IgA deposits predominantly along glomerular basement membranes in a patient with rapidly progressive glomerulonephritis

Objective: To describe the clinical and pathological features of a rare type of rapidly progressive glomerulonephritis（RPGN） characterized as IgA deposit predominantly along glomerular basement membranes.Methods: A case with RPGN characterized as IgA deposit predominantly along glomerular basement membranes was described.The clinical and pathological features,as well as its response to treatment were analyzed.Results: The patient manifested clinically as RPGN without pulmonary hemorrhage and vasculitis related systematic symptoms.No positive results were found among ANAs,ANCAs and anti-GBM antibodies detection.Light microscopic evaluation showed circumferential crescents in more than 50 percent of the glomeruli.No vasculitis related changes were found.Direct immunofluorescence of frozen and paraffin specimens showed finely granular staining for deposits of IgA along the glomerular basement membranes.Circulating IgA anti-GBM antibodies were negative by indirect immunofluorescence detection.Electron microscopic examination showed segmental electron-dense deposits in subepithelial area and in the glomerular basement membrane.There were occasional small mesangial electron-dense deposits.Therapy with pulse methylprednisolone and intravenous cyclophosphamide was less effective.Conclusion: This case is a rare type of RPGN,which attribute hardly to the present RPGN classification.Its clinical characteristics should be noticed.