What Is Mucosa-Associated Lymphoid Tissue?

Mucosa-associated lymphoid tissue, commonly abbreviated as MALT, is an essential part of the immune system located in the mucous membranes lining various parts of the body. These mucous membranes are found in areas such as the respiratory tract, digestive tract, and urogenital tract. MALT plays a critical role in defending the body against pathogens that enter through these mucosal surfaces.

Function of MALT

MALT contains clusters of immune cells including lymphocytes and macrophages that monitor and respond to foreign invaders like bacteria, viruses and toxins. It acts as a first line of defence by recognising harmful agents and triggering immune responses to neutralise them. This tissue also helps develop immune tolerance, preventing unnecessary reactions to harmless substances such as food particles.

Types and Locations

There are several specialised types of MALT depending on their location. For example, gut-associated lymphoid tissue (GALT) is found in the intestines, while bronchus-associated lymphoid tissue (BALT) is located in the respiratory tract. Other examples include nasopharynx-associated lymphoid tissue (NALT) in the nasal passages and conjunctiva-associated lymphoid tissue (CALT) near the eyes.

Clinical Significance

Sometimes, MALT can give rise to certain types of lymphoma, known as MALT lymphomas. These are cancers of the immune cells within the tissue and most commonly affect the stomach but can occur in other mucosal sites. Understanding MALT is important for recognising its role in both immune defence and certain diseases.

Summary

Mucosa-associated lymphoid tissue is a vital part of the immune system found in mucous membranes throughout the body. It helps protect against infections entering through mucosal surfaces and contributes to immune regulation. Its involvement in some lymphomas highlights its clinical importance.