IMMUNODEPRESSION FOLLOWING NEUROSURGICAL PROCEDURES

Objective: To determine the influence of a selective, sterile central nervous system surgery on immune reactivity, particularly whether a de crease of monocytic human leukocyte antigen-DR expression, indicating immunodepression, occurs after neurosurgery and if this measurement is useful for identification of patients with a high risk of infection. Design: Prospective study. Setting: Department of neurosurgery and int ensive care unit in a university hospital. Patients and Interventions: Blood samples were obtained from 46 patients at least once during the first 3 days after undergoing sterile central nervous system surgery, Fourteen of these patients developed infectious complications as defi ned by clinical and microbiological criteria, In ten of 46 patients, p aired samples of blood and cerebrospinal fluid were collected from a v entricle drain at the following times: I day before surgery; several t imes on the day of surgery; and every day after surgery for at least 6 days. Measurements and Main Results: Monocytic human leukocyte antige n-DR expression, as measured by flow cytometry on days 1 through 3 aft er surgery in 46 patients, was lower in 14 patients who developed infe ction after neurosurgery (p < .0001), In all ten closely monitored pat ients, monocytic human leukocyte antigen-DR expression decreased tempo rarily after surgery. Of these patients, only one patient showed a per sistent and considerably decreased monocytic human leukocyte antigen-D R expression, This patient was the only patient in this subgroup who d eveloped sepsis syndrome. In order to assess whether the monocytic hum an leukocyte antigen-DR decrease was associated with a preceding infla mmatory response, local and systemic concentrations of interleukin (IL )-1 beta, IL-6, IL-8, tumor necrosis factor-alpha, and interferon-gamm a were measured in this subgroup, These cytokines were not detectable in plasma during the first days after surgery, In contrast, considerab le increases of IL-6 and IL-8 concentrations were detectable in cerebr ospinal fluid within hours after surgery. Conclusions: A decrease of m onocytic human leukocyte antigen-DR expression occurs after neurosurge ry and is associated with a preceding, strong, intracranial (but not s ystemic) inflammatory response, A very low monocytic human leukocyte a ntigen-DR expression (<30% positive monocytes) suggests the possibilit y of infection, Measurement of monocytic human leukocyte antigen-DR ex pression could help to detect patients with a high risk of infection a fter neurosurgery. Our results suggest that even sterile central nervo us system surgery may contribute to general immunodepression. The loca l intracranial inflammatory response may be involved in this process.