Expression of Langerin in and its diagnostic value for Langerhans cell histiocytosis

Objective Langerin is a newly discovered specific immunomarker of Langerhans cells,which plays a critical role in the formation of Birbeck granules.The aim of this study was to assess the specificity and utility of Langerin in the diagnosis of Langerhans cell histiocytosis(LCH).Methods We retrieved the data of 23 cases of LCH and 18 cases of various non-Langerhans cell histiocytic disorders(N-LCHD) from pathology files,and determined the expressions of Langerin,CD1a and S-100 protein of both LCH and N-LCHD by pathohistological observation and immunohistochemical examination.Results Histologically,all the 23 cases of LCH showed proliferation of large oval cells with indented,grooved or folded nuclei,inconspicuous nucleoli,thin nuclear membranes,and moderately abundant and slightly eosinophilic cytoplasm,accompanied by infiltration of variable numbers of eosinophils.The expressions of Langerin in LCH and N-LCHD were 100% and 0%,respectively(P0.05),those of CD1a were 95.65% and 5.6%(P0.05),and those of S-100 protein were 100% and 72.2%.The sensitivities of Langerin,CD1a and S-100 protein in the LCH group were 100%,95.65% and 100%,and their specificities were 100%,94.4% and 27.8%,respectively.Conclusion Langerin is a highly sensitive and specific immunomarker of LCH,and useful for the diagnosis and differential diagnosis of LCH.