Inflammatory cells of immunosuppressive phenotypes in oral lichen planus have a proinflammatory pattern of expression and are associated with clinical parameters.

OBJECTIVES: We sought to investigate the expression of cells with immunosuppressive/protumorigenic phenotypes in oral lichen planus (OLP), such as M2-tumor-associated macrophages (TAM2), myeloid-derived suppressive cells (MDSCs), and regulatory T cells (Tregs) in association with clinical parameters.
MATERIALS AND METHODS: Cases of hyperkeratotic (HK)-OLP (n = 23) and erosive (E)-OLP (n = 26) were immunohistochemically stained to determine the percentages of CD163-TAM2, CD80-MDSCs, and FOXP3-Tregs of proinflammatory CD121a-Th17, CD4 and CD8 lymphocytes, and of cells positive for nuclear factor kappa B (NF-κB) and transforming growth factor beta. Clinical parameters included symptoms, treatment approach, treatment response, and others.
RESULTS: The inflammatory infiltrate in HK-OLP and E-OLP contained immunosuppressive cells; however, their pattern of expression was compatible with a proinflammatory response [membranous CD163-TAM2 staining (not extracellular), CD80+ lymphocytes (not macrophages), and a few Tregs]. The presence of CD4+, CD8+, and CD121a+ T lymphocytes was extensive. TAM2 were more frequent in E-OLP than in HK-OLP (P = 0.017). A higher frequency of CD80+ lymphocytes was associated with partial to no response to treatment (P = 0.028). Nuclear expression of NF-κB in the inflammatory cells was absent.
CONCLUSIONS: The pattern of expression of the immunosuppressive cells, together with numerous CD4+, CD8+, and Th17-CD121a+ lymphocytes, suggest an extensive proinflammatory response rather than an immunosuppressive/protumorigenic response. CLINICAL RELEVANCE: The frequency of selective types of inflammatory cells calls for individual profile analyses of inflammatory infiltrates and individually adjusted treatment.