Mucosal and Skin Langerhans Cells - Nurture Calls.

Langerhans cells (LCs) are classically viewed as unique antigen-presenting cells (APCs) that originate from embryonic precursors and maintain themselves independently in the epidermis. However, recent studies have demonstrated that murine LCs in mucosal epithelia arise and are continuously replenished from circulating bone marrow (BM) precursors. This has led to the emergence of a novel perspective proposing that LCs can evolve from various origins. Because both embryonic and BM precursors differentiate into LCs only after entering the epithelium, this highlights its crucial role in nurturing LC development to perfectly comply with the physiological functions of the tissue. Thus, current evidence suggests plasticity of LC differentiation, revealing novel developmental mechanisms that are controlled by environmental cues.