High white blood cells are a symptom diagnosed through blood tests, and they are a reaction to certain diseases in the body, the more common ones are as follows: 1. Infections caused by diseases, that is, diseases caused by bacteria and viruses, the more common ones are pneumonia, meningitis, cholecystitis, measles, encephalitis B, etc. 2. 4, tumors, especially leukemia. 5, poisoning, common in heavy metals, such as lead, mercury and so on.