Leukocytes can be classified into five types, namely neutrophils, eosinophils, basophils, lymphocytes and monocytes. The percentage of lymphocytes is the percentage of cells of that form in the total white blood cell count. The percentage of lymphocytes under normal physiological conditions is: 20%-40%.
Lymphocytes are produced by lymphoid organs and are an important cellular component of the body’s immune response function, producing and transporting antibodies and defending against viral infections.
Decrease in the percentage of lymphocytes: mainly seen in the application of adrenocorticosteroids, alkylating agents, anti-lymphocyte globulin and other treatments, as well as radiation damage, immunodeficiency diseases, gammaglobulin deficiency. The absolute number of lymphocytes is reduced and the percentage is decreased. In some other cases, the number of other cells increases, such as leukemia and severe bacterial infections, and the number of neutrophils increases dramatically and the percentage of lymphocytes decreases relatively.
Increased percentage of lymphocytes: mainly seen in infectious diseases and mainly viral infections, such as: measles, chickenpox, mumps, viral hepatitis, epidemic hemorrhagic fever, but also in whooping cough, tuberculosis, brucellosis, syphilis, etc. The number of lymphocytes increases in these cases, as well as their percentage. In addition, lymphocytosis can occur in neoplastic diseases (leukemia, lymphoma), during recovery from acute infectious diseases, and after organ transplantation. There are also conditions that can cause a decrease in the number of other cells and a relative increase in the percentage of lymphocytes, such as abnormal hematopoiesis.
Therefore, the determination of lymphocyte percentage helps to understand the immune function status of the body to judge the disease development, but there are many reasons for the change of lymphocyte percentage, and it is not very meaningful to diagnose the disease based on low lymphocyte percentage in blood routine alone, and it can only be used as an initial screening, and it also needs to be combined with clinical symptoms and other relevant laboratory tests.