CHARACTERIZATION OF LYMPHOCYTE SUBPOPULATIONS IN PERIAPICAL LESIONS BY FLOW-CYTOMETRY

The mechanisms by which the bacterial root-canal infection leads to pe riapical bone destruction (cysts or granulomas) are not yet well under stood. Previous works have shown elements of an active immune response in the lesions. In the present study, flow cytometry was used to impr ove the characterization of immune cells. Semiquantitative immunohisto chemical analysis showed the presence of plasma cells, macrophages and B and T cells. The simultaneous use of several antibodies in flow cyt ometry allowed a more precise phenotype of the lymphocytes. The cysts displayed an abundance of B lymphocytes at the same time as a relative scarcity of CD8(+) cells. CD4(+) lymphocytes were the dominant lymhoc yte population in most cases. A small number of gamma delta T lymphocy tes and natural killer cells was found. These preliminary results show that flow cytometry may be used to characterize immune cells from inf lamed tissue and opens the possibility for further functional studies.