Anti-inflammatory profile of circulating immune cells after surgery for seizure

The central nervous system has been described as the coordinator of the inflammatory response to infection through the hypothalamo-pituitary axis and the autonomic nervous system. Brain lesions have been associated with impaired immunity and postoperative infections. We studied alterations of the inflammatory response in relation to neurohormonal patterns after neurosurgery for seizure.

Nine patients were studied before, during and immediately after operation, and then on days 1, 2 and 4 post-operatively. Monocyte HLA-DR (mHLA-DR) expression and plasma interleukin (IL)-10, IL-12 and MIF were measured ex vivo and after an in vitro 6-h our lipopolysaccharide (LPS) stimulation of whole blood. Corticotropin (ACTH), cortisol, arginine vasopressin, prolactin, epinephrine and norepinephrine were quantified in plasma. The effect of plasma mediators on LPS stimulation was studied by replacing plasma with standard culture medium.

Surgery resulted in decreased ex vivo mHLA-DR expression, but no change in IL-10 or IL-12 plasma levels. mHLA-DR was low in LPS culture over the 4 postoperative days, whereas IL-10 release was increased and not counterbalanced by IL-12p40 production. The hormonal plasma pattern showed increased prolactin during anesthesia and peaks of cortisol, ACTH and arginine vasopressin during waking, but no alteration in catecholamine levels. mHLA-DR expression in LPS culture was not modified by plasma replacement, except immediately after surgery.

Postoperatively, mHLA-DR expression was associated with an anti-inflammatory phenotype of whole blood. The anti-inflammatory profile was not related to the plasma mediators measured, suggesting that neural control might take place upstream in the circulation, at the level of progenitors in bone marrow.