Co-localization of terminal C5b-9 complement complexes and macrophages in human atherosclerotic arterial walls.

The co-localization of terminal C5b-9 complement complexes and macrophages was investigated in human arteries with atherosclerosis using a double-labeling immunohistochemical technique. Macrophages were found in all the atherosclerotic arteries, with the accumulation correlating positively with the degree of atherosclerosis. This accumulation was associated with an increase of C5b-9 deposits, as well as with an increase in the number of deposits containing both complement components and macrophages ('co-localization'). This co-localization was found to pertain both to intact macrophages and to macrophage remnants. These data suggest that C5b-9 complement complex might be formed on macrophages with subsequent promotion of inflammatory events and progression of the atherosclerotic lesions.