Syracuse

Involvement of granzyme B and granulysin in the cytotoxic response in lichen planus.

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Ammar, Mohammed | Mokni, M. | Boubaker, S. | El Gaied, Amel | Ben Osman, A. | Louzir, H.

Edité par CCSD ; Wiley -

International audience. BACKGROUND: Lichen planus is an inflammatory dermatosis involving either skin and/or mucosal epithelial surfaces. A cell-mediated cytotoxicity response is the main suspected mechanism of this dermatosis. Granzyme B and granulysin are components of the cytoplasmic granules of cytotoxic T lymphocytes and natural killers. They are involved in cell-mediated apoptosis. This work studies the possible implication of granzyme B and granulysin in the cell-mediated cytotoxicity response in lichen planus. METHODS: In situ expression of granzyme B and granulysin was studied by real-time reverse transcriptase polymerase chain reaction in 15 biopsies of lichen planus. The distribution and the phenotype of the inflammatory infiltrate and the expression of granzyme B were studied by immunohistochemistry in seven other biopsies of lichen planus. RESULTS: Granzyme B and granulysin mRNA expression was one to two hundred times greater than in biopsies of normal skin. Immunohistochemical study revealed that the lymphohistiocytic infiltrate consisted mainly of CD4+ and CD8+ lymphocytes. Granzyme B+ cells were observed close to apoptotic keratinocytes. CONCLUSION: Our results suggest a central role for cell-mediated cytotoxicity by the granule exocytosis pathway probably because of auto-cytotoxic T-cell clones in the pathogenesis of lichen planus.

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