A controlled immunohistochemical study of inflammatory cells in disc herniation tissue.

STUDY DESIGN: The presence and abundance of inflammatory cells was studied immunocytochemically in lumbar disc herniations (DH) and macroscopically normal discs for comparison.

OBJECTIVES: The objective of the study was to characterize inflammatory cells that appear in herniated disc tissue and to study the relative abundance of various types of inflammatory cells.

SUMMARY OF BACKGROUND DATA: Only few macrophages were observed in control discs, whereas abundant macrophages were present in half of the DH. Other types of inflammatory cells were less often abundant in the present material. In about a third of the DH interleukin-1 beta-expressing cells were also observed.

METHODS: Twenty-four DH and control tissue from five discs were studied immunocytochemically, using specific monoclonal antibodies to various types of inflammatory cells and interleukin-1 beta. The results were compared with corresponding clinical data. Macrophages were studied with an antibody to CD68 antigen and Ber-MAC3 antibody separately.

RESULTS: The obtained results suggest a variable inflammatory cell response in DH, which seems to be often dominated by macrophages at the time of operation. Thus previous suggestions of sometimes very active inflammation in DH tissue are supported.

CONCLUSIONS: Inflammation may be important in disc tissue pathophysiology, possibly also in discogenic pain mechanisms.