A comparative immunohistochemical evaluation of CD68 and TRAP protein expression in central and peripheral giant cell granulomas of the jaws

Abstract

Giant cell granulomas of the jaws are lesions that arise either peripherally in periodontal ligament and mucoperiosteum or centrally in the bone. The aim of this study was to evaluate expression of CD68 and tartrate-resistant acid phosphatase (TRAP) proteins in multinucleated giant cells and mononuclear cells. Formalin-fixed and paraffin-embedded tissue section of 20 specimens of central giant cell granuloma and 20 cases of peripheral giant cell granuloma were immunohistochemically analyzed for CD68 and TRAP proteins expression rate using Biotin-Streptavidin method. In central giant cell granuloma, more than 99% of multinucleated giant cells were positive for TRAP antibody and about 90% were positive for CD68. In mononuclear cells of this lesion, 14% of cases were positive with TRAP antibody and 8% with CD68. In peripheral giant cell granuloma, TRAP antibody was positive in 99% of giant cells and in 13% of mononuclear cells. A proportion of 97% of giant cells and 6% of mononuclear cells reacted positively with CD68. Immunohistochemical evidence of this study shows that giant cells and a group of mononuclear cells of stroma in both peripheral and central giant cell granuloma express TRAP antibody severely that is specific for osteoclast. Also, these cells are positive reactive to CD68, which is the macrophage marker and therefore it can be mentioned that giant cells are osteoclast, although their origins are macrophagic/monocytic or their precursors, and maybe mononuclear cells in stroma have a role in formation of giant cells.