A positive Mantoux test 48 hours after intradermal purified protein derivative injection shows induration caused predominantly by which cytokine produced during the effector phase?

• A IL-5
• B GM-CSF
• C IL-13
• D IFN-gamma ✓

Explanation

The tuberculin response is a classic delayed type IV hypersensitivity reaction. Memory Th1 cells recognize antigen presented by local APCs and secrete IFN-gamma, which activates macrophages, the principal effector cell of this reaction, producing induration through cytokine-mediated inflammation over 24 to 72 hours. IL-5 and IL-13 are Th2 cytokines associated with eosinophilia and allergy, while GM-CSF plays a supporting hematopoietic role but is not the signature mediator tested here.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.