Changes in T lymphocyte subsets after severe traumatic brain injury

NEURAL REGENERATION RESEARCH Volume 2, Issue 2, January 2007 Online English edition of the Chinese language journal

Cite this article as: Neural Regen Res,2007,2(2),126-8

Research Letter

Changes in T lymphocyte subsets after severe traumatic brain injury Yulu Miao1, Mingxia Zhang2, Yulin Nie1, Wan Zhao1, Bin Huang1, Zhengming Jiang1, Shaoxiong Yu1, Zhibin Huang1, Hongjin Fu1 1Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City, Shenzhen 518112, Guangdong Province, China; 2Central Laboratory, Shenzhen Hospital of Prevention and Cure for Chronic Disease, Shenzhen 518000, Guangdong Province, China

Abstract BACKGROUND: Besides local changes of cranial parenchymal cells, hemorrhage, etc., severe traumatic brain injuries also cause the changes of total body fluid and various functions, and the changes of lymphocytes and T lymphocyte subsets should be paid more attention to. OBJECTIVE: To reveal the changing laws of T lymphocyte subsets after severe traumatic brain injury, and compare with mild to moderate brain injury. DESIGN: A comparative observation. SETTINGS: Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City; Central Laboratory of Shenzhen Hospital of Prevention and Cure for Chronic Disease. PARTICIPANTS: All the subjects were selected from the Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City from August 2002 to August 2005. Thirty patients with severe brain 8 points, were taken as the experimental group, including injury, whose Glasgow coma score (GCS) was 21 males and 9 females, aging 1662 years. Meanwhile, 30 patients with mild traumatic brain injury were taken as the control group (GCS ranged 1415 points), including 18 males and 12 females, aging 1558 years. All the subjects were in admission at 6 hours after injury, without disease of major organs before injury. Informed consents were obtained from all the patients or their relatives. The T lymphocytes and the subsets in peripheral blood were detected with METHODS: immunofluorescent tricolor flow cytometry at 1, 3, 7 and 14 days after injury in both groups. The conditions of pulmonary infections were observed at 4 days after injury. The differences of measurement data were compared with the t test. MAIN OUTCOME MEASURES: Changes of T lymphocytes subsets at 114 days after severe and mild or moderate traumatic injury. RESULTS: Finally, 28 and 25 patients with mild to moderate traumatic brain injury, whereas 25 and 21 patients with severe traumatic brain injury were analyzed at 7 and 14 days respectively, and the missed ones Changes of T lymphocyte subsets: At 1 and 3 days after injury, died due to the development of disease. CD3, CD4, CD8, CD4/CD8 began to decrease, whereas CD8 increased in the experimental group, which were very significantly different from those in the control group (t =2.773.26, P < 0.01), and began to recover at 7 days, which were significantly different from those in the control group (t = 2.062.24, P < Conditions of pulmonary 0.05), and generally recovered to the normal levels at 14 days (P > 0.05). infections: At 4 days after injury, the rate of pulmonary infection was significantly different between the experimental group and control group [73% (22/30), 0, 2=37.29, P < 0.01]. CONCLUSION: Patients with severe traumatic brain injury suffer from damages of cellular immune function at early period (within 7 days), and they are easily to be accompanied by pulmonary infections. Key Words: brain injuries; T-lymphocyte subsets; immunity, cellular

Received:2006-11-02;Accepted:2007-01-05 (06-S-11-1037/H) Corresponding author: Yulu Miao, Master, Associate chief physician, Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City, Shenzhen 518112, Guangdong Province, China E-mail: [email protected]

126

Yulu Miao , Master, Associate chief physician, Department of Neurosurgery, District Buji Longgang Hospital of People's Shenzhen City, Shenzhen Guangdong 518112, Province, China Miao YL,Zhang MX,Nie YL,Zhao W,Huang B,Jiang ZM,Yu SX,Huang ZB,Fu HJ.Changes in T lymphocyte after severe subsets traumatic brain injury.Neural Regen Res 2007;2(2):126-8 www.sjzsyj.com/Journal/ 0702/07-02-126.html

Miao YL, et al. / Neural Regeneration Research,2007,2(2):126-8

INTRODUCTION Most severe traumatic brain injuries are accompanied by infections, especially pulmonary infection, and the occurrence of infection is associated with the changes of organic immunological function. What are the laws of the changes of organic immunological function after severe traumatic brain injury, especially that of T lymphocytes? Whether immune therapy is feasible? The infections occur most at 310 days after injury, which is generally concordant with the peak time of intracranial hypertension. How does severe traumatic brain injury affect the organic immunity. This study was to reveal the changing rules of T lymphocyte subsets from clinical data after severe traumatic brain injury, so as to provide a theoretical evidence for the immune interventions.

SUBJECTS AND METHODS Subjects All the subjects were selected from the Department of Neurosurgery, Longgang District Buji People's Hospital of Shenzhen City from August 2002 to August 2005. Thirty patients with severe brain injury, whose Glasgow coma score (GCS) was 8 points, were taken as the experimental group, including 21 males and 9 females, aging 1662 years, there were 12 cases of brain contusion and laceration accompanied by subarachnoid hemorrhage, 10 cases of intracranial hematoma, 5 cases of brain stem injury and 3 cases of diffuse axonal injury. Thirty patients with mild traumatic brain injury were taken as the control group (GCS ranged 1415 points), including 18 males and 12 females, aging 1558 years, there were 21 cases of brain concussion, 3 cases of skull fracture accompanied by cerebral concussion, 5 cases of scalp contusion and 1 case of scalp contusion accompanied by skull fracture. All the subjects were in admission at 6 hours after injury, without disease of major organs before injury. Informed consents were obtained from all the patients or their relatives. Those with obvious infections were excluded. Methods Reagents and equipment Tricolour fluorescent labeling monoclonal antibody CD4 FITC/CD8 PE/CD3 PerCP (Catalog No.340298, IVD) and negative homeotype contrast 1FITC/ 1PE/CD3 PerCP (Catalog No.340369, IVD) were purchased from BectonDickinson Company (USA); Erythrocytolysin was BD FACSTM lysing solution (Catalog No. 349202, IVD); FACSCalibur flow cytometry was produced by BD Company (USA). Detection methods Blood samples (3 mL) of peripheral vein were collected in all the subjects at 1, 3, 7 and 14 days after injury, and the flow

cytometry was used to detect the changes of T lymphocyte subsets after injury. Venous blood samples (1 mL) were collected in all the subjects, anticoagulated with heparin, then packed in 2 tubes, and each was added with 100 L whole blood. Then 10 L above-mentioned tricolour fluorescent labeling monoclonal antibody and homeotype contrast were added, kept avoiding light at room temperature for 20 minutes; Add with erythrocatalysis (2 mL), mixed, haematolysis for 5 minutes, centrifugated and then deserted the supernatant, washed with phosphate buffer solution (PBS) for twice. The cells were resuspended in 1% paraformaldehyde 500 L, and 30 000 cells were collected with FACS Calibur CellQuest software using flow cytometry, the percentages of positive cells stained by fluorescent antibody were recorded, and the positive rates of CD3, CD4 and CD8 antigen reaction were calculated. Pulmonary infection The conditions of pulmonary infections were observed at 4 days after injury, and the pulmonary infections were diagnosed as follows: fever, signs of consolidation in lung, coarse rales, obvious increase of hemogram, and lung inflammatory lesions displayed by X-ray examination. Statistical analysis The statistical analysis was performed by the second author using SPSS 11.0 software. The data were expressed as Mean SD, and the differences of the measurement data were compared with the t test.

RESULTS Quantitative analysis of the participants Totally 30 patients with severe traumatic brain injury and 30 patients with mild to moderate traumatic brain injury were enrolled, and some of them died at 7 and 14 days after injury due to the development of disease, thus 28 and 25 patients with mild to moderate traumatic brain injury, whereas 25 and 21 patients with severe traumatic brain injury were analyzed at 7 and 14 days respectively. Changes of T lymphocyte subsets at different time points after injury in both groups (Table 1) At 1 and 3 days after injury, CD3, CD4, CD8, CD4/CD8 began to decrease, whereas CD8 increased in the experimental group, which were very significantly different from those in the control group (P < 0.01), and began to recover at 7 days, which were significantly different from those in the control group (P < 0.05), and generally recovered to the normal levels at 14 days (P > 0.05). Conditions of pulmonary infections At 4 days after injury, the rate of pulmonary infection was significantly different between the experimental group and 2 control group [73% (22/30), 0, =37.29, P < 0.01].

127

Miao YL, et al. / Neural Regeneration Research,2007,2(2):126-8

Table 1 Changes of T lymphocyte subsets at different time points after injury in patients with traumatic brain injury (x s)

Group

n

Control 1 d after injury 30 3 d after injury 30 7 d after injury 28 14 d after injury 26 Experimental 1 d after injury 30 3 d after injury 30 7 d after injury 25 14 d after injury 21

CD3 (%)

CD4 (%)

CD8 (%)

CD4/CD8

68.50 70.03 67.74 71.74

7.90 8.12 7.25 9.25

55.73 54.26 56.62 57.86

8.10 6.14 5.94 6.27

27.24 24.39 29.40 37.75

3.47 2.05 2.76 2.22 7.00 1.93 6.09 1.53

0.31 0.56 0.47 0.33

58.50 53.84 62.63 73.63

6.72 5.56 7.16 8.15

40.35 31.28 50.45 55.45

4.32 3.92 5.59 5.72

35.33 32.17 36.23 36.57

7.20 1.14 3.35 0.97 7.54 1.39 5.40 1.52

0.24 0.37 0.26 0.38

t =2.773.26, P < 0.01, comparison between control and experimental groups at 1 and 3 days after injury; t = 2.062.24, P < 0.05, comparison of the two groups at 7 days after injury

DISCUSSION T lymphocytes take part in cellular immune function in human body, and the T lymphocytes in peripheral blood can be classified into two subgroups with different functions: CD4 and CD8. The numbers of CD4 and CD8, and CD4/CD8 reflect the state changes of organic immunity. CD3 represent the total count of mature T lymphocytes in peripheral blood, and the increase of CD3 indicates the enhancement of immune function, vice versa. Our results showed that The numbers of CD3 and CD4 were decreased, whereas CD8 were increased after severe traumatic brain injury, suggesting that the immunity was low, and the organ was at the state of immunosuppression, which occurred at about 7 days after brain injury, and were concordant with the peak of brain edema. Our results

128

supported that stress could result in the changes of hypothalamic-pituitary-adrenal function, nervous system, especially hypothalamus and sympathetic nerve were directly involved in the immunomodulation[1], the pathological changes of severe traumatic brain injury, including deformation of brain tissue, ischemia, hypoxia, infarction and edema, could lead to the imbalance of neuroendocrine immunoloregulation network[2]. After severe traumatic brain injury, the changing laws of T lymphocyte subsets were as follows: CD3, CD4 and CD4/CD8 began to decrease at 1 day after injury, and obviously decreased at 3 days, whereas began to recover at 7 days, and generally recovered to the normal levels at 14 days, which were concordant with the time phase of brain edema after brain injury, indicating that traumatic brain injury directly damaged immune function, especially the cellular immune function[3], whereas coma and unable to eat aggravated the low immunity. Therefore, severe traumatic brain injury is easily accompanied by infection, especially that in lung[4], which reached about 70%.

REFERENCES 1. Yan RF, Zhou Y, Su ZZ, et al. Dynamical changes of sex hormones and T-cell phenotype after traumatic brain injury. Zhonghua Chuangshang Zazhi 2003;19(12):724-7 2. Mazzeo AT, Kunene NK, Gilman CB, et al. Severe human traumatic brain injury, but not cyclosporin a treatment, depresses activated T lymphocytes early after injury. J Neurotrauma 2006;23(6):962-75 3. Sacks GS, Brown RO, Teague D, et al. Early nutrition support modifies immune function in patients sustaining severe head injury. JPEN J Parenter Enteral Nutr 1995;19(5):387-92 4. Quattrocchi KB, Frank EH, Miller CH, et al. Severe head injury: effect upon cellular immune function. Neurol Res 1991;13(1):13-20

(Edited by Yu MK/Yin YL/Wang L)