Immune modulation after total hip surgery. A prospective ex vivo study

Area of Science:

• Immunology
• Surgical Complications
• Cytokine Response

Background:

• Major trauma and surgery can suppress the immune system.
• Immunosuppression increases susceptibility to septic complications.
• Understanding immune responses after orthopedic surgery is crucial.

Purpose of the Study:

• To investigate lipopolysaccharide (LPS)-induced releases of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in whole blood.
• To assess these immune responses in patients undergoing total hip replacement.

Main Methods:

• Whole blood assay measuring ex vivo LPS-induced TNF-alpha and IL-6 releases.
• Analysis conducted at 1, 6, 9, and 12 days post-surgery.
• Low- and high-dose LPS stimulation with white blood cell count analysis.

Main Results:

• TNF-alpha release was significantly reduced at days 6 and 12 post-surgery.
• Reduced TNF-alpha release correlated with monocyte counts at day 9.
• Interleukin-6 (IL-6) increased at day 1 but normalized, with no significant change in LPS-induced levels compared to pre-surgery.

Conclusions:

• Patients undergoing major orthopedic surgery exhibit a reduced capacity for LPS-induced TNF-alpha release postoperatively.
• This attenuated TNF-alpha response may heighten susceptibility to gram-negative sepsis.
• The findings highlight a potential mechanism for increased infection risk after major orthopedic procedures.