Lymphocyte activation is attenuated by stellate ganglion block

Background and Objectives. Clinical evidence suggests that stellate ganglio n block (SGB) might modulate the immune system. Little is known, however, a bout the immunologic effects of SGB. We examined how SGB affected immune fu nctions by analyzing the activation response of lymphocytes during SGB. Met hods. Twenty-four volunteers were randomly subdivided into three groups. Th e SGB group (SGB; n = 9) received 6 mt 1% lidocaine at the sixth cervical v ertebra (C6) transverse process and showed Horner's sign and elevation of i psilateral facial and upper limb temperature. The lidocaine group (n = 7) h ad 6 mt 1% lidocaine injected into subcutaneous tissue at the neck and show ed no remarkable clinical effects. The saline group (placebo; n = 8) receiv ed 6 mt saline solution injected at approximately the CG transverse process and showed no remarkable clinical effects. Peripheral blood samples were d rawn before and 30 minutes after drug administration. Samples were incubate d for 4 hours under the stimulation of mitogen. Using now cytometry, we mea sured the ne nova expression of CD69, which is one of the initial markers o f lymphocyte activation and which reflects the cell activation process. The changes in pre- and post-values were calculated and compared among the thr ee groups. results. In only the SGB group, the helper T-cell activation was significantly reduced, and the cytotoxic T-cell activation also tended to decrease after SGB. Conclusions. SGB may depress immune system activity for a short time, as reflected in the T-cell activation response.