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

Histological features of tuberculosis are caseation necrosis and epithelioid cell granuloma formation. Both phenomena are interpreted as expression of cellular immunity. Caseation necrosis is thought to be immunopathology and epithelioid cell granuloma formation is considered to be expression of protective immunity. Recently roles of cytokines for granuloma formation are gradually elucidated. In this symposium, mechanisms and functions of necrosis and granuloma formation Dr. Akagawa reported differentiation of two types of phenotypically different macrophages from human monocytes by GM (granulocyte-macrophage)-CSF or M (macrophage)-CSF. Interestingly such a basic differentiation induced by CSF was affected by IL-4 (interleukin-4). Langerhans-like dendritic cells were generated by cooperation of GM-CSF and IL-4, and multinucleated cells were generated by cooperation of IL-4 and M-CSF. Dr. Fukuda reported human Langerhans cell granulomatosis (LCG) from the pathological and immunohistochemical standpoints. In situ proliferation of LCs in the LCG was demonstrated by immunohistochemistry using antibody to PCNA (proliferating cell nuclear antigen) which is used to detect proliferating cells. In the course of granuloma formation, damage and disruption of lung structure such as alveolar basement membrane and elastic tissue framework, and reactive intraluminar fibrosis was observed. Mechanism of cystic dilation was also reported. Cytokines might play important roles in these events. Dr. Ina demonstrated experimental epithelioid cell granuloma formation. Extract (granuloma inducing factor, GIF) from Schistosoma mansoni Egg-induced granuloma, TNF -alpha, or IL-1 beta were coated, individually on the surface of beads, then these beads were inoculated to rat's skins or cultured with rat's monocytes. Four weeks later, epithelioid cell granuloma was demonstrated histologically and electronmicroscopically around beads in vitro and in vivo. GIF-induced granuloma was more organized than cytokine-induced ones. In vitro using human monocytes, activated macrophages accumulated around beads of which cytokines or GIF were coated. It was suspected that many cytokines or other factors are needed to make epithelioid cell granuloma. Dr. Sakamoto showed the presence of acid fast bacilli and various inflammatory cells including lymphocytes and macrophages in the tuberculous caseous necrosis after exudative reaction (E-necrosis) by immunohistochemistry. But no acid fast bacilli or inflammatory cells were found in the caseous necrosis after productive reaction (P-necrosis). TNF-alpha (tumor necrosis factor-alpha) and IL-4 were stained in the E-necrosis and IL-4 and ICAM-1 (intercellular adhesion molecule-1) were positively stained in the cytoplasm of epithelioid cells by immunohistochemistry. It was suspected that many cells and cytokines were involved in epithelioid cell granuloma formation and caseous necrosis formation.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[The 69th annual meeting symposium. II: Mechanism of necrotizing granuloma formation and its function]. 779 74

Langerhans' cell histiocytosis (LCH) is characterized by an accumulation and/or proliferation of cells with a Langerhans' cell (LC) phenotype. The aetiology and pathogenesis of LCH are unknown; it is suggested that LCH is caused by an immunological dysregulation. Production of cytokines is a central feature of immunological regulation. LCH lesions and normal LCs were studied for the presence of cytokines known to influence the functioning of LCs: IL-1 alpha, IL-1 beta, IL-4, GM-CSF, IFN-gamma, TGF-alpha, TGF-beta, bFGF, and TNF-alpha. Cytokines were abundantly present within LCH lesions; LCH cells stained for IL-1 alpha, IL-1 beta, IL-4, GM-CSF, TGF-alpha, TGF-beta, TNF-alpha, and IFN-gamma. Macrophages, lymphocytes, eosinophil granulocytes, and, surprisingly, multinucleated giant cells were also sources of cytokines. These results suggest that cytokines play a prominent role in the pathogenesis of LCH and may explain phenomena that often occur in LCH, such as osteolysis and fibrosis and the recruitment of typical inflammatory infiltrates. The results also suggest that a 'down-regulatory' signal is lacking in LCH, resulting in an accumulation and/or proliferation of abnormal LCs.
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PMID:The presence of cytokines in Langerhans' cell histiocytosis. 901 61

Langerhans cell histiocytosis (LCH) is characterized by a clonal proliferation and retention of cells with a Langerhans cell (LC)-like phenotype at various sites within the body. The present study set out to elucidate whether aberrant expression of chemokine receptors or dysregulation of chemokine production in LCH lesions could explain abnormal retention of these cells. Immunohistochemical analysis on 13 LCH biopsies of bone, skin, and lymph node all expressed the immature dendritic cell (DC) marker CCR6 on the lesional LCs and absence of the mature DC marker CCR7. Furthermore, regardless of the tissue site, LCH lesions markedly overexpressed CCL20/MIP-3alpha, the ligand for CCR6. The lesional LCs appeared to be the source of this CCL20/MIP-3alpha production as well as other inflammatory chemokines such as CCL5/RANTES and CXCL11/I-TAC. These may explain the recruitment of eosinophils and CD4+CD45RO+ T cells commonly found in LCH lesions. The findings of this study emphasize that, despite abundant TNF-alpha, lesional LCs remain in an immature state and are induced to produce chemokines, which via autocrine and paracrine mechanisms cause not only the retention of the lesional LCs but also the recruitment and retention of other lesional cells. We postulate that the lesional LCs themselves control the persistence and progression of LCH.
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PMID:Aberrant chemokine receptor expression and chemokine production by Langerhans cells underlies the pathogenesis of Langerhans cell histiocytosis. 1274 70