Soluble IL-1RII and IL-18 are associated with incipient upper extremity soft tissue disorders

Abstract

Previous studies suggest a role for IL-1β in the pathophysiology of upper extremity soft tissue disorders (UESTDs). We studied the levels of interleukin-1 family members in patients with incipient UESTDs and compared them with healthy controls. In this case control study, we included 163 patients with UESTDs and symptom duration shorter than 1month and 42 healthy controls matched for age and gender at the group level. Serum levels of cytokines IL-1α, IL-1β, IL-1Ra, IL-6, IL-8, IL-18, IL-33, TNFα and sensitized C-reactive protein as well as IL-1 family soluble receptors sIL-1RII and sST2 were assessed. We used unconditional logistic regression models to study the associations between cytokines and UESTDs. After adjustment for potential confounders, the serum levels of sIL-1RII (p<0.001) and sST2 (p=0.014) were higher in the patients than the controls. The level of IL-18 was lower in the patients than the controls (p=0.005). There were no significant differences between the patients and controls regarding the levels of IL-1α, IL-1β, IL-1Ra, IL-33, IL-6, IL-8, TNFα, or sensitized C-reactive protein. The levels of circulating sIL-1RII and IL-18 are associated with incipient UESTDs, suggesting an important role for these IL-1 family members in the early course of UESTDs.