There are many reasons for low neutrophils in the blood count, but first of all, mildly low neutrophils are not a cause for concern. If the neutrophil count drops significantly, consider the presence of viral infections, autoimmune diseases, such as influenza virus infection, systemic lupus erythematosus, dry syndrome, etc. Severe cases are also considered to be caused by physical or chemical factors, such as patients after radiotherapy or chemotherapy for tumors. Patients with aplastic anemia may also have a significant decrease in neutrophils, and timely improvement of bone marrow examination is recommended.