Langerin

Langerin (CD207) is a type II calcium dependent C-type lectin that only exists in Langerhans cells. As a specific mannose receptor, Langerin can bind to mannose and transport it to Birbeck granules, participating in antigen presentation and immune tolerance. Using electron microscopy to observe Birbeck particles is the gold standard for diagnosing LC related diseases, while the combination of Langerin with CD1a and S100 is an important complemental method. Therefore, in clinical practice, Langerin has become a highly specific and sensitive diagnostic biomarker for LC histiocytosis (LCH) and LC sarcoma (LCS). Meanwhile, Langerin expression is found in some littoral cell angioma (LCA) of spleen, which is beneficial for distinguishing LCA from other vascular tumors, but the specific mechanism is still unclear. In addition, Langerin+ dendritic cells may drive matrix hardening and fibroblast activation by producing TGF-β1, thereby leading to skin fibrosis.