What is the absolute count of lymphocytes?
Absolute lymphocyte count refers to the number of lymphocytes per liter of blood. When suffering from infectious diseases, especially viral infectious diseases, the absolute lymphocyte count will increase. In the case of using anti-immune drugs, alkylating agents, and immune deficiency diseases, the absolute lymphocyte count will decrease.
T cells, or thymus-dependent lymphocytes, are derived from bone marrow-derived lymphoid stem cells and differentiate in the thymus. Mature T cells migrate to peripheral lymphoid organs or lymphoid tissues and remain relatively quiescent before encountering specific antigen molecules, known as naive T cells.
B cells, or bone marrow-dependent lymphocytes, originate from the bone marrow and account for 50~10% of the total number of blood lymphocytes. Naive B cells that mature in the bone marrow leave the bone marrow and migrate to surrounding lymphoid organs and tissues. After being stimulated by antigens, they proliferate and differentiate into effector B cells, namely plasma cells, which synthesize and secrete antibodies to perform immune functions. A small number transform into memory B cells for storage, with the same role as memory T cells.
NK cells, or natural killer cells, are derived from lymphoid stem cells in the bone marrow, accounting for 10~15% of the total number of blood lymphocytes. They lack the molecular marker characteristics of B cells and T cells and can directly kill virus-infected cells, tumor cells, and allogeneic cells. NK cells resemble large lymphocytes and contain many variable-sized azurophilic granules in the cytoplasm, hence they are also known as large granular lymphocytes.
① Infectious diseases: such as measles, rubella, chickenpox, mumps, etc.; ② Certain hematological diseases: such as lymphocytic leukemia, lymphoma, etc.; ③ Recovery period of acute infectious diseases; ④ Rejection reaction period after organ transplantation, etc.
The main reasons for decreased numbers are the use of chemical drugs such as adrenal corticosteroids or exposure to radiation, suffering from immune deficiency diseases, and patients in the acute phase of certain infectious diseases.
