Peripheral helper T cells in human diseases.

Peripheral helper T cells (Tph) are a specialized subset of CD4+ T cells with the ability to help B cells and induce antibody production. Although usually located in ectopic lymphoid-like structures (ELS), inside the peripheral blood, Tph cells can also be identified. The aberrant proliferation and functions of Tph cells are commonly found in the patients with disease. In this review, first we will summarize the biological characteristics of Tph cells, such as the expression of surface molecules, transcription factors and cytokines, and discuss its B cell help functions. Tph cells also have roles in a wide range of human diseases, including autoimmune diseases, infectious diseases, malignancies etc. Therefore, there is a strong interest in targeting Tph cells to improve treat strategies of human diseases.

An analysis of abnormalities in the B cell receptor repertoire in patients with systemic sclerosis using high-throughput sequencing.

Systemic sclerosis is a chronic multisystem autoimmune disease that is associated with polyclonal B cell hyperreactivity. The CDR3 of BCRs is the major site of antigen recognition. Therefore, we analyzed the BCR repertoire of patients with SSc. The BCR repertoires in 12 subjects including eight SSc patients and four healthy controls were characterized by high-throughput sequencing, and bioinformatics analysis were studied. The average CDR3 length in the SSc group was significantly shorter. The SSc patient displayed more diverse BCR. Moreover, SSc patients with mild skin sclerosis, anti-Scl70, interstitial lung disease or female sex were more diversified. B cells from the SSc patients showed a differential V and J gene usage. SSc patients had distinct BCR repertoires.These findings reflected the differences of BCR repertoires between SSc patients and controls. The higher-usage genes for the BCR sequence might be potential biomarkers of B cell-targeted therapies or diagnosis for SSc.

Aire deficient dendritic cells promote the T follicular helper cells differentiation.

Autoimmune regulator (Aire), primarily expressed in medullary thymic epithelial cells (mTECs), maintains central immune tolerance through the clearance of self-reactive T cells. Aire can also be expressed in dendritic cells (DCs), and DCs can mediate T follicular helper (TFH) cell differentiation and self-reactive B cell activation through inducible costimulator molecule ligand (ICOSL) and interleukin 6 (IL-6), which can cause autoimmune diseases. To confirm whether Aire in DCs affects TFH cell differentiation and to determine the role of Aire in the maintenance of peripheral immune tolerance, this study observed the effects of Aire deficiency on TFH cells using Aire knockout mice. The results showed that Aire deficiency caused increased number of TFH cells, both in vivo and in vitro. Further studies showed that Aire deficiency promoted TFH differentiation through the upregulation of ICOSL and IL-6 in DCs. Thus Aire could suppress the expression of ICOSL and IL-6 to inhibit TFH cell differentiation.

The Role of Dendritic Cells in the Differentiation of T Follicular Helper Cells.

T follicular helper cells (TFH) are a subset of recently discovered CD4+ T cells. Their major function is to participate in the formation of germinal centres (GCs) and promote B cell proliferation and differentiation to play important roles in the production of antibodies. Currently, the functions of TFH cells are clear. However, the early differentiation of these cells is not clear. Dendritic cells (DCs) participate in the differentiation of TFH cells. Therefore, this article reviewed the research progress regarding the influence of DCs on the differentiation of TFH cells and their major underlying mechanisms.

Deficiency of autoimmune regulator impairs the immune tolerance effect of bone marrow-derived dendritic cells in mice.

As a transcription factor, autoimmune regulator (Aire) participates in thymic negative selection and maintains immune tolerance mainly by regulating the ectopic expression of tissue-restricted antigens (TRAs) in medullary thymic epithelial cells (mTECs). Aire is also expressed in dendritic cells (DCs). DCs are professional antigen-presenting cells (APCs) that affect the differentiation of T cells toward distinct subpopulations and participate in the immune response and tolerance, thereby playing an important role in maintaining homeostasis. To determine the role of Aire in maintaining immune tolerance by bone marrow-derived dendritic cells (BMDCs), in the present study we utilized Aire-knockout mice to examine the changes of maturation status and TRAs expression on BMDCs, additionally investigate the differentiation of CD4+ T cells. The results showed that expression of costimulatory molecule and major histocompatibility complex class II (MHC-II) molecule was increased and expression of various TRAs was decreased in BMDCs from Aire-knockout mice. Aire deficiency reduced the differentiation of naïve CD4+ T cells into type 2T helper (Th2) cells and regulatory T cells (Tregs) but enhanced the differentiation of naïve CD4+ T cells into Th1 cells, Th17 cells, and follicular helper T (Tfh) cells. The results demonstrate that Aire expressed by BMDCs plays an important role in the maintenance of homeostasis by regulating TRA expression and the differentiation of T cell subsets.

Analysis of Factors Influencing Diagnostic Accuracy of T-SPOT.TB for Active Tuberculosis in Clinical Practice.

T-SPOT.TB didn't perform a perfect diagnosis for active tuberculosis (ATB), and some factors may influence the results. We did this study to evaluate possible factors associated with the sensitivity and specificity of T-SPOT.TB, and the diagnostic parameters under varied conditions. Patients with suspected ATB were enrolled prospectively. Influencing factors of the sensitivity and specificity of T-SPOT.TB were evaluated using logistic regression models. Sensitivity, specificity, predictive values (PV), and likelihood ratios (LR) were calculated with consideration of relevant factors. Of the 865 participants, 205 (23.7%) had ATB, including 58 (28.3%) microbiologically confirmed TB and 147 (71.7%) clinically diagnosed TB. 615 (71.7%) were non-TB. 45 (5.2%) cases were clinically indeterminate and excluded from the final analysis. In multivariate analysis, serous effusion was the only independent risk factor related to lower sensitivity (OR = 0.39, 95% CI: 0.18-0.81) among patients with ATB. Among non-TB patients, age, TB history, immunosuppressive agents/glucocorticoid treatment and lymphocyte count were the independent risk factors related to specificity of T-SPOT.TB. Sensitivity, specificity, PV+, PV-, LR+ and LR- of T-SPOT.TB for diagnosis of ATB were 78.5%, 74.1%, 50.3%, 91.2%, 3.0 and 0.3, respectively. This study suggests that influencing factors of sensitivity and specificity of T-SPOT.TB should be considered for interpretation of T-SPOT.TB results.

Association between acute gastrointestinal injury and biomarkers of intestinal barrier function in critically ill patients.

BACKGROUND: To assess the associations of biomarkers of intestinal barrier function and other clinical variables with acute gastrointestinal injury (AGI) grade, and of these clinical variables with mortality in critically ill patients. METHODS: This was a single-center, observational, prospective study. Patients were included if they were diagnosed with AGI and underwent tests for the measurement of plasma levels of intestinal fatty acid-binding protein (i-FABP), D-lactate (D-la), and lipopolysaccharide. General characteristics, AGI grades, Acute Physiology and Chronic Health Evaluation (APACHE) II scores, Sepsis-related Organ Failure Assessment (SOFA) scores, intra-abdominal pressure (IAP), and 28-day mortality were recorded and compared among patients with different AGI grades. RESULTS: Among the 90 included patients, the APACHE II score, IAP, and LPS and D-la levels significantly differed between the four AGI grades. Multinomial logistic regression analysis with grade I as the reference for grades II, III, and IV revealed that high APACHE II scores increased the odds of AGI grade III (odds ratio [OR], 1.754; 95% confidence interval [CI], 1.225-2.511) and grade IV (OR, 1.493; 95% CI, 1.079-2.066). Similarly, IAP increased the odds of AGI grade III (OR, 1.622; 95% CI, 1.111-2.369) and grade IV (OR, 1.518; 95% CI, 1.066-2.162). Elevated D-la increased the odds of AGI grades II (OR, 1.059; 95% CI, 1.005-1.117), III (OR, 1.155; 95% CI, 1.052-2.268), and IV (OR, 1.088; 95% CI, 1.013-1.168). In contrast, i-FABP and LPS did not increase the odds of any AGI grade. SOFA scores could independently predict the odds of death in AGI patients (OR, 1.223; 95% CI, 1.007-1.485). CONCLUSION: AGI patients exhibit loss of gastrointestinal barrier function, and D-la could serve as a better marker of AGI grade than i-FABP or lipopolysaccharide.

Utilizing a novel sorbent in the solid phase extraction for simultaneous determination of 15 pesticide residues in green tea by GC/MS.

Pesticide residues exceeding standard in green tea is a widespread problem of the world's attention, containing organochlorine pesticides (OCPs), organophosphorus pesticides (OPPs), and pyrethroids. In this research, three dimensionally honeycomb Mg-Al layered double oxide (TDH-Mg-Al-LDO) combined with graphitized carbon black (GCB), packed as a column, was used as a novel solid phase extraction sorbent, applying in simultaneous determination of 15 pesticide residues in green tea coupled with GC-MS. Compared with different type of SPE column, it showed that TDH-Mg-Al-LDO exhibited great advantages in the extraction of 15 pesticide residues from green tea, which was seldom reported before. Different experiment conditions, such as combination order of Mg-Al-LDO and GCB, dosage of sorbents, type and volume of eluting solvent were thoroughly studied and optimized. The limits of detection (LODs) of 15 pesticides ranged from 0.9 to 24.2ng/g and the limits of quantifications (LOQs) were ranging from 3.0 to 80.0ng/g. The recoveries using this method at three spiked concentration levels (10, 100 and 500ng/g for Fenthion, P,P'-DDE, O,P'-DDT, P,P'-DDD and Bifenthrin, 100, 500 and 2000ng/g for the others) range from 71.1 to 119.0%. The relative standard deviation (RSD) was from 0.1 to 7.6% in all case. The result indicated that the proposed analytical method had been successfully applied for the simultaneous determination of 15 pesticide residues in commercial green tea.

Design of invisibility anti-cloak for two-dimensional arbitrary geometries.

In this paper, we derive the material parameter formulae for designing an electromagnetic invisibility anti-cloak of two-dimensional arbitrary geometry, which is conformal with the cloaked object. Different shapes of electromagnetic invisibility anti-cloaks are proposed to verify the correctness and effectiveness of the proposed formulae. The simulation results show that the invisibility anti-cloak can break cloak shielding and make the external electromagnetic waves into the cloak. This is not only to realize the transfer of information, but will not affect the role of cloak of stealth.

[Study on cytogenetic changes with relation to FAB classification in 397 patients with acute leukemias].

The purpose of study was to investigate the cytogenetic abnormality of acute leukemias (AL), to analyze the relationship in the chromosomal abnormality and the AL FAB types, and to explore the impact of the chromosomal abnormalities on the prognostic factors of AL. The chromosome karyotypes of 397 patients with AL were analyzed by means of bone marrow short-term culture and G banding technique. The results showed that in 319 out of 397 patients, the chromosome karyotypes could be analyzed, and the chromosomal abnormality occurred in 175 patients (54.9%). In the patients with acute lymphocytic leukemia (ALL), acute myelogenous leukemia (AML) and acute mixed-lineage leukemia (AMLL), the chromosomal abnormality occurred respectively in 33 of 120 patients (27.5%), 129 of 252 patients (51.2%) and 13 of 25 patients (52.0%). Hyper-diploids, hypo-diploids and diploids occurred in 41 of 175 patients (23.4%), 22 of 175 patients (12.5%), and 112 of 175 patients (64.0%) respectively. In patients with AML the FAB type-associated chromosomal abnormality occurred in 69 of 129 patients (53.5%). It is concluded that chromosomal abnormalities exist in about 55% AL patients. Some special chromosomal abnormalities are cytogenetic characteristics of AL, and obviously correlated with AL FAB types, the combination of chromosomal detection with cytogenetics is useful for the diagnosis of AL, and the evaluation of therapeutic effects and prognosis.

[Sensitivity of interferon-gamma release assay T-SPOT. TB in diagnosing extrapulmonary tuberculosis].

OBJECTIVE: To evaluate the sensitivity of an interferon-gamma release assay T-SPOT. TB in the diagnosis of bacteriologically or histologically confirmed extrapulmonary tuberculosis. METHOD: Totally 31 patients with bacteriologically or histologically confirmed extrapulmonary tuberculosis in Peking Union Medical College Hospital received T-SPOT. TB assay to detect early secreting antigen target 6 or culture filtrate protein 10 peptides-specific T cells in the peripheral blood mononuclear cells (PBMCs). RESULTS: T-SPOT. TB assay showed positive results in 29 patients with extrapulmonary tuberculosis and the sensitivity was 93.5% (95% CI 84.8% - 100%). The median of spot forming cells (SFCs) in response to early secreting antigen target 6 peptides was 196/10(6) PBMCs (interquartile range, 72-532/10(6) PBMCs), the median of SFCs in response to culture filtrate protein 10 peptides was 276 SFCs/10(6) PBMCs (interquartile range, 72-568/10(6) PBMCs), and the median of the incorporate SFCs was 612/10(6) PBMCs (interquartile range, 192-1 152/10(6) PBMCs). CONCLUSION: T-SPOT. TB is highly sensitive in diagnosing extrapulmonary tuberculosis.