Memory T Cells (CD45RO) Role and Evaluation in Pathogenesis of Lichen Planus and Lichenoid Mucositis.

INTRODUCTION: Memory T cells have the ability to survive in a quiescent state for longer periods and are responsible for the rapid responses on subsequent exposure to antigen. Analyzing memory T cells in Oral Lichen planus (OLP) and Lichenoid Mucositis (LM) suggest that these cells may play a role in the immunopathogenic mechanisms.

AIM: To identify and evaluate Memory T cells in Lichen Planus (LP), Lichenoid Mucositis (LM) and Normal Mucosa (NM) using CD45RO monoclonal antibody immunohistochemically.

MATERIALS AND METHODS: A total of 30 cases (15 cases of OLP and 15 cases of LM) clinically and histopathologically diagnosed, and 10 cases of NM were stained for CD45RO monoclonal antibody, immunohistochemically using Biotin Streptavidin method. Staining intensity of CD45RO expression was statistically analysed using Chi-square Test.

RESULTS: The present study demonstrated a higher expression of CD45RO in connective tissue layer of OLP (53.3% intense staining) when compared to LM (20% intense staining) and no intense staining in NM. The difference in staining intensity pattern between the study groups was statistically significant (p=0.014).

CONCLUSION: This study demonstrates a statistically significant rise in memory T cells in LP than in LM, indicating the possible different immunopathogenic mechanisms.