IL6 and Mental deterioration: In a group of 10 patients undergoing major knee surgery, the one patient who developed POD had a greater increase in CSF IL-6 and IL-8 than the patients without POD.61 In a group of 27 patients having either a knee or hip replacement, the six patients who went on to develop long-term cognitive decline had higher CSF cytokine levels of IL-6, IL-8, CCL3, CCL8, and CXCL6.67