Correlations among inflammatory markers in plasma, saliva and oral mucosal transudate in post-menopausal women with past intimate partner violence

The relationship between psychosocial factors and an increased risk for disease has been related to a heightened pro-inflammatory status reflected in increased circulating levels of pro-inflammatory cytokines and/or C-reactive protein (CRP). Routinely, epidemiological studies rely on measurements of inflammatory markers in serum or plasma, but the use of biological fluids such as saliva or oral mucosal transudate (OMT) may offer potential advantages. This study investigated correlations among plasma CRP and levels of IL-6 and soluble IL-6 receptor (sIL-6R) in plasma, saliva and OMT in a population of middle aged women with histories of past intimate partner violence (IPV). A total of 67 women without existing chronic diseases participated in the study, which included two visits each in which psychological tests were administered, and blood, saliva and OMT samples were collected. Although significantly higher plasma CRP levels were found in past IPV sufferers compared to controls, there were no significant differences in IL-6 or sIL-6R levels in plasma, saliva or OMT between the two groups. There were only relatively modest correlations between IL-6 levels in plasma and those in saliva or OMT and between plasma IL-6 and CRP levels. A significant correlation between IL-6 and sIL-6R levels in both saliva and OMT, but not in plasma, was also detected. No significant correlations were found between levels of IL-6 in saliva or OMT and periodontal health measures. Results indicate that IL-6 and sIL-6R levels in saliva or OMT do not closely reflect those in plasma, and therefore are not a good surrogate for systemic levels.

Research highlights
► Higher levels of CRP in women with past IPV compared to controls.
► No differences in IL-6 or sIL-6R in plasma, saliva or OMT in IPV+ women vs. controls.
► Modest correlation of plasma, but not saliva or OMT, IL-6 levels and CRP.
► Positive correlation of IL-6 and sIL-6R levels in saliva and OMT.
► IL-6 levels in saliva or OMT are not good surrogates for systemic IL-6.