Leukotriene B4 (LTB4) is produced from arachidonic acid via the 5-lipoxygenase pathway. Its primary function in acute inflammation is:

• A Vasodilation and increased permeability by direct action on vascular smooth muscle
• B Potent chemotactic agent for neutrophils and eosinophils, activating integrin upregulation and migration ✓
• C Bronchoconstriction and mucus hypersecretion in asthmatic airways
• D Platelet aggregation and vasoconstriction via thromboxane receptor

Explanation

LTB4 is one of the most potent known chemotactic agents, acting through BLT1 receptors on neutrophils and eosinophils to stimulate directional migration, activate beta2 integrin (LFA-1) upregulation enabling firm adhesion to endothelium, and prime oxidative burst. Vasodilation is mediated by prostaglandins (PGI2, PGE2) and histamine. Bronchoconstriction and mucus hypersecretion are properties of cysteinyl leukotrienes (LTC4, LTD4, LTE4). Platelet aggregation is TXA2-mediated.

Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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