What does it mean if my T-cells are low?

Low or high T-cells could indicate different problems affecting your immune system. 

Low T-cells are a more common occurrence than having high T-cells and may indicate a condition that you’re born with or a condition that you acquire that’s preventing your body from producing sufficient T-cells.  

Some of the conditions that cause the body to produce fewer T-cells include cancers that affect the blood or lymph nodes, HIV, immunodeficiency disorders, or viral infections such as influenza. Low T-cells may also result as a side effect of certain medications or treatments, or exposure to radiation. In rare cases, it is a result of congenital T cell deficiency.  

Regardless of the reason, T-cell insufficiency makes it more difficult for your body to protect you against harmful pathogens. Having an extremely low T-cell count can be life-threatening.