A low absolute CD3 count often indicates that the body’s immune function is in a low state. The main causes of low CD3 absolute counts are inflammatory infections, immune system diseases, and immune function deficiencies. 1. Infection. When the body is invaded by bacteria, viruses and other pathogenic microorganisms, resulting in widespread infection, the body’s CD3 count will decrease accordingly. 2. Immune system diseases. Low absolute CD3 counts can be seen in connective tissue diseases and immune system diseases, such as rheumatic diseases, systemic lupus erythematosus, dermatomyositis and dry syndrome. 3. Immunodeficiency: CD3 is an antigen on T-cells, and a decrease in T-cells will result in a decrease in the absolute CD3 count. AIDS will cause a significant reduction in the number of T cells in the body, thus causing a low absolute CD3 count. In addition, severe tuberculosis, anemia, leukemia, etc., may lead to a decrease in CD3 absolute count. Low CD3 absolute count not only depends on the indicators of the examination, but also should be combined with the clinical examination and personal medical history to make a comprehensive judgment, you can consult a professional physician’s opinion.