Autoantibodies to glomerular antigens in patients with Wegener's granulomatosis.

Patients with Wegener's granulomatosis have autoantibodies to a neutrophil cytoplasmic antigen. As these patients often present with severe glomerulonephritis we investigated whether the same autoantigen was expressed in glomeruli by using both cultured human glomerular cells and frozen normal human kidney sections. Glomeruli were isolated from normal human kidney cortex by differential sieving and plated on to coverslips in growth medium containing various supplements. Cell types were identified by a series of markers and designated either epithelial, endothelial or mesangial. In single and double staining experiments, glomerular cells were incubated with a monoclonal antibody to the neutrophil cytoplasmic antigen (MCAW8), control mouse monoclonal IgG, sera from patients with Wegener's granulomatosis and control normal human serum. MCAW8 and Wegener's patient sera bound specifically to cultured epithelial and endothelial cells. MCAW8 was also found to bind to the glomerular epithelium in frozen sections. We conclude that autoantibodies to glomerular antigens are present in serum of patients with Wegener's granulomatosis and may be important in the pathogenesis of rapidly progressive glomerulonephritis.