Histiocytes

Histiocytes are a type of immune cell that reside in many tissues throughout the human body. They are part of the mononuclear phagocyte system, a network of cells that play a crucial role in the body's defense against disease. Histiocytes are derived from monocytes, a type of white blood cell that circulates in the bloodstream.

Function

Histiocytes have several important functions in the body. They are primarily involved in the immune response, where they help to fight off infections and diseases. They do this by engulfing and digesting foreign substances, such as bacteria and viruses, a process known as phagocytosis. In addition to their role in immunity, histiocytes also play a role in tissue repair and inflammation.

Types of Histiocytes

There are several different types of histiocytes, each with their own specific functions. These include:

• Macrophages: These are the most common type of histiocyte. They are found in tissues throughout the body and are responsible for engulfing and digesting foreign substances.

• Dendritic cells: These histiocytes are found in the skin and mucous membranes. They are responsible for presenting antigens to T cells, a type of white blood cell that plays a key role in the immune response.

• Langerhans cells: These histiocytes are found in the skin and are involved in the immune response to skin infections.

Diseases Involving Histiocytes

There are several diseases that involve histiocytes, including:

• Histiocytosis: This is a group of diseases characterized by an overproduction of histiocytes. There are several types of histiocytosis, including Langerhans cell histiocytosis and non-Langerhans cell histiocytosis.

• Hemophagocytic lymphohistiocytosis: This is a rare and potentially life-threatening condition characterized by an overactive immune response. It is caused by an excessive number of histiocytes and T cells that attack the body's own tissues and organs.

See Also

• Mononuclear phagocyte system
• Immune system
• White blood cell
• Phagocytosis