Concomitant immunocytochemical study of macrophage cells and blood vessels in disc herniation tissue.

Twenty disc herniations (DH) were studied immunocytochemically for macrophages and blood vessels. Serial thin frozen sections were immunostained with an antibody specific for tissue macrophages (monoclonal antibody to CD68 antigen) and the endothelium of blood vessels (polyclonal antibody to von Willebrand factor). With this method, blood vessels, often abundant, were observed in as many as 16/20 (80%) of the DH studied, 12 disc extrusions and 8 sequestrated discs, whereas abundant macrophages were noted in 11/20 (55%) of the DH. Macrophages were present only in areas with blood vessels and had presumably infiltrated the tissue from them. As has been noted previously, some blood vessels are apparently newly formed as a result of tissue injury, whereas others were present in the disc prior to herniation. This is suggested by the lack of a clear correlation between the presence or absence of blood vessels and the preoperative duration of radicular pain. In areas of the DH where cartilage fragments occurred, both macrophages and blood vessels were particularly abundant.