Yi-miao Zhang

Plasma soluble urokinase receptor levels are increased but do not distinguish primary from secondary focal segmental glomerulosclerosis

In this study, we measured soluble urokinase receptor levels, a possible permeability factor, in the plasma of patients with primary focal segmental glomerulosclerosis (FSGS) and determined their association with clinical and pathological data in 74 patients with primary FSGS. Healthy donors and patients with minimal change disease, membranous nephropathy, and secondary FSGS were used as controls. The plasma-soluble urokinase receptor levels, measured by commercial ELISA kits, of patients with primary FSGS (median: 2923, interquartile range 2205-4360 pg/ml) were significantly higher than those of patients with minimal change disease (median 2050 pg/ml), membranous nephropathy (median 2029 pg/ml), and normal individuals (median 1739 pg/ml). There was no significant difference in plasma-soluble urokinase receptor levels between the 74 patients with primary and 14 patients with secondary FSGS. The soluble urokinase receptor levels increased in the order of tip variant, to a not otherwise specified variant and a cellular variant. The soluble urokinase receptor levels were significantly but negatively correlated with creatinine clearance at presentation but positively correlated with crescent formation in patients with primary FSGS. During follow-up, receptor levels decreased significantly in patients with complete remission. Thus, plasma-soluble urokinase receptor levels did not differentiate primary and secondary FSGS, and although significantly elevated in FSGS, they showed considerable overlap with other glomerular diseases.

Urinary soluble urokinase receptor levels are elevated and pathogenic in patients with primary focal segmental glomerulosclerosis

BackgroundFocal segmental glomerulosclerosis (FSGS) is a major cause of end-stage renal disease. Recent studies have proposed that plasma soluble urokinase receptor (suPAR) might be a causative circulating factor but this proposal has caused controversy. This study aimed to measure urinary suPAR levels in patients with primary FSGS and its significance in the pathogenesis of FSGS.MethodsSixty-two patients with primary FSGS, diagnosed between January 2006 and January 2012, with complete clinical and pathologic data were enrolled, together with disease and normal controls. Urinary suPAR levels were measured using commercial ELISA kits and were corrected by urinary creatinine (Cr). The associations between urinary suPAR levels and clinical data at presentation and during follow up were analyzed. Conditionally immortalized human podocytes were used to study the effect of urinary suPAR on activating β3 integrin detected by AP5 staining.ResultsThe urinary suPAR level of patients with primary FSGS (500.56, IQR 262.78 to 1,059.44 pg/μmol Cr) was significantly higher than that of patients with minimal change disease (307.86, IQR 216.54 to 480.18 pg/μmol Cr, P = 0.033), membranous nephropathy (250.23, IQR 170.37 to 357.59 pg/μmol Cr, P <0.001), secondary FSGS (220.45, IQR 149.38 to 335.54 pg/μmol Cr, P <0.001) and normal subjects (183.59, IQR 103.92 to 228.78 pg/μmol Cr, P <0.001). The urinary suPAR level of patients with cellular variant was significantly higher than that of patients with tip variant. The urinary suPAR level in the patients with primary FSGS was positively correlated with 24-hour urine protein (r = 0.287, P = 0.024). During follow up, the urinary suPAR level of patients with complete remission decreased significantly (661.19, IQR 224.32 to 1,115.29 pg/μmol Cr versus 217.68, IQR 121.77 to 415.55 pg/μmol Cr, P = 0.017). The AP5 signal was strongly induced along the cell membrane when human differentiated podocytes were incubated with the urine of patients with FSGS at presentation, and the signal could be reduced by a blocking antibody specific to uPAR.ConclusionsUrinary suPAR was specifically elevated in patients with primary FSGS and was associated with disease severity. The elevated urinary suPAR could activate β3 integrin on human podocytes.Please see related article http://www.biomedcentral.com/1741-7015/12/82.

Delayed severe pneumonia in mycophenolate mofetil-treated patients with IgA nephropathy

BACKGROUND Mycophenolate mofetil (MMF), a relatively new immunosuppressant, is widely used in the field of transplantation and also for autoimmune diseases with good tolerance. It has been reported that MMF possesses potent activity against pneumocystis pneumonia (PCP). This study investigated the effects of this treatment on the occurrence of severe pneumonia (SP) including PCP and its risk factors. METHODS This was a retrospective cohort study. Of 850 IgA nephropathy (IgAN) patients that were followed up in our renal centre, 32 received MMF (1-1.5 g/day) and 47 were treated with cyclophosphamide (CTX; 50-100 mg/day). All the patients also received prednisone. SP was defined as diffuse bilateral lung infiltrate with respiratory failure, and PCP was diagnosed by detecting organisms in sputum and bronchoalveolar lavage. RESULTS Patients given MMF or CTX did not differ in their distribution of age, sex, renal function or prednisone dosage. However, 6 of the 32 patients developed SP around the third month after the initiation of MMF administration: 3 were diagnosed with PCP, 2 with suspected PCP and in the other PCP could not be excluded. SP did not occur in patients treated with CTX. Most SP cases (five of six) presented with abrupt onset and rapidly progressed to respiratory failure, from which four died. The deterioration of renal function was strongly associated with the occurrence of SP. Six patients (6 of 16) with chronic renal function impairment (eGFR < 60 ml/min/1.73 m(2)) developed SP while none of the patients with eGFR > 60 ml/min/1.73 m(2) did. Absolute lymphocyte counts decreased significantly in patients with eGFR < 60 ml/min/1.73 m(2) after 3 months of MMF treatment compared to the counts before MMF was initiated (1.71 +/- 0.23 versus 2.43 +/- 0.17 x 10(9)/l, P = 0.04). This effect was more pronounced in patients with SP, which had significantly lower counts than patients without SP (0.22 +/- 0.04 versus 1.91 +/- 0.20 x 10(9)/l, P = 0.001). The occurrence of SP or PCP in patients with chronically impaired renal function was also associated with lymphopenia. CONCLUSIONS This study is the first report of delayed SP including PCP following MMF plus corticosteroids in patients with IgAN. Chronically impaired renal function might be a risk factor for severe infection, and lymphocyte counts may serve as useful and convenient tools for monitoring the intendance of the occurrence of PCP. This finding and its risk factors need to be further evaluated.

MHC Class II Risk Alleles and Amino Acid Residues in Idiopathic Membranous Nephropathy

Epitopes of phospholipase A2 receptor (PLA2R), the target antigen in idiopathic membranous nephropathy (iMN), must be presented by the HLA-encoded MHC class II molecules to stimulate autoantibody production. A genome-wide association study identified risk alleles at HLA and PLA2R loci, with the top variant rs2187668 within HLA-DQA1 showing a risk effect greater than that of the top variant rs4664308 within PLA2R1. How the HLA risk alleles affect epitope presentation by MHC class II molecules in iMN is unknown. Here, we genotyped 261 patients with iMN and 599 healthy controls at the HLA-DRB1, HLA-DQA1, HLA-DQB1, and HLA-DPB1 loci with four-digit resolution and extracted the encoded amino acid sequences from the IMGT/HLA database. We predicted T cell epitopes of PLA2R and constructed MHC-DR molecule-PLA2R peptide-T cell receptor structures using Modeler. We identified DRB1*1501 (odds ratio, 4.65; 95% confidence interval [95% CI], 3.39 to 6.41; P<0.001) and DRB1*0301 (odds ratio, 3.96; 95% CI, 2.61 to 6.05; P<0.001) as independent risk alleles for iMN and associated with circulating anti-PLA2R antibodies. Strong gene-gene interaction was noted between rs4664308(AA) and HLA-DRB1*1501/DRB1*0301. Amino acid positions 13 (P<0.001) and 71 (P<0.001) in the MHC-DRβ1 chain independently associated with iMN. Structural models showed that arginine13 and alanine71, encoded by DRB1*1501, and lysine71, encoded by DRB1*0301, facilitate interactions with T cell epitopes of PLA2R. In conclusion, we identified two risk alleles of HLA class II genes and three amino acid residues on positions 13 and 71 of the MHC-DRβ1 chain that may confer susceptibility to iMN by presenting T cell epitopes on PLA2R.

Circulating Antibodies against Thrombospondin Type-I Domain-Containing 7A in Chinese Patients with Idiopathic Membranous Nephropathy

BACKGROUND AND OBJECTIVES Thrombospondin type-I domain-containing 7A (THSD7A) was recently identified as the target antigen in about 10% of patients with M-type phospholipase A2 receptor (PLA2R)-negative membranous nephropathy in European and North American populations. The prevalence of THSD7A in other populations and their clinical associations deserve further clarification. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Immunofluorescence assay was performed to investigate anti-THSD7A antibodies in 578 consecutive patients with biopsy-proven idiopathic membranous nephropathy, 114 patients with secondary membranous nephropathy, 64 disease controls, and 20 healthy controls. Glomerular expression of THSD7A antigen was examined by immunohistochemistry. Anti-PLA2R antibodies and glomerular PLA2R expression were also screened. RESULTS Among the 578 patients with idiopathic membranous nephropathy, 12 (2%) patients were identified as THSD7A-positive: ten patients were THSD7A-positive alone, which accounted for 16% (ten of 64) of PLA2R-negative patients; two patients were dual-positive for both anti-THSD7A and anti-PLA2R antibodies and showed enhanced expression of both antigens colocalized in glomeruli. Among the 114 patients with secondary membranous nephropathy, one among 44 (2%) patients with cancer had anti-THSD7A antibodies, whereas 18 of 44 (41%) had anti-PLA2R antibodies. No anti-THSD7A antibody was detected in other disease controls or healthy individuals. Clinical features were comparable between the patients with and without THSD7A. During follow-up, two patients who achieved remission had a clearance of circulating antibodies against THSD7A, whereas antibodies increased in parallel with proteinuria in a patient with a relapse. CONCLUSIONS THSD7A-associated membranous nephropathy has a low prevalence in Chinese patients. The double-positive patients suggest dual autoimmune responses.

Clinical Significance of IgM and C3 Glomerular Deposition in Primary Focal Segmental Glomerulosclerosis

BACKGROUND AND OBJECTIVES Glomerular IgM deposition is commonly shown in primary FSGS and sometimes accompanied by C3 deposition. Clinical presentation and treatment outcomes of these patients are not investigated in detail. DESIGN, SETTING, PARTICIPANTS, &MEASUREMENTS One hundred six consecutive patients with biopsy-proven primary FSGS from 2004 to 2014 were enrolled retrospectively. Clinical features and treatment outcomes were compared between patients with and without IgM/C3 deposition. RESULTS Fifty-eight (54.7%) patients presented with IgM glomerular deposition on sclerotic segments. C3 and C1q depositions were shown exclusively in patients with IgM deposition (34.5% versus 0.0%; P<0.001 and 8.6% versus 0.0%; P=0.04, respectively). Patients with IgM deposition were younger (median; range: 24.5; 18.8-39.0 versus 46.5; 26.0-64.0 years old; P=0.001), had higher level of serum IgM (142.5; 96.3-206.0 versus 107.0; 71.0-140.0 mg/dl; P=0.01), and had higher level of eGFR (median; range 97.7; 48.0-135.8 versus 62.1; 33.7-93.9 ml/min per 1.73 m(2); P=0.01) at the time of kidney biopsy. The percentage of sclerosis lesions was significantly higher in patients with C3 deposition (median; range: 21.7%; 15.3%-31.1% versus 9.2%; 6.6%-20.0%; P=0.002). Although patients received comparable immunosuppressive treatments during 58.9 (29.5-81.1) months of follow-up, a significantly higher prevalence of refractory cases (no response or steroid dependent) occurred in patients with combined IgM and C3 deposition compared with patients with IgM deposition alone or without IgM deposition (58.8% versus 22.2% versus 15.6%, respectively; P=0.004). Multivariate analysis identified combined IgM and C3 deposition (odds ratio, 11.32; 95% confidence interval, 2.26 to 56.65; P=0.003) as an independent risk factor for refractory patients; 19 of 98 patients developed renal dysfunction when their serum creatinine levels increased >30% from baseline and reached >1.5 mg/dl. Combined IgM and C3 deposition (hazard ratio, 5.67; 95% confidence interval, 1.34 to 23.84; P=0.02) was identified as an independent risk factor for renal dysfunction. CONCLUSIONS Patients with primary FSGS and IgM and C3 deposition showed unfavorable therapeutic responses and worse renal outcomes, which indicate that IgM and C3 deposition might involve disease progression via complement activation.

Ultrastructural changes of podocyte foot processes during the remission phase of minimal change disease of human kidney

The current study was designed to observe the ultrastructural changes of podocyte foot processes during the remission phase and its relationship with the amount of the proteinuria in patients with minimal change disease (MCD).

Low-Dose Cyclosporine Treatment in Chinese Nephrotic Patients With Idiopathic Membranous Nephropathy: An Uncontrolled Study With Prospective Follow-up

Introduction:The optimal dose of cyclosporine A (CsA) in treatment of nephrotic proteinuria in idiopathic membranous nephropathy (IMN) remains inconclusive. We evaluated the efficacy and safety of low-dose CsA combined with low-dose prednisone as induction therapy for Chinese nephrotic patients with IMN. Methods:We conducted a prospective observational cohort study in 18 patients with IMN and nephrotic proteinuria. Twelve patients were refractory to other immunosuppressive therapies. The initial dose of CsA was 1 to 1.5 mg/kg/d combined with 0.15 to 0.50 mg/kg/d prednisone. The dose of CsA was adjusted monthly by 20% to 30% according to efficacy and the 12-hour trough blood concentration (C0) of CsA around 100 ng/mL for 6 months; when proteinuria was <1 g/d, CsA was tapered gradually to a dose of 0.6 to 1 mg/kg/d. Results:Two patients discontinued CsA because of refractory hypertension. The remaining 16 patients had been followed up for 44 ± 15 weeks. Remission was observed in 11 patients (68.8%: complete remission, 6 and partial remission, 5). The effective dose of CsA for remission was 2.1 ± 0.4 (1.5–2.5) mg/kg/d, and the mean C0 of CsA was 92.5 ± 23.5 (58–124) ng/mL. All the 16 patients experienced well-controlled adverse effects, including hypertension (n = 12), hyperuricemia (n = 12), increase of serum creatinine (n = 2), etc. Conclusions:Low-dose CsA combined with low-dose prednisone was effective and safe as induction therapy in majority of Chinese nephrotic patients with IMN, including those refractory to other immunosuppressive regimens.

Clinical Features and Outcomes in Patients With Membranous Nephropathy and Crescent Formation.

AbstractCases of membranous nephropathy (MN) with crescent formation, in the absence of lupus, hepatitis B virus infection, anti-glomerular basement membrane (GBM) nephritis, or antineutrophil cytoplasmic antibody (ANCA), are on record. Clinical presentation and treatment outcomes in these patients are unclear.All patients with biopsy-proven MN diagnosed between years 2008 and 2014 and followed up were enrolled retrospectively. Patients with ANCA, anti-GBM antibodies, lupus, hepatitis B virus infection, or malignance were excluded. Clinical features and outcomes were compared between MN patients with and without crescent.Out of 401 consecutive patients with idiopathic MN, 28 (6.9%) showed crescent formation in 4.9% (2.2%–16.7%) of glomeruli. Mean age of these patients was 50.1 ± 11.1 years, and they presented with heavy proteinuria (6.5 ± 4.8 g/24 h) and hematuria; 21.4% of these patients had declined estimated glomerular filtration rate (<60 mL/min/1.73 m2) on biopsy. Anti-phospholipase A2 receptor antibody was detectable in 79.7% of these patients. These clinical features were comparable to the MN patients without crescent (P > 0.05). Twelve (42.9%) patients received steroids plus immunosuppressive therapy similar to that in patients without crescent (41.3%). Fewer patients with crescents achieved remission (67.9% vs 86.7%, P = 0.029). Crescent formation was a risk factor for no response to the treatments (odds ratio [OR] = 3.1, P = 0.033). Higher percentage of crescents predicted more risk for no remission (OR = 1.2, P = 0.038). Patients with crescents presented more frequencies of abnormal serum creatinine during follow-up (10.7% vs 1.3%, P = 0.031). Crescent formation was also a risk factor for worse renal outcome (relative risk = 10.2, P = 0.046).MN patients with crescents showed unfavorable therapeutic response and tended to have worse renal outcomes. More aggressive treatments and renal protection might be considered to improve the outcomes.

Efficacy and safety of leflunomide in treatment of steroid-dependent and steroid-resistant adult onset minimal change disease.

OBJECTIVE To observe the efficacy and safety of leflunomide combined with prednisone therapy (LEF therapy) in the treatment of patients with adult onset steroid-dependent and steroid-resistant minimal change disease (MCD). METHODS 16 MCD patients who had been treated with LEF therapy were retrospectively analyzed. 87.5% (14/16) of the patients were steroid-dependent and 12.5% (2/16) of the patients were steroid-resistant. The initial dose of LEF was 10 - 20 mg/day combined with prednisone 0.25 - 1.0 mg/kg/day, gradually tapering after 8 weeks. Clinical and laboratory data at baseline, 2nd, 4th, 8th, 12th, 24th, and 48th week were analyzed compared with initial course of prednisone monotherapy (PRED monotherapy) and cyclophosphamide combined with prednisone therapy (CTX therapy). RESULTS All the 16 patients achieved different levels of remission in LEF therapy. 93.8% (15/16) of the patients, including the two steroid-resistant patients, achieved complete remission. During the treatment, 8 patients had adverse effects which could be well tolerated. Compared LEF therapy with PRED monotherapy (n = 16), the dose of prednisone to maintain remission was reduced (from median 22.5 mg/day to median 7.5 mg/day, p = 0.041); relapse rate during the follow-up decreased from 100% to 31.3% (p = 0.002); the median time before relapse increased from 20.3 weeks to 32.5 weeks. Compared LEF therapy with CTX therapy (n = 12), the dose of prednisone to maintain remission was reduced significantly (from median 22.5 mg/day to median 5.0 mg/day, p = 0.003); relapse rate during the follow-up decreased from 100% to 31.3% (p = 0.001); the median time before relapse increased from 11.7 weeks to 32.5 weeks. CONCLUSIONS LEF therapy seems to be effective in steroid-resistant and steroiddependent MCD. This therapy may reduce the amount of prednisone to maintain remission and reduce the relapse rate compared with PRED monothrerapy and CTX therapy. LEF therapy was usually well tolerated.