Mucosa-associated lymphoid tissue

Mucosa-associated lymphoid tissue (MALT) is a diffuse system of small concentrations of lymphoid tissue found in various submucosal membrane sites of the body, such as the gastrointestinal tract, nasal passages, thyroid, breast, lung, salivary glands, eye, and skin. The term MALT is often used synonymously with mucosa-associated lymphoid tissue.

Structure

MALT is populated by lymphocytes such as T cells and B cells, as well as plasma cells and macrophages, each of which is well situated to encounter antigens passing through the mucosal epithelium. In the case of the gut, MALT acquires antigens from the lumen of the gut via specialized cells, known as M cells, that reside in the Peyer's patches.

Function

The primary function of MALT is to facilitate the immune response within the mucosa. Antigens that are found in the mucosa are taken up by the M cells and delivered to the underlying lymphoid tissue where an immune response is initiated.

Clinical significance

MALT is involved in the pathogenesis of various diseases, including MALT lymphoma, a type of B-cell lymphoma, which is associated with chronic inflammation as a result of persistent infections or autoimmune diseases.

See also

• Gut-associated lymphoid tissue
• Bronchus-associated lymphoid tissue
• Nasal-associated lymphoid tissue
• Lymphatic system
• Immune system