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Journal of Dental Specialities

Quantitative and qualitative analysis of T- lymphocytes in varying patterns of oral lichen planus - An immunohistochemical study

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Author Details: Juneja S, Srivastava D, Raina S, Kumar K, Shetty DC, Rathore AS

Volume : 3

Issue : 1

Online ISSN : 2393-9834

Print ISSN : 2320-7302

Article First Page : 29

Article End Page : 35


Background: Oral lichen planus (OLP) is a T- cell mediated autoimmune disease in which the T cells trigger apoptosis of the basal cells of the oral epithelium. An early event involves keratinocyte antigen expression or unmasking of an antigen that may be a self-peptide. Later, the T- cells (mostly CD8 positive and some CD4 positive cells) migrate into the epithelium resulting in basal cell degeneration facilitated by a chemokine-mediated migration. These migrated CD8 positive cells are activated directly by antigen binding to major histocompatibility complex (MHC) - I on keratinocyte or through activated CD4 positive lymphocytes. Subsequent antigen presentation to CD4 positive T cells & interleukin (IL)-12 activates CD4+ T helper cells which activate CD8 positive T cells through receptor interaction, interferon-γ and IL-2. The activated CD8 positive T cells in turn kill the basal keratinocytes through tumor necrosis factor (TNF) - α or granzyme B activated apoptosis.
Aims and Objectives: To evaluate CD4 & CD8 positive T-lymphocytes qualitatively & quantitatively and their distribution in various clinical variants of oral lichen planus.
Methodology: The study comprised of a total 20 cases of OLP (atrophic-erosive and reticular variant) and 5 cases of normal oral mucosa which were histopathologically confirmed and then subjected to immunohistochemical staining with CD8 positive and CD4 positive antibodies using heat induced epitope retrieval method.
Results: The mean number of CD4 positive and CD8 positive cells were higher in atrophic-erosive variant of oral lichen planus (OLP) in comparison to the reticular variant.
Conclusion: Increased count of T lymphocytes in atrophic-erosive variant as compared to reticular OLP suggests their possible role in immunological mechanism in the pathogenesis of OLP and probably explains the reason for their higher malignant transformation rate as compared to other clinical forms of OLP. 

Key words: Oral Lichen planus, Keratinocytes, Oral Mucosa, Premalignant, CD4 Positive T-Lymphocytes, CD8 Positive T-Lymphocytes