mastcellernas

Mast cells are a type of white blood cell that play a crucial role in the immune system, particularly in allergic reactions and defense against pathogens. They are found in connective tissues throughout the body, with high concentrations in areas that interface with the external environment, such as the skin, lungs, and gastrointestinal tract. Mast cells are characterized by their abundant granules, which contain a variety of potent mediators.

These mediators include histamine, heparin, proteases, and cytokines. When a mast cell is activated, typically by binding of an allergen to IgE antibodies on its surface, it undergoes degranulation. This process releases the contents of its granules into the surrounding tissue. The released histamine, for example, causes vasodilation and increased vascular permeability, leading to symptoms like redness, swelling, and itching. Other mediators contribute to inflammation, recruit other immune cells, and can affect smooth muscle contraction, contributing to symptoms such as bronchoconstriction in asthma.

Mast cells are also involved in immunity to parasites and bacteria. They can participate in wound healing and tissue remodeling. Their dysregulation, however, is implicated in various allergic diseases, including asthma, allergic rhinitis, and anaphylaxis. Understanding the function and activation of mast cells is essential for developing effective treatments for these conditions.