A cross-sectional study comparing the inflammatory profile of menstrual effluent vs. peripheral blood

Background and Aims: Cytokine profiles of peripheral blood and other bodily fluids provide diagnostic indicators for assessing inflammatory processes. Menstrual effluent may provide a noninvasive source of biological material for monitoring cytokine levels in blood and in endometrial tissues. This pilot study investigated the potential of measuring cytokines in menstrual effluent, and compared the cytokine profiles of menstrual versus peripheral blood.Methods: Seven healthy donors (aged >= 18 and <= 45 years) collected menstrual effluent on day 2 of menses. Matched peripheral blood samples were collected by venous blood draw on the same day. Levels of 62 cytokines were measured in all samples by 62-plex Luminex assay.Results: Peripheral blood and menstrual effluent cytokine profiles were tenuously correlated (r(2) = 0.26, p < 0.0001), with higher levels detected in menstrual effluent for 48/62 cytokines. Thirty five cytokines were significantly elevated in menstrual effluent compared to peripheral blood samples (IL-8, CCL2, CCL4, LIF, IL-1RA, IL-6, IL-18, HGF, CCL3, FGF-2, TNF-alpha, VEGF-A, IL-1 alpha, CXCL1, IL-9, IL-10, EGF, CXCL5, CSF3, EOTAXIN, TGF-alpha, TRAIL, CXCL10, VEGF-D, IL-12P40, CXCL9, IL-18 RESISTIN, IL-22, IL-21, CSF1, IFN-gamma, IL-17A, CXCL12, IL-12p70). Two cytokines (LEPTIN, CSF2) were expressed at significantly lower levels in menstrual effluent compared to peripheral blood. Linear regression of individual cytokines found low predictive power (linear regression p > 0.05) for 53/62 cytokines in menstrual effluent versus peripheral blood. Levels of TGF-8 (r(2) = 0.87, p = 0.002) and CCL7 (r(2) = 0.63, p = 0.033) were significantly positively correlated between matched menstrual and peripheral blood samples.Conclusion: In this group of study participants, the cytokine profile of menstrual effluent was quantitatively distinct from peripheral blood, and also characterized by higher levels of inflammatory signaling. This pattern of comparative menstrual blood cytokine profiles points to a need for further studies to evaluate the relationship between peripheral and menstrual blood cytokines in broader populations including both healthy and diseased states.