Balance of interleukin-1 beta and interleukin-1 receptor antagonist in human periapical lesions

J Endod. 1998 Feb;24(2):116-9. doi: 10.1016/s0099-2399(98)80089-7.


Interleukin-1 beta (IL-1 beta) has been considered as a major potent mediator of bone resorption and implicated in the development of human periapical lesions. Among naturally occurring interleukin-1 (IL-1) inhibitors, IL-1 receptor antagonist (IL-1ra) is a 22 kDa protein that shares homology with IL-1 beta and IL-1 alpha, binds to IL-1 receptor with similar affinity to IL-1, and has no known agonist properties. In this study, we measured the periapical exudate (PE) levels of IL-1 beta and IL-1ra from human periapical lesions. PE samples were collected from root canals during routine endodontic treatments, and the enzyme-linked immunosorbent assay was used to measure PE-IL-1 beta and IL-1ra. Detectable levels of both IL-1 beta and IL-1ra were found in 25 of 29 clinical samples. Relatively high levels of IL-1ra compared with IL-1 beta (mean IL-1ra:IL-1 beta ratio = 128:7; range: 0.9 to 495.4), and significantly positive correlation between IL-1ra and IL-1 beta levels was found. The PE-IL-1ra:IL-1 beta ratios obtained from symptomatic lesions were significantly lower than those from asymptomatic lesions. These results suggest that IL-1ra-mediated IL-1 antagonism occurred to block locally produced IL-1 activity, and the balance of IL-1 to IL-1ra production may be crucial in the development of periapical lesions.

Publication types

  • Comparative Study

MeSH terms

  • Analysis of Variance
  • Down-Regulation
  • Exudates and Transudates
  • Humans
  • Inflammation Mediators / metabolism*
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1 / biosynthesis
  • Interleukin-1 / immunology
  • Interleukin-1 / metabolism*
  • Periapical Abscess / immunology
  • Periapical Abscess / metabolism*
  • Prognosis
  • Sialoglycoproteins / immunology
  • Sialoglycoproteins / metabolism*
  • Statistics, Nonparametric


  • IL1RN protein, human
  • Inflammation Mediators
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1
  • Sialoglycoproteins