Anti-heparan sulfate antibody and functional loss of glomerular heparan sulfate proteoglycans in lupus nephritis:

BackgroundThe purpose of this study was to evaluate the features of heparan sulfate proteoglycans (HSPGs) as agrins of the glomerular basement membrane (GBM) and circulating anti–heparan sulfate (HS) antibodies in lupus nephritis, comparing titers among the following groups: lupus nephritis (LN), non-renal lupus, non-lupus nephritis, and healthy controls.MethodsThe stage of nephritis was determined based on the kidney biopsy. Alcian blue staining and immunohistochemical (IHC) staining for agrin were performed for histological evaluation of GBM HSPGs in normal glomeruli, non-lupus membranous glomerulonephritis (MGN), and lupus MGN. The results were used for measurement of the serum anti-HS antibody titers using an enzyme-linked immunosorbent assay (ELISA) in the following groups: 38 healthy controls, 38 non-lupus nephritis, 37 non-renal lupus, and 38 LN.ResultsGlomerulus HSPGs were stained bluish-green along the GBM with Alcian blue. However, IHC staining against agrin was almost completely negative in the...