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.
Autoantibodies ; Glomerulonephritis, Membranous ; Humans ; Immunohistochemistry ; Receptors, Phospholipase A2 ; Thrombospondins

OBJECTIVETo evaluate the application of immunohistochemistry and fluorescence staining method in the detection of phospholipase A2 receptor (PLA2R) on paraffin section of renal biopsy tissue,and to find an accurate and fast method for the detection of PLA2R in renal tissue.

METHODSThe PLA2R of 193 cases were detected by immunohistochemical staining,and the antigen was repaired by the method of high pressure cooker (HPC) hot repair plus trypsin repair. The 193 samples including 139 cases of idiopathic membranous nephropathy (IMN), 15 cases of membranous lupus nephritis, 8 cases of hepatitis B virus associated membranous nephropathy, 18 cases of IgA nephropathy, and 13 cases of minimal change diseases. To compare the dyeing effects, 22 paraffin sections of renal biopsy tissue of IMN cases with positive PLA2R were stained by using 4 different.

METHODSof antigen repairing,which included HPC hot repair, HPC hot repair plus trypsin repair, water bath heat repair, and water bath heat repair plus trypsin repair. To compare the dyeing effects, 15 paraffin sections of renal biopsy tissue of IMN cases with positive PLA2R were stained by using 3 different.

METHODSof antigen repairing,which included water bath heat repair plus trypsin repair, protease K digestion repair, and pepsin digestion repair.

RESULTSIn 193 cases, the positive rate of PLA2R in IMN cases was 90.6% (126/139), and the other 54 patients without IMN were negative. Twenty-two IMN patients were positive for PLA2R by using the HPC heat repair plus trypsin repaire or the water bath heat repair plus trypsin repair;while only a few cases of 22 IMN cases were positive by using the HPC hot repair alone or water bath heat repair alone. Fifteen IMN patients were positive for PLA2R by using water bath heat repair plus trypsin repair,protease K digestion repair,and pepsin digestion repair, but the distribution of positive deposits and the background were different.

CONCLUSIONSPLA2R immunohistochemical staining can effectively identify IMN and secondary MN. For immunohistochemical staining and immunofluorescence staining, the preferred method of antigen repair is water bath heat repair plus trypsin repair.

Fluorescent Antibody Technique ; Glomerulonephritis, IGA ; Glomerulonephritis, Membranous ; Humans ; Immunohistochemistry ; Paraffin ; Receptors, Phospholipase A2 ; Staining and Labeling

OBJECTIVETo highlight current knowledge about M-type phospholipase A2 receptor (PLA2R) which is the first human autoantigen discovered in adult idiopathic membranous nephropathy.

DATA SOURCESRelevant articles published in English from 2000 to present were selected from PubMed. Searches were made using the terms "idiopathic membranous nephropathy, M-type PLA2R and podocyte."

STUDY SELECTIONArticles studying the role of M-type PLA2R in idiopathic membranous nephropathy were reviewed. Articles focusing on the discovery, detection and clinical observation of anti-PLA2R antibodies were selected.

RESULTSM-type PLA2R is a member of the mannose receptor family of proteins, locating on normal human glomeruli as a transmembrane receptor. The anti-PLA2R in serum samples from MN were primarily IgG4 subclass. Technologies applied to detect anti-PLA2R autoantibody are mainly WB, IIFT, ELISA and so on. Studies from domestic and overseas have identified a strongly relationship between circulating anti-PLA2R levels and disease activity.

CONCLUSIONRecent discoveries corresponding to PLA2R facilitate a better understanding on IMN pathogenesis and may provide a new tool to its diagnosis, differential diagnosis, risk evaluation, response monitoring and patient-specific treatment.

Animals ; Autoantigens ; metabolism ; Glomerulonephritis, Membranous ; immunology ; metabolism ; Humans ; Podocytes ; metabolism ; Receptors, Phospholipase A2 ; metabolism

Objective To investigate the feasibility of IgG4 as a biomarker of the activity and outcome of phospholipase A2 receptor (PLA2R)-associated membranous nephropathy (PLA2R-MN). Methods Serum and urine samples were collected from 56 patients with PLA2R-MN,13 patients with secondary membranous nephropathy (SMN),and 10 patients with primary IgA nephropathy (IgAN) when kidney biopsy was performed in the Department of Nephrology,Hangzhou Hospital of Traditional Chinese Medicine from April 2017 to January 2018.Sandwich enzyme-linked immunosorbent assay was employed to measure the serum and urinary IgG4 levels. Results The PLA2R-MN group had higher median serum IgG4/IgG ratio than the SMN group (P=0.009) and the IgAN group (P<0.001) and higher median urinary IgG4/creatinine ratio than the SMN group (P=0.008).In the patients with PLA2R-MN,the median serum IgG4/IgG ratio and urinary IgG4/creatinine ratio were significantly higher in the renal insufficiency group than in the normal renal function group (P=0.049,P=0.015).Moreover,the median serum IgG4/IgG ratio was higher in those with a serum albumin level<30 g/L than in those with a serum albumin level ≥30 g/L (P=0.005).Fifty-three patients with PLA2R-MN were followed up for at least 1 year,and the serum IgG4/IgG ratios of the patients in remission were lower than those of the patients without remission (P=0.005).The median serum IgG4/IgG ratio of 23 patients in remission decreased from 5.82% (4.54%,10.20%)(at initial enrollment) to 2.91% (2.11%,5.37%)(after 1-year follow up) in remission patients (P<0.001).The receiver operating characteristic curve showed that the patients with a serum IgG4/IgG ratio<10.24% had a higher possibility of remission (P=0.005). Conclusion Serum and urinary IgG4 levels may be an indicator of the activity in PLA2R-MN patients and thus may be a predictive biomarker of the outcomes.
Biomarkers ; Creatinine ; Glomerulonephritis, Membranous/pathology* ; Humans ; Immunoglobulin G ; Receptors, Phospholipase A2 ; Serum Albumin

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.
Humans ; Autoantibodies ; Clinical Relevance ; Colonic Neoplasms ; EGF Family of Proteins ; Glomerulonephritis, Membranous/diagnosis* ; Nephrotic Syndrome ; Receptors, Phospholipase A2/metabolism* ; Thrombospondins/metabolism*

OBJECTIVETo investigate the prevalence of PLA2R1 in renal biopsy specimens of patients with idiopathic membranous nephropathy (IMN) and explore the relationship between PLA2R1 and IMN.

METHODSA total of 108 adult patients with biopsy-proved glomerular diseases were enrolled in this study, including 41 with IMN, 2 with hepatitis B-associated membranous nephropathy, 8 with V lupus nephritis, 27 with IgA nephropathy, 19 with minimal change nephropathy, 5 with mild mesangial proliferative glomerulonephritis, and 6 with focal segmental glomeruloselerosis (FSGS). Indirect immunofluorescence assay was used to detect PLA2R1 in the biopsy specimens and the clinical variables of the IMN patients were analyzed.

RESULTSIn 35 of the 41 (85.37%) patients with IMN, PLA2R1 was detected with a fine granular pattern in the subepithelial deposits along the glomerular capillary loops. PLA2R1 antigen was not detected in patients with other glomerulopathies. No significant differences were found in age, serum creatinine, serum albumin, or 24-h urinary protein level between PLA2R1-positive and negative patients with IMN (P>0.05).

CONCLUSIONAccording to our results, 85.37% of adult patients with biopsy-proven IMN are positive for PLA2R1 antigen, which, however, does not contribute to variations of the patients' clinical manifestations.

Adult ; Biopsy ; Glomerulonephritis, Membranous ; metabolism ; Humans ; Kidney ; metabolism ; pathology ; Kidney Function Tests ; Kidney Glomerulus ; pathology ; Nephrosis, Lipoid ; metabolism ; Receptors, Phospholipase A2 ; metabolism

Angiopoietin-like 4 Protein ; Angiopoietins ; analysis ; blood ; urine ; Antibodies ; analysis ; blood ; urine ; Disease Progression ; Glomerulonephritis, Membranous ; diagnosis ; metabolism ; Humans ; Receptors, Phospholipase A2 ; immunology

BACKGROUNDAccording to the renal phospholipase A2 receptor (PLA2R) immunohistochemistry, idiopathic membranous nephropathy (iMN) could be categorized into PLA2R-associated and non-PLA2R-associated iMN. This study aimed to examine whether the non-PLA2R-associated iMN had any difference in clinical features compared with PLA2R-associated iMN.

METHODSA total of 231 adult patients diagnosed as iMN were recruited to this retrospective study. Renal PLA2R expression was examined by immunofluorescence. Among these patients, 186 (80.5%) with complete baseline clinical data were used for further study. Urinary protein excretion, serum albumin, and creatinine were analyzed. For those patients with follow-up longer than 1 year, the relationship between PLA2R and response to immunosuppressants were analyzed. The t-test was used for parametric analysis and the Mann-Whitney U-test was used for nonparametric analysis. Categorical variables were described as frequencies or percentages, and the data were analyzed with Pearson's Chi-square test or Fisher's exact test.

RESULTSOf the 231 iMN patients, 189 showed renal detectable PLA2R expression (81.8%). The baseline serum creatinine, serum albumin, and urine protein excretion were not significantly different between PLA2R-associated (n = 145) and non-PLA2R-associated iMN patients (n = 41). However, about 1/3 of the non-PLA2R-associated iMN had abnormal serological tests, significantly more common than PLA2R-associated iMN (31.7% vs. 8.3%, P = 0.000). The non-PLA2R-associated iMN had lower C4 levels compared with PLA2R-associated iMN (P = 0.004). The non-PLA2R-associated iMN patients also showed a better response to immunosuppressants (complete remission [CR] 42.9%; partial remission [PR] 14.3%) compared with PLA2R-associated iMN (CR 3.2%; PR 48.4%, P = 0.004) at the 3rd month.

CONCLUSIONSThere were no significant differences in serum creatinine, albumin, and urine protein excretion between PLA2R-associated and non-PLA2R-associated iMN, while the non-PLA2R-associated iMN patients showed more abnormal serological tests. The non-PLA2R-associated iMN seemed to respond more quickly to the immunosuppressive therapy compared with PLA2R-associated iMN.

Adult ; Autoantibodies ; metabolism ; Female ; Glomerulonephritis, Membranous ; drug therapy ; metabolism ; pathology ; urine ; Humans ; Immunosuppressive Agents ; therapeutic use ; Kidney ; metabolism ; pathology ; Male ; Middle Aged ; Receptors, Phospholipase A2 ; metabolism ; Retrospective Studies

BACKGROUND: Phospholipase A2 receptor (PLA2R) has been identified as a major autoantigen in primary membranous nephropathy (MN). We evaluated the association between anti-PLA2R antibodies and clinical outcome in Korean patients with primary MN. METHODS: A total of 66 patients with biopsy-proven MN were included. Serum level of anti-PLA2R antibodies was measured by enzyme-linked immunosorbent assay. Biochemical parameters were estimated initially and at follow-up. RESULTS: Anti-PLA2R antibodies were detected in 52.1% and 27.8% of patients with primary and secondary MN, respectively. Forty-eight patients with primary MN were grouped based on presence or absence of anti-PLA2R antibodies. Proteinuria was more severe in anti-PLA2R-positive patients than in anti-PLA2R-negative patients (urine protein/creatinine ratio 7.922 ± 3.985 g/g vs. 4.318 ± 3.304 g/g, P = 0.001), and anti-PLA2R antibody level was positively correlated with proteinuria. The incidence of chronic kidney disease stage ≥ 3 was higher in anti-PLA2R-positive patients compared with anti-PLA2R-negative patients (P = 0.004). The probabilities of spontaneous remission were higher in anti-PLA2R-negative patients compared with anti-PLA2R-positive patients (P < 0.001). Multivariate analysis demonstrated that anti-PLA2R antibodies are an independent risk factor for developing chronic kidney disease stage ≥ 3 and for not reaching spontaneous remission. CONCLUSION: Detection of anti-PLA2R antibodies at diagnosis in patients with primary MN can predict prognosis and guide treatment decisions.
Antibodies ; Diagnosis ; Enzyme-Linked Immunosorbent Assay ; Follow-Up Studies ; Glomerulonephritis, Membranous* ; Humans ; Incidence ; Multivariate Analysis ; Prognosis ; Proteinuria ; Receptors, Phospholipase A2 ; Remission, Spontaneous ; Renal Insufficiency, Chronic ; Risk Factors

OBJECTIVE: To evaluate the value of pharmacogenetic testing for improving the efficacy and safety of treatment with cyclosporine, tacrolimus, and cyclophosphamide (CTX) for PLA2R-related membranous nephropathy and for determing individualized and precise treatment plans for the patients. METHODS: A total of 63 patients with PLA2R-related membranous nephropathy hospitalized in the Department of Nephrology at our hospital from January, 2019 to October, 2021 were enrolled in this study. Thirty-three of the patients underwent pharmacogenetic testing before taking the immunosuppressive drugs selected based on the results of genetic screening for sensitive targets, and the other 30 patients were empirically given immunosuppressive drugs according to the guidelines (control group). The clinical efficacy and adverse effects of the immunosuppressive drugs were analyzed for all the patients. The two groups of patients were compared for demographic and biochemical parameters including 24-h urine protein, serum albumin, renal function, and serum anti-phospholipase A2 receptor antibody both before and at 3 months after the beginning of the treatment. RESULTS: Among the 33 patients undergoing pharmacogenetic testing, 51.5% showed a GG genotype for cyclosporine, and 61.6% had an AG genotype for tacrolimus; for CTX, 51.5% of the patients showed a homozygous deletion and 63.6% had an AA genotype. After treatment for 3 months, serum anti-phospholipase A2 receptor antibody, 24-h urine protein, and serum albumin levels were significantly improved in pharmacogenetic testing group as compared with the control group (P < 0.05). CONCLUSION Individualized and precise administration of immunosuppressive drugs based on pharmacogenetic testing better controls proteinuria and serum antiphospholipase A2 receptor antibodies and increases serum albumin level in patients with PLA2R-related membranous nephropathy.
Humans ; Autoantibodies ; Cyclosporine/therapeutic use* ; Glomerulonephritis, Membranous/diagnosis* ; Homozygote ; Immunosuppressive Agents/therapeutic use* ; Pharmacogenomic Testing ; Receptors, Phospholipase A2 ; Sequence Deletion ; Serum Albumin ; Tacrolimus/therapeutic use*