A novel class of autoantigens of anti-neutrophil cytoplasmic antibodies in necrotizing and crescentic glomerulonephritis: the lysosomal membrane glycoprotein h-lamp-2 in neutrophil granulocytes and a related membrane protein in glomerular endothelial cells.

422

388

Abstract. Renal transplant rejection is caused by a lymphocyterich inflammatory infiltrate that attacks cortical tubules and endothelial cells. Immunosuppressive therapy reduces the number of infiltrating cells; however, their exit routes are not known. Here a Ͼ50-fold increase of lymphatic vessel density over normal kidneys in grafts with nodular mononuclear infiltrates is demonstrated by immunohistochemistry on human renal transplant biopsie susing antibodies to the lymphatic endothelial marker protein podoplanin. Nodular infiltrates are constantly associated with newly formed, Ki-67-expressing lymphatic vessels and contain the entire repertoire of T and B lymphocytes to provide specific cellular and humoral alloantigenic immune responses, including Ki-67 ϩ CD4 ϩ and CD8 ϩ

“…This antigen was also used to raise monoclonal antibodies, as described (9). Rabbit antibodies to human LYVE-1 and Prox-1 were obtained from Dr. Kari Alitalo (University of Helsinki).…”

Section: Reagentsmentioning

confidence: 99%

Lymphatic Neoangiogenesis in Human Kidney Transplants Is Associated with Immunologically Active Lymphocytic Infiltrates

Kerjaschki¹,

Regele²,

Moosberger³

et al. 2004

422

388

“…18,19 LAMP-2 is a heavily glycosylated membrane protein that traffics from the cell surface to lysosomes, where it is most abundant and is critical for cellular homeostasis and responses to stress. 20 We originally discovered autoantibodies to human LAMP-2 (hLAMP-2) as part of a systematic search for autoantibodies to glomerular membrane proteins in piFNGN 21 and have reported their high prevalence in piFNGN. We consistently find that .80% of patients presenting with piFNGN in European cohorts have circulating autoantibodies to hLAMP-2 that rapidly became undetectable after immunosuppressive treatment.…”

mentioning

confidence: 99%

Autoantibodies to hLAMP-2 in ANCA-Negative Pauci-Immune Focal Necrotizing GN

Peschel

Basu

Benharkou

et al. 2014

Pauci-immune focal necrotizing GN (piFNGN) is usually associated with ANCAs that are thought to be pathogenic. However, 10%-15% of patients are ANCA negative and the cause of their injury is unknown. We previously reported a high frequency of autoantibodies to human lysosome-associated membrane protein-2 (hLAMP-2) in ANCA-associated piFNGN, and have now investigated whether the same is true in ANCA-negative patients. Of 11 patients, 8 (73%) had anti-hLAMP-2 antibodies detected by ELISA and confirmed by immunoblotting and indirect immunofluorescence. The autoantibodies from all 8 patients bound to native LAMP-2 purified from human glomeruli and recombinant hLAMP-2 expressed in ldlD cells, both with molecular masses of 110 kD. However, in contrast to anti-LAMP-2 antibodies from ANCA-positive patients, these antibodies from ANCA-negative patients failed to bind the more complexly glycosylated native neutrophil hLAMP-2 (190 kD). Treatment with the deglycosylating enzyme, endo-b-galactosidase, reduced the mass of neutrophil hLAMP-2 to 110 kD and enabled autoantibody binding. Similarly, pretreating neutrophils with endo-b-galactosidase or neuraminidase converted ANCA assay results from negative to positive. Finally, IgG from LAMP-2-positive ANCAnegative patients bound specifically to normal human kidney sections and to human glomerular endothelial cells in culture. In conclusion, in patients with ANCA-negative piFNGN, we have identified autoantibodies to hLAMP-2 that bind native glomerular but not neutrophil hLAMP-2, suggesting a role in pathogenesis.

“…28,29 H-lamp-2 was identified as a potential PMN-associated autoantigen in ANCAassociated vasculitis. 30 An interesting aspect of this study was that apparently autoantibodies against h-lamp-2 reacted not only with PMN but also with an unidentified protein on renal microvascular EC. However, in our study, no cross-reactivity of AECA with neutrophils was observed.…”

Section: Discussionmentioning

confidence: 99%

Anti–Endothelial Cell Autoantibodies Selectively Activate SAPK/JNK Signalling in Wegener’s Granulomatosis

Holmén¹,

Elsheikh²,

Christensson³

et al. 2007

The pathogenic role of anti-endothelial cell antibodies (AECA) in vascular injury is debated. It was previously shown that many patients with Wegener's granulomatosis (WG) have AECA that react with human kidney microvascular endothelial cells (EC). In addition, during active disease, renal endothelium strongly expresses the inflammatory molecules vascular adhesion protein-1 (VAP-1) and MHC class I-related antigen A (MICA). This study sought to determine whether AECA mediates this upregulation of VAP-1 and MICA and to define better the signaling pathways that are activated by these autoantibodies upon binding to EC in the kidney. Stimulation of human kidney microvascular EC with AECA IgG upregulated surface expression of MICA and VAP-1, elicited a rapid Ca 2ϩ flux, induced high levels of the chemokines monocyte chemoattractant protein-1 and granulocyte chemotactic protein-2, induced specific phosphorylation of stress-activated protein kinase (SAPK)/c-Jun N-terminal kinase (JNK) and the transcription factors c-Jun and activating transcription factor-2, and activated NF-B. Specific inhibitors of SAPK/JNK significantly reduced AECA-induced chemokine production and phosphorylation of c-Jun and activating transcription factor-2 and abrogated protein expression of MICA but not VAP-1. In kidney sections from patients with WG, infiltrating cells that expressed the ligand for MICA (NKG2D ϩ ) were identified, as were CD8 ϩ and 32 ␥␦ ϩ T cells. In conclusion, AECA may be involved in the pathogenesis of WG, and the SAPK/JNK pathway and the endothelial inflammatory protein VAP-1 may be novel therapeutic targets for vasculitis.