Fatigue in primary Sjögren's syndrome--a link to sickness behaviour in animals?

Brain Behav Immun. 2009 Nov;23(8):1104-8. doi: 10.1016/j.bbi.2009.06.151. Epub 2009 Jun 26.


Interleukin-1beta (IL-1beta) is involved in the regulation of sickness behaviour in response to infection and inflammation in animals. Human fatigue can be considered an element of sickness behaviour and is a prominent and often disabling phenomenon in autoimmune diseases such as primary Sjögren's syndrome (PSS). The role of the IL-1 system in the fatigue of patients with PSS was explored. A cerebrospinal fluid (CSF) analysis of IL-1beta, IL-1Ra, and IL-1sRII was performed in 54 PSS patients and 53 control subjects. Fatigue was evaluated in the patients using the Fatigue Severity Scale (FSS) and a fatigue visual analogue scale (VAS); mood was evaluated using the Beck Depression Inventory (BDI). There were higher CSF levels of IL-1Ra pg/mL in PSS patients vs. controls (median 38.4: range 15.4-81.7 vs. 33.7: 7.3-163.1, p=0.026). Fatigue VAS scores were associated with increasing CSF levels of IL-1Ra in PSS patients (R(2)=0.11, p=0.015). In a subgroup analysis of the non-depressed PSS patients (N=37; 69%), the association between VAS scores and IL-1Ra was even stronger (R(2)=0.20, p=0.006). The positive association between VAS scores and IL-1Ra remained significant in a multiple regression analysis adjusting for age and BDI scores. Increased levels of IL-1Ra in the CSF are associated with increasing fatigue in PSS patients, indicating that the activated IL-1 system is a possible biological factor associated with fatigue.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Depression / cerebrospinal fluid
  • Fatigue / cerebrospinal fluid*
  • Fatigue / complications
  • Female
  • Humans
  • Illness Behavior
  • Inflammation Mediators / cerebrospinal fluid
  • Interleukin 1 Receptor Antagonist Protein / cerebrospinal fluid*
  • Interleukin-1beta / cerebrospinal fluid
  • Male
  • Middle Aged
  • Quality of Life
  • Receptors, Interleukin-1 Type II / metabolism*
  • Severity of Illness Index
  • Sjogren's Syndrome / cerebrospinal fluid*
  • Sjogren's Syndrome / complications
  • Surveys and Questionnaires


  • Inflammation Mediators
  • Interleukin 1 Receptor Antagonist Protein
  • Interleukin-1beta
  • Receptors, Interleukin-1 Type II