出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/04/03 21:34:30」(JST)
| This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2008) |
| Histiocyte | |
|---|---|
| Latin | macrophagocytus mobilis |
| Code | TH H2.00.03.0.01009 |
A histiocyte is an animal cell that is part of the mononuclear phagocyte system (also known as the reticuloendothelial system or lymphoreticular system). The mononuclear phagocytic system is part of the organism's immune system. The histiocyte is a tissue macrophage[1][2] or a dendritic cell[3] ("histo-" = "tissue", and "-cyte" = "cell").
Contents
|
Histiocytes are derived from the bone marrow by multiplication from a stem cell. The derived cells migrate from the bone marrow to the blood as monocytes. They circulate through the body and enter various organs where they undergo differentiation into histiocytes which are part of the mononuclear phagocytic system (MPS).
However, the term "histiocyte" has been used for multiple purposes in the past, and some cells called "histocytes" don't appear to derive from monocytic-macrophage lines.[4] (The term Histiocyte can also simply refer to a cell from monocyte origin outside the blood system, such as in a tissue (as in rheumatoid arthritis as palisading histiocytes surrounding fibrinoid necrosis of rheumatoid nodules).
Some sources consider Langerhans cell derivatives to be histocytes.[5] The Langerhans cell histiocytosis embeds this interpretation into its name.
Histiocytes have common histological and immunophenotypical characteristics (demonstrated by immunostains). Their cytoplasm is eosinophilic and contains variable amounts of lysosomes. They bear membrane receptors for opsonins, such as IgG and the fragment C3b of complement. They express LCAs (leucocyte common antigens) CD45, CD14, CD33 and CD4 (also expressed by T Helper Cells).
These histiocytes are part of the immune system by way of two distinct functions: phagocytosis and antigen presentation. Phagocytosis is the main process of macrophages and antigen presentation the main property of dendritic cells (so called because of their star-like cytoplasmic processes).
Macrophages and dendritic cells are derived from common bone marrow precursor cells that have undergone different differentiation (as histiocytes) under the influence of various environmental (tissue location) and growth factors such as GM-CSF, TNF and IL-4. The various categories of histocytes are distinguishable by their morphology, phenotype and size.
A subset of cells differentiates into Langerhans cells; this maturation occurs in the squamous epithelium, lymph nodes, spleen, and bronchiolar epithelium. Langerhans cells are antigen presenting cells but have undergone further differentiation. Skin Langerhans cells express CD1a as do cortical thymocytes (cells of the cortex of the thymus gland). They also express S-100, and their nucleus contains tennis-racket like ultra-structural inclusions called Birbeck granules.
Histiocytoses describe neoplasias where the proliferative cell is the histiocyte.
The most common histiocyte disorders are Langerhans' cell histiocytosis and haemophagocytic lymphohistiocytosis.[6]
|
|||||||||||||||||||||||||||||||||||||||||||||||||||
全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.
| リンク元 | 「100Cases 33」「組織球性」 |
| 拡張検索 | 「diffuse histiocytic lymphoma」「histiocytic lymphoma」「malignant histiocytic disorder」「histiocytic sarcoma」 |