High NK cells indicate that the body may be suffering from an infection or some kind of disease etc. NK cells, also known as natural killer cells, belong to the body’s immune cells.NK cells have the ability of anti-tumor, anti-virus, and improve immunity.High NK cells may be related to inflammatory infectious diseases, immune diseases, and tumor diseases. 1. Inflammatory infectious diseases: when the body is infected by bacteria, fungi, chlamydia and other pathogens, the respiratory, urinary and other systems may be infected, resulting in inflammation, which leads to high NK cells and corresponding symptoms, such as coughing, coughing up sputum, urinary urgency, painful urination and so on. 2. Immune diseases: NK cells are important immunoregulatory cells, which have a regulatory effect on B cells, T cells and other immune cells. When suffering from immune diseases such as systemic lupus erythematosus, it will cause blood system dysfunction and NK cells may be high. 3. Tumor diseases: NK cells are the body’s anti-tumor line of defense, with broad-spectrum anti-tumor effects, when the body has a tumor, NK cells may proliferate and play a role in killing tumor cells, so the cells will be high. There are many other causes of high NK cells, and infectious diseases are one of the more common ones. When NK cells are elevated, it is recommended that the patient go to the hospital in time to clarify the cause of the disease and give the corresponding treatment and management.