Evaluation of Cytokine Levels in Fibromyalgia Syndrome Patients and its Relationship to the Severity of Chronic Pain^†

Abstract

Objective

This study was designed to examine the relationship between the levels of various cytokines [interleukin [IL]-2, IL-4, IL-6, IL-10, and interferon gamma] and the severity of pain assessed by means of various pain indices [widespread pain index, fibromyalgia syndrome [FMS] score, and visual analog scale].

Method

Twenty-six FMS patients along with 20 healthy normal controls were identified by the help of new the American College of Rheumatology criteria for FMS classification. Various plasma cytokines levels were estimated by enzyme linked immune sorbent assays.

Result

We observed a mean increase of 242.8 percent in the levels of IL-6 and a mean increase of 136.41 percent in the levels of IL-4. Significant decrease was also observed in the levels of anti-inflammatory cytokines. The severity of pain estimated by the means of various pain scores was also found to be positively correlated with the levels of IL-6.

Conclusion

Our study indicates the probable role of IL-6 being responsible for the increase in the pain sensation and pain severity in the FMS patients.

Keywords:

• Fibromyalgia syndrome
• cytokines
• pro-inflammatory
• pain sensation
• pain sensitivity

ACKNOWLEDGEMENTS

All authors have equally contributed for the article. There is no conflict of interest among the authors. The authors acknowledge the following departments for providing the individual research fellowship and contingency grant to their respective students: Directorate of Forensic Science, Ministry of Home Affairs Government of India provided the individual research fellowship to Dipti Malhotra. Council for Scientific and Industrial Research provided individual research fellowship to Vivek Kumar. Indian council of Medical Sciences and Research provided individual research fellowship to Namita Nasare and Sajjad A. Dar [each research scholar has their own research fellowship]. The part of contingency fund from each funding agency was used for purchase of the ELISA kits.