Hamadan University of Medical Sciences Avicenna Journal of Dental Research 2423-7582 5 1 2013 06 25 Type and Portions of Peripheral Blood T Lymphocytes in Oral Lichen Planus 1 4 10.17795/ajdr-20187 EN Seyed Javad Kia Arash Mansourian Masoumeh Nikkhah Nariman Nikparto Najmeh Shanbezadeh Journal Article 10.17795/ajdr-20187 2013 03 02 2013 06 01 Background: Lichen planus is a disease with unknown etiology that affects the skin and the mucous membranes. Immune dysregulation in the pathogenesis of oral lichen planus (OLP) is well-known phenomenon. Objectives: In this study, we compared the levels of the peripheral blood T lymphocytes between patients with OLP and control group. Patients and Methods: In this study, 32 and 16 patients respectively with and without OLP were recruited. Five milliliters of the participants' peripheral venous blood was drew in an EDTA-containing test tube and the levels of CD3+, CD4+, and CD8+ cells, CD4+/CD8+ and CD4+/ CD3+ ratio were measured by means of two-color flow cytometry. The data were analyzed in SPPS v.19 by employing Mann-Whitney U test. Results: There were no significant difference among the levels of CD3+, CD4+, and CD8+ lymphocytes and the ratio of CD4+/CD8+ and CD4+/CD3+ lymphocytes between patients and control group; however, there was a significant difference between male and female patients with respect to the levels of CD3+ and CD4+ lymphocytes and the ratio of CD4+/CD8+ and CD4+/CD3+ lymphocytes. Conclusions: Our results confirm that only local immune mechanism known as skin-associated lymphoid tissue, not a systemic immunologic disorder, was involved in the OLP.