What Are the Functions of Leukotrienes?

Leukotrienes belong to a group of biochemicals responsible for causing the hypersensitivity associated with allergies and asthma. Leukotrienes signal the immune system that a response is needed and are associated with helpful responses such as white blood cell production and inflammation. When those responses occur without need for an immune system response, such as during an asthma attack, leukotrienes take on a pathological role, according to the British Medical Journal website.

Signal Molecules

• Leukotrienes belong to a family of molecules responsible for signaling the body when an immune system response is needed, such as when a potentially harmful organism or substance is found. Leukotrienes cause an immune response in a very specific area of the body. That response is designed to neutralize or oust the harmful organism or substance and, when functioning properly, protects the body from harm.

Defense against Disease

• Leukotrienes aid the body in defending itself against disease in several ways. Leukotrienes cause the accumulation of white blood cells at the site of an infection. White blood cells are responsible for destroying potential pathogens, such as bacteria and fungi. Leukotrienes prolong the lives of white blood cells and increase the activity of macrophages, cells that consume pathogenic invaders. According to the online Journal of Immunology, the presence of leukotrienes generally indicates a healthy and productive immune system response, while a deficiency of leukotrienes indicates a higher susceptibility to infection and has been associated with conditions like HIV.

Inflammation

• Inflammation is a normal immune system response that concentrates bodily resources in an area to heal an injury or infection. Leukotrienes stimulate inflammation, allowing the body to work on healing. However, when the body creates inflammation in response to a substance that is not harmful, allergic reactions result.

Role in Pathology

• In pathology, leukotrienes are primarily associated with the onset of asthma attacks and the increased sensitivity to allergens because they cause the immune system to overreact to a perceived attack. James Deal of the University of California Stanislaus draws the analogy that "the response of the immune system can be seen as an overreaction to a potential home invasion; to prevent bodily harm the windows and doors are shut as tight as can be." Leukotrienes cause the airway to constrict while also causing muscle twitching, both of which make it difficult for people to breathe during an asthma attack. Leukotrienes also cause inflammation and increased mucus production, which worsens the problem. Allergy sufferers also feel the effects of leukotrienes, which cause nasal congestion. Leukotrienes cause blood vessels in the nose to dilate, causing nasal tissue to swell and produce the congestion associated with nasal allergies.