Lymphocytes are a class of cells derived from bone marrow hematopoietic stem cells that develop and mature in lymphoid organs and have the role of producing and transporting antibodies and defending against viral infections, and are an important cellular component of the body’s immune response function.
Leukocytes are mainly composed of neutrophils, monocytes, eosinophils, basophils and lymphocytes, therefore, two indicators of the percentage and absolute value of these cells are present in the routine blood tests. The lymphocyte percentage is the percentage of lymphocytes in the total white blood cell count. Under normal physiological conditions the lymphocyte percentage is 20-40%, below 20% is called a low lymphocyte percentage.
A decrease in lymphocyte percentage is mainly seen with a decrease in the absolute number of lymphocytes, for example, with the application of treatments such as adrenocorticosteroids, alkylating agents, anti-lymphocyte globulin, as well as with radiation damage, cellular immunodeficiency disease, congenital gammaglobulin deficiency. In some other cases a relative decrease in the lymphocyte percentage can occur, mainly due to an increase in the number of other cells, such as leukemia and severe bacterial infections, where the number of neutrophils increases significantly and the lymphocyte percentage decreases relatively.
Therefore, there are more causes of low lymphocyte percentage, but it is not significant to diagnose the disease based on low lymphocyte percentage in blood routine alone, it can only be used as an initial screening, and the diagnosis needs to be confirmed by combining clinical symptoms and other relevant laboratory tests.