We have previously reported that the Notch signaling pathway is active in LCH lesions and that the Notch ligand Jagged2 (JAG2) induces CD1a and langerin expression in monocytes in vitro.
Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the presence of abnormal CD1a-positive (CD1a<sup>+</sup> )/CD207<sup>+</sup> histiocytes.
Immunohistochemistry shows positivity for S100 and CD1a in Langerhans-cell histiocytoses (LHCH) of the L group, while CD68 positivity with S100 and CD1a negativity are typical in histiocytoses of the C group of cutaneous and mucocutaneous histiocytoses.
Langerhans cell histiocytosis (LCH) is a rare systemic disorder characterized by the accumulation of CD1a+/Langerin+ LCH cells and wide-ranging organ involvement.
Lung biopsy showed fibrosis of the interalveolar septa, architectural distortion and large cells with foamy cytoplasm and convoluted nuclei that were marked by CD68, S-100 and the specific antibody CD1a that allowed establishing the diagnosis of pulmonary LCH.
Langerhans cell histiocytosis (LCH) is a rare proliferative disease of cells of the CD1a+/CD207+ myeloid dendritic cell lineage that may infiltrate one or more organs or systems at all ages.
Separately genotyping each CD1a-positive area from the same pulmonary LCH lesion demonstrated that these concurrent BRAF and NRAS mutations were carried by different cell clones.
Langerhans cell histiocytosis (LCH) remains a poorly understood disorder with heterogeneous clinical presentations characterized by focal or disseminated lesions that contain excessive CD1a+ langerin+ cells with dendritic cell features known as "LCH cells."
Diagnosis of ECD involves the analysis of histiocytes in tissue biopsies: these are typically foamy and CD68+ CD1a- in ECD, whereas in Langerhans cell histiocytosis (LCH) they are CD68+ CD1a+.
The presence of CD1a(+) T-cells in all of the LCH lesions that we have studied to date warrants further investigation into their biological function to determine whether these cells are important in the pathogenesis of LCH.
Langerhans cell histiocytosis (LCH) is a rare disease characterized by heterogeneous lesions including CD207(+)/CD1a(+) dendritic cells that can result in significant morbidity and mortality.
To determine whether LCH LC have altered telomere lengths, we used dual detection of CD1a expression by immunofluorescence and telomere length by fluorescence in situ hybridization of LCH LC and lymphocytes in local, multisystem and systemic LCH and compared these with telomere lengths of LC and lymphocytes in reactive lymph nodes.
Besides the expression of several genes known to be highly expressed in LCs and LCH such as CD1a, LYZ, and CD207, high expression of genes not previously reported to be expressed in LCs, such as GSN, MMP12, CCL17, and CCL22, was also identified.
The study was performed on 50 specimens from 32 children (19 boys and 13 girls), median age 3 1/4 years, range 5 months to 12 1/3 years with a definite diagnosis of LCH based on CD1a positivity.