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Ipertesto Neoplasie










Le cellule di Langerhans (LC) fanno parte, con le cellule interdigitate delle zone paracorticali del linfonodo, del sistema cellulare con funzione di "presentazione dell'antigene". Il profilo immunofenotipico delle LC, utile per la loro individuazione su sezioni di tessuto, comprende la proteina S100, l'antigene CD1a e la Langerin, una proteina implicata nella genesi dei granuli di Birbeck. 





  S100 CD1a LANGERIN  
ISTIOCITOSI A CL +++ +++ ++  


In questo caso di istiocitosi a cellule di Langerhans linfonodale si evidenziano aggregati 

di cellule monocitoidi caratterizzate da intensa espressione di CD1a ed S100. 



                    Linfonodo con Istiocitosi a cellule di Langerhans E.E.



    CD1a                                  CD1a



  CD1a                                S100






J Clin Pathol 1982 Mar;35(3):327-37
Combined immunological and histochemical analysis of skin and lymph node lesions in histiocytosis X.

Thomas JA, Janossy G, Chilosi M, Pritchard J, Pincott JR

The immunological phenotype of the cells involved in skin and lymph node lesions from two cases of histiocytosis X (H-X) were analysed by immunofluorescence techniques using combinations of heterologous and monoclonal antisera to Ia-like antigen and human cortical thymocyte (HTA-1) determinant. These cells were also characterised by a new technique using simultaneous immunofluorescence and enzyme histochemistry for acid phosphatase (ACPase). The major cell type in the lesions was found to express the same Ia+, HTA-1+ phenotype as normal epidermal Langerhans' cells (LC) and was unreactive for ACPase. Additional cell types included Ia-, HTA-1- multinucleate giant cells and residual lymphoid populations. These findings endorse previous concepts that H-X is a proliferation of abnormal LC and emphasise the heterogeneous nature of the cells involved in the disease.

J Invest Dermatol 1988 Apr;90(4):441-7
The phenotypic spectrum of histiocytosis X cells.

Groh V, Gadner H, Radaszkiewicz T, Rappersberger K, Konrad K, Wolff K, Stingl G

Department of Dermatology I, University of Vienna Medical School, Austria.

Proliferating cells in histiocytosis X (histiocytosis X cells) share many structural and immunophenotypic features with Langerhans cells, leading to the assumption that histiocytosis X represents a proliferative disorder of Langerhans cells. Because, depending on their state of activation and/or differentiation, Langerhans cells exhibit a varying immunophenotype, we investigated whether histiocytosis X cells display a similar phenotypic heterogeneity and, if so, whether the heterogenous biological behavior of histiocytosis X is reflected by differences in the immunophenotype of the proliferating cells. In 21 patients suffering from different clinical manifestations of histiocytosis X, proliferating cells uniformly expressed class I and II alloantigens, T200, CD1, CD4, and S100 protein. In 12 of 21 cases, histiocytosis X cells additionally exhibited immunocytochemically detectable amounts of C3b and C3bi receptors and certain monocyte/macrophage antigens (CDw14, Ki-M1, Ki-M6). This immunophenotypic heterogeneity of histiocytosis X cells could not be correlated with clinical course, prognosis, and final outcome of the disease in a given patient. The capacity of histiocytosis X cells to immunophenotypically mimic various states of Langerhans cell activation and/or differentiation, however, underscores the concept of histiocytosis X as a proliferative disorder of Langerhans cell origin.

Mol Biol Cell 2002 Jan;13(1):317-35
Birbeck granules are subdomains of endosomal recycling compartment in human epidermal Langerhans cells, which form where Langerin accumulates.

Mc Dermott R, Ziylan U, Spehner D, Bausinger H, Lipsker D, Mommaas M, Cazenave JP, Raposo G, Goud B, de la Salle H, Salamero J, Hanau D.

Unite Mixte de Recherche 144 Centre National de la Recherche Scientifique, Laboratoire Mecanismes Moleculaires du Transport Intracellulaire, Institut Curie, 75248 Paris, France.

Birbeck granules are unusual rod-shaped structures specific to epidermal Langerhans cells, whose origin and function remain undetermined. We investigated the intracellular location and fate of Langerin, a protein implicated in Birbeck granule biogenesis, in human epidermal Langerhans cells. In the steady state, Langerin is predominantly found in the endosomal recycling compartment and in Birbeck granules. Langerin internalizes by classical receptor-mediated endocytosis and the first Birbeck granules accessible to endocytosed Langerin are those connected to recycling endosomes in the pericentriolar area, where Langerin accumulates. Drug-induced inhibition of endocytosis results in the appearance of abundant open-ended Birbeck granule-like structures appended to the plasma membrane, whereas inhibition of recycling induces Birbeck granules to merge with a tubular endosomal network. In mature Langerhans cells, Langerin traffic is abolished and the loss of internal Langerin is associated with a concomitant depletion of Birbeck granules. Our results demonstrate an exchange of Langerin between early endosomal compartments and the plasma membrane, with dynamic retention in the endosomal recycling compartment. They show that Birbeck granules are not endocytotic structures, rather they are subdomains of the endosomal recycling compartment that form where Langerin accumulates. Finally, our results implicate ADP-ribosylation factor proteins in Langerin trafficking and the exchange between Birbeck granules and other endosomal membranes.