Las células del sistema inmune accesorio

Abstract

In the reticulo- Endothelial System (RES9, named at present Accesory Inmune System (AIS), two chieff groups of cells can be recognized:

1- Antigen - presnting cells: Dendritic cells

2- Antigen - processing cells: Macrophages (or Histiocytic cell) 

These cells are wildely disseminated into human organs and tissues: lymphoid organs, blood, liver, endocrine glands, lung, skin, blood vessels, central and peripheral nervous systems (CNS and PNS), placenta. kidney, and soft tissues.

Dendritics cells and macrophages can be observed in tissues with silver impregnation technique of Del Río Hortega - Polak, or with multiple specific immunohistochemical stains.

The origin of macropage / monocyte is from common pluripoyencial bone marrow progenitor cell, with susequently stages of maturation:

Colony - Forming Units (CFU-S), Colony- Forming Units of Granulocyte / Macrophage (CFU-G/M), Colony - Forming Units of Macrophages/ Monocytes. 

The origin of dentritic cells is heterogenous. Their lineage is from the same bone marrow precursors of macrophages/ monocytes, but there are recent evidences that also may have a lymphoid origin.

Macrophages play important roles in: 1- Phagocytosis. 2- Natural Immunity. 3- Secretion of Cytokines. 4- Antigen presentation. The primary function of dentritic cells is the presentation of antigen and activation of T lymphocytes. 

Nonmalignant reactive disorders and true malignant neoplasms of macrophages and dentritic cells, have been actually reviewed.

Between the main entities of these groups there are:

1- Nonmalignant reactive macrophages disorders: Hemophagocytic Syndromes. Sinus Histiocytosis with Massive Lymphadenopathy (Rosai- Dorfman disease) 

And nonmalignant reactive Langerhans cells disorders: Langehans's - cell Histiocytosis (Histiocytosis X)

2- True malignant Histiocytic Sarcoma (Reticulum cell Sarcoma). Malignant Histiocytosis. Microglioma of CNS

3- True Malignant neoplasm of dentritic cells: Folicular Dentritic Cell Sarcoma and Interdigitating Dentritic Cell Sarcoma. 

True malignant Langerhans cell neoplasm has not been yet clearly demonstrated.

Finally, it is important to note that marcrophages and dentritic cells are commonly observed as reactive cells in numerous malignant tomors (carsinomas, sarcomas, lymphomas, etc) However, their precise role has yet to be determined.