Lymphocytes are divided into three main categories: T cells, B cells and natural killer (NK) cells are the main immune cells in the body, and observing changes in their numbers helps to understand the state of the body’s immune function. Absolute lymphocyte reduction refers to a decrease in the absolute value of peripheral blood lymphocytes.
Normal reference value of lymphocytes: adults (0.8-4) × 10*9/L. The number of lymphocytes is affected by both physiological and pathological factors. Absolute lymphocyte reduction is commonly seen for the following reasons: lymphocyte reduction during recovery from influenza: HIV infection, which selectively destroys CD4+ cells leading to a significant reduction in CD4+ cells and an inverted CD4+/CD8+ ratio; tuberculosis, where early lymphocyte reduction CD4+ cells are significantly reduced and lymphocytes can return to normal if treatment is effective; alkylating agents (cyclophosphamide etc.) can cause a significant decrease in leukocytes, accompanied by a significant decrease in lymphocytes, and the decrease in lymphocytes can persist for several years after stopping treatment; radiation therapy can destroy lymphocytes, with each low-dose radiation therapy producing more destruction than 2 high-dose radiation therapies per week; immune diseases such as systemic lupus erythematosus, rheumatoid arthritis, mixed connective tissue disease, and polymyositis, due to antibodies producing anti-lymphocyte antibodies, resulting in Lymphocyte destruction and reduction, and the degree of reduction correlates with the titer of the antibody; congenital immunodeficiencies, such as various types of severe combined immunodeficiency, ataxia capillaris, malnutrition, or zinc deficiency, can cause lymphocytopenia to varying degrees. Certain drugs can also cause lymphopenia, such as menadione, nitrogen mustard phenylbutyrate, cortisone, epinephrine, lithium, nicotinic acid, steroids, etc.
Therefore, there are many factors leading to decreased absolute lymphocyte values, and it is not very meaningful to diagnose the disease based on low percentage of lymphocytes in routine blood alone, which needs to be combined with clinical symptoms and other relevant laboratory tests.