Main cytokine involved in erythema nodusum leprosum

The main cytokine, involved in erythema nodusum leprosum (ENL) reaction is:

a) Interleukin—2
b) Interferon-gamma
c) Tumor necrosis factor—alpha
d) Macrophage colony stimulating factor

Correct answer : c) Tumor necrosis factor—alpha (factual question)