A 14-year-old boy with typical features of Papillon-Lefevre syndrome (PLS) is presented. The purpose of this report was to study the immunopheno-typic features of the peripheral blood and gingival tissue lymphocytes with monoclonal antibodies in the patient. Peripheral blood T-cells, helper-T cells, suppressor-T cells, HLA-DR+ cells and IL-2R+ cells were determined using appropriate monoclonal antibodies and indirect immunofluorescence methods. B-cells were identified using the direct immunofluorescence technique. The gingival tissue was processed for both histopathological and immunohistological examinations. Gingival tissue lymphocytes were identified using monoclonal and polyclonal antibodies with the immunoperoxidase technique. Although we have not detected any significant alterations in the peripheral blood B-cell and T-cell populations, NK cells were significantly increased. HLA-DR+ cells and IL-2R+ cells were within normal limits. Histopathology of the diseased tissue revealed predominance of plasma cells in the lamina propria. The majority of the plasma cells were bearing IgG isotype. Most of the CD3+ T-cells were located beneath the pocket epithelium with an almost equal distribution of CD4+ and CD8+ T-lymphocytes, in situ. These findings indicate that PLS is a IgG+ plasma cell dominated lesion with the participation of T-lymphocytes, having similar distributions of both subsets. While the etiopathogenesis of the syndrome still has to be elucidated, these immunohistological findings could be used for further studies in this intriguing entity.