EARLY ACTIVATION OF γδ T LYMPHOCYTES IN PATIENTS WITH SEVERE SYSTEMIC INFLAMMATORY RESPONSE SYNDROME

Abstract

Innate immunity plays an important role in host defense after severe insult. γδ T lymphocytes are recognized as the first line of defense against microbial invasion. In this study, we evaluated γδ T lymphocytes in the peripheral blood of patients with severe systemic inflammatory response syndrome (SIRS), and examined on role of these cells. Thirty-seven patients with severe SIRS (SIRS criteria and serum C-reactive protein ≥ 10 mg/dL) and 27 healthy volunteers were studied. Severe SIRS was caused by trauma in 14 patients (Injury Severity Score of 30.1 ± 10.8) and by sepsis in 23 patients. The counts of γδ and αβ T lymphocytes were determined by flow cytometry of cells stained with monoclonal antibodies to γδ and αβ T lymphocyte receptors. The activation of these cells was evaluated by flow cytometry of cells stained with monoclonal antibodies to CD69 and HLA-DR. Serial counts and activation of γδ and αβ T lymphocytes were also determined in eight trauma patients (Injury Severity Score of 31.0 ± 13.5) during a 2-week observation period. The count of γδ T lymphocytes in the peripheral blood of SIRS patients (30.1 ± 6.0/μL) was significantly lower (P < 0.05) than that of the healthy volunteers (104.3 ± 10.9/μL). The expression of CD69, an index of early activation of T lymphocytes, was significantly greater on γδ T lymphocytes from SIRS patients (patients 23.9% ± 3.4%, healthy controls 4.8% ± 0.6%, P < 0.05). In trauma patients, the expression of CD69 on γδ T lymphocytes increased rapidly within 48 h after injuries. In conclusion, γδ T lymphocytes are activated and decreased in the peripheral blood of severe SIRS patients. In trauma patients, the activation of γδ T lymphocytes occurs in the fairly acute phase after injuries. These results suggest a significant role for γδ T lymphocytes as early responders after severe insult.