Objective:Serum soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is a useful biomarker of bacterial infection. However, the diagnostic value of sTREM-1 of alveolar fluid in pulmonary infection is still unclear. This article aimed to explore the value of sTREM-1 of alveolar fluid in the early diagnosis of ventilator-associated pneumonia (VAP) by systematic review of relevant literatures.Methods:CNKI, Wanfang, VIP, PubMed/Medline and Embase databases were retrieved. Articles on diagnosis of VAP by sTREM-1 before June 30, 2019 were collected. QUADAS-2 scale provided by Cochrane Collaboration Network was used to evaluate the quality of diagnostic experiments. RevMan 5.3 and Stata 13.0 software were used to complete Meta-analysis. The levels of sTREM-1 between VAP and non-VAP patients were analyzed by Meta-analysis, and then diagnostic test Meta-analysis was conducted. Heterogeneity, sensitivity and publication bias were analyzed.Results:A total of 24 articles were enrolled. QUADAS-2 scale indicated that the selected literature had low bias and high clinical adaptability. ① In Meta-analysis of sTREM-1 level in alveolar fluid, 20 articles were selected and found to have high heterogeneity ( I2 = 94.4%, P = 0.000). The random effects models were used for Meta-analysis. It was indicated that the sTREM-1 level in alveolar fluid of VAP group was significantly higher than that of non-VAP group with significant difference [standardized mean difference ( SMD) was 1.47, 95% confidence interval (95% CI) was 1.00-1.95, Z = 6.14, P = 0.000]. By subgroup analysis and Meta-regression analysis, no source of heterogeneity was found. Sensitivity analysis suggested that the results of this Meta-analysis were robust and credible, and Begg funnel plot analysis showed that there was no significant publication bias ( Z = 1.46, P = 0.143). ② A total of 18 articles were included in the Meta-analysis of diagnostic experiments. Deek funnel plot showed publication bias ( P = 0.012). The combined sensitivity was 0.87 (95% CI was 0.81-0.91), specificity was 0.80 (95% CI was 0.73-0.86), and diagnostic odds ratio ( DOR) was 26 (95% CI was 13-50). Subgroup analysis of three different sources of alveolar fluid (bronchoalveolar lavage fluid, endotracheal aspiration fluid and exhaled ventilator condensate) showed that STREM-1 had a certain value in early diagnosis of VAP. The I2 of combined DOR was 35.4%, and I2 of sensitivity was 79.46%, I2 of specificity was 77.61%, suggesting heterogeneity in the selected literature. Subgroup analysis found that nationality, subject design, sample source, sample size and diagnostic "gold criteria" were related to heterogeneity, but not age. The area under synthetic receiver operating characteristic (SROC) curve (AUC) was 0.90 (95% CI was 0.87-0.92). Conclusions:The detection of sTREM-1 level in alveolar fluid can be used for the early diagnosis of VAP with high sensitivity and specificity. If combined with other biomarkers, it may have more diagnostic value.

Objective:To investigate ability of HCA587/MAGE-C2 protein combined with different adjuvants inducing antigen-specific immune response and antitumor effects in mice model.Methods:C57BL/6J mice were immunized with HCA587 protein com-bined with Freund's complete adjuvant(CFA)/Freund's incomplete adjuvant(IFA)and different doses of CpG ODN 1826(CpG),cellular and humoral immunity levels induced by different schemes were compared.ELISpot was used to evaluate frequency of IFN-γ-producing splenocytes.HCA587-specific antibodies were detected by ELISA.Intracellular cytokine staining(ICCS)analysis was mea-sured by flow cytometry.A tumor-bearing animal model was created by subcutaneously injection of B16-HCA587 tumor cells into right flank of C57BL/6J mice,which was treated with strategy with the strongest cellular and humoral immune response in immune compari-son protocol.Vernier calipers were used to measure tumor volume,and Log-rank test was used to analyze survival curve.Results:HCA587 protein combined with CFA and 50 μg CpG elicited strongest specific IFN-γ-secreting splenocytes and anti-HCA587 anti-bodies,which induced highest IFN-γ+CD4+T cells(P<0.05).In tumor treatment model,HCA587 protein combined with CFA and 50 μg CpG significantly inhibited tumor growth(P=0.026),while Log-rank test showed no significant effect on survival(P>0.05).Conclusion:HCA587 protein vaccine formulated with CFA and 50 μg CpG causes a significant cellular and humoral immune response and partial antitumor effect in mice model,providing new experimental data for preclinical research of tumor antigen protein vaccine.