Neural epidermal growth factor-like 1 protein (NELL-1) associated membranous nephropathy

Membranous nephropathy is characterized by deposition of immune complexes along the glomerular basement membrane. PLA2R and THSD7A are target antigens in 70% and 1-5% of primary membranous nephropathy cases, respectively. In the remaining cases, the target antigen is unknown. Here, laser microdissection of glomeruli followed by mass spectrometry was used to identify novel antigen(s) in PLA2R-negative membranous nephropathy. An initial pilot mass spectrometry study in 35 cases of PLA2R-negative membranous nephropathy showed high spectral counts for neural tissue encoding protein with EGF-like repeats, NELL-1, in six cases. Mass spectrometry failed to detect NELL-1 in 23 PLA2R-associated membranous nephropathy and 88 controls. NELL-1 was localized by immunohistochemistry, which showed bright granular glomerular basement membrane staining for NELL-1 in all six cases. Next, an additional 23 NELL-1 positive cases of membranous nephropathy were identified by immunohistochemistry in a discovery cohort of 91 PLA2R-negative membranous nephropathy cases, 14 were confirmed by mass spectrometry. Thus, 29 of 126 PLA2R-negative cases were positive for NELL-1. PLA2R-associated membranous nephropathy and controls stained negative for NELL-1. We then identified five NELL-1 positive cases of membranous nephropathy out of 84 PLA2R and THSD7A-negative cases in two validation cohorts from France and Belgium. By confocal microscopy, both IgG and NELL-1 co-localized to the glomerular basement membrane. Western blot analysis showed reactivity to NELL-1 in five available sera, but no reactivity in control sera. Clinical and biopsy findings of NELL-1 positive membranous nephropathy showed features of primary membranous nephropathy. Thus, a subset of membranous nephropathy is associated with accumulation and co-localization of NELL-1 and IgG along the glomerular basement membrane, and with anti-NELL-1 antibodies in the serum. Hence, NELL-1 defines a distinct type of primary membranous nephropathy. Membranous nephropathy is characterized by deposition of immune complexes along the glomerular basement membrane. PLA2R and THSD7A are target antigens in 70% and 1-5% of primary membranous nephropathy cases, respectively. In the remaining cases, the target antigen is unknown. Here, laser microdissection of glomeruli followed by mass spectrometry was used to identify novel antigen(s) in PLA2R-negative membranous nephropathy. An initial pilot mass spectrometry study in 35 cases of PLA2R-negative membranous nephropathy showed high spectral counts for neural tissue encoding protein with EGF-like repeats, NELL-1, in six cases. Mass spectrometry failed to detect NELL-1 in 23 PLA2R-associated membranous nephropathy and 88 controls. NELL-1 was localized by immunohistochemistry, which showed bright granular glomerular basement membrane staining for NELL-1 in all six cases. Next, an additional 23 NELL-1 positive cases of membranous nephropathy were identified by immunohistochemistry in a discovery cohort of 91 PLA2R-negative membranous nephropathy cases, 14 were confirmed by mass spectrometry. Thus, 29 of 126 PLA2R-negative cases were positive for NELL-1. PLA2R-associated membranous nephropathy and controls stained negative for NELL-1. We then identified five NELL-1 positive cases of membranous nephropathy out of 84 PLA2R and THSD7A-negative cases in two validation cohorts from France and Belgium. By confocal microscopy, both IgG and NELL-1 co-localized to the glomerular basement membrane. Western blot analysis showed reactivity to NELL-1 in five available sera, but no reactivity in control sera. Clinical and biopsy findings of NELL-1 positive membranous nephropathy showed features of primary membranous nephropathy. Thus, a subset of membranous nephropathy is associated with accumulation and co-localization of NELL-1 and IgG along the glomerular basement membrane, and with anti-NELL-1 antibodies in the serum. Hence, NELL-1 defines a distinct type of primary membranous nephropathy. see commentary on page 29 see commentary on page 29 Membranous nephropathy (MN) results from antibodies targeting an antigen in the glomerular basement membrane (GBM).1Beck Jr., L.H. Salant D.J. Membranous nephropathy: from models to man.J Clin Invest. 2014; 124: 2307-2314Crossref PubMed Scopus (109) Google Scholar, 2Ronco P. Debiec H. Pathophysiological advances in membranous nephropathy: time for a shift in patient's care.Lancet. 2015; 385: 1983-1992Abstract Full Text Full Text PDF PubMed Scopus (194) Google Scholar, 3Couser W.G. Primary membranous nephropathy.Clin J Am Soc Nephrol. 2017; 12: 983-997Crossref PubMed Scopus (245) Google Scholar The target antigen has been identified as M-type phospholipase A2 receptor (PLA2R) and thrombospondin type-1 domain-containing 7A (THSD7A) in approximately 70% and 1% to 5% of primary MN, respectively.4Beck Jr., L.H. Bonegio R.G. Lambeau G. et al.M-type phospholipase A2 receptor as target antigen in idiopathic membranous nephropathy.N Engl J Med. 2009; 361: 11-21Crossref PubMed Scopus (1419) Google Scholar, 5Tomas N.M. Hoxha E. Reinicke A.T. et al.Autoantibodies against thrombospondin type 1 domain-containing 7A induce membranous nephropathy.J Clin Invest. 2016; 126: 2519-2532Crossref PubMed Scopus (127) Google Scholar, 6Tomas N.M. Beck L.H. Meyer-Schwesinger C. et al.Thrombospondin type-1 domain-containing 7A in idiopathic membranous nephropathy.N Engl J Med. 2014; 371: 2277-2287Crossref PubMed Scopus (496) Google Scholar The target antigen(s) in the remaining PLA2R- and THSD7A-negative primary MN has remained elusive. The aim of this study was to identify an antigen(s) in the remaining primary MN. We used the novel methodology of laser microdissection and mass spectrometry to identify the major proteins in MN followed by immunostaining to localize and characterize the unique proteins. In the first step, we established that PLA2R antigen can be detected in PLA2R-positive MN. In the second step, we determined whether we could detect unique protein(s) with similar expression to PLA2R in a subset of PLA2R-negative MN. We initially selected 35 cases (pilot cohort) of PLA2R-negative MN on kidney biopsy for analysis by tandem mass spectrometry (MS/MS), and detected the unique protein, NELL-1, a neural tissue encoding protein with epidermal growth factor (EGF)-like repeats in 6 cases. We then analyzed the 35 cases of the pilot MS/MS and 91 additional PLA2R-negative MN cases by immunohistochemistry (IHC) for NELL-1 staining (discovery cohort). IHC confirmed the 6 positive NELL-1 cases of the pilot cohort and detected an additional 23 cases of NELL-1, bringing the total of NELL-1–positive cases to 29 (Figure 1). We performed MS/MS in 14 available samples of the 23 additional IHC NELL-1–positive cases from the discovery cohort to confirm the presence of NELL-1. Glomeruli were dissected (Figure 2a) and MS/MS studies from 35 PLA2R-negative MN cases (pilot cohort) detected the unique protein NELL-1 in 6 cases of the pilot cohort (Figure 2b). The average total spectral count for NELL-1 was 63.1 (SD ± 21.6) per case and is comparable to total spectral counts of PLA2R (86.1, SD ± 27.5) and Exostosin-1 (EXT1)/Exostosin-2 (EXT2) (EXT1: 65.3, SD ± 34.6; EXT2: 83.4, SD ± 38.4) in PLA2R-associated and EXT1/EXT2-associated MN, respectively.7Sethi S. Madden B.J. Debiec H. et al.Exostosin 1/exostosin 2–associated membranous nephropathy.J Am Soc Nephrol. 2019; 30: 1123-1136Crossref PubMed Scopus (107) Google Scholar All controls including PLA2R-associated MN cases were negative for NELL-1. MS/MS showed baseline spectral counts of PLA2R (average: 9.6, SD ± 8.6) in NELL-1–associated MN. The spectral counts of NELL-1 in the 6 cases, along with representative sequence coverage map of NELL-1 from 1 case are shown in Figure 2b and c. We subsequently performed MS/MS in 14 of 23 cases of the discovery cohort cases that were positive for NELL-1 by IHC. All cases showed similar high spectral counts of NELL-1 (Figure 2d). An example of MS/MS spectra match to a sequence from NELL-1 is shown in Supplementary Figure S1. All 4 classes of Igs were detected in NELL-1–associated MN: IgG1 was the most abundant Ig (average: 63.6, SD ± 13.1), followed by IgG3 (average: 53.2, SD ± 19.6), IgG2 (average: 50.6, SD ± 23.9), and IgG4 (average: 35.5, SD ± 18.2). We performed IHC staining for NELL-1 in 126 cases of PLA2R-negative MN from the pilot and discovery cohorts. Twenty-nine cases (23.0%) were positive for NELL-1 (6 in the pilot and 23 in the discovery cohort). All 29 positive cases showed bright (2–3+/3) granular staining for NELL-1 along the GBM. Importantly, there was no significant mesangial staining. NELL-1 staining in 6 cases is shown in Figure 3a. Segmental granular capillary wall staining for NELL-1 was seen in 6 cases (20.6%). Review of electron microscopy confirmed the segmental subepithelial deposits in all 6 cases (Supplementary Figure S2). There was no staining along the Bowman’s capsule, tubular basement membranes, or in vessel walls. The positive NELL-1 granular staining mirrored the granular IgG along the GBM seen in each case. All control cases were negative for NELL-1. Representative negative staining for NELL-1 in PLA2R-associated MN, focal segmental glomerulosclerosis, IgA nephropathy, and diabetes is shown in Figure 3b. Representative NELL-1 staining in the remaining NELL-1–positive MN is also shown in the Supplementary Figure S3.Figure 3Immunohistochemical (IHC) stain for neural epidermal growth factor-like 1 protein (NELL-1) in NELL-1–associated membranous nephropathy (MN), M-type phospholipase A2 receptor (PLA2R)–associated MN, and control cases. (a) The bright granular capillary wall staining for NELL-1 along the glomerular basement membranes in 6 cases of NELL-1–associated MN are shown. Note the segmental capillary wall staining in case 9. (b) The negative NELL-1 staining in control cases are shown. There was no capillary wall staining for NELL-1 in (A,B) 2 cases of PLA2R-associated MN, (C) an additional case that was PLA2R-negative but also NELL-1–negative, (D) IgA nephropathy, (E) focal segmental glomerulosclerosis (FSGS), and (F) diabetic glomerulus. Note very weak podocyte staining for NELL-1 but negative capillary wall staining. (c) Immunofluorescence (IF) and IHC show bright capillary wall staining for NELL-1 of 3 cases of the French validation cohort. (A,B) Case 1 (patient 30) was stained by both IHC and IF, and (C,D) the remaining 2 cases (patients 31 and 32) were stained with IF only. (d) IF shows capillary wall staining for NELL-1 of (A,B) 2 cases of the Belgian validation cohort. Bars = 20 μm. To optimize viewing of this image, please see the online version of this article at www.kidney-international.org.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Five of 90 cases (5.9%) of PLA2R- and THSD7A-negative MN were positive for NELL-1 staining in the validation cohorts. Three of 45 cases (6.7%) were positive for NELL-1 staining. The first positive case (patient 30) was detected at the Mayo Clinic and the remaining 2 cases (patients 31 and 32) at Tenon Hospital. Both IHC and immunofluorescence (IF) studies for NELL-1 were done in the first case (patient 30), while IF studies were done for NELL-1 detection in the other 2 cases (patients 31 and 32) (Figure 3c). Two of 39 cases (5.1%) (patients 33 and 34) were positive for NELL-1 staining by IF staining (Figure 3d). Those cases were recruited at Cliniques universitaires Saint-Luc in Brussels and detected at Tenon Hospital. We performed confocal IF microscopy to show that the NELL-1 and IgG colocalize along the GBM (Figure 4). Superimposition of the 2 signals (yellow, Figure 4c and f) and laser quantitative analysis (Figure 4g) confirm the colocalization of NELL-1 and IgG, further corroborating that the subepithelial deposits contain both NELL-1 and IgG. A second case is shown in Supplementary Figure S4. Western blot analyses were performed using recombinant human NELL-1 to determine the presence of circulating anti-NELL-1 antibodies in the serum of 5 patients—4 patients from the validation cohort and 1 from the discovery cohort. All 5 patients showed reactivity against NELL-1 under nonreducing conditions (patients are labeled as MN in Table 1); NELL-1 was detected as a 280-kDa homodimer and a 420-kDa homotrimer. Furthermore, sera were available at different points in patient MN2. The MN2 sera were tested both prior to and during follow-up (Figure 5a). Sera from patients with PLA2R-associated MN, minimal change disease, and IgA nephropathy did not show any reactivity against NELL-1. There was no reactivity under reducing conditions where NELL-1 resolves as monomeric bands of about 130 kDa, suggesting that NELL-1 autoantibody recognizes conformation-dependent epitopes.Table 1Laboratory and kidney biopsy findings of NELL-1–associated MNCaseAgeSexUrinary protein g/24 haMean urinary protein 7 ± 3.7 g/24 h.Serum creatinine mg/dlbMean serum creatinine 1.7 ± 1.3 mg/dl; cases 30, 31, 32, and 34 were associated with malignancies.Sclerosed/total glomeruliIFTAIFEM1 (MN5)cMN1 to the 5 cases in which serum was available and Western blot studies were performed Figure to the 5 cases in which serum was available and Western blot studies were performed Figure to the 5 cases in which serum was available and Western blot studies were performed Figure to the 5 cases in which serum was available and Western blot studies were performed Figure to the 5 cases in which serum was available and Western blot studies were performed Figure electron IF, immunofluorescence microscopy of out of and tubular MN, membranous not not NELL-1, neural epidermal growth factor-like 1 segmental to urinary protein 7 ± 3.7 g/24 serum creatinine 1.7 ± 1.3 mg/dl; cases 30, 31, 32, and 34 were associated with to the 5 cases in which serum was available and Western blot studies were performed Figure in a electron IF, immunofluorescence microscopy of out of and tubular MN, membranous not not NELL-1, neural epidermal growth factor-like 1 segmental to we also characterized the NELL-1 and showed that the IgG is IgG1 in patients and and IgG2 and IgG4 were also along with IgG1 in patient MN2 (Figure We identified 29 cases of NELL-1–associated MN from the pilot and discovery cohorts (patients There were patients and 14 patients The at was 63.1 ± The serum creatinine and at was 1.7 ± and ± g/24 respectively. urinary protein was not done in 7 the of 1 patient with positive including were The kidney biopsy of all cases of NELL-1–associated MN showed the findings of GBM on microscopy, bright IgG and 3 staining along the capillary wall on IF microscopy, and subepithelial deposits on electron an average of glomeruli were of which ± were IF microscopy showed bright staining for IgG (2–3+/3) and in all cases. 1 case showed and 2 cases showed The remaining cases were negative for and All cases showed staining for (2–3+/3) and (2–3+/3) IF staining for PLA2R was negative in all cases. microscopy showed subepithelial deposits in all cases, and in 6 cases, the subepithelial deposits were in a segmental but not all the capillary and mesangial deposits were not were not The 3 positive NELL-1 cases of the French validation cohort were also and 1 (patient 30) (patient and the (patient 32) In all 3 patients of that was at the time or a the of MN. (patient of the 2 positive NELL-1 cases of the Belgian validation cohort was while the other (patient 34) was an patient 34 of MN. The and findings are shown in Table MN is the most of in is by against target antigens in the GBM and of on the of the target MN is also as PLA2R-positive and negative MN. In the negative cases, the target antigen(s) elusive. We identified 2 novel and in patients with MN associated with S. Madden B.J. Debiec H. et al.Exostosin 1/exostosin 2–associated membranous nephropathy.J Am Soc Nephrol. 2019; 30: 1123-1136Crossref PubMed Scopus (107) Google Scholar We used a of laser and IHC to identify and We that we could identify the antigen(s) of the remaining to of primary PLA2R- and THSD7A-negative MN cases using the microdissection with MS/MS for the of a of proteins along with of using total spectral In this we were to identify to glomerular proteins per most of which are with total spectral we that PLA2R was the most abundant protein in PLA2R-associated MN with the S. Madden B.J. Debiec H. et al.Exostosin 1/exostosin 2–associated membranous nephropathy.J Am Soc Nephrol. 2019; 30: 1123-1136Crossref PubMed Scopus (107) Google Scholar Here, we detected a novel protein, NELL-1, in glomeruli dissected from PLA2R-negative MN. The NELL-1 spectral counts were the and were comparable to the and basement membrane proteins and were similar to the counts of PLA2R and in PLA2R- and EXT1/EXT2-associated MN. The high NELL-1 spectral count was also by the sequence coverage for the NELL-1 There were NELL-1 spectral counts in PLA2R-positive MN and control cases. IHC confirmed MS/MS and bright granular capillary wall NELL-1 staining that was the GBM and mirrored the IgG staining. There was of MS/MS and that all NELL-1–positive MN cases detected on MS/MS (pilot cohort) were positive on IHC and all NELL-1–positive MN cases detected on IHC (discovery cohort) were also positive for NELL-1 on there was segmental positive IHC staining for NELL-1 in a electron microscopy in cases also showed segmental subepithelial The of NELL-1 staining along the GBM and with the subepithelial deposits that this protein is from the circulating antigens or immune is that NELL-1 is from mesangial or there was no mesangial or staining in the NELL-1–positive MN. Furthermore, IF confocal microscopy studies showed that both NELL-1 and IgG to the that NELL-1 is the target antigen for the IgG. was further confirmed by of circulating antibodies to NELL-1 in the sera of 5 In 1 patient in sera was available at different time reactivity to NELL-1 at the time of with and that the patient was but the of is in with results seen in PLA2R-associated MN where of PLA2R L.H. Beck et of in membranous nephropathy.J Am Soc Nephrol. PubMed Scopus Google Scholar that NELL-1 can be used for follow-up to be confirmed in further et for a to membranous nephropathy.J Am Soc Nephrol. 2017; PubMed Scopus Google Scholar NELL-1–associated MN be to the of MN, including PLA2R- and MN. is seen in has no has no IgG4 with and there is an of features as for on in validation disease, and IgG performed in cases of NELL-1–positive MN by IF and MS/MS showed that the was the IgG in PLA2R-positive MN is to be The kidney biopsy also shows no features that to a as features on microscopy, Ig staining including on IF microscopy, and in and mesangial or deposits on electron NELL-1 is a to a that is in neural tissue encoding a protein with EGF-like S. S. E. et encoding a protein with EGF-like repeats is in neural of PubMed Scopus Google Scholar expression is in all and the expression was in the as and kidney very of S. S. E. et encoding a protein with EGF-like repeats is in neural of PubMed Scopus Google Scholar 2 to NELL-1, and been et and of two novel human and encoding proteins with six EGF-like PubMed Scopus (109) Google Scholar The of NELL-1 and are about suggesting that the 2 proteins are distinct with different The and are in and in the PubMed Scopus Google Scholar NELL-1 a protein of and including a 4 and 6 EGF-like repeats (Figure et of NELL-1, a growth factor associated with in PubMed Scopus Google Scholar The is the and the repeats are the protein S. et and expression analysis of neural proteins and PubMed Scopus Google Scholar NELL-1 is in and The of NELL-1 H. et and of recombinant human protein in human kidney PubMed Scopus Google H. et of PubMed Scopus Google Scholar NELL-1 is in patients with of the where is H. et NELL-1 in PubMed Scopus Google et of a in during PubMed Scopus Google Scholar NELL-1 also the S. et in Clin Invest. PubMed Scopus Google Scholar In the NELL-1 expression is in while is in the glomeruli 5% to of glomerular NELL-1 at the et and of two novel human and encoding proteins with six EGF-like PubMed Scopus (109) Google Scholar human kidney were on NELL-1 was in the of the suggesting that NELL-1 is as an and be in the H. et and of recombinant human protein in human kidney PubMed Scopus Google Scholar was shown NELL-1 expression is in of while is in and is to an in the et and on of and in human 2015; PubMed Scopus Google Scholar To the of of NELL-1 has not been in any kidney NELL-1–associated MN to be unique kidney associated with of NELL-1. is the case for PLA2R and S. et al.Thrombospondin type 1 7A to the and membrane of Am Soc Nephrol. 2019; 30: PubMed Scopus Google Scholar anti-NELL-1 antibodies a conformation-dependent both in 280-kDa and 420-kDa a studies are to determine NELL-1 at the podocyte and the of anti-NELL-1 antibodies in podocyte and a of 126 of NELL-1–positive MN were detected in the cohort cases at the Mayo Clinic with the of cases of from the French and Belgian validation cohorts. be to as is seen in the of PLA2R- and S. et A2 receptor (PLA2R) and glomerular PLA2R expression in patients with membranous 2016; PubMed Scopus Google Scholar Thus, with to a study showed of PLA2R-associated MN at the Tenon et of PLA2R detected by of antibodies with detection of PLA2R antigen in membranous nephropathy: a study 14 2017; PubMed Scopus Google Scholar while there was a of of MN at the Mayo Clinic a study on MN a of the patients from 6 C. et for thrombospondin type 1 domain-containing 7A in membranous 2019; Full Text Full Text PDF PubMed Scopus Google Scholar while 1 of patients in Membranous of et or in the of membranous nephropathy.N Engl J Med. 2019; PubMed Scopus Google Scholar and 2 of patients at Mayo Clinic and to be THSD7A positive was detected in 4 of 5 NELL-1–positive cases of the validation while of the 29 NELL-1 of the pilot and discovery Mayo Clinic cohort cases The findings that NELL-1–associated MN can in different including as is also the case for PLA2R-associated MN. also the whether the subset of NELL-1–positive MN associated with can be as primary MN. studies are to this 34 cases were identified in PLA2R-negative with all cohorts and that is the of THSD7A cases in the study of N.M. Beck L.H. Meyer-Schwesinger C. et al.Thrombospondin type-1 domain-containing 7A in idiopathic membranous nephropathy.N Engl J Med. 2014; 371: 2277-2287Crossref PubMed Scopus (496) Google Scholar the findings that NELL-1 is the second most antigen in primary MN. studies are to the of NELL-1–positive MN. In we identified a novel protein NELL-1 in a subset of PLA2R-negative MN in NELL-1–associated MN to be a distinct type of primary MN. were in the of and Mayo for and and microscopy, IF microscopy including PLA2R and electron microscopy was performed in each case of MN. The was from the The study was by the Mayo Clinic Review control cases, we performed MS/MS on cases that cases of time kidney cases of minimal change disease, cases of focal segmental glomerulosclerosis, 7 cases of diabetic glomerulosclerosis, 5 cases of IgA nephropathy, and 23 cases of PLA2R-associated MN. control we used 20 cases that 4 cases of focal segmental glomerulosclerosis, 4 cases of IgA nephropathy, 4 cases of and cases of PLA2R-associated MN. Two validation cohorts were kidney biopsy of tissue were by the et and analyzed in the by IHC for NELL-1. All 23 cases were PLA2R- and THSD7A-negative MN. An additional cases of PLA2R- and THSD7A-negative MN were stained for NELL-1 at using IF kidney biopsy of tissue of PLA2R- and THSD7A-negative MN were in the cases were stained for NELL-1 at using each case were and on a membrane laser microdissection and using a the glomeruli were to approximately to per case. were with and for MS/MS The were identified by tandem MS/MS using a Mass to a All MS/MS samples were analyzed using and to a human was used to and protein were at by the with protein a 2 and a using E. et for proteins by tandem mass PubMed Scopus Google Scholar of laser and MS/MS are in the Supplementary and Supplementary Table and IHC staining were performed at the using the were at 5 and IHC staining was performed for the NELL-1 stain were for 20 using 2 and in for 5 The NELL-1 primary was to in and for The detection used was the primary and and was by in and from the To this were with were for 5 using and followed by in and this is not the with the the was were from the and in for 5 were in of and in 3 of prior to in IF staining was performed on for using target high in The NELL-1 primary was to in serum and and at 4 with biopsy Next, the were with IgG IgG was then with the tissue as were in and with of NELL-1 and IgG along the glomerular basement membrane was by confocal microscopy using a and analyzed with The protein recombinant human NELL-1 was with nonreducing or reducing and for 5 were to and in were to membranes to and the membranes were with were at 4 with sera from controls and antibodies against NELL-1 were and for 2 at with human or IgG, proteins were with detection in nonreducing were with IgG antibodies then with IgG All the no We to the Mayo of the Mayo Clinic of and and the Mayo and the the of the for in and the We are to the of the patients in the of and at Tenon the 20 to from the of and to for in Western We to and all of the Tenon for in and We also the from the for from the of of the Cliniques universitaires for and for and the the the kidney IHC and and performed the laser microdissection and in performed the IHC. and tissue for the validation cohort and also performed the confocal studies and Western blot and and tissue for the Belgian validation cohort. The was and by with as from the of the Download with Supplementary and membranous nephropathy: a of nephropathy (MN) is primary or associated with each with unique glomerular The discovery of the phospholipase A2 receptor (PLA2R) antigen in primary MN of MN and to major antigens in MN the THSD7A antigen and et identified a NELL-1, in primary MN, the of patients antigen unknown. PDF In this and a novel of that kidney followed by kidney In this was followed by a of the kidney significant tubular kidney tubular and of the at followed by a PDF