According to MedicineNet, a low granulocyte count can be caused by bacterial or viral infections, certain cancers, chemotherapy drugs, radiation treatment or certain autoimmune disorders. A low granulocyte count can also occur in healthy people without any known cause. Granulocytes are immune cells that are filled with toxic granules. These granules release toxic compounds that target and kill bacteria and virus particles.
MedicineNet states that a low granulocyte count is also known as neutropenia. Neutropenia is classified by a neutrophil count of less than 1,500 neutrophils per microliter. Neutrophils are the most abundant type of granulocyte. Other types of granulocytes include basophils and eosinophils. If the number of neutrophils falls below the threshold number of 1,500 cells per microliters, then patients will be unable to adequately fight off infections in their bodies.
According to MedicineNet, patients can have mild, moderate or severe neutropenia depending on the number of neutrophils they have circulating in their bloodstreams. Mild cases often produce no symptoms, while severe cases can be serious. Treatment of the condition involves treating the underlying cause of the low blood counts. Once the underlying cause of the neutropenia is treated, the patient’s neutrophil level should return to normal.