Lymphocytes are mainly divided into three categories: T cells, B cells and natural killer (NK) cells, which are the main immune cells of the body.
Normal reference value of lymphocytes: adults (0.8-4) × 10*9/L. The number of lymphocytes is affected by both physiological and pathological factors.
Physiological increase of lymphocytes includes higher in the afternoon and evening than in the morning. Lymphocytes can reach more than 50% in infants 1 week after birth, which can last for 6-7 years, and then gradually decrease to adult level.
Pathological increase in lymphocytes is commonly caused by: infectious diseases (recovery from typical acute bacterial infections, acute infectious diseases caused by certain viruses, recovery from or chronic phase of certain chronic infections such as tuberculosis); neoplastic diseases (predominantly primitive and naive lymphocytosis: acute lymphocytic leukemia, acute transformation of chronic lymphocytic leukemia; predominantly mature lymphocytosis: chronic lymphocytic leukemia, lymphocytic lymphoma); post-transplantation of tissues (increased absolute value of lymph count in the pre-rejection period, which can be used as one of the indicators for monitoring the rejection of tissue and organ transplants); certain hematological diseases (aplastic anemia, granulocytopenia and granulocyte deficiency are relatively high lymphocytes); drugs (aspirin, levodopa, phenobarbital etc.).
Therefore, it is not very meaningful to diagnose diseases based on high absolute values of lymphocytes in routine blood alone, but needs to be combined with clinical symptoms and other relevant laboratory tests.