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 contain 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 normal physiological percentage of lymphocytes is 20%-40%, and above 40% is called high lymphocyte percentage.
Increased lymphocyte percentage is mainly seen in infectious diseases and mainly viral infections such as: infectious mononucleosis, measles, chicken pox, mumps, viral hepatitis, epidemic hemorrhagic fever, but also in whooping cough, tuberculosis, brucellosis, syphilis, etc. The number of lymphocytes increases in these conditions, as does the percentage. In addition, lymphocytosis can occur in a variety of lymphomas (including acute lymphocytic leukemia, chronic lymphocytic leukemia, and some lymphomas), in recovery from acute infectious diseases, and after transplant rejection. There are also conditions that cause a decrease in the number of other cells and thus a relative increase in the percentage of lymphocytes, but not in the absolute value of lymphocytes, such as aplastic anemia, granulocytopenia, and granulocyte deficiency.
In general, there are many causes of high lymphocyte percentage, but a high percentage of lymphocytes in routine blood tests alone is not very meaningful for diagnosing the disease and needs to be combined with clinical symptoms and other relevant laboratory tests.