Detection of activated platelets in urinary sediments by immunofluorescence using monoclonal antibody to human platelet GMP-140 in patients with IgA nephropathy

The presence of activated platelets in the urinary sediments was studied by indirect immunofluorescence using monoclonal antigranular membrane protein (GMP)‐140 antibody. GMP‐140 is generally expressed on the activated‐platelets and ‐vascular endothelial cells. The purpose of the present study was to determine if the presence of activated platelets in the urinary sediments is correlated with glomerular injuries in patients with IgA nephropathy. Fourteen patients with IgA nephropathy and 11 patients with diffuse mesangial proliferative glomerulonephritis without glomerular IgA deposition (PGN) were examined. The number of activated platelets in the urinary sediments was markedly increased in patients in the advanced stage of IgA nephropathy. The ratio of activated platelets to total platelets in the urinary sediments was also increased in such patients. It appears that the detection of activated platelets in the urinary sediments is useful in determining the degree of histological changes in IgA nephropathy. © 1993 Wiley‐Liss, Inc.