Inflammatory mediators in allergic response

• A. Histamine
• B. Epinephrine
• C. Leukotrienes
• D. Sepsis

Answer: (C)

In allergic inflammation, lipid mediators derived from arachidonic acid play a central role, with leukotrienes standing out for driving the sustained inflammatory phase. Leukotrienes are produced by 5-lipoxygenase and include LTC4, LTD4, and LTE4. They are potent inducers of bronchoconstriction, increase vascular permeability, promote mucus production, and attract eosinophils. This combination makes them key contributors to the ongoing inflammation seen in allergic reactions, especially in the airways, where symptoms can persist and worsen over time.

Histamine is a fast-acting mediator released from mast cells and basophils that causes immediate effects like vasodilation and increased permeability, itching, and smooth muscle contraction, but its action is relatively short-lived compared with the sustained impact of leukotrienes. Epinephrine is a systemic hormone that counteracts many allergic mediator effects and is used therapeutically in anaphylaxis, not as a primary inflammatory mediator produced during the allergic cascade. Sepsis is a systemic inflammatory response to infection, not a mediator of allergic inflammation.

Thus, leukotrienes best capture the inflammatory mediator aspect of allergic responses, due to their strong, prolonged effects on the airways and vessel walls.