Mucosa-associated lymphoid tissue (MALT)

Mucosa-associated lymphoid tissue (MALT) is a diffuse collection of secondary lymphoid tissues found in various submucosal membrane sites throughout the body, including the gastrointestinal tract, respiratory tract, genitourinary tract, thyroid, breast, lung, salivary glands, eye, and skin[1][3]. It is composed of immune cells such as T cells and B cells (including plasma cells), dendritic cells, and macrophages. These tissues are strategically located to encounter antigens that enter the body through mucosal surfaces—the main entry points for pathogens[1][2][4]. MALT plays a crucial role in initiating local immune responses against specific antigens encountered at these surfaces. Specialized epithelial cells called M cells sample luminal antigens and deliver them to underlying antigen-presenting cells within the follicles. The activated T helper cells then assist B cell activation; both cell types can migrate to other parts of the body’s mucosal surfaces to provide protection[1][4]. Subtypes of MALT include gut-associated lymphoid tissue (GALT), bronchus-associated lymphoid tissue (BALT), nasal-associated lymphoid tissue (NALT), conjunctival-, larynx-, skin-, vulvo-vaginal-, testis-, and others[3]. Some forms are organized into discrete structures like Peyer’s patches or tonsils (“O-MALT”), while others are more diffusely distributed (“D-MALT”)[3]. Although “Mucosa-associated lymphoid tissue” is not a single molecular target but rather an anatomical/functional entity comprising multiple cell types and structures involved in immunity at mucosal barriers[1][3], it is clinically relevant due to its involvement in diseases such as infections or certain cancers like MALT lymphoma. Because it refers to a complex anatomical structure/system rather than a discrete molecule or receptor typically considered as drug targets (e.g., enzymes or receptors), this entry should be marked as incorrect for use as a canonical therapeutic target.

Other names

mucosa-associated lymphatic tissuemucosal-associated lymphoid tissuemucosal immune systemMALT system