Differences in neuroimmune signalling between male and female patients suffering from knee osteoarthritis

The primary aim was to identify cytokines involved in blood borne, neuroimmune joint-to-CNS signalling in knee osteoarthritis (OA) patients. Monocyte chemoattractant protein 1 (MCP1) and Interleukin-8 (IL-8) were elevated in the cerebrospinal fluid (CSF) in patients indicating neuroinflammation. Significant positive correlations were found for MCP1 across CSF, serum and synovial fluid (SF), in female, but not male patients. The results revealed sex differences in neuroimmune signalling and implicated MCP1 in blood borne joint-to-CNS signalling in female patients. Symptom severity correlated with IL-6 and IL-8 levels in SF, but was inversely associated with IL-6 and IL-8 levels in CSF, indicating that neuroinflammation in OA may be an adaptive, possibly neuroprotective mechanism promoting symptom reduction. [Display omitted] •Patients with painful knee osteoarthritis (OA) had elevated CSF concentrations of MCP1 and IL-8.•MCP1 correlated across CSF and serum as well as serum and synovial fluid, indicating joint-to-CNS signalling.•Profound sex differences in neuroimmune signalling were documented.•Cytokines were associated with analgesia centrally and hyperalgesia peripherally.•Targeting neuroimmune communication could become a new treatment strategy in OA.