Neutrophils themselves are chemotactic and have a phagocytic and bactericidal role in immunology. It is mainly derived from bone marrow, and low neutrophils in white blood cells are seen mainly in typhoid, paratyphoid, measles, influenza and other such infectious diseases. It is also seen in patients who have undergone chemotherapy and radiotherapy and in certain blood disorders such as aplastic anemia, granulocytopenia, myelodysplastic syndrome and hypersplenism, as well as other autoimmune diseases, which can have low white blood cell neutrophils.