Anatomy & Organs

Langhans giant cells – structure, function & diseases

Langhans giant cells

The Langhans giant cells are immune cells from fused macrophages and form a typical component of inflammatory granulomas.

Their exact function in the immune system has not yet been fully elucidated. They have been observed in the context of infections such as leprosy and chronic inflammation such as Crohn’s disease or sarcoid.

What are Langhans giant cells?

Macrophages are the scavenger cells of the immune system . These are mobile and mononuclear cells of the cellular defense system. They arise in the serum from circulating peripheral monocytes, which migrate into tissue and can spend several weeks there as tissue macrophages.

Macrophages can fuse as part of a granulomatous inflammatory immune reaction to form what are known as Langhans giant cells. This immunological cell type is named after Theodor Langhans and thus after the director of the Pathological Institute at the University of Bern. In the 19th century he coined the term “giant cell” and used it to describe greatly enlarged cells with multiple cell nuclei . Although they were discovered more than a century ago and their structure has been well understood to this day, the exact function of the Langhans giant cells in the context of the immune system has not yet been conclusively researched.

Other cells from the giant cell group are the Sternberg giant cells, the foreign body giant cells and the osteoclasts or megakaryocytes . Similarly specialized macrophages are the so-called epithelial cells. Langhans giant cells are among the inflammatory infiltrates, which also include neutrophilic granulocytes.

Anatomy & Structure

Like all other giant cells, the Langhans giant cells have several cell nuclei and are greatly enlarged cells with a diameter of around 0.3 millimeters. Foreign body giant cells are formed by macrophage fusion during foreign body phagocytosis.The Langhans giant cells can be distinguished from them anatomically by the horseshoe-shaped rows at the edge that underlie their individual cell nuclei in the cytoplasmic tissue. Some Langhans giant cells are equipped with Schaumann bodies and asteroid bodies. The Schaumann bodies are round-oval inclusions made of proteins and calcium that carry a lamellar layer. Asteroid bodies, on the other hand, are star-shaped inclusions.

Langhans giant cells a characteristic component of the granuloma. This is the knot-like formation of new tissue that forms as a reaction to chronic inflammatory stimuli or allergies . In addition to giant cells and endothelial cells, they also contain epitheloid cells and mononuclear inflammatory cells such as lymphocytes or simple macrophages.

Function & Tasks

The fusion of macrophages to form Langhans giant cells has so far been observed primarily in the context of granulomatous diseases. Such diseases can have different causes. The giant cells were detectable, for example, in infectious diseases such as leprosy , tuberculosis and schistosomiasis . Langhans giant cells have also been detected as an inflammatory infiltrate of the chronic inflammatory processes in the context of Crohn’s disease , sarcoid and rheumatoid arthritis .

The specific task of the Langhans giant cells has not yet been scientifically clarified. Presumably, they play a role in the phagocytosis of specific antigens and can therefore be assigned to the phagocytes. Phagocytosis is the uptake of extracellular solid particles and corresponds to a subtype of endocytosis. Phagocytes flow around foreign bodies in order to absorb them through invagination and constriction processes at the cell membrane. This is how large vesicles, the so-called phagosomes, form, which confluent with lysosomes. Thanks to the lyosomal enzymes , the phagosomes form phagolysosomes.

The enzymatic degradation of the antigens then begins within the phagolysosome. The phagocytosis of Langhans giant cells has been speculated primarily in the context of tuberculosis. In this disease they presumably absorb the tuberculous Mycobacterium tuberculosis and render it harmless. However, since this phenomenon was only observed at a low level of activity, the cells are primarily associated with the secretion of lysosomal enzymes. Only their specialization in granulomatous inflammation and thus their immunological activity is certain.

Diseases

The Langhans giant cells are a component of many granulomatous diseases of a chronic and acute nature. In the past, the enlarged cells from fused macrophages have also been associated with diseases such as myositis , in addition to those mentioned above .This is an inflammatory disease of the skeletal muscles . As a rule, myositis becomes noticeable through a progressive loss of strength and weakness, primarily in the muscles close to the trunk. Difficulty swallowing or muscle pain and muscle wastingare also common symptoms. Calcium salts sometimes accumulate and cause metaplasia in the affected muscles. The result is muscle ossification. Autoimmune processes are discussed as causes of myositis. This group of diseases is also often associated with other primary diseases, which can be of a viral, bacterial or parasitic nature. For example, leprosy and tuberculosis are associated with primary viral diseases.

Since the Langhans giant cells were mainly observed in connection with these two diseases, they also play a role in myositis such as tuberculotic myositis. Clinically, this form of myositis is manifested by swelling of the soft tissues. The tissue becomes necrotic and is colonized by Langhans giant cells. However, this form of myositis is extremely rare in Europe. Typical granulomas can be observed in lymph node tuberculosis. This disease shows a central necrosis with epitheloid cells and the Langhans giant cells in circumference. Acid-fast rods are often found in the necrotic tissue.

In patients with a poor immune system, however, the disease usually progresses without granuloma formation. In countries like Asia, unlike in Europe, the diseases mentioned are an everyday phenomenon. Granulomatous reactions also occur in syphilis , toxoplasmosis , fungal infections and parasitic infections. Granulomas have also been observed in carcinomas .

Lisa Newlon
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Hello! I am Lisa Newlon, and I am a medical writer and researcher with over 10 years of experience in the healthcare industry. I have a Master’s degree in Medicine, and my deep understanding of medical terminology, practices, and procedures has made me a trusted source of information in the medical world.