[Association of traumatic severity with change in lymphocyte subsets in the early stage after trauma].

Objective: To investigate the association of traumatic severity with changes in lymphocyte subsets in the early stage after trauma.

Methods: Sixty-three male patients admitted within 4 hours after trauma were enrolled. According to injury severity score (ISS), the patients were divided into two groups: mild trauma group (ISS<16, n=35) and severe trauma group (ISS≥16, n=28). At admission, the patients peripheral blood were extracted to detect T lymphocytes subsets, blood routine test, blood biochemical and arterial blood gas analysis which were used to calculate the acute physiology and chronic health evaluation II (APACHEII) scores. The correlation of lymphocyte subsets and ISS score, and the correlation of lymphocyte subsets and APACHEII score were both analyzed statistically. Another 20 cases of healthy male adults were enrolled as the control group.

Results: Compared with the healthy control group, CD3(+) T cell contents in blood were decreased obviously in mild trauma group and severe trauma group (0.648±0.112, 0.647±0.110 vs. 0.708±0.082, both P<0.05); CD4(+) T cells contents in severe group were decreased significantly (0.317±0.086 vs. 0.389±0.064, P<0.05), and natural killer (NK) cells were significantly increased (0.217±0.107 vs. 0.158±0.068, P<0.05). B cells content in severe group was decreased significantly than that of mild group (0.114±0.060 vs. 0.155±0.075, P<0.05). There were no significant difference in CD8(+) and CD4/CD8 ratio among the healthy control group, mild trauma group and severe trauma group (CD8(+): 0.260±0.074, 0.260±0.091, 0.271±0.105; CD4/CD8 ratio: 1.69±0.75, 1.56±0.83, 1.34±0.65, all P>0.05). Except that there were negative correlation between CD3(+) T cells and the ISS scores (r=-0.42, P=0.03), the other lymphocyte subsets showed no correlation with the ISS scores and the APACHEII scores (mild trauma group with ISS scores: CD3(+) r=-0.10, CD4(+) r=-0.31, CD8(+) r=0.18, B cells r=0.20, NK cells r=-0.04; mild trauma group with APACHEII scores: CD3(+) r=0.04, CD4(+) r=-0.07, CD8(+) r=0.06, B cells r=-0.10, NK cells r=0.05, severe trauma group with ISS scores: CD4(+) r=-0.12, CD8(+) r=-0.17, B cells r=0.02, NK cells r=0.31,all P>0.05;severe trauma group with APACHEII scores:CD3(+) r=-0.24, CD4(+) r=0.11, CD8(+) r=-0.26, B cells r=0.15, NK cells r=0.08, all P>0.05).

Conclusions: CD3(+) and CD4(+) T cells decreased and NK cells increased significantly in blood in the early stage after severe trauma. CD3(+) T cells are independent indexes which reflect body injury. Therefore, it is necessary to monitor the changes of immune cells dynamically after severe trauma.