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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 pathogenesis of Langerhans cell histiocytosis (LCH) remains poorly understood. To further elucidate LCH pathogenesis, we analyzed the expression of 10 cytokines relevant to cellular recruitment and activation at the protein level in 14 patients and identified the lesional cells responsible for cytokine production in situ by immunohistochemistry. The cytokines investigated included the hematopoietic growth factors interleukin-3 (IL-3), IL-7, and granulocyte-macrophage colony-stimulating factor (GM-CSF); the lymphocyte regulatory cytokines IL-2, IL-4, and IL-10; the inflammatory regulators IL-1alpha and tumor necrosis factor-alpha (TNF-alpha); and the effector cell-activating cytokines IL-5 and interferon-gamma (IFN-gamma). In all specimens, CD1a(+) histiocytes (LCH cells) and CD3(+) T cells produced large amounts of cytokines, creating a true cytokine storm. IL-2, IL-4, IL-5, and TNF-alpha were produced exclusively by T cells, whereas only IL-1alpha was produced by LCH cells. Equal numbers of LCH cells, T cells, and macrophages produced GM-CSF and IFN-gamma. Equal numbers of LCH cells and macrophages produced IL-10, whereas IL-3 was produced by T cells and macrophages. IL-7 was only produced by macrophages. Eosinophils, present in some specimens, were partially responsible for the production of IL-5, IFN-gamma, GM-CSF, IL-10, IL-3, and IL-7. Expression of all cytokines, abundant in most biopsies, was irrespective of age, gender, or site of biopsy. These findings emphasize the role of T cells in LCH. The juxtaposition of T cells and LCH cells suggests that both cells interact in a cytokine amplification cascade, resulting from stimulation of autocrine and paracrine stimulatory loops. This cascade can be linked directly to the development of LCH through recruitment, maturation, and proliferation of LCH cells. The cytokines studied are known to be involved in the development of other characteristic features of LCH, such as fibrosis, necrosis, and osteolysis.
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PMID:Differential In situ cytokine profiles of Langerhans-like cells and T cells in Langerhans cell histiocytosis: abundant expression of cytokines relevant to disease and treatment. 1059 64

Langerhans cell histiocytosis (LCH) consists of lesions composed of cells with a dendritic Langerhans cell (LC) phenotype. The clinical course of LCH ranges from spontaneous resolution to a chronic and sometimes lethal disease. We studied 25 patients with various clinical forms of the disease. In bone and chronic lesions, LCH cells had immature phenotype and function. They coexpressed LC antigens CD1a and Langerin together with monocyte antigens CD68 and CD14. Class II antigens were intracellular and LCH cells almost never expressed CD83 or CD86 or dendritic cell (DC)-Lamp, despite their CD40 expression. Consistently, LCH cells sorted from bone lesions (eosinophilic granuloma) poorly stimulated allogeneic T-cell proliferation in vitro. Strikingly, however, in vitro treatment with CD40L induced the expression of membrane class II and CD86 and strongly increased LCH cell allostimulatory activity to a level similar to that of mature DCs. Numerous interleukin-10-positive (IL-10(+)), Langerin(-), and CD68(+) macrophages were found within bone and lymph node lesions. In patients with self-healing and/or isolated cutaneous disease, LCH cells had a more mature phenotype. LCH cells were frequently CD14(-) and CD86(+), and macrophages were rare or absent, as were IL-10-expressing cells. We conclude that LCH cells in the bone and/or chronic forms of the disease accumulate within the tissues in an immature state and that most probably result from extrinsic signals and may be induced to differentiate toward mature DCs after CD40 triggering. Drugs that enhance the in vivo maturation of these immature DCs, or that induce their death, may be of therapeutic benefit.
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PMID:Differentiation of Langerhans cells in Langerhans cell histiocytosis. 1156 38

We report a 1-year-old girl with Evans syndrome coexisting with histologically confirmed Langerhans cell histiocytosis (LCH) affecting the cervical lymph nodes, liver, and spleen. Anti-cardiolipin antibody, anti-SS-A antibody, and anti-SS-B antibody as well as a direct antiglobulin test and platelet-associated IgG were all positive at the onset, and these autoantibodies became negative with the resolution of LCH by chemotherapy. Serum T-helper-2 (Th2) cytokine levels such as those of interleukin (IL)-6 and IL-10 were high whereas those of Th1 cytokines such as IL-2 and interferon-gamma were low at the onset, and this cytokine imbalance was normalized during the resolution of LCH. These results suggest that cytokine imbalance due to LCH led to multiple autoimmune phenomena in the present patient.
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PMID:Evans syndrome in a patient with Langerhans cell histiocytosis: possible pathogenesis of autoimmunity in LCH. 1822 17

Although numerous macrophages are found in the lesions of Langerhans cell histiocytosis (LCH), their activation phenotypes and their roles in the disease process have not been clarified. Paraffin-embedded LCH samples were examined on immunohistochemistry and it was found that CD163 can be used to distinguish infiltrated macrophages from neoplastic Langerhans cells (LC). The number of CD163-positve macrophages was positively correlated with the number of multinucleated giant cells (MGC), indicating that most MGC are derived from infiltrated macrophages. A significant number of CD163-positive macrophages were positive for interleukin (IL)-10 and phospho-signal transducer and activator of transcription-3 (pSTAT3), an IL-10-induced signal transduction molecule. This indicates that these macrophages are polarized to anti-inflammatory macrophages of M2 phenotype. Tumor-derived macrophage-colony-stimulating factor (M-CSF) was considered to responsible for inducing M2 differentiation of infiltrated macrophages. The number of CD163-positive macrophages in different cases of LCH varied, and interestingly the density of CD163-positive macrophages was inversely correlated with the Ki-67-positivity of LC. Although the underlying mechanism is not fully elucidated, macrophage-derived IL-10 was considered to be involved in the suppression of tumor cell proliferation via activation of STAT3.
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PMID:Macrophages in Langerhans cell histiocytosis are differentiated toward M2 phenotype: their possible involvement in pathological processes. 2005 49