Accumulation of leukocytes within the glomerulus is a key event in the pathogenesis of glomerulonephritis. This process is mediated by pairs of adhesion molecules. We have examined the expression pattern of selectins (E and P), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in 30 renal biopsies with IgA nephropathy, diffuse crescentic glomerulonephritis, and minimal change disease. Normal controls were obtained from four nephrectomy specimens with renal cell carcinoma. ICAM-1 expression was significantly increased in the glomerular endothelial and mesangial cells in cases with IgA nephropathy compared with normal controls. VCAM-1 was expressed in glomerular mesangial cells in all cases with IgA nephropathy and diffuse crescentic glomerulonephritis, but faintly expressed in 3 cases with minimal change disease and not expressed in normal controls. P-selectin was faintly expressed in the glomeruli in cases with IgA nephropathy and diffuse crescentic glomerulonephritis. E-selectin was only expressed in the vascular endothelium in one case with IgA nephropathy and in the other with diffuse crescentic glomerulonephritis. ICAM-1 and VCAM-1 were strongly expressed in the crescents. However, selectin was not expressed in the crescent. These results suggest that adhesion molecules, particularly ICAM-1 and VCAM-1, play an important role in the pathogenesis of glomerular damage and crescent formation in primary glomerular diseases.