Search

Background: Myeloid-derived suppressor cells (MDSCs) have been reported to expand and have a potent ability in the expansion of regulatory T cells in malignant and infectious disease. The current study was performed to investigate the role of MDSCs and possible immune mechanisms in dampening immune responses of community acquired pneumonia (CAP). Methods: This was a single-center cross-sectional study. The distribution of MDSCs subsets, the PD-1/PD-L1(L2) level of MDSCs subsets and Tregs in the peripheral blood of adult CAP patients and healthy control were measured by flow cytometry analysis. Results: Peripheral blood mononuclear cells (PBMCs) from 63 adult CAP patients contained an elevated frequency of both G-MDSC (4.92±0.30 vs 2.25±0.21,p<0.0001) and M-MDSC (19.40±1.30 vs 9.64±0.57,p<0.001) compared to healthy controls. Treg in the peripheral blood of CAP patients exhibited increased expression of PD-1 and CTLA-4, accompanied by no difference of their frequency. Moreover, up-regulated expression of PD-L1 on MDSC subsets in the peripheral blood of CAP patients was also revealed. Of note, the frequency of circulating MDSCs subset displayed a positive correlation with neutrophil count percentage in blood in CAP patients. Conclusions: In summary, the significant expansion of circulating MDSCs subsets and the up-regulated expression of PD-1/PD-L1 level in CAP patients may suggest the possible involvement of PD-1/PD-L1axis in MDSCs mediated immune regulation on Treg at least partially in CAP patients. [ABSTRACT FROM AUTHOR]

Background. IRAK-M, negatively regulating Toll-like receptor, is shown the dual properties in the varied disease contexts. We studied the effect of IRAK-M deficiency on cigarette smoking- (CS-) induced airway inflammation under acute or subacute conditions in a mouse model. Methods. A number of cellular and molecular techniques were used to detect the differences between IRAK-M knockout (KO) and wild type (WT) mice exposed to 3-day or 7-week CS. Results. Airway inflammation was comparable between IRAK-M KO and WT mice under 3-day CS exposure. Upon short-term CS exposure and lipopolysaccharide (LPS) inhalation, IRAK-M KO mice demonstrated worse airway inflammation, significantly higher percentage of Th17 cells and concentrations of proinflammatory cytokines in the lungs, and significantly elevated expression of costimulatory molecules CD40 and CD86 by lung dendritic cells (DCs) or macrophages. Conversely, 7-week CS exposed IRAK-M KO mice demonstrated significantly attenuated airway inflammation, significantly lower concentrations of proinflammatory cytokines in the lungs, significantly increased percentage of Tregs, and lower expression of CD11b and CD86 by lung DCs or macrophages. Conclusions. IRAK-M plays distinctive effect on CS-induced airway inflammation, and influences Treg/Th17 balance and expression of costimulatory molecules by DCs and macrophages, depending on duration and intensity of stimulus. [ABSTRACT FROM AUTHOR]

Background: Ulcerative colitis (UC) is considered an immune-mediated disease. The disorder of T-lymphocyte subsets plays an important role in the pathogenesis of UC. The aim of this study was to evaluate the significance of peripheral blood T-lymphocyte subsets in assessing disease severity and predicting clinical outcomes in UC patients. Methods: The retrospective case-control study was performed in 116 UC patients with active disease and 90 healthy controls (HC). The UC patients included were followed up for 180 days. Analyses of t-test, Spearman's correlation coefficient, multivariable Cox regression analysis, receiver operating characteristic (ROC) curves and cumulative survival analysis were done. Results: The UC patients had lower proportions of CD4+T cells (42.85%±9.77% vs 45.71%±7.94%, P=0.021) and higher proportion of CD8+T cells (27.88%±8.86% vs 25.00%±6.47%, P=0.008) than HC. The severely active UC patients had higher proportion of CD3+HLA-DR+ T cells (8.83%±6.55% vs 2.80%±1.55%, P<0.001; 8.83%±6.55% vs 4.06%±5.01%, P<0.001) and CD8+T cells (31.35%±8.49% vs 26.98%±7.98%, P=0.029; 31.35%±8.49% vs 25.46%±9.15%, P=0.003) than mild and moderate group, whereas lower proportion of CD4+CD25+T cells (2.86%±1.35% vs 3.46%±1.07%, P=0.034) than mild group and CD4+T cells (40.40%±9.36% vs 44.73%±10.39%, P=0.049) than moderate group. The area under the curve (AUC) of CD3+HLA-DR+ T cells for assessing severely active UC was 0.885, with the cut-off value of 5.33%. The sensitivity was 76.32% and specificity was 89.74%. The combination of CD3+HLA-DR+ T cells and CRP had stronger assessment value with AUC of 0.929. The AUC of CD8+T cells, CD4+/CD8+ ratio and CD4+CD25+T cells for assessing disease severity was 0.677, 0.669 and 0.631 respectively. Within the 180 days follow-up, 24 patients (20.69%) had UC-related readmission or surgery, with higher proportion of CD3+HLA-DR+ T cells (10.66%±9.52% vs 3.88%±2.56%, P=0.003) and CD8+T cells (31.19%±10.59% vs 27.01%±8.20%, P=0.039) than those without readmission and surgery. The proportion of CD3+HLA-DR+ T cells was the independent predictor of UC-related readmission or surgery (HR=1.109, P=0.002). The AUC of CD3+HLA-DR+ T cells for predicting readmission or surgery was 0.796 with the cut-off value of 5.38%. UC patients with CD3+HLA-DR+T cells proportion>5.38% had a shorter time to readmission or surgery (log-rank test, P<0.001). Conclusions: The combination of CD3+HLA-DR+T cells and CRP may be potential biomarker of disease severity in UC patients. The high proportion of CD3+HLA-DR+T cells may be associated with an increased risk of readmission or surgery in UC patients. [ABSTRACT FROM AUTHOR]