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Query: UMLS:C0019621 (Langerhans cell histiocytosis)
 3,250 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Langerhans' cell histiocytosis (LCH) is characterized by an accumulation of cells with a Langerhans' cell (LC) phenotype. Most patients present with solitary skin or bone lesions, but multi-organ lesions may appear. Twenty-two LCH-tissue sections from 13 children and adolescents, with lesions at different sites, were investigated for the expression of leukocyte cellular adhesion molecules. Surprisingly, the LCH cells showed expression for CD2 in 11 lesions. Staining of LCH cells for CD11a and CD11b was positive in six and three lesions, respectively. Staining for CD11c, CD44, CD54, and CD58 was found consistently positive in all lesions. The strong reactivity for CD54 (intercellular adhesion molecule-1) and CD58 (leukocyte function antigen-3) is in contrast with the epidermal LC. LCs in culture are known to up-regulate the expression of CD54 and CD58. These changes are thought to reflect the in vivo situation during migration of activated LCs from the skin to the draining lymph node. It can be concluded that the abnormal cells in LCH not only share characteristics with the epidermal LC, but have additional characteristics of the activated LC, a cell capable of migration. The presumed immunological dysregulation in LCH may affect the expression of cellular adhesion molecules, reflected by the inconsistent expression of CD11a and CD11b and the unexpected expression of CD2. These features may contribute to migration of LCs to aberrant sites in combination with abnormal persistence and proliferation.
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PMID:Langerhans' cell histiocytosis: expression of leukocyte cellular adhesion molecules suggests abnormal homing and differentiation. 751 Apr 55

Langerhans cell histiocytosis (LCH) is characterized by lesions with an accumulation and/or proliferation of Langerhans cells (LCs). Little is known of the etiology and pathogenesis of LCH. Although the relation between the LCH cell and normal LCs is currently uncertain, the localizations of the LCH cells is considered aberrant when compared with normal LCs. Cellular adhesion molecules (CAMs) are known to play an important role in a variety of cell functions such as migration, antigen presentation, and activation. Aberrant migration of LCs may play a role in the pathogenesis of LCH. We investigated CAMs in 27 tissue specimens of 20 patients with LCH retrieved from our files during the last 15 years. LCH cells showed strong expression of CAMs such as CD54, CD58, and the beta 1-integrin alpha 4 that are upregulated during activation of normal LCs. In contrast, CAMs not found on normal LCs could be demonstrated in a number of cases on LCH cells like CD2, CD11a, and CD11b. Also CD62L, normally expressed only by epidermal LCs, could be detected on LCH cells. The integrins alpha 5 and alpha 6, not or only weakly found on epidermal LCs and highly expressed by activated LCs, could not be demonstrated on LCH cells. Our data suggest abnormal expression of CAMs on LCH cells that may contribute to abnormal migration of LCs in LCH. The aberrant phenotype of LCH cells has characteristics of both epidermal LCs and activated LCs and may be indicative of an arrested state of activation and/or differentiation of LCs.
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PMID:Expression of cellular adhesion molecules in Langerhans cell histiocytosis and normal Langerhans cells. 757 61