Langerhans cell histiocytosis: intrinsic immunoeditingproperties

Non-classical HLA-molecules physiologically protect the fetus from maternal allorecognition, this mechanism seems to be used by some tumors during their development. PD-L1 is physiologically expressed mainly on antigen presenting cells, some types of tumors use this ligand to supress host immune reactions. The expression of non-classical immunomodulatory molecules (HLA-G, HLA-E, HLA-F) as well as the expression of immune checkpoint regulator programmed death ligand (PD-L1) is not characterized in Langerhans cell histiocytosis (LCH). Our data suggest that non-classical immunomodulatory molecules and immune checkpoint molecules may play role in immunoediting process during development of LCH. Further studies regarding immunoediting properties including non-classical HLA molecules and immune checkpoints ligands appear warranted for better understanding and therapy of this enigmatic disorder.