Heterozygous lymphocytes, are lymphocytes that are morphologically atypical and the percentage of heterozygous lymphocytes is the percentage of such heterozygous lymphocytes in the peripheral blood as a percentage of all white blood cell degrees. Heterotypic lymphocytes can be seen in the peripheral blood of normal individuals, but not more than 2%. If the percentage of heterozygous lymphocytes is increased, it is common to have the following conditions Infectious diseases, especially viral infections such as infectious mononucleosis and epidemic hemorrhagic fever, the heterozygous lymphocytes in the peripheral blood can be up to 10% or more. In addition, an increase in allogeneic lymphocytes can also occur after drug allergy, blood transfusion, hemodialysis or extracorporeal circulation, other immunologic diseases, granulocyte deficiency, and radiation therapy.