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

The clinical, histologic, and immunohistologic features of three cases of pre-T-cell (CD7+/CD2-) lymphoblastic lymphoma in adults are reported. The patients were adults over age 50 years who had a relatively indolent nodal disease, partial involvement of lymph nodes, and primitive immunophenotype. The phenotype of the three cases was TdT+, HLA-DR+, CD34+, CD71+, CD38+, and CD7+, most resembling the normal prothymocyte, and in contrast to normal thymocytes, which generally coexpress CD1+, CD4+, and CD8+. The prethymic T-cell character was further supported by germline T-cell receptor beta and gamma chain genes. In contrast to most reported cases with this early immunophenotype, these patients had nodal disease but not peripheral blood involvement. Two of the three cases were associated with Langerhans' cell histiocytosis (histiocytosis X), a previously unreported association. Because of the Langerhans' cell histiocytosis and the relatively indolent clinical presentation, the differential diagnosis in all cases included both a benign process and a lower-grade lymphoma. Recognition of this unusual form of adult lymphoblastic lymphoma is essential for correct diagnosis and treatment.
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PMID:Prethymic adult lymphoblastic lymphoma. A clinicopathologic and immunohistochemical analysis. 147 28

The immunophenotypic properties of the abnormal cells in routine specimens from 16 cases of Langerhans cell histiocytosis (LCH) were examined. In five cases, cryostat sections were also available. The abnormal cells expressed a similar phenotype and were positive for HLA-DR, S-100 protein, peanut agglutinin (PNA), CD1a, CD4 and several macrophage-associated markers, including CD11c, CDw32 and CD68 (the latter detectable in routine sections with antibody KP1). Staining with CD14, CD35 (C3b receptor), and CD11b (C3bi receptor) was negative with the exception of one of the cases in which a proportion of the cells showed faint positivity with CD11b. Staining for pan-T-cell (CD2, CD3, CD5) and pan-B-cell (CD19, CD22) antigens was negative in all lesions. It is concluded that LCH expresses a characteristic phenotype with some heterogeneity with regard to macrophage markers and that immunohistochemical methods in cryostat sections and routine specimens form a useful supplement to other techniques for the diagnosis of this condition.
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PMID:Immunohistochemical study of the abnormal cells in Langerhans cell histiocytosis (histiocytosis x). 210 27

The morphological, ultrastructural and immunophenotypic properties of Histiocytosis-X (H-X) cells were investigated in a lymph node involved by Letterer-Siwe (L-S) disease. H-X cells were T6+ (CD1a), S-100+, T4+ (CD4) and HLA-DR+; in addition they were consistently T11+ (CD2) and were stained by antibodies directed against receptors for transferrin (T9), C3bi (OKM-1/CD11b), IgG-Fc (Leu-11/CD16) and Interleukin-2 (IL-2R/CD25). On immunostained cytosmears, T6+ cells were highly polymorphic and a prominent fraction (45%) showed immature morphology, characterized by lymphoid appearance. Cells expressing macrophage markers (ANAE, AACT, Leu-M3/CD14, PAM-1) were 10-fold fewer than T6+ cells and did not show a lymphoid morphology. At TEM level, H-X cells were characterized by poor content of LC granules and by the presence of myelin-like laminated bodies and of lysosome-like dense bodies. The immunophenotypic properties of H-X cells were compared to those of epidermal Langerhans cells (LCs) and of LCs present in lymph nodes of three cases of dermatophatic lymphadenitis. Epidermal LCs were T6+/HLA-DR+, and sometimes faintly T4+. Lymph node LCs were T6+, S-100+, T4+, HLA-DR+, and showed the same variety of surface receptors detected in H-X cells; furthermore, in a case with massive infiltration of the paracortex by T6+ cells, lymph node LCs were faintly T11+ and some of the T6+ cells had lymphoid aspect. Our findings suggest that the H-X cell population of L-S disease is not homogeneous, but is composed of discrete cell subsets with distinctive antigenic and morphological traits closely resembling those of cells of LC lineage at different maturational stages.
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PMID:Letterer-Siwe disease: immunohistochemical evidence for a proliferative disorder involving immature cells of Langerhans lineage. 313 61

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

The immunophenotype and proliferation fraction have been investigated in 26 cases of Langerhans' cell histiocytosis (LCH). In all cases LCH cells were positive for S-100 protein, CD1a, or both. In most cases LCH cells expressed the macrophage-associated marker CD68 and in two cases they contained lysozyme. Expression of both cytoplasmic CD2 and CD3 was observed in cryostat sections. An unexpected finding was the presence of placental alkaline phosphatase in LCH cells. Langerhans' cells in normal skin were negative for both CD2 and CD3, but a proportion contained placental alkaline phosphatase. In four cases of Rosai-Dorfman disease the histiocytic cells, which share certain immunophenotypic properties with Langerhans' cells, also were positive for placental alkaline phosphatase. A significant proportion of LCH cells stained positively with the antibody to proliferating cell nuclear antigen and also with the proliferation marker Ki-S1. A good correlation between the percentage of Ki-67-positive and proliferating cell nuclear antigen- and Ki-S1-positive cells, respectively, was observed. Thus, in comparison with their putative precursors, LCH cells have an aberrant phenotype and are proliferating locally. This might suggest that LCH is a neoplastic rather than a reactive process.
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PMID:Langerhans' cell histiocytosis (histiocytosis X): immunophenotype and growth fraction. 769 Jul 35

Langerhans cell histiocytosis (LCH) is related to the proliferation of cells, which are similar to Langerhans cells (LC) but possess many abnormal characteristics. Lesions are widespread and this fact suggests that LCH cells or their precursors are present in the blood of patients. In five adult patients, we have isolated and cultured CD34+ blood progenitors of dendritic cells. We studied their phenotype by flow cytometry and their functional properties in mixed culture with heterologous lymphocytes and with autologous lymphocytes in the presence of tri-nitro-phenyl antigen (TNP). The amount of CD34+ precursors was dramatically higher than controls but a high mortality occurred during the in vitro differentiation. The phenotype of surviving cells was similar to LC phenotype (CD1a+, CD83+, Lag+) but some of them expressed CD2. These cells were able to induce T cell proliferation in mixed culture. They could not initiate primary response to TNP, except in a patient treated with thalidomide. In our hands, these CD34+ cells may be precursors of LCH cells.
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PMID:Presence of circulating abnormal CD34+ progenitors in adult Langerhans cell histiocytosis. 1040 33

Four patients presented with acute leukemia of ambiguous or myeloid lineage in association with Langerhans cell histiocytosis and provide evidence suggesting a common origin of the two neoplasms. One patient had a non-constitutional trisomy 21 in both the leukemic blasts and the Langerhans cells indicative of a clonal relationship. A second case expressed CD2, CD13, and CD117 on both the Langerhans cells and the blasts suggesting a possible clonal relationship. All four cases exhibited geographic intermingling of the Langerhans cell histiocytosis and acute leukemia and shared unique features including extramedullary leukemia involving lymph nodes in all cases with Langerhans cell histiocytosis only present in sites involved by acute leukemia. T-cell antigen expression was present in all cases with one meeting criteria for mixed phenotype acute leukemia, T/myeloid, not otherwise specified. These findings support the concept that coexistent Langerhans cell histiocytosis and acute leukemia is clonally related in some cases. Furthermore, these cases of acute myeloid or acute leukemia of ambiguous lineage with Langerhans cell histiocytosis share some unique features suggesting a common underlying neoplastic hematopoietic stem cell.
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PMID:Langerhans cell histiocytosis in acute leukemias of ambiguous or myeloid lineage in adult patients: support for a possible clonal relationship. 2418 34