Langerhans cells and their role in oral mucosal diseases

Abstract

Dendritic cells are arguably the most potent antigen-presenting cells and may be the only cells capable of initiating the adaptive immune response. The epithelial residents of dendritic cells are Langerhans cells, which serve as the "sentinels" of the mucosa, altering the immune system not only to pathogen entry but also of tolerance to self antigen and commensal microbes. Oral mucosal Langerhans cells are capable of engaging and internalizing a wide variety of pathogens and have been found responsive to nickel in patients with nickel allergies, oral Candida species, oral lichen planus, lichenoid drug eruptions, graft versus host diseases, periodontal diseases median rhomboid glossitis, human immunodeficiency virus infection, hairy leukoplakia of the tongue, and oral squamous cell carcinoma. Review focuses on the role of antigen-presenting cells in particular Langerhans cells to better understand the mechanisms underlying immune responses. In this review, comprehensive detail about mucosal diseases has been compiled using the PubMed database and through textbooks.

Keywords: Antigen-presenting cells; Dendritic cells; Langerhans cells; Oral mucosal diseases.

Figure 1

Showing CD1a positive Langerhans cells with dendritic processes within the oral mucosa (a) At 40× (b) At 100× magnification

Figure 2

Origin of Langerhans cells from the bone marrow precursor cells

Figure 3

Schematic representation of LCs migration from the oral mucosa to the regional lymph node. The right side of the scheme shows the functional properties of mature and immature LCs