Heterozygous lymphocytes are, as the name implies, morphologically abnormal lymphocytes. It is usually a relatively mature lymphocyte that has turned into a relatively not particularly mature state, which is commonly referred to as the revertant phenomenon. The morphological manifestations of anaplastic lymphocytes are mainly the enlargement of the cell body compared to normal lymphocytes, the deepening of chromatin color, and the possible appearance of vacuoles, all of which are morphological changes. Clinically, there are some normal people who may have a small amount of anisotropic lymphocytes, which usually does not exceed 2%, i.e., not more than 2% in peripheral blood. If more than 5% of anisotropic lymphocytes are found, it is still regarded as an abnormal state. The most common clinical cause of abnormal lymphocytes is viral infections, such as a disease called infectious mononucleosis in hematology, which means that the heterozygous lymphocytes will be >10%, and this is a disease that we often mention the presence of heterozygous lymphocytes, other viral infections, including herpes virus, epidemic hemorrhagic fever caused by hantavirus, and other Other viral infections, including herpes virus, epidemic hemorrhagic fever caused by hantavirus, and other viruses, may cause an increase in abnormal lymphocytes in the blood or bone marrow; of course, in addition to viral infections, there are also some oral medications and connective tissue diseases that may cause secondary increases in allogeneic lymphocytes.