Promyelocytes are a stage in the development of granulocytes that can develop into mature granulocytes that can play a role. They can develop into mature granulocytes and play roles such as sterilization, phagocytosis of foreign bodies, and participation in allergic reactions. The process of granulocyte development includes primitive granulocytes, early juvenile granulocytes, etc. Among them, early juvenile granulocytes have more cytoplasmic volume, and the cytoplasm contains a varying number of purplish-red non-specific particles, which are round or oval and uniformly large granulomas. Early granulocytes can develop into neutrophils, which can reach the site of infection and play a bactericidal role in the presence of inflammation; they can also develop into eosinophils, which can kill parasites and phagocytosis of foreign objects in the body; early granulocytes can also develop into basophils, which can participate in the allergic reaction to dilate local small blood vessels. For more information, please consult a hematologist.