Lenfoid

Lenfoid is a term used in some contexts to denote lymphoid tissue or tissues and cells associated with the lymphatic immune system. In modern English usage, the standard term is lymphoid. The word appears in older texts and in certain languages as an equivalent or variant spelling, but it generally refers to components derived from or resembling lymphocytes and related immune cells, including B and T lymphocytes, and their supportive cells and structures.

Lymphoid tissue is organized into primary and secondary lymphoid organs. Primary lymphoid organs, such as the bone marrow and thymus, are where lymphocytes develop and mature. Secondary lymphoid organs, including lymph nodes, the spleen, and mucosa-associated lymphoid tissue (MALT), are sites where immune responses are initiated. Lymphoid tissue can be diffuse or organized into lymphoid follicles, which may contain germinal centers where B cells proliferate and differentiate during an immune response.

Functionally, lymphoid tissue supports antigen recognition and the initiation of adaptive immune responses. It provides an environment for lymphocyte activation, clonal expansion, and differentiation into effector and memory cells. Lymphoid tissue also filters antigens from lymph and blood, enabling coordinated humoral and cell-mediated immunity.

Clinical notes often focus on changes in lymphoid tissue. Lymphadenopathy, or enlarged lymph nodes, can result from infection, autoimmune disease, or malignancy such as lymphoma. Other conditions include lymphoid hyperplasia, immunodeficiency-related alterations, and age-related involution of lymphoid organs. The term lenfoid is largely superseded by lymphoid in contemporary medical writing.