Which is the following is the main cytokine involved in erythema nodosum leprosum (ENL) reaction?

Tumor necrosis factor-alpha play a central role in the pathobiology of type II lepra reaction/ ENL. Elevated levels of TNF alpha have been demonstrated in patients with erythema nodosum leprosum. ENL occur exclusively in patients near the lepromatous end of the leprosy spectrum. Type I leprae reactions: It occurs in almost half of patients with borderline forms of leprosy but not in patients with pure lepromatous disease. TNF alpha, IL 1, 2, 12 are increased during type I leprae reaction. Lucio's phenomenon is an unusual reaction seen exclusively in patients from the Caribbean and Mexico who have the diffuse lepromatous form of lepromatous leprosy. Like ENL, the Lucio phenomenon is probably mediated by immune complexes. Ref: Gelber R.H. (2012). Chapter 166. Leprosy. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.