Recruitment of dendritic cells in oral lichen planus

• Published in: The Journal of pathology 2005-03, Vol.205 (4), p.426-434
• Main Authors: Santoro, Amerigo, Majorana, Alessandra, Roversi, Luca, Gentili, Francesca, Marrelli, Simona, Vermi, William, Bardellini, Elena, Sapelli, Pierluigi, Facchetti, Fabio
• Format: Article
• Language: English
• Subjects: Antigens, CD - analysis; Antigens, CD1 - analysis; Antigens, Surface - analysis; Cell Adhesion Molecules - analysis; dendritic cells; Dendritic Cells - chemistry; Dendritic Cells - pathology; Epithelial Cells - chemistry; Epithelial Cells - pathology; Fluorescent Antibody Technique - methods; Humans; IFN‐α; Immunohistochemistry - methods; Interleukin-3 Receptor alpha Subunit; Langerhans cells; Langerhans Cells - chemistry; Langerhans Cells - pathology; Lectins, C-Type - analysis; Lichen Planus, Oral - metabolism; Lichen Planus, Oral - pathology; Lysosomal Membrane Proteins; Mannose-Binding Lectins - analysis; Membrane Glycoproteins; Mouth Mucosa - chemistry; Mouth Mucosa - pathology; Nerve Tissue Proteins - analysis; oral lichen planus; Phenotype; plasmacytoid dendritic cells; Receptors, CCR7; Receptors, Cell Surface - analysis; Receptors, Chemokine - analysis; Receptors, Immunologic; Receptors, Interleukin-3 - analysis; Stromal Cells - chemistry; Stromal Cells - pathology
• ISSN: 0022-3417; 1096-9896
• DOI: 10.1002/path.1699

Using immunohistochemistry the presence of different dendritic cell (DC) subsets was analysed in 16 biopsies from patients with oral lichen planus (OLP). A significant increase of CD1a+/Langerin+ Langerhans cells, DC‐SIGN+ DC and CD123+/BDCA2+ plasmacytoid DCs (PDCs) was found in the epithelium and in the stroma of OLP biopsies compared to normal oral mucosa. A proportion of DCs were mature DC‐LAMP+ and expressed S100 or CD11c, typically found in the interdigitating DCs of nodal T‐cell areas. Double staining revealed that mature DCs co‐expressed CCR7, thus indicating the development of a nodal migratory phenotype upon maturation. Significant recruitment of PDCs producing IFN‐α was demonstrated by the expression of MxA within the lichenoid inflammatory infiltrate and close cell‐to‐cell contacts between PDCs and mature DCs were observed, with a significant correlation between the numbers of these two populations. Moreover, PDCs were also found to contain Granzyme‐B, an associated‐cytotoxic granule protein, inducing target cell apoptosis. Taken together, these results suggest that PDCs may promote maturation of DCs and amplify the cytotoxicity of lymphoid cells. Finally, the recruitment of different subtypes of DC, such as Langerhans cells, stromal DC‐SIGN+ DCs and PDCs, associated with a significant proportion of mature DCs, acquiring a CCR7+ ‘migratory’ phenotype, indicate that they may play a pivotal role in the development of the lichenoid inflammatory infiltrate that occurs typically in OLP. Copyright © 2005 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.