TNF and intervertebral disk degenerative disorder: For instance, in animal IDD model, T-helper cells, T-killer cells and B cells were activated and attracted by NP exudate (Geiss et al. 2007); T cells and neutrophils were proposed to secret molecules that promote inflammation, autophagy or apoptosis (including well-studied TNF and IL-1β), thereby contributing to the IDD (Risbud and Shapiro 2014).