Basophils

Basophils are a type of white blood cell and a part of the immune system. They are one of the least common types of granulocytes, representing about 0.5% to 1% of circulating leukocytes in the blood. Basophils play a role in the body's immune response by releasing histamine and other chemicals during allergic reactions and inflammation.

Structure

Basophils are characterized by their large granules, which stain dark blue or purple with basic dyes. These granules contain various substances, including histamine, heparin, and other mediators of inflammation. The nucleus of a basophil is typically bilobed, although it can be difficult to see due to the dense granules.

Function

Basophils are involved in the body's response to allergens and parasites. When activated, they release histamine, which increases the permeability of blood vessels and allows other immune cells to access the affected tissue. This process contributes to the symptoms of allergic reactions, such as swelling, itching, and redness.

Basophils also release heparin, an anticoagulant that helps to prevent blood clotting. Additionally, they play a role in the defense against parasites by releasing toxic granules that can damage or kill the invaders.

Development

Basophils develop from hematopoietic stem cells in the bone marrow. They share a common progenitor with other granulocytes, such as neutrophils and eosinophils. The differentiation of basophils is regulated by various cytokines and growth factors, including interleukin-3 (IL-3).

Clinical Significance

Elevated levels of basophils, a condition known as basophilia, can be associated with various medical conditions, including chronic myeloid leukemia, allergic reactions, and inflammatory disorders. Conversely, low levels of basophils, known as basopenia, can occur in conditions such as acute infections and hyperthyroidism.

See Also

• White blood cell
• Granulocyte
• Histamine
• Allergic reaction
• Inflammation
• Hematopoietic stem cell
• Chronic myeloid leukemia