Immature neutrophil

Immature neutrophils are a type of white blood cell that are not fully developed. In the bone marrow, neutrophils undergo a maturation process before being released into the bloodstream. Immature neutrophils, also known as band cells or stab cells, are an intermediate stage in neutrophil development. They are characterized by their band-shaped nucleus, which distinguishes them from the segmented nucleus of mature neutrophils. The presence of a higher number of immature neutrophils in the blood, a condition known as left shift, can be an indicator of an ongoing infection or other inflammatory conditions, as it suggests the bone marrow is releasing neutrophils into the bloodstream prematurely in response to a perceived threat.

Physiology

Neutrophils are a critical component of the immune system, playing a key role in the body's defense against bacterial infections. The development of neutrophils in the bone marrow, a process known as granulopoiesis, involves several stages, starting from a myeloblast and progressing through intermediate forms such as promyelocytes, myelocytes, metamyelocytes, and finally, band cells before reaching the mature segmented form. This maturation process is regulated by various growth factors, including granulocyte colony-stimulating factor (G-CSF).

Clinical Significance

The evaluation of immature neutrophils is an important diagnostic tool in medicine. An increased proportion of immature neutrophils can be found in a variety of conditions, including:

• Infections, particularly bacterial infections
• Inflammatory conditions
• Leukemia
• Following the administration of growth factors such as G-CSF
• In response to physical or emotional stress

The presence of a left shift is often associated with a worse prognosis in patients with acute conditions, as it indicates a high demand for neutrophils that the bone marrow is struggling to meet.

Laboratory Evaluation

The assessment of immature neutrophils is typically performed through a complete blood count (CBC) with a differential, where the percentage of different types of white blood cells is measured. A manual review of a blood smear may also be performed to visually assess the presence of band cells and other immature forms. Advanced automated hematology analyzers can also provide an estimate of the immature granulocyte percentage (IG%), which includes immature neutrophils among other immature granulocytes.

Treatment and Management

The presence of immature neutrophils is not a disease in itself but an indicator of an underlying condition. Therefore, treatment is directed at the underlying cause. For bacterial infections, antibiotics may be prescribed. In cases of severe neutropenia or conditions that impair the production of neutrophils, G-CSF or other growth factors may be administered to stimulate the production of neutrophils in the bone marrow.

See Also

• Neutrophilia
• Neutropenia
• Complete blood count
• Bone marrow