From the Guidelines
Immature granulocytes are young white blood cells that haven't fully developed and are normally found in the bone marrow rather than circulating blood, and their presence in peripheral blood can indicate an infection, inflammation, or other stress on the bone marrow. According to the study published in the Annals of Oncology 1, immature granulocytes are mentioned in the context of a complete haematological response, where their absence in the differential is a criterion for response. Some key points about immature granulocytes include:
- They are precursors to mature neutrophils, eosinophils, and basophils
- Their presence in peripheral blood can indicate a "left shift" where the bone marrow releases these cells before they've completed their maturation process
- Elevated immature granulocyte counts may suggest serious conditions like sepsis, tissue necrosis, or leukemia
- The presence of these cells can help physicians understand how the body is responding to illness and guide treatment decisions In the context of chronic myeloid leukemia (CML), the presence of immature granulocytes in peripheral blood can be an indicator of disease progression or response to treatment, as noted in the study 1. Overall, immature granulocytes play an important role in the diagnosis and management of various medical conditions, and their presence or absence can provide valuable information for healthcare providers.
From the Research
Definition of Immature Granulocytes
- Immature granulocytes (IGs) include metamyelocytes, myelocytes, and promyelocytes, which are the precursors of neutrophils 2.
- These cells are produced in the bone marrow and play a crucial role in the host defense during bacterial and fungal infections, as well as in the antiviral immune response.
Role of Immature Granulocytes in Infections
- Increased IG counts in peripheral blood indicate enhanced bone marrow activity and have been evaluated in various clinical conditions, such as severe acute pancreatitis, systemic inflammatory response syndrome, and infectious complications following open-heart surgery under cardiopulmonary bypass 2.
- IGs have been associated with disease severity, patient outcomes, and the development of complications in patients with COVID-19 infection 2.
- Immature granulocyte percentage (IG%) has been shown to be an indicator for the risk of sepsis, with an IG% count greater than 3% being a predictor of sepsis 3.
Interaction with Intestinal Flora
- The level of myelopoiesis in the bone marrow is influenced by intestinal flora, with the elimination of intestinal bacteria leading to a decrease in the level of granulocytes in the bone marrow 4.
- The interaction of granulocytes or epithelial cells with intestinal bacteria may accelerate the production of free radicals, superoxids, cytokines, or unknown factors that stimulate the generation of granulocytes in the bone marrow 4.
Infection of Immature Granulocytes
- Primary bone marrow progenitors of both granulocytic and monocytic lineages are susceptible to infection with the agent of human granulocytic ehrlichiosis 5.
- Infection of bone marrow progenitors may contribute to the hematologic manifestations of human granulocytic ehrlichiosis, and the ability of the agent to interact with monocytes has significant implications regarding disease pathogenesis and host response 5.