The effects of neurosurgical stress on peripheral lymphocyte subpopulations.

Study Objective: To observe changes in the peripheral lymphocyte subpopulations as an index of cellular immunity during neurosurgical procedures.

Design: Clinical study.

Setting: Operating room of a university hospital.

Patients: 11 patients with early intracranial disease who were scheduled to undergo elective neurosurgery with general anesthesia. Patients in the control group (n = 10) underwent minor surgeries such as ophthalmologic, otorhinolaryngological, or orthopedic surgeries.

Interventions: Blood was sampled before anesthesia induction (t0) for baseline and at 1 hour (t(1)) and 2 hours (t(2)) following surgical incision.

Measurements: Detection and quantification of lymphocyte subpopulations were performed at each time point using single-label and double-label analyses of monoclonal antibodies against lymphocyte membrane surface markers.

Main Results: Significant changes in patients who underwent a neurosurgical procedure included: the percentage of total T cells (CD3+) from 57.54 +/- 3.50% at t(0) to 51.41 +/- 4.26% at t(1) and 46.29 +/- 4.02% at t(2); the percentage of inducer T cells (CD4+, Leu8+) from 27.39 +/- 2.26% at t(0), to 23.26 +/- 2.30% at t(1) and 20.82 +/- 2.70% at t(2); the CD4/CD8 ratio, from 1.78 +/- 0.25% at t(0) to 1.35 +/- 0.12% at t(1) and 1.22 +/- 0.17% at t(2). The percentage of suppressor T cells (CD8+, Leu15+) increased significantly from 10.8 +/- 1.07% at t(0) to 13.64 +/- 1.62% at t(1), and 14.82 +/- 1.24% at t(2). The percentages of the natural killer cell subsets also increased significantly. Control group patients who underwent minor surgeries showed no significant changes.

Conclusions: Neurosurgery-induced significant suppression of cellular immunity was demonstrated in peripheral lymphocyte subpopulations, probably from the surgical stress on the central nervous system.