INTERFERON-GAMMA-PRODUCING CELLS AND INDUCIBLE NITRIC-OXIDE SYNTHASE-PRODUCING CELLS IN PERIAPICAL GRANULOMAS

Periapical granulomas contain a large number of T lymphocytes and mono cytes/ macrophages and a small number of B lymphocytes and polymorphon uclear leukocytes. Sections from eight periapical granulomas were stai ned by a variety of immunohistochemical methods. The vascular endothel ial cells stained positively for intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Helper T cells were identified by immunostaining for CD4 and stained positively for interferon-gamma (IF N-gamma). However, CD4-positive T cells did not stain for interleukin- 4 (IL-4). Monocytes/macrophages were identified by immunostaining for CD68 and stained positively for IL-1 alpha or inducible nitric oxide s ynthase (iNOS). IL-1 beta could not be detected in the same samples. N o cytokine expression was observed in B cells identified by immunostai ning for CD20. IFN-gamma- and iNOS-positive cells could not be detecte d in clinically healthy periodontal ligament being used as a negative control. These results suggest that the IFN-gamma-producing T cells an d iNOS-positive cells may modulate the progress of disease in local in flammation sites such as in periapical granulomas.