify the utility of this system. MATERIALS AND METHODS: A total of 101 lupus nephritis patients from a large Chinese cohort who underwent renal biopsy in Peking University First Hospital were reevaluated by 2 renal pathologists, who had no knowledge of the clinical findings. The association between clinical data at the time of initial renal biopsy and follow-up and pathological features were further analyzed on all patients selected. RESULTS: The mean age of the cohort was 33 years with a male/female ratio of 1:9, and a median follow-up period of 128 months. The presence and extent of mesangial hypercellularity, endocapillary hypercellularity, global and segmental glomerulosclerosis, neutrophil exudation/karyorrhexis, glomerular hyaline deposits, extracapillary proliferation (crescents), tubular atrophy/interstitial fibrosis, and interstitial inflammation were significantly correlated with several clinical renal injury indices (systemic lupus erythematosus disease activity index, serum creatinine value, proteinuria, and C3 level) at the time of biopsy. By multivariable Cox hazard analysis, fibrous crescents, tubular atrophy/interstitial fibrosis, and the modified National Institutes of Health chronicity index were independent risk factors for patients' composite renal outcomes (hazard ratio [HR] 4.100 [95% CI 1.544-10.890], p = 0.005; HR 8.584 [95% CI 2.509-29.367], p = 0.001; and HR 3.218 [95% CI 1.138-9.099], p = 0.028; respectively). CONCLUSIONS: The 2018 revision of the ISN/RPS classification for lupus nephritis has utility for prediction of clinical renal outcomes.

Podocyte Involvement in Renal Thrombotic Microangiopathy: A Clinicopathological Study.

BACKGROUND: The current study aimed to evaluate the associations between podocyte injury and clinicopathological features in renal thrombotic microangiopathy (TMA) based on a Chinese cohort, which might be underscored in this disease. METHODS: The clinical, laboratory, and renal histopathological data of patients with renal biopsy-proven TMA from 2000 to 2015 in our institute were collected. Foot process effacement (FPE) was quantified by foot process width (FPW) by electron microscopy. Podocytes in the renal specimens were also detected by stainings for podocyte-specific markers, including Wilms tumor 1 (WT-1), synaptopodin, and podocalyxin. The associations between FPW and clinico-histopathological data were further analyzed. A composite end-point was defined by all-cause death or end-stage renal disease to address the predictive value of FPW. RESULTS: Sixty-three patients with renal biopsy-proven TMA were enrolled. The FPW of renal TMA patients was 1,090 ± 637 nm (range, 572-4,748 nm), which was significantly higher than the normal range in our center (p = 0.005). By immunohistochemistry and immunofluorescence assays, we found decreased expressions of synaptopodin, podocalyxin, and WT-1 and continued stainings of WT-1 in some podocytes without detectable synaptopodin stainings in the areas of sclerotic tufts and cellular crescents. The FPW value was correlated with the serum albumin concentration (rs = -0.281, p = 0.026), proteinuria amount (rs = 0.255, p = 0.047), serum creatinine levels (rs = 0.339, p = 0.007), and eGFR (rs = -0.335, p = 0.007). According to ROC curve analysis, the optimal cutoff level of FPW for predicting the composite end-point was 869 nm. In patients with FPW ≥ 869 nm, FPW levels were further correlated with the severity of mesangiolysis (rs = 0.351, p = 0.033) and glomerulosclerosis (rs = 0.369, p = 0.025) in pathological evaluations. Patients without clinical remission also had higher FPW than those with remission (1,240 ± 793 vs. 925 ± 344 nm, p = 0.013). The multivariate Cox hazard model showed that FPW ≥ 869 nm was an independent risk factor for the composite end-point (hazard ratio: 3.64, 95% CI: 1.37-9.66, p = 0.009). CONCLUSION: The podocyte injury was prevalent and the FPW levels were closely associated with clinicopathological features, especially prognosis, in renal TMA patients.

Renal pathologic spectrum and clinical outcome of monoclonal gammopathy of renal significance: A large retrospective case series study from a single institute in China.

OBJECTIVES: To analysis the pathological spectrum and prognosis of monoclonal gammopathy of renal significance (MGRS) patients. METHODS: Patients with renal biopsy-proven MGRS from 1999 to 2017 in Peking University First Hospital were included, clinical data, renal pathology type, treatment and prognosis were collected. RESULTS: One hundred and eighty-seven patients were enrolled, accounting for 0.7% of renal biopsies. Seventy-seven per cent of the MGRS patients were amyloidosis. Eighteen patients (9.6%) were monoclonal immunoglobulin deposition disease. Others included 10 patients (5.3%) with proliferative glomerulonephritis with monoclonal immunoglobulin (G) deposits, seven patients (3.7%) with cryoglobulinaemic glomerulonephritis, five patients (2.6%) with light chain proximal tubulopathy, two patients (1.1%) with fibrillary disease and one patient (0.5%) with C3 glomerulonephritis. Sixty-three per cent were treated with chemotherapy and/or stem cell transplantation. The mean follow-up time was 27 ± 32 months. One patient developed multiple myeloma at 17-month during follow-up. At the end of follow-up, 61 patients (33%) died, and 47 patients (25%) reached end-stage renal disease (ESRD). For the 144 amyloid patients, low estimated glomerular filtration rate (eGFR), decreased blood pressure, presence of cardiac involvement and absence of chemotherapy or high-dose melphalan/autologous peripheral blood stem cell transplantation were identified as independent risk factors for death. Low eGFR, decreased blood pressure, and presence of cardiac involvement were identified as independent risk factors for ESRD. For the 43 non-amyloid patients, no factor was identified for the risk of death. Low eGFR was identified as independent risk factor for ESRD. CONCLUSION: MGRS was an uncommon form of hematologic disorder related renal injury with a wide spectrum of pathologic lesions, and amyloidosis was the most common type. Treatment with chemotherapy and/or high-dose melphalan/autologous peripheral blood stem cell transplantation improved amyloid patients' survival.

Association of vascular endothelial growth factor and renal thrombotic microangiopathy-like lesions in patients with Castleman's disease.

AIM: Renal thrombotic microangiopathy (TMA) is a common pathological manifestation of Castleman's disease (CD)-associated renal lesions. Increased level of plasma vascular endothelial growth factor (VEGF) has been shown in single-case reports. We aimed to investigate the dysregulation of VEGF in the pathogenesis of CD-associated TMA-like lesions (CD-TMA) in a larger cohort. METHODS: Nineteen patients with clinico-pathologically diagnosed CD with renal involvement were enrolled. Ten patients with pregnancy TMA or TMA of unknown reasons were enrolled as TMA control group. The plasma levels of VEGF, soluble Flt-1 and interleukin-6 (IL-6) were detected using enzyme-linked immunosorbent assay kits. The expression of VEGF in the kidney biopsied tissue sections and the lymph node specimens were detected by immunostaining. RESULTS: The plasma levels of VEGF and IL-6 levels were the highest in CD-TMA group compared to TMA control group and healthy controls. The levels of plasma VEGF was positively correlated with that of IL-6, and increased expression of VEGF and IL-6 was also observed in the lymph nodes from CD-TMA patients. However, the expression of VEGF in the glomerular podocytes was significantly decreased in CD-TMA group as well as in the TMA control. CONCLUSION: Our findings suggest that renal VEGF expression might be important in the pathogenetic mechanism of CD-associated TMA-like lesions.

Elevation of erythrocyte sedimentation rate and C-reactive protein levels reflects renal interstitial inflammation in drug-induced acute tubulointerstitial nephritis.

BACKGROUND: A renal biopsy is needed to define active inflammatory infiltration and guide therapeutic management in drug-induced acute tubulointerstitial nephritis (D-ATIN). However, factors such as various contraindications, refusal of informed consent and limited technical support may stop the biopsy process. It is thus of great importance to explore approaches that could deduce probable pathologic changes. METHODS: A total of 81 biopsy-proven D-ATIN patients were enrolled from a prospective cohort of ATIN patients at Peking University First Hospital. The systemic inflammation score (SIS) was developed based on the CRP and ESR levels at biopsy, and patients were divided into high-SIS, median-SIS, and low-SIS groups. The demographic data, clinicopathologic features, and renal outcomes were compared. RESULTS: The SIS was positively correlated with inflammatory cell infiltration and was inversely correlated with interstitial fibrosis. The number of interstitial inflammatory cells increased significantly with increasing SISs. The proportions of neutrophils and plasma cells were the highest in the high-SIS group compared with the other two groups. Prednisone (30-40 mg/day) was prescribed in all patients. The high-SIS group tended to have more favorable renal restoration than the other two groups. By 12 months postbiopsy, a decreased eGFR (< 60 mL/min/1.73 m2) was observed in 66.7% of medium-SIS patients, 32.4% of high-SIS patients, and 30.4% of low-SIS patients. CONCLUSION: The SIS was positively correlated with active tubulointerstitial inflammation and therefore could help to aid therapeutic decisions in D-ATIN.

The predictive value of crescents in the disease progression of lupus nephritis based on the 2018 International Society of Nephrology/Renal Pathology Society Revision System: a large cohort study from China.

Objective: This study analyzed the associations of different crescents' fraction and clinical features in a Chinese lupus nephritis cohort based on the 2018 revision of ISN/RPS classification system.Methods: A total of 288 lupus nephritis patients with complete clinicopathological data and well follow-up was enrolled. The fraction of glomeruli with cellular or fibrocellular crescents based on the new system was reevaluated. The association between crescents fractions and the outcomes were further analyzed.Results: The median follow-up period was 76.5 months. Cellular or fibrocellular crescents were present in 146 (50.7%) of the total individuals. The percentage of crescents were significantly associated with severe clinical renal injury indices and other renal pathological parameter. According to the survival receiver operating characteristic (survival ROC) curve, the optimal cutoff level of cellular or fibrocellular crescents for predicting the composite events was 7.39%. By multivariable Cox hazard analysis, the presence of crescents was predictive of survival from the composite events with a hazard ratio [HR] of 2.5 (95% CI 1.190-5.431; p = .02). Furthermore, when we used absent, present in less than 7.39% of glomeruli, and present in greater than or equal to 7.39% of glomeruli as cutoffs in all the patients, a gradation appeared, with adjusted HRs of 2.9 (95% CI 1.326-6.313; p = .008) for crescents in greater than or equal to 7.39% of glomeruli, in reference to no crescents.Conclusion: We proposed that the crescents were not uncommon and had important clinical significance in lupus nephritis. The cutoff point of crescents as prognosticator might be nearly 7.39%.

Diagnostic roles of urinary kidney injury molecule 1 and soluble C5b-9 in acute tubulointerstitial nephritis.

Acute tubulointerstitial nephritis (ATIN) is a common cause of acute kidney injury characterized by inflammatory cells infiltrating in the interstitium. The present study aimed to explore noninvasive biomarkers that might indicate activity of pathological injuries and help direct treatment. Fifty-four patients with clinical-pathologically diagnosed ATIN from January 1, 2014, to June 30, 2016, at Peking University First Hospital were enrolled. Urine samples were collected on the morning of renal biopsy and assessed for urinary kidney injury molecule-1 (KIM-1) and urinary soluble C5b-9 (sC5b-9). Immunofluorescence staining for KIM-1 and C5b-9 was performed in biopsied kidney sections from ATIN cases. The clinical and pathological relevance of the two urinary biomarkers was analyzed. Both urinary KIM-1 and sC5b-9 values were significantly elevated in patients with ATIN compared with healthy controls. The urinary KIM-1 level positively correlated with urinary N-acetyl-ß-d-glucosaminidase (r = 0. 542, P = 0.001) and the pathological tubular injury score (r = 0.469, P < 0.001), whereas the urinary sC5b-9 level was related to pathological activity scores for tubular injury (r = 0.413, P = 0.002), interstitial inflammation (r = 0.388, P = 0.004), and treatment response (r = 0.564, P < 0.001). Urinary KIM-1 tended to have better diagnostic value for tubular injury than urinary sC5b-9, whereas only urinary sC5b-9 was able to demonstrate severe interstitial inflammation. A combination of urinary KIM-1 and sC5b-9 had an area under the receiver-operating characteristic curve of 0.864 (95% confidence interval: 0.766-0.963, P < 0.001, sensitivity: 75%, specificity: 88%) for acute tissue injury in ATIN. KIM-1 expression was markedly increased in renal tubular cells in both ATIN and acute tubular necrosis conditions, whereas a significant upregulation of C5b-9 was only detected in the tubular cells and interstitial cells in ATIN cases. Urinary KIM-1 is a specific biomarker for renal tubular injury in ATIN, whereas urinary sC5b-9 is valuable in demonstrating severe interstitial inflammation. The combination of these two biomarkers helps identify patients at an acute injury stage and, therefore, might facilitate clinical evaluation and guide immunosuppressive therapy.

Urine macrophages reflect kidney macrophage content during acute tubular interstitial and glomerular injury.

Macrophage polarization is a major contributing factor in acute kidney injury (AKI). We aim to determine its biomarker value in differentiating etiologic causes of various intrinsic renal AKI. A total of 205 patients with renal intrinsic AKI were enrolled. Urinary sCD163 was quantified and macrophage subtypes in urine and in renal biopsy were determined. Compared to healthy controls and AKI due to interstitial or tubular injuries (0 pg/µmol), urinary sCD163 was markedly higher in glomerulopathy, especially in diffuse proliferative glomerulonephritis (275.5 pg/µmol) and significantly correlated with cellular crescent formation. Urine sediment analysis of M1/M2 ratio could differentiate acute tubulointerstitial nephritis (M1/M2 > 2.35) from crescentic glomerulonephritis (M1/M2 < 0.27). Urinary sCD163 levels and M2 subtype positively correlated with infiltrated M2 in the glomeruli, whereas urine M1 positively correlated with infiltrated M1 in the interstitium. Of note, urinary sCD163 showed better diagnositic performance in differentiating disease etiologies compared to tradiational urinary biomarkers of AKI (NGAL and KIM-1) and markers of myeloid cells (CD11b) and pan macrophages (CD68). Thus markers of macrophage polarization could be viewed as the noninvasive "liquid biopsy" in the presence of various intrinsic kidney diseases.

Renal injury in Seipin-deficient lipodystrophic mice and its reversal by adipose tissue transplantation or leptin administration alone: adipose tissue-kidney crosstalk.

Seipin deficiency is responsible for type 2 congenital generalized lipodystrophy with severe loss of adipose tissue (AT) and could lead to renal failure in humans. However, the effect of Seipin on renal function is poorly understood. Here we report that Seipin knockout (SKO) mice exhibited impaired renal function, enlarged glomerular and mesangial surface areas, renal depositions of lipid, and advanced glycation end products. Elevated glycosuria and increased electrolyte excretion were also detected. Relative renal gene expression in fatty acid oxidation and reabsorption pathways were impaired in SKO mice. Elevated glycosuria might be associated with reduced renal glucose transporter 2 levels. To improve renal function, AT transplantation or leptin administration alone was performed. Both treatments effectively ameliorated renal injury by improving all of the parameters that were measured in the kidney. The treatments also rescued insulin resistance and low plasma leptin levels in SKO mice. Our findings demonstrate for the first time that Seipin deficiency induces renal injury, which is closely related to glucolipotoxicity and impaired renal reabsorption in SKO mice, and is primarily caused by the loss of AT and especially the lack of leptin. AT transplantation and leptin administration are two effective treatments for renal injury in Seipin-deficient mice.-Liu, X.-J., Wu, X.-Y., Wang, H., Wang, S.-X., Kong, W., Zhang, L., Liu, G., Huang, W. Renal injury in Seipin-deficient lipodystrophic mice and its reversal by adipose tissue transplantation or leptin administration alone: adipose tissue-kidney crosstalk.

Immunological features and functional analysis of anti-CFH autoantibodies in patients with atypical hemolytic uremic syndrome.

OBJECTIVE: Atypical hemolytic uremic syndrome (aHUS) is associated with defective complement regulation. Anti-complement factor H (CFH) antibodies were thought to participate in the pathogenesis of aHUS. The aim of this study was to address the functions and properties of CFH autoantibodies in a Chinese Han cohort of aHUS patients. METHODS: Thirty-six anti-CFH antibody-positive aHUS patients at the acute phase of the disease were involved in this study. Clinical data of the patients were collected. Anti-CFH immunoglobulin G (IgG) subclasses and antibody isotypes were detected by ELISA. Epitope mapping was performed using recombinant CFH fragments (SCRs 1-4, SCR 7, SCRs 11-14, and SCRs 19-20). Purified IgG from plasma from seven patients were used for functional analyses. RESULTS: All patients presented with the classic triad of HUS. The anti-CFH autoantibodies mostly bound to the SCRs 19-20 domains of CFH but not the SCRs 1-4 domains. CFI cofactor activity was not disturbed by the anti-CFH antibody in any of the seven patients. Purified IgG interfered with the binding of CFH to C3b and CFH-mediated sheep erythrocyte protection in all seven patients. IgG from 4/5 (80%) patients tested inhibited the binding of CFH to glomerular endothelial cells. CONCLUSIONS: Our study suggests that the properties of CFH antibodies from patients with aHUS, including the recognition of SCRs and IgG subclasses, can influence and impair the biological role of CFH and therefore contribute to aHUS susceptibility.

Membranoproliferative glomerulonephritis with deposition of monoclonal IgG evolved from polyclonal IgG: a case report with two consecutive renal biopsies.

BACKGROUND: Proliferative glomerulonephritis with monoclonal Immunoglobulin (G) deposits (PGNMID) is a rare kind of MGRS with intact monoclonal IgG deposition. Seventy percent of PGNMID patients were negative for M-spike. CASE PRESENTATION: A 51-year-old Chinese woman presented with 16-month history of chronic nephritic syndrome. Her first biopsy showed a MPGN pattern, and the IF showed polyclonal IgG deposition but with IgG3λ dominance, MGRS was highly suspected. But the serum/urine IFE and bone marrow examination was negative for monoclonal gammopathy. She was treated with RAS inhibitors, and monitored carefully in the outpatient clinic. When the proteinuria was not controlled by RAS inhibitors, immunosuppressive agents were initiated. The second biopsy was done due to her acute kidney injury 9 months later, showing a MPGN pattern with acute tubulointerstitial disease, but the IF showed monoclonal IgG3λ deposition. The κ light chain, IgG1, IgG2 and IgG4 were absent. Electron microscopic examination revealed electron-dense deposits in the mesangial, subendothelial and subepithelial area which is the same as the first renal biopsy. The final diagnose of this patient was PGNMID (IgG3λ) with non-organized deposits. Repeated serum/urine IFE and free light chain still failed to identify monoclonal gammopathy. The patient was treated with steroid and cyclophosphamide, and her serum creatinine decreased. CONCLUSIONS: Some of the PGNMID patients may be derived from polyclonal immune complex mediated glomerulonephritis.