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Int J Clin Exp Pathol 2013;6(6):1009-1014

Review Article
Immune cascades in human intervertebral disc: the pros and cons

Zhen Sun, Ming Zhang, Xu-Hong Zhao, Zhi-Heng Liu, Yang Gao, Dino Samartzis, Hai-Qiang Wang, Zhuo-Jing Luo

Department of Orthopaedics, Xijing Hospital, Fourth Military Medical University, 127 Changle Western Road, Xi’an, P. R. China; Department of
Oral and Maxillofacial Surgery, PLA General Hospital, Beijing, P. R. China; Department of orthopaedics, Air Force General Hospital, 30 Fucheng
Road, Beijing, P. R. China; Department of Orthopaedics and Traumatology, University of Hong Kong, Pokfulam, Hong Kong, SAR China. Equal
contributors.

Received April 2, 2013; Accepted April 28, 2013; Epub May 15, 2013; Published June 1, 2013

Abstract: The unique structural hallmark of the intervertebral disc has made its central composition, the nucleus pulposus (NP), excluded from
the immunologic tolerance. Consequently, the intervertebral disc is identified as an immune-privileged organ. Traditionally, local detrimental
immune activities caused by NP at the lesion sites of the disc are noted as a significant factor contributing to disc degeneration. However, given
the beneficial activities of immune cells in other immune-privileged sites on basis of current evidence, the degenerate disc might need the
assistance of a subpopulation of immune cells to restore its structure and lessen inflammation. In addition, the beneficial impact of immune
cells can be seen in the absorption of the herniated NP, which is an important factor causes the mechanical compression of nerve roots.
Consequently, a modulated immune network in degenerate disc is essential for the restoration of this immune-privileged organ. Until now, the
understandings of immune response in disc degeneration still rest on the harmful aspect. Further studies are needed to explore its beneficial
influence. Accordingly, there are no absolutely the pros and cons in terms of immune reactions caused by NP. (IJCEP1304001).

Keywords: Intervertebral disc degeneration, nucleus pulposus, immune privilege, immune reaction

Address correspondence to: Hai-Qiang Wang and Zhuo-Jing Luo, Department of Orthopaedics, Xijing Hospital, Fourth Military Medical
University, 127 Changle Western Road Xi’an, P. R. China, 710032. Phone: +86 29 84775285; Fax: +86 29 84775285; E-mail: hqwang@fmmu.
edu.cn (Hai-Qiang Wang); zjluo@fmmu.edu.cn (Zhuo-Jing Luo)