TNF and Leigh syndrome: Pathogenically, LS is characterized by a predominant Th1 immune response, leading to the overproduction of pro-inflammatory cytokines and mediators such as IL-1, IL-7, IL-15, IFN-γ, TNF-α, CD25 (IL-2 receptor), caspase-1, ICAM-1, and its ligand CD11a [17,26,46,47,48,49].