IL17A and intervertebral disk degenerative disorder: A study analyzing the samples of NP tissue obtained from the IDD patients by the surgical intervention reported that the expression levels of IL-17A and TNFα in the discs of the AF-disrupted group were significantly higher than those in the AF intact group, and the IL-17A and TNFα expression levels were correlated (Wang et al., 2015; Liu et al., 2016).