The formation of NETs (neutrophil extracellular traps) during infection involves release of:

• A Granule-derived defensins via exocytosis
• B Decondensed chromatin studded with antimicrobial proteins (elastase, histones, MPO) ✓
• C Pre-formed cytokine stores from specific granules
• D Reactive oxygen species only

Explanation

NETosis (NET formation) involves NADPH oxidase-dependent nuclear decondensation mediated by PAD4-mediated histone citrullination, followed by rupture of the nuclear envelope and expulsion of chromatin. The released chromatin is decorated with neutrophil granule proteins — MPO, elastase, cathepsin G, and histones — forming a web-like structure that traps and kills extracellular bacteria and fungi. NETs also contribute to immunothrombosis and tissue injury in sepsis and SLE. Defensins are secreted separately. Pre-formed cytokines are not stored in neutrophil granules (unlike mast cells).

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.