ABSTRACT
Objective To study the impacts of B7-H3 molecule on the proliferation of T lymphocytes in different activation conditions and on the secretion of relevant cytokines.Methods Peripheral blood samples were collected from healthy subjects to separate peripheral blood mononuclear cells (PBMC) by Ficoll density gradient centrifugation.T lymphocytes were isolated from some of the PBMCs and purified with T Cell Enrichment Kit.PBMC and purified T lymphocytes were activated by anti-CD3/CD28 monoclonal antibodies (McAb) in vitro.Flow cytometry analysis was used to detect the expression of CD28 and CTLA-4 on T lymphocytes at different time points for further analyzing the activation states of T lymphocytes.On this basis, human B7-H3-Fc fusion protein was added into the mixed co-cultivation system on days 0, 1, 2, 3 and 4, and Hu-Fc fusion protein was used as isotype control.CCK-8 method was performed to detect the proliferation of T lymphocytes in each group.ELISA method was used to detect the secretion of cytokines (IL-2, IL-10 and IFN-γ) and to analyze the immune responses induced by stimulating T lymphocytes at different states of activation with B7-H3.Results B7-H3 molecule significantly inhibited the quiescent T lymphocytes from secreting IL-2 and IL-10, but had no significant impact on IFN-γ secretion.Moreover, it significantly promoted the activated T lymphocytes to secret IL-2 and IFN-γ, but had no obvious impact on IL-10 secretion.Results of the cell proliferation assay showed that B7-H3 molecule inhibited the in vitro proliferation of T lymphocytes in the PBMC, but had no obvious impact on purified T lymphocytes.ConclusionThe regulatory effects of B7-H3 molecule on the immune functions of T lymphocytes vary with the activation states of T lymphocytes.
ABSTRACT
Objective To observe the incidence of acute gastrointestinal injury (AGI) in intensive care unit (ICU) patients, and to approach the value of serum citrulline and intestinal fatty acid binding protein (IFABP) on diagnosis of AGI in critical patients. Methods A prospective study was conducted. 576 critical patients admitted to ICU of Yantai Yuhuangding Hospital from February 2016 to February 2017 were enrolled. According to the AGI classification proposed by European Society of Intensive Care Medicine (ESICM) in 2012, the AGI and severity of the patients were observed. The general data, severity and prognosis of patients with different AGI grades were recorded. According to the random number table, 20 patients with normal kidney function from AGI Ⅰ to Ⅳ were selected. The femoral artery blood was collected within 12 hours of ICU admission, and serum citrulline level was detected by high performance liquid chromatography (HPLC). Serum IFABP level was determined by enzyme-linked immunosorbent assay (ELISA). Twenty healthy subjects were selected as controls. The receiver operating characteristic curve (ROC) was drawn, and the predictive values of citrulline and IFABP for AGI diagnosis were evaluated. Results ① 576 patients were enrolled in the analysis. Of which 530 patients (92.0%) had AGI, and 289 patients with gradeⅠ (54.5%), 154 with grade Ⅱ (29.1%),64 with grade Ⅲ (12.1%), and 23 with grade Ⅳ (4.3%). With the increase in AGI classification, acute physiology and chronic health evaluation system Ⅱ (APACHE Ⅱ) score, sequential organ failure score (SOFA), the length of ICU stay and 28-day mortality were gradually increased. ② Compared with health control group, the levels of serum citrulline in patients with different AGI grades were significantly decreased, and IFABP was significantly increased. With the increase in AGI classification, the citrulline level was gradually decreased, and IFABP level was gradually increased [citrulline levels (μmol/L) in AGIⅠ,Ⅱ,Ⅲ,Ⅳ groups were 14.1±3.6, 12.7±3.1, 8.3±2.7, and 5.6±3.4, F = 3.287, P = 0.027, and IFABP levels (ng/L) were 526.7±204.9, 698.4±273.8, 894.7±455.9, and 1 062.8±532.2, F = 2.903, P = 0.043]. ROC curve analysis showed that citrulline had a higher predictive value for AGI diagnosis. The area under the ROC curve (AUC) was 0.927. When the cut-off value of citrulline was 9.7 μmol/L, the sensitivity and specificity were 87.5% and 87.5%, respectively. The AUC of IFABP was 0.043, which has no predictive value for the diagnosis of AGI. Conclusions The AGI is extremely common in ICU. The higher the AGI grade is, the worse the prognosis is. Citrulline has high diagnostic value for AGI in critical patients, but IFABP has no predictive value on the diagnosis of AGI.