APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Natural killer (NK) cells are innate lymphocytes that provide cytokines critical for early host defense against pathogens. One subset of human NK cells (CD56bright) constitutively expresses the high-affinity interleukin 2 (IL-2) receptor and produces immunoregulatory cytokines.

Detailed explanation-2: -Natural Killer (NK) Cells are lymphocytes in the same family as T and B cells, coming from a common progenitor. However, as cells of the innate immune system, NK cells are classified as group I Innate Lymphocytes (ILCs) and respond quickly to a wide variety of pathological challenges.

Detailed explanation-3: -Natural killer (NK) cells represent a subgroup of white blood cells. Since their identification in 1975 (1, 2), NK cells have been classified as lymphocytes on the basis of their morphology, their expression of many lymphoid markers, and their origin from the common lymphoid progenitor cell in the bone marrow.

Detailed explanation-4: -Natural killer (NK) cells are lymphocytes of the innate immune system that participate in early defense against foreign cells and autologous cells undergoing various forms of stress, such as microbial infection or tumour transformation [1, 2].