Clinical Significance of Thrombospondin Type 1 Domain-Containing 7A and Neural Epidermal Growth Factor-Like 1 Protein in M-Type Phospholipase A2 Receptor-Negative Membranous Nephropathy / 中国医学科学院学报

Objective To investigate the clinical significance of thrombospondin type 1 domain-containing 7A (THSD7A) and neural epidermal growth factor-like 1 protein (NELL1) in phospholipase A2 receptor (PLA2R)-negative membranous nephropathy (MN). Methods A total of 116 PLA2R-negative MN patients treated in Hangzhou TCM Hospital Affiliated to Zhejiang Chinese Medical University from 2014 to 2021 were enrolled in this study.Immunohistochemistry was employed to detect THSD7A and NELL1 in the renal tissue.The pathological characteristics,treatment,and prognosis were compared between positive and negative groups. Results The 116 PLA2R-negative MN patients included 23 THSD7A-positive patients and 9 NELL1-positive patients.One patient was tested positive for both proteins.The THSD7A-positive group showed higher positive rate of IgG4 (P=0.010),more obvious glomerular basement membrane (GBM) thickening (P=0.034),and higher proportion of stage Ⅱ MN and lower proportion of stage I MN (P=0.002) than the THSD7A-negative group.The NELL1-positive group had lower positive rates of C1q and IgG2 (P=0.029,P=0.001),less obvious GBM thickening (P<0.001),more extensive inflammatory cell infiltration (P=0.033),lower proportion of deposits on multi-locations (P=0.001),and lower proportion of atypical MN (P=0.010) than the NELL1-negative group.One patient with THSD7A-positive MN was diagnosed with colon cancer,while none of the NELL1-positive patients had malignancy.Survival analysis suggested that THSD7A-positive MN had worse composite remission (either complete remission or partial remission) of nephrotic syndrome than the negative group (P=0.016),whereas NELL1-positive MN exhibited better composite remission of nephrotic syndrome than the negative group (P=0.015).The MN patients only positive for NELL1 showed better composite remission of nephrotic syndrome than the MN patients only positive for THSD7A (P<0.001). Conclusions THSD7A- and NELL1-positive MN is more likely to be primary MN,and there is no significant malignancy indication.However,it might have a predictive value for the prognosis of MN.

The 493th case: recurrent edema of bilateral lower extremeties / 中华内科杂志

A 43-year-old male patient with onset of edema caused by nephrotic proteinuria and low titer of anti-M type phospholipase-A 2-receptor (PLA 2R) antibody was diagnosed as idiopathic membranous nephropathy by renal biopsy. Administrated with prednisone 40 mg once a day and cyclosporine 100 mg twice a day as front-line regimen, the patient relapsed after transient partial remission. When treatment was combined with cyclophosphamide 100 mg once a day, the 24-hour total urine protein and titer of anti-PLA 2R antibody were even elevated. Therefore, the patient received rituximab 1 g intravenously in April 2019, October 2019 and October 2020 respectively. CD19 positive B lymphocytes in peripheral blood were eliminated from 71/μl to zero. Immunosuppressants and corticosteroids were withdrawn successively. On the last follow-up in November 2020, the anti-PLA 2R antibody was negative, and the 24-hour total urine protein and serum albumin was 4.4 g and 34 g/L, respectively. This case suggested the potential efficacy of rituximab for refractory membranous nephropathy. Further studies should explore whether the titer of anti-PLA 2R antibody indicates the dose of rituximab.

Clinical features and prognostic analysis of primary membranous nephropathy in children with positive glomerular M-type phospholipase A2 receptor / 中华实用儿科临床杂志

Objective:To analyze the clinical and prognosis of primary membranous nephropathy (PMN) in children with positive glomerular M-type phospholipase A2 receptor (PLA2R).Methods:A total of 69 children diagnosed with PMN by renal biopsy admitted to the Department of Pediatrics of Eastern Theater Command General Hospital from January 2006 to December 2018 were retrospectively analyzed, including 40 males and 29 females, with an average age of 14.86 years.According to the immunofluorescence of renal pathology, they were divided into PLA2R positive group and PLA2R negative group.Pathological features between 2 groups were compared by the t test, Mann- Whitney U test and Chi- square test.Kaplan-Meier method was used to compare the long-term renal survival rate and cumulative remission rate between 2 groups. Results:A total of 69 pediatric PMN patients were included.The po-sitive rates of serum anti-PLA2R antibody and positive expression of PLA2R in renal tissues were 53.6% (37 cases) and 82.6% (57 cases), respectively.The proportion of children with clinical manifestations of large proteinuria [55 cases(96.5% ) vs.9 cases(75.0%), P=0.034] was significantly higher in the PLA2R positive group than that of the PLA2R negative group.Blood urea nitrogen level was significantly higher in the PLA2R positive group than that of PLA2R negative group[1.14(0.93, 1.54) mg/L vs.0.80 (0.44, 1.18) mg/L, P=0.049], while estimate glomerular filtration rate(eGFR) [162.26 (139.81, 185.53) mL/(min·1.73 m 2) vs.199.52 (157.58, 212.01) mL/(min·1.73 m 2), P=0.034] and serum IgG [3.58 (2.50, 5.43) g/L vs.5.14 (4.35, 6.03) g/L, P=0.016] were significantly lower.The cumulative remission rate was significantly higher in the PLA2R negative group than that of PLA2R positive group ( P<0.001). The 24 h urinary protein ≥50 mg/kg ( HR=0.119, 95% CI: 0.021-0.595, P=0.010)was an independent risk factor for renal prognosis, and PLA2R( HR=0.263, 95% CI: 0.125-0.551, P<0.001) and 24 h urinary protein ≥50 mg/kg ( HR=0.568, 95% CI: 0.125-0.551, P=0.041)were independent predictors of urinary protein remission.PLA2R ( HR=1.020, 95% CI: 0.698-1.682, P=0.656)was not associated with renal prognosis. Conclusions:The severity of PMN in children with positive PLA2R was higher than that in those with negative PLA2R.The long-term cumulative remission rate of PLA2R negative children with PMN was higher than that of PLA2R positive children.

Clinical significance of Mtype phospholipase A2 receptor and thrombospondin Type 1 domaincontaining 7A in primary membranous nephropathy / 中南大学学报(医学版)

OBJECTIVES@#To evaluate the value of thrombospond in Type I domain-containing 7A (THSD7A) and M-type phospholipase A2 receptor (PLA2R) in primary membranous nephropathy (PMN) and to explore the relationship between their antibody levels and prognosis.@*METHODS@#Renal tissues in 128 patients with membranous nephropathy in the Second Xiangya Hospital of Central South University were collected from February 2015 to August 2017, including 108 patients with primary membranous nephropathy (PMN group) and 20 patients with secondary membranous nephropathy (SMN) (SMN group). Indirect immunofluorescence method was used to detect the expression of PLA2R antigen in kidney tissues,and the glomerular expression of THSD7A antigen was examined by immunohistochemistry and indirect immunofluorescence. The serum levels of anti-PLA2R antibodies and THSD7A antibodies were also detected by ELISA. According to the results of PMN examination,the patients were also divided into a PLA2R-related membranous nephropathy group and a THSD7A-related membranous nephropathy group.@*RESULTS@#The positive rate of PLA2R in the renal tissues in the PMN group was higher than that in the SMN group (78% in the PMN group, 35% in the SMN group, <0.01),while the positive rate of anti-PLA2R antibody in the PMN group was also higher than that in the SMN group (50% in the PMN group, 25% in the SMN group, <0.05).The serum level of anti-PLA2R antibody was positively correlated with 24 h urine protein (=0.254, <0.05) and negatively correlated with serum albumin (=-0.236, <0.05). The expression of THSD7A was positive in glomeruli in 7 cases of the PMN group (6%) by immuno-histochemistry, and which was positive in 1case of the SMN group (5%).The serum levels of anti-THSD7A antibody in the PMN group were higher than those in the SMN group [(0.49±0.26) pg/mL in the PMN group,(0.34±0.27) pg/mL in the SMN group, <0.05]. There was no difference in the clinical characteristics between the PLA2R-related membranous nephropathy group and the THSD7A-related membranous nephropathy group.@*CONCLUSIONS@#PLA2R and THSD7A are the target antigen of PMN, and the associated autoantibodies are helpful for the differential diagnosis of PMN. The anti-PLA2R antibody levels can reflect the severity of the disease and evaluate the effect of treatment. The incidence of THSD7A membranous nephropathy is low, and monitoring the serum anti-THSD7A antibody levels can assess patients' condition and predict disease outcome.

Clinical application of homemade ELISA kit for anti-human phospholipase A2 receptor antibody / 生物工程学报

To develop and evaluate an ELISA kit for Anti-PLA2R IgG. Recombinant M-type phospholipase A2 receptor (PLA2R) protein expressed in HEK293 was taken as coating antigen, HRP-labeled rabbit anti-human IgG was taken as a tracer, to test the anti-PLA2R IgG on the basis of the principle of ELISA. The detection linear range, accuracy, linear correlation, repeatability, and stability were evaluated. In addition, we made a comparison with enrolled anti-PLA2R IgG kit. The detection linear range of the kit is no more than 2 RU/mL. The relative deviation of the kit accuracy is in -15%-15%. There is a linear correlation coefficient of higher than 0.990 0 within 2-500 RU/mL range. The CV of the repeatable test is lower than 15% when the kit was put in 37 ℃ one week, 2-8 ℃ one year, the performance remains. The consistency of testing with comparison in enrolled anti-PLA2R IgG kit is 98.9% (positive: 97.2%, negative: 100%). The Anti-PLA2R IgG ELISA Kit which we developed is nearly identical to the reference standard in specific and sensitive of clinics. It's successfully used to determine anti-PLA2R titer and help clinical diagnosis.

Diagnostic value of renal phospholipase A2 receptor and serum anti-phospholipase A2 receptor antibody in membranous nephropathy / 中南大学学报(医学版)

Objective:To examine the expression ofphospholipase A2 receptor (PLA2R) in renal tissues and the level of anti-PLA2R antibody in serum in patients with idiopathic membranous nephropathy (IMN) and secondary membranous nephropathy (SMN),and to evaluate their diagnostic value in IMN.Methods:A total of 73 patients,who were diagnosed between May,2014 and February,2015 in the Department of Nephrology of the Second Xiangya Hospital,Central South University,were divided into three groups:an IMN group (n=48),an SMN group (n=17) and a minimal change disease group (n=8) according to the renal biopsy.PLA2R expression in renal tissues and the level of antiPLA2R antibody in serum were detected by indirect immunofluorescence technique.Results:The positive rate and fluorescence intensity for PLA2R in the renal tissues in the IMN group were higher than those in the SMN group (91.7％ in the IMN group vs 29.4％ in the SMN group,P＜0.05),while the positive rate and serum level for anti-PLA2R antibody in the IMN group were higher than those in the SMN group (85.4％ in the IMN group vs 29.4％ in the SMN group,P＜0.05);the expression of PLA2R in renal tissues and the serum level for anti-PLA2R antibody were not detected in the minimal change disease group,The serum level of anti-PLA2R antibody was positively correlated with 24 h urine protein (r=0.432,P＜0.01) and negatively correlated with serum albumin (r=-0.307,P＜0.05).Conclusion:The expression of PLA2R in renal tissues and the serum level of anti-PLA2R antibody might be potential markers for diagnosis oflMN.

Expression difference of renal tissue M-type phospholipase A2 receptor 1 antigen and its antibody in patients with membranous nephropathy / 重庆医学

Objective To detect the expression levels of renal tissue M-type phospholipase A2 receptor 1(PLA2R1) antigen and its antibody in the patients with membranous nephropathy(MN).Methods Fifty-eight cases of biopsy-proved idiopathic membranous nephropathy(IMN),fifteen cases of hepatitis B-associated membranous nephropathy(HBV-MN) and seventeen cases of V type lupus nephritis(V-LN) were selected.Renal tissue PLA2R1 antigen was detected by indirect immunofluorescence and colocaliazed with IgG4.Serum anti-PLA2R1 antibody was simultaneously examined.The expression difference of PLA2R1 antigen and antiPLA2R1 antibody in MN was analyzed.And the differences of clinical data were analyzed between PLA2R1 positive and negative patients.Results The PLA2R1 antibody was not found in the renal tissue and serum of the patients with LN and HBV-MN;PLA2R1 antigen was found in 81.03％ of IMN patients,and its antibody was found in serum of 70.69％ of IMN patients.PLA2R1 antigen and IgG4 co-localization all deposited along glomerular capillary loop presenting as fine granules.The 24 h urine protein level in the patients with PLA2R1 antigen deposition in renal tissues was higher than that in the patients without PLA2R1 deposition (P＜0.05),moreover serum albumin level was lower than that in the patients without PLA2R1 deposition(P＜0.05).Conclusion The sensitivity and specificity of renal tissue PLA2R1 antigen in the diagnosis of IMN are higher.The expression of PLA2R1 antigen in renal tissue by biopsy is significantly correlated with the clinical severity.

The clinical value of plasma M type phospholipase A2 receptor antibody and IgG subtypes deposition in diagnosis of hepatitis B virus-associated membranous nephropathy / 国际检验医学杂志

Objective To investigate the different expressions of plasma M type phospholipase A2 receptor antibody and IgG subtypes deposition of kidney tissues in idiopathic membranous nephropathy and hepatitis B virus-associated membranous nephropa-thy,and to evaluate the significance of plasma M type phospholipase A2 receptor antibody and IgG subtypes in diagnosis of hepatitis B virus-associated membranous nephropathy.Methods Plasma samples were obtained from patients with idiopathic membranous nephropathy,hepatitis B virus-associated membranous nephropathy and minimal change disease,respectively,before immunosup-pressive therapy.Concentration of plasma M type phospholipase A2 receptor antibody was detected by sandwich ELISA and concen-tration of IgG subtypes were measured by immunofluorescence.Results Concentration of plasma M type phospholipase A2 receptor antibody was (15.4±7.2)μg/mL in idiopathic membranous nephropathy group,higher than that in the hepatitis B virus-associated membranous nephropathy group (10.3±5.7)μg/mL (P <0.01),between idiopathic membranous nephropathy group and hepatitis B virus-associated membranous nephropathy group.There was no distinct difference of IgG subtypes deposition in glomerlar capil-lary wall.Conclusion There is obvious clinical significance of concentration of plasma M type phospholipase A2 receptor antibody in differential diagnosis of idiopathic membranous nephropathy and hepatitis B virus-associated membranous nephropathy,while no distinct significance of IgG subtypes deposition.

Anti-PLA2R autoantibodies in serum and IgG subclass deposits on glomeruli in undetermined atypical membranous nephropathy / 中华肾脏病杂志

Objective To investigate the characteristic of autoantibodies of M-type phospholipase A2 receptor (PLA2R) in serum and the glomerular IgG subclass deposits in undetermined atypical membranous nephropathy (MN) patients.Methods From Feb 2004 to Nov 2011,53 cases diagnosed as MN by kidney puneture biopsy in our hospital were included into the study.There were 20 undetermined atypical membranous nephropathy (UAMN),20 idiopathic membranous nephropathy (IMN) and 13 secondary membranous nephropathy (SMN) which were composed of lupus membranous nephropathy (LMN) and HBV related membranous nephropathy (HBV-MN).Clinlical and pathological characteristics were analyzed.The autoantibodies of PLA2R in serum were detected and the glomerular IgG subclass deposits were observed.Results (1) The average age underwent renal biopsy was (37.9±3.8) years of UAMN,(50.1±3.0) years of IMN and (49.5±4.5) years of SMN.The difference in onset average age at disease was significant between UAMN and IMN (P =0.0178).The female/male ratio (F/M) in UAMN,IMN and SMN was 0.8∶ 1,0.7∶1 and 0.6∶ 1(P ＞ 0.05).(2) Compared with SMN,the level of 24-hours urinary protein excretion (3.47 g vs 7.89 g,P =0.023),the ratio of amount urinary protein patients (50.0％ vs 84.6％,P=0.043),the level of serum IgG [(8.40±3.58) g/L vs (10.09±4.69) g/L,P =0.025] and the positive rate of ANA in serum (10.0％ vs 53.8％,P =0.006) in UAMN were all much lower.There were no significant statistical differences in serum albumin,serum creatinine,eGFR,positive rate of HBsAg,HBeAg or HCV,as well as the ratio of hypo-albuminemia and nephrotic syndrome among the three groups.(3) IF positive rate of IgA,IgM and C1q in UAMN were all significantly higher than that in IMN (P ＜ 0.01).There were no significant differences in IF positive rate of IgA,IgM,C1q,IgG and C3 between UAMN and SMN.The IF strength of IgA,IgG,IgM,C3 and C1q in UAMN showed no significant differences between UAMN and SMN.(4) The serum autoantibodies of PLA2R were only detected in 10 cases of IMN group (50％) with all the other cases negative.This detection rate of serum autoantibodies of PLA2R showed significant statistical differences among the three groups (P ＜ 0.01),but no differences between UAMN and SMN (the detection rate in both groups were 0％).(5) IgG1 deposits was the dominant IgG on the glomeruli in UAMN group (40％),as well as in SMN group (76.9％).IgG4 deposits was the dominant IgG on the glomeruli in IMN group (60％).The positive rate of IgG1 and IgG3 in UAMN showed no significant statistical differences when compared with IMN or SMN.The positive rate of IgG2 in UAMN was significantly lower than in SMN (30.0％ vs 69.2％,P ＜ 0.05).The positive rate of IgG4 in UAMN was significantly lower than in IMN (20％ vs 60％,P ＜ 0.05).The positive rate of IgG1,IgG2 and IgG3 in SMN were all significantly higher than in IMN.Conclusions None of the UAMN group had autoantibodies of PLA2R in serum,and IgG1 deposits was the dominant IgG subclass on the glomeruli which indicated the similarity with the SMN group.At the same time,UAMN was significantly different from SMN in clinical manifestations.