Increased frequencies of T helper type 17 cells in tuberculous pleural effusion

CyTOF analysis for differential immune cellular profiling between latent tuberculosis infection and active tuberculosis

Limited data exist about the comparative immune cell population profile determined by cytometry by time-of-flight (CyTOF) analysis between active tuberculosis (TB) and latent TB infection (LTBI). In this study, we performed CyTOF analysis using peripheral blood mononuclear cells (PBMCs) to compare the differential immune cellular profile between active TB and LTBI. A total of 51 subjects (active TB [n = 34] and LTBI [n = 17]) were included. CyTOF analysis of 16 subjects (active TB [n = 8] and LTBI [n = 8]) identified a significantly higher Th17-like cell population in active TB than in LTBI. This finding was validated in the remaining 35 subjects (active TB [n = 26] and LTBI [n = 9]) using flow cytometry analysis, which consistently reveals a higher percentage of Th17 cell population in active TB (p = 0.032). The Th1/Th17 ratio represented good ability to discriminate between active TB and LTBI (AUC = 0.812). Among patients with active TB, the Th17 cell percentage was found to be lower in more advanced forms of the disease. Additionally, Th17 cell percentage positively correlated with the levels of IL-6 and neutrophil-lymphocyte ratio, respectively. In conclusion, CyTOF analysis of PBMCs showed a significantly higher percentage of Th17 cells in active TB although fairly similar immune cell populations between active TB and LTBI were observed.

Comparative evaluation of interleukin-10, transforming growth factor-β, and interleukin-17 in gastrointestinal tuberculosis and crohn's disease

Background

Gastrointestinal tuberculosis (GITB) and Crohn's disease (CD) are close mimickers and difficult to discriminate. Recent work has focused on the immunological differences between GITB and CD based on cytokines related to T-regulatory cells and Th17 cells. In the present cross-sectional study, suspected cases of GITB or CD underwent extensive clinical, radiological, endoscopic, histological, and microbiological assessment. The diagnosis was based on standard criteria and response to antitubercular therapy endoscopically.

Methods

Interleukin (IL)-10, transforming growth factor-β (TGF-β), and IL-17 were measured and compared between GITB and CD along with other parameters. Fisher's exact test and Mann-Whitney U test were used as per the data type.

Results

Of the 27 patients, 11 had CD, 9 had GITB, and 7 had other conditions. Chronic diarrhea, involvement of left and long segments of the colon, and aphthous ulcers were significantly more frequent in CD; however, transverse ulcers were in GITB. IL-10 was reduced in both GITB (median-interquartile range [IQR] 9.54 [3.65-24.04]) and CD (median-IQR 13.28 [6.91-22.50]) compared to control (median-IQR 26.72 [10.34-35.43]). TGF-β showed little variation, but IL-17 was below the detection limit in most cases. None of these cytokines were significantly different between CD and GITB. The sensitivity and specificity of multiplex Mycobacterium tuberculosis-polymerase chain reaction were 44.44% and 100%, respectively.

Conclusion

Serum cytokine profiling (IL-10, IL-17, and TGF-β) could not significantly differentiate GITB and CD. Moreover, extensive molecular, transcriptomic, chemokines, and cytokine analyses may shed light on these aspects.

Molecular and Cellular Mechanisms of M. tuberculosis and SARS-CoV-2 Infections—Unexpected Similarities of Pathogenesis and What to Expect from Co-Infection

Tuberculosis is still an important medical and social problem. In recent years, great strides have been made in the fight against M. tuberculosis, especially in the Russian Federation. However, the emergence of a new coronavirus infection (COVID-19) has led to the long-term isolation of the population on the one hand and to the relevance of using personal protective equipment on the other. Our knowledge regarding SARS-CoV-2-induced inflammation and tissue destruction is rapidly expanding, while our understanding of the pathology of human pulmonary tuberculosis gained through more the 100 years of research is still limited. This paper reviews the main molecular and cellular differences and similarities caused by M. tuberculosis and SARS-CoV-2 infections, as well as their critical immunological and pathomorphological features. Immune suppression caused by the SARS-CoV-2 virus may result in certain difficulties in the diagnosis and treatment of tuberculosis. Furthermore, long-term lymphopenia, hyperinflammation, lung tissue injury and imbalance in CD4+ T cell subsets associated with COVID-19 could propagate M. tuberculosis infection and disease progression.

Anaphylatoxins orchestrate Th17 response via interactions between CD16+ monocytes and pleural mesothelial cells in tuberculous pleural effusion

The complement system is activated in tuberculous pleural effusion (TPE), with increased levels of the anaphylatoxins stimulating pleural mesothelial cells (PMCs) to secrete chemokines, which recruit nonclassical monocytes to the pleural cavity. The differentiation and recruitment of naive CD4⁺ T cells are induced by pleural cytokines and PMC-produced chemokines in TPE. However, it is unclear whether anaphylatoxins orchestrate CD4⁺ T cell response via interactions between PMCs and monocytes in TPE. In this study, CD16⁺ and CD16^- monocytes isolated from TPE patients were cocultured with PMCs pretreated with anaphylatoxins. After removing the PMCs, the conditioned monocytes were cocultured with CD4⁺ T cells. The levels of the cytokines were measured in PMCs and monocyte subsets treated separately with anaphylatoxins. The costimulatory molecules were assessed in conditioned monocyte subsets. Furthermore, CD4⁺ T cell response was evaluated in different coculture systems. The results indicated that anaphylatoxins induced PMCs and CD16⁺ monocytes to secrete abundant cytokines capable of only inducing Th17 expansion, but Th1 was feeble. In addition, costimulatory molecules were more highly expressed in CD16⁺ than in CD16⁻ monocytes isolated from TPE. The interactions between monocytes and PMCs enhanced the ability of PMCs and monocytes to produce cytokines and that of monocytes to express HLA-DR, CD40, CD80 and CD86, which synergistically induced Th17 expansion. In the above process, anaphylatoxins enhanced the interactions between monocytes and PMCs by increasing the level of the cytokines IL-1β, IL-6, IL-23 and upregulating the phenotype of CD40 and CD80 in CD16⁺ monocytes. Collectively, these data indicate that anaphylatoxins play a central role in orchestrating Th17 response mainly via interactions between CD16⁺ monocytes and PMCs in TPE.

Tuberculous pleural effusion is characterized by intense chronic accumulations of fluid and lymphocyte cells and monocytes/macrophages in the pleural space. Complement mediators play important roles in providing protection against Mycobacterium tuberculosis. Our results demonstrated that Mycobacterium tuberculosis infection induced the amplification of complement activation in TPE. Complement activation produces anaphylatoxins that induce PMCs and CD16⁺ monocytes to secrete abundant cytokines capable of only inducing Th17 expansion, but Th1 was feeble. In addition, costimulatory molecules were more highly expressed in CD16⁺ than in CD16⁻ monocytes isolated from TPE. The interactions between monocytes and PMCs enhanced the ability of PMCs and monocytes to produce cytokines and that of monocytes to express HLA-DR, CD40, CD80 and CD86, which synergistically induced Th17 expansion. In the above process, anaphylatoxins enhanced the interactions between monocytes and PMCs by increasing the level of the cytokines IL-1β, IL-6, IL-23 and upregulating the phenotype of CD40 and CD80 in CD16+ monocytes. In summary, these data highlighted the importance of anaphylatoxins and the innate immune system in eliciting pathogenic T cell responses in TPE and suggested that monocytes, especially the CD16⁺ subset, might be an efficient target for controlling inflammation.

Predominance of Th1 Immune Response in Pleural Effusion of Patients with Tuberculosis among Other Exudative Etiologies

Pleural tuberculosis (PlTB), a common form of extrapulmonary TB, remains a challenge in the diagnosis among many causes of pleural effusion. We recently reported that the combinatorial analysis of interferon gamma (IFN-γ), IFN-γ-inducible protein 10 (IP-10), and adenosine deaminase (ADA) from the pleural microenvironment was useful to distinguish pleural effusion caused by TB (microbiologically confirmed or not) among other etiologies. In this cross-sectional cohort study, a set of inflammatory mediators was quantified in blood and pleural fluid (PF) from exudative pleural effusion cases, including PlTB (n = 27) and non-PlTB (nTB) (n = 25) patients. The levels of interleukin-2 (IL-2), IL-4, IL-6, IL-10, IL-17A, IFN-γ, tumor necrosis factor (TNF), IP-10, transforming growth factor β1 (TGF-β), and ADA were determined using cytometric bead assay, enzyme-linked immunosorbent assay (ELISA), or biochemical tests. IFN-γ, IP-10, TNF, TGF-β, and ADA quantified in PF showed significantly higher concentrations in PlTB patients than in nTB patients. When blood and PF were compared, significantly higher concentrations of IL-6 and IL-10 in PF were identified in both groups. TGF-β, solely, showed significantly increased levels in PF and blood from PlTB patients when both clinical specimens were compared to those from nTB patients. Principal-component analysis (PCA) revealed a T helper type 1 (Th1) pattern attributed mainly to higher levels of IP-10, IFN-γ, TGF-β, and TNF in the pleural cavity, which was distinct between PlTB and nTB. In conclusion, our findings showed a predominantly cellular immune response in PF from TB cases, rather than other causes of exudative effusion commonly considered in the differential diagnosis of PlTB.

Altered peripheral blood Th17 and follicular T-helper subsets in patients with pulmonary tuberculosis

Tuberculosis (TB) is one of the most common infections worldwide. Eradication of an intracellular pathogen M. tuberculosis requires to induce a Th1 response by activating IFNγ-producing tissue macrophages. Along with Th1 cells, various subsets of Th17 and follicular T-helper cells (Tfh) able to secrete a broad range of cytokines, including IFNγ, can also be involved in eliminating bacterial pathogens. It justified analyzing in this study changes in percentage of various peripheral blood Th subsets, including Th1, Th2, Th17 and Tfh cells, in TB patients. For this, major CD3+CD4+ T cell subsets were assessed by using multicolor flow cytometry in TB patients (n = 40) and healthy volunteers (n = 30). It was found that in TB patients vs. control group percentage of peripheral blood CD45RA–CCR7+ central memory (CM) Th was decreased also affecting frequency of some functional T cell subsets, e.g. either lowering Th2 cells (9.11% (6.95; 13.77) vs. 7.21% (5.64; 9.84), p = 0.012) or elevating CCR6+ Th17 subsets (35.92% (27.72; 41.06) vs. 40.39% (35.41; 47.79; p = 0.016), respectively, but not influencing Th1 and Tfh subsets frequencies. Moreover, percentage of total CCR6+ CM Th cells in TB patients vs. control was decreased in CCR4–CXCR3+ Th17.1 cell subset (42.87% (33.64; 49.45) vs. 52.26% (46.45; 56.95), p 0.001), whereas standard CCR4+CXCR3– Th17 and CCR6+ DP Th17 subsets were elevated (p = 0.005 and p = 0.002, respectively). In addition, altered Tfh subset composition associated with the increased (p = 0.021) percentage of CXCR3–CCR6– Tfh2 cells, but decreased CXCR3+CCR6– Tfh1 cells (p = 0.036) was observed. Finally, frequency of peripheral blood Th subsets noted above was also analyzed within effector memory (CD45RA–CCR7–) cells. It was found that in TB patients vs. volunteers frequency of Th17.1 cells was also significantly lower (p = 0.006) in CCR6+ EM Th (54.43% (41.19; 91.92) vs. 61.76% (54.01; 65.63), whereas percentage of double-positive Th17 was significantly increased (20.83% (15.12; 30.87) and 12.93 % (9.80; 19.01), respectively, p 0.001). Thus, it suggests that during M. tuberculosis infection percentage of IFNγ-producing Th17 and Tfh cells was reduced compared to control group also affecting both central memory Th cells patrolling peripheral lymphoid organs as well as effector memory Th cells able to exit to site of infection. 

Immune activation and regulatory T cells in Mycobacterium tuberculosis infected lymph nodes

Background

Lymph node tuberculosis (LNTB) is the most frequent extrapulmonary form of tuberculosis (TB). Studies of human tuberculosis at sites of disease are limited. LNTB provides a unique opportunity to compare local in situ and peripheral blood immune response in active Mycobacterium tuberculosis (Mtb) disease. The present study analysed T regulatory cells (Treg) frequency and activation along with CD4+ T cell function in lymph nodes from LNTB patients.

Results

Lymph node mononuclear cells (LNMC) were compared to autologous peripheral blood mononuclear cells (PBMC). LNMC were enriched for CD4+ T cells with a late differentiated effector memory phenotype. No differences were noted in the frequency and mutifunctional profile of memory CD4+ T cells specific for Mtb. The proportion of activated CD4+ and Tregs in LNMC was increased compared to PBMC. The correlation between Tregs and activated CD4+ T cells was stronger in LNMC than PBMC. Tregs in LNMC showed a strong positive correlation with Th1 cytokine production (IL2, IFNγ and TNFα) as well as MIP-1α after Mtb antigen stimulation. A subset of Tregs in LNMC co-expressed HLA-DR and CD38, markers of activation.

Conclusion

Further research will determine the functional relationship between Treg and activated CD4+ T cells at lymph node sites of Mtb infection.

Electronic supplementary material

The online version of this article (10.1186/s12865-018-0266-8) contains supplementary material, which is available to authorized users.

A subset of CD1c+ dendritic cells is increased in patients with tuberculosis and promotes Th17 cell polarization

The role of primary subsets of DCs in Mycobacterium tuberculosis infection in humans is incompletely understood. In this study, we identified a CD1c DC subset with phenotype of CD1c⁺CD11c⁺CD19^-CD11b⁺ that was significantly increased in tuberculous pleural effusions and in peripheral blood from patients with TB compared with that from healthy controls (p < 0.0001). Sputum smear/culture-positive patients with tuberculosis had significantly higher frequency of CD1c⁺CD11b⁺ DC subset than sputum smear/culture-negative patients (p < 0.0001). After effective anti-TB chemotherapy, the frequency of CD1c⁺CD11b⁺ DC subset in peripheral blood and tuberculous pleural effusions was decreased. CD1c⁺CD11b⁺ DC subset from tuberculous pleural effusions expressed higher levels of TLR2, TLR4, CD172a, CD206 and FcεRⅠ, but lower levels of CD80, CD83 and CD86 compared with CD1c⁺CD11b^- DC subset. Expression of IL-1β, IL-6, IL-8, IL-23, TNF-α, IFN-γ and TGF-β mRNA in CD1c⁺CD11b⁺ DCs was higher than in CD1c⁺CD11b^- DC subset. Co-culture of autologous naive CD4⁺ T cells with sorted CD1c⁺CD11b⁺ DCs expressed significantly increased levels of IL-17A and RORγt transcripts as compared with those co-cultured with CD11b^- subset. In conclusion, a CD1c⁺CD11b⁺ DC subset with elevated frequency in patients with tuberculosis was identified and it promoted Th17 cell differentiation.

Circulating HLA-DR+CD4+ effector memory T cells resistant to CCR5 and PD-L1 mediated suppression compromise regulatory T cell function in tuberculosis

Chronic T cell activation is a hallmark of pulmonary tuberculosis (PTB). The mechanisms underpinning this important phenomenon are however, poorly elucidated, though known to rely on control of T effector cells (Teff) by regulatory T cells (Treg). Our studies show that circulating natural Treg cells in adults with PTB preserve their suppressive potential but Teff cells from such subjects are resistant to Treg-mediated suppression. We found this to be due to expansion of an activated Teff subset identified by Human Leukocyte Antigen (HLA)-DR expression. Sensitivity to suppression was restored to control levels by depletion of this subset. Comparative transcriptome analysis of Teff cells that contain HLA-DR⁺ cells versus the fraction depleted of this population identified putative resistance mechanisms linked to IFNG, IL17A, IL22, PD-L1 and β-chemokines CCL3L3, CCL4 expression. Antibody blocking experiments confirmed HLA-DR⁺ Teff cells, but not the fraction depleted of HLA-DR⁺ effectors, to be resistant to Treg suppression mediated via CCR5 and PD-L1 associated pathways. In the presence of HLA-DR⁺ Teff cells, activation of NFκB downstream of CCR5 and PD-L1 was perturbed. In addition, HLA-DR⁺ Teff cells expressed significantly higher levels of Th1/Th17 cytokines that may regulate Treg function through a reciprocal counter-balancing relationship. Taken together, our study provides novel insight on how activated HLA-DR⁺CD4⁺ T cells may contribute to disease associated inflammation by compromising Treg-mediated suppression in PTB.

An important marker of progression to PTB following Mycobacterium tuberculosis (Mtb) infection in humans is elevated frequencies of HLA-DR⁺CD4⁺ T cells, reflecting chronic T cell activation. However, the mechanisms by which activated HLA-DR⁺CD4⁺ T cells contribute to disease process is not known. We show that CD25^- HLA-DR⁺CD4⁺ memory Teff from PTB patients are resistant to suppression mediated by Treg cells. An unbiased transcriptome analysis identified several key pathways that contribute to this resistance. Specifically, presence of HLA-DR⁺CD4⁺ T cells renders the effector population resistant to CCR5 and PD-L1 mediated suppression by Treg cells. In addition, the HLA-DR⁺CD4⁺ memory Teff cells express elevated levels of Th1/Th17 cytokines known to counter-regulate and dampen Treg suppression. These findings provide fresh insight to disease process in TB and identify HLA-DR⁺ Teff resistant to Treg suppression as a potential functional marker of disease.

Increased Concentrations of Extracellular Histones in Patients with Tuberculous Pleural Effusion

Background

Extracellular histones have recently been suggested as critical mediators in many inflammatory diseases. However, the role of extracellular histones in tuberculous pleural effusion (TPE) is unclear. The goal of this study was to explore the potential involvement of extracellular histones in patients with TPE.

Material/Methods

Samples of pleural effusion and peripheral blood were obtained from 58 patients with tuberculosis. Extracellular histones were determined in both TPE and serum samples. Moreover, the biomarkers for cellular damage, inflammatory cell activation, and systemic inflammation including lactate dehydrogenase (LDH), myeloperoxidase (MPO), S100A8/A9, as well as multiple inflammatory cytokines were measured.

Results

Extracellular histone levels were significantly elevated in TPE (4.762 mg/mL [3.336, 7.307]) and serum samples (1.502 mg/mL [1.084, 2.478]) from tuberculosis patients as compared with the serum (0.585 mg/mL [0.285, 0.949]) from healthy controls. Notably, extracellular histones in TPE were also much higher than in serum of patients (P=0.002). LDH, MPO, and S100A8/A9 levels were all increased in TPE, along with a remarkable elevation of various cytokines. A correlation analysis showed that extracellular histones were positively associated with LDH, MPO, and S100A8/A9, and a panel of inflammatory cytokines in TPE.

Conclusions

These results suggest that high concentrations of extracellular histones are markedly present in TPE, which may play an inflammatory role towards the progression of tuberculosis.

The immune characterization of interferon-β responses in tuberculosis patients

We aimed to assess the immunoregulatory effects of IFN‐β in patients with tuberculous pleurisy. IFN‐β, IFN‐γ and IL‐17 expression levels were detected, and correlations among these factors in different culture groups were analyzed. Pleural fluid mononuclear cells (PFMC) from tuberculous pleural effusions, but not peripheral blood mononuclear cells (PBMC) from healthy donors, spontaneously expressed IFN‐β, IL‐17 and IFN‐γ. Moreover, exogenous IFN‐β significantly inhibited the expression of IL‐17 in PFMC. By contrast, IFN‐β simultaneously enhanced the levels of IFN‐γ. To further investigate the regulation of IL‐17 and IFN‐γ by endogenous IFN‐β, an IFN‐β neutralizing antibody was simultaneously added to bacillus Calmette‐Guérin (BCG)‐stimulated PFMC. IL‐17 expression was significantly increased, but IFN‐γ production was markedly decreased in the experimental group supplemented with the IFN‐β neutralizing antibody. Simultaneously, IL‐17 production was remarkably increased in the experimental group supplemented with the IFN‐γ neutralizing antibody. Taken together, in our study, we first found that freshly isolated PFMC, but not PBMC from healthy donors, spontaneously expressed IFN‐β, IL‐17 and IFN‐γ in vivo. Moreover, IFN‐β suppressed IL‐17 expression and increased IFN‐γ production. Furthermore, both IFN‐β and IFN‐γ down‐regulated IL‐17 expression. These observations suggest that caution is required when basing anti‐tuberculosis treatment on the inhibition of IFN‐β signaling.

Decreased T helper 17 cells in tuberculosis is associated with increased percentages of programmed death ligand 1, T helper 2 and regulatory T cells

Background

Tuberculosis (TB) is one of the most common infectious diseases worldwide. During active tuberculosis, T helper (Th) 17 cells are decreased, however the association with inhibitory immune regulation is unclear.

Methods

We enrolled 27 patients with TB and 20 age- and sex-matched controls and studies their lymphocyte status. Peripheral blood lymphocytes were isolated and programmed death-1 (PD-1) and programmed death ligand 1 (PD-L1) were measured on Th17 cells by using flow cytometry after the cells were stimulated with phorbol 12-myristate 13-acetate and ionomycin for 6 h. In addition, Th2 and regulatory T cells were measured and analyzed.

Results

The TB group had lower levels of Th17 cells but higher levels of Th2 and Treg cells than the controls. In Th17 cells, the percentage of PD-L1 was higher in the TB group than that in the controls. In Th2 and Treg cells, the percentage of cytotoxic T-lymphocyte associated protein 4 (CTLA-4) was lower in the TB group and PD-1 was higher in Treg cells in the TB group. In the patients with extra-pulmonary TB, levels of Th1, Th2 and T17 cells were lower than those with pulmonary TB. The percentage of PD-1 on Th1 lymphocytes positively correlated with radiographic score.

Conclusions

Lower level of Th17 in TB patients may be associated with increased percentage of PD-L1 and increasing levels of Th2 and Treg cells which influenced by CTLA-4.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0580-3) contains supplementary material, which is available to authorized users.

Imbalance of Th17 and Treg in peripheral blood mononuclear cells of active tuberculosis patients

Objective

Maintaining a right balance between Th17 and Treg might be critical to the immunopathogenesis of active tuberculosis (TB). This study aimed to assess whether the Th17/Treg balance is altered in active TB patients.

Methods

250 study subjects (90 active TB patients, 80 latent TB subjects, and 80 healthy controls) were recruited for the study. The expression of Th17 and Treg in peripheral blood mononuclear cells (PBMCs) in the 250 subjects was investigated by flow cytometry. Plasma levels of cytokines IL-17 and IL-10, which are related to Th17 and Treg, respectively, were determined by ELISA.

Results

The percentages of Th17 and Treg in PBMCs from active TB patients were significantly higher than those from latent TB or control groups (Th17: 4.31 ± 1.35% vs. 1.58 ± 0.71% or 1.15 ± 0.49%, p < 0.05; Treg: 11.44 ± 2.69% vs. 7.54 ± 1.56% or 4.10 ± 0.99%, p < 0.05). The expression of IL-17 and IL-10 was significantly increased in active TB patients in comparison to that in latent TB or control groups (IL-17: 16.85 ± 9.68 vs. 7.23 ± 5.19 or 8.21 ± 5.51 pg/mL, p < 0.05; IL-10: 28.70 ± 11.27 vs. 20.25 ± 8.57 or 13.94 ± 9.00 pg/mL, p < 0.05).

Conclusions

Our study demonstrated an altered balance of Treg/Th17 in active TB patients, with higher percentages of Th17 and Treg in PBMCs. Further research on this imbalance may offer a new direction for TB treatment.

Increased soluble and membrane-bound PD-L1 contributes to immune regulation and disease progression in patients with tuberculous pleural effusion

Soluble and membrane-bound programmed death ligand-1 (sPD-L1 and mPD-L1, respectively) have been demonstrated to participate in the immune suppression of non-small cell lung cancer. However, the contribution of sPD-L1 and mPD-L1 to immune regulation and disease progression in patients with pleural effusions remains unknown. The present study evaluated the levels of sPD-L1 and membrane-bound PD-1/PD-L1 in the peripheral blood and pleural effusions of patients with tuberculous pleural effusion (TPE), malignant pleural effusion (MPE) and non-tuberculous non-malignant pleural effusion (n-TB n-M). Furthermore, selected T lymphocytes and cluster of differentiation (CD)14⁺ monocytes were co-cultured to investigate the potential effect of the PD-1/PD-L1 pathway in TPE. Levels of sPD-L1 and PD-L1 on CD14⁺ monocytes were increased in the TPE group, as compared with the MPE and n-TB n-M groups. Furthermore, sPD-L1 levels and the expression levels of PD-L1 on CD14⁺ monocytes were demonstrated to be positively correlated with interferon (IFN)-γ concentration in pleural effusions. Therefore, IFN-γ may increase the expression of PD-L1 on CD14⁺ monocytes in vitro. Cell counting kit-8 analysis demonstrated that anti-PD-L1 antibody was able to partially reverse the proliferation of T lymphocytes in the co-culture system. The results of the present study indicated that sPD-L1 or mPD-L1 are associated with the immune regulation and disease progression of TPE, and may serve as possible biomarkers of TPE. Furthermore, sPD-L1 and the PD-1/PD-L1 pathway of TPE may be associated with the Th1 immune response; therefore, an anti-PD-1/PD-L1 pathway suggests a potential immune therapy strategy for the treatment of TPE.

Expression Profiles of Cytokine mRNAs in the Pleural Fluid Reveal Differences Among Tuberculosis, Malignancies, and Pneumonia-Exudative Pleural Effusions

INTRODUCTION

Tuberculosis (TB) and malignant diseases are the most common causes of lymphocytic pleural effusion in adults. Serum and pleural fluid cytokine levels have been analyzed to help in the differential diagnosis, but with limited results.

PURPOSE

This study investigates transcription levels of selected cytokine genes in pleural effusion of patients under investigation for TB.

METHODS

This was a prospective study that included adult patients under investigation for pleural effusion in Brazil. The expression of 19 cytokine genes was analyzed by RT-qPCR.

RESULTS

The majority of cytokine-related genes expressed in pleural fluid of TB patients were similar in non-TB patients, except for RORA and RORC genes, which showed a statistically higher level in TB. All cytokines in the Th17 pattern were induced in TB patients' pleural fluid. Patients with malignant pleural effusion expressed higher levels of IFN-α1, IFN-β1, TNF-α, IL-4 and IL-6, and suppression of TGFβ-1.

CONCLUSION

There is still a lot to understand about the cytokine roles in the pro- and anti-inflammatory environment of exudative pleural effusions. The data presented here showed an increased expression of Th17 pattern cytokines genes in TB patients that could be used as markers to differentiate tuberculous pleuritis from other common causes of exudative pleural effusion.

High IL-35 pleural expression in patients with tuberculous pleural effusion

Background

IL-35 is a novel anti-inflammatory and immunosuppressive cytokine primarily produced by Treg cells, and is involved in inflammatory diseases and autoimmune diseases. However, its roles in tuberculous pleural effusion (TPE) remain unknown. We aimed to investigate the potential involvement of IL-35 in TPE.

Material/Methods

Thirty TPE patients and 20 lung cancer patients with malignant pleural effusion (MPE) were recruited. Samples of pleural effusion (100 mL) were collected after traditional pleurocentesis. Blood was sampled from TPE patients. Mononuclear cells were isolated by Ficoll-Hypaque gradient. Proportions of Th1, Th17, and IL-35-producing cells were analyzed by flow cytometry. IL-35 was assessed by real-time RT-PCR, ELISA, and immunofluorescence. An ELISPOT assay was used to assess the effect of IL-35 on pleural effusion mononuclear cells (PEMCs).

Results

Proportions of IL-35-producing cells were higher in TPE compared with MPE (49.4±6.0 vs. 15.8±5.4%, P<0.001) and blood from TPE patients (49.4±6.0% vs. 16.6±3.1, P<0.001). IL-35, IL-17 and IFN-γ were elevated in TPE compared with MPE (all P<0.01). ELISPOT assay showed that IL-35 reduced the proportion of IFN-γ-producing CD4⁺ T cells in TPE. IL-35 mRNA expression was higher in TPE compared with MPE (P<0.001). Immunofluorescence showed that IL-35-positive cells were present in pleural tissues from TPE patients.

Conclusions

Results suggest that there is an imbalance in IL-35 metabolism in TPE. However, further studies are required to assess the exact relationship with the immune system response to tuberculosis. IL-35 might play a role in TPE and might be targeted as a treatment for TPE.

The changes and its significance of Th17 and Treg cells and related cytokines in patients with tuberculosis pleurisy

BACKGROUND

Tuberculous pleurisy is a kind of tuberculosis, it is well known that Th1 lymphocytes play a key role in the treatment of tuberculosis infection. However, latest studies show that Th17 lymphocyte may also play an important role tuberculosis infection. There is close relationship between Treg and Thl7 cells, and changes in the number or the function of the two kinds of cells may lead to diseases. The current researches on Thl7 and Treg cells maily focus on autoimmune diseases, however, reports about their role in tuberculosis are limited. In this study, we investigate the function of th17 and Treg cells and the above cytokines in the pathogenesis of tuberculosis pleurisy; by determining the expression of Th17 and Treg cells in peripheral CD4 T cells and the related cytokines in patients with tuberculous compared with healthy people.

RESULTS

Th17 cells in patients were higher than that in the Healthy control group, expression of Treg cells in patients were lower than that in the healthy group; IL-17, IL-23 levels in peripheral blood and hydrothorax from the patients were higher than that in the healthy group; IL-17, IL-23 and IL-6 levels in hydrothorax were higher than that in peripheral blood. There was no difference in IL-6 level in peripheral blood between the patients and healthy control; TGF- β level in peripheral blood from the healthy group was higher than that in peripheral blood and hydrothorax from the patients. And there were no differences in TGF- β level between peripheral blood and hydrothorax. Th17 cells were negatively correlated with Treg cells ,but were positive correlation with IL-17, IL-23, IL-6 levels in peripheral blood; TGF- β level was positive correlation with Treg cells in the peripheral blood, but no correlation with Th17 cells.

CONCLUSION

Th17 and Treg cells may be involved in the immune pathological mechanism of tuberculous pleurisy and changes of related cytokines may be involved in the differentiation of Th17 and Treg cells and inflammatory response. Thus, Th17 and Treg cells and related cytokines may be important immunopathogenesis for tuberculous pleurisy.

Elevated pleural effusion IL-17 is a diagnostic marker and outcome predictor in lung cancer patients

BACKGROUND

Interleukin 17 (IL-17) is a proinflammatory cytokine produced mainly by CD4(+) T-lymphocytes and may be important in tumor cell growth and progression. In this study, we aimed to evaluate the diagnostic and prognostic value of pleural effusion levels of IL-17 in lung cancer patients with malignant pleural effusion (MPE).

METHODS

Pleural effusion samples were collected from 78 lung cancer patients with MPE and from 45 patients with nonmalignant pleural effusion. Pleural fluid concentrations of IL-17 were measured by using enzyme-linked immunosorbent assays.

RESULTS

Malignant effusion exhibited higher IL-17 levels than nonmalignant effusion (20.49 ± 5.27 pg/ml vs. 13.16 ± 2.25 pg/ml; P < 0.01). Lung cancer patients with pleural fluid IL-17 levels below 15 pg/ml had longer overall survival than those patients with higher levels (10.8 months vs. 4.7 months; P < 0.05). On the basis of multivariate analysis, we found that pleural fluid IL-17 level was an independent prognostic factor in lung cancer patients with MPE.

CONCLUSIONS

Measurement of IL-17 levels might be a useful diagnostic and prognostic test for lung cancer patients with MPE.

Diagnostic value of pleural interleukin 17 and carcinoembryonic antigen in lung cancer patients with malignant pleural effusions

Interleukin 17 (IL-17) has been found to be increased in some human cancers; however, the possible implication of IL-17 in regulating antitumor responses in lung cancer patients with malignant pleural effusions (MPE) remains to be elucidated. This study aimed to investigate the diagnostic value of pleural IL-17 and carcinoembryonic antigen (CEA) in MPE and benign pleural effusions (BPE). Pleural effusion samples from 108 patients were classified on the basis of diagnosis as MPE (n = 56) and BPE (n = 52). The concentration of IL-17 was determined by enzyme-linked immunosorbent assay (ELISA). The CEA levels were also determined in all patients. A significant difference was observed in the levels of CEA (P < 0.01) between MPE and BPE. The concentration of IL-17 in MPE was significantly higher compared to that in BPE (P < 0.01). With a cutoff point of 15.7 pg/ml, IL-17 had a sensitivity of 76.8 % and a specificity of 80.8 % for differential diagnosis. The combined detection of IL-17 and CEA had a sensitivity of 96.4 % and a specificity of 92.3 % to distinguish MPE from BPE. The combined detection of IL-17 and CEA may be more valuable in the differential diagnosis between MPE and BPE.

Interleukin-17A is involved in bacteria-related acute pleural inflammation

BACKGROUND AND OBJECTIVE

The role of pro-inflammatory interleukin-17A (IL-17A), in pleural diseases is unknown. We sought to investigate IL-17A expression and its clinical implications in patients with pleural effusion (PE) and IL-17A involvement in the pathobiology of pleural inflammation elicited by bacterial products.

METHODS

Pleural and blood IL-17A content was examined in 84 patients with PE of different aetiologies, and the diagnostic value of pleural IL-17A was explored in 92 patients with neutrophil-predominant PE. IL-17A contribution in pleural inflammation was evaluated in mice injected intrapleurally with either IL-17A or bacterial products with or without IL-17A-neutralizing antibodies.

RESULTS

IL-17A was upregulated in the pleural space of patients with parapneumonic PE. It was detected in a minority of patients with tuberculous PE and very uncommonly in patients with malignant or other pleural exudates. Pleural fluid (PF) IL-17A levels were correlated with markers of acute pleural inflammation, as well as vascular endothelial growth factor and IL-8 levels. Among patients with neutrophil-predominant PE, PF IL-17A was detected only in those with parapneumonic PE, although the sensitivity of the test was low (<50%). Intrapleural injection of IL-17A elicited a neutrophil-predominant inflammatory response in mice, and IL-17A neutralization partially blocked pleural neutrophilia induced by intrapleural administration of bacterial products.

CONCLUSIONS

IL-17A is involved in pleural inflammation related to bacterial infection. Moreover, pleural IL-17A levels may be helpful in uncovering an infectious aetiology among patients with neutrophil-predominant PE.

Regulation of CD4(+) T cells by pleural mesothelial cells via adhesion molecule-dependent mechanisms in tuberculous pleurisy

Background

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) have been demonstrated to be expressed on pleural mesothelial cells (PMCs), and to mediate leukocyte adhesion and migration; however, little is known about whether adhesion molecule-dependent mechanisms are involved in the regulation of CD4⁺ T cells by PMCs in tuberculous pleural effusion (TPE).

Methods

Expressions of ICAM-1 and VCAM-1 on PMCs, as well as expressions of CD11a and CD29, the counter-receptors for ICAM-1 and VCAM-1, respectively, expressed on CD4⁺ T cells in TPE were determined using flow cytometry. The immune regulations on adhesion, proliferation, activation, selective expansion of CD4⁺ helper T cell subgroups exerted by PMCs via adhesion molecule-dependent mechanisms were explored.

Results

Percentages of ICAM-1-positive and VCAM-1‒positive PMCs in TPE were increased compared with PMC line. Interferon-γ enhanced fluorescence intensity of ICAM-1, while IL-4 promoted VCAM-1 expression on PMCs. Percentages of CD11a^highCD4⁺ and CD29^highCD4⁺ T cells in TPE significantly increased as compared with peripheral blood. Prestimulation of PMCs with anti‒ICAM-1 or ‒VCAM-1 mAb significantly inhibited adhesion, activation, as well as effector regulatory T cell expansion induced by PMCs.

Conclusions

Our current data showed that adhesion molecule pathways on PMCs regulated adhesion and activation of CD4⁺ T cells, and selectively promoted the expansion of effector regulatory T cells.

Efficient, long term production of monocyte-derived macrophages from human pluripotent stem cells under partly-defined and fully-defined conditions

Human macrophages are specialised hosts for HIV-1, dengue virus, Leishmania and Mycobacterium tuberculosis. Yet macrophage research is hampered by lack of appropriate cell models for modelling infection by these human pathogens, because available myeloid cell lines are, by definition, not terminally differentiated like tissue macrophages. We describe here a method for deriving monocytes and macrophages from human Pluripotent Stem Cells which improves on previously published protocols in that it uses entirely defined, feeder- and serum-free culture conditions and produces very consistent, pure, high yields across both human Embryonic Stem Cell (hESC) and multiple human induced Pluripotent Stem Cell (hiPSC) lines over time periods of up to one year. Cumulatively, up to ∼3×10⁷ monocytes can be harvested per 6-well plate. The monocytes produced are most closely similar to the major blood monocyte (CD14⁺, CD16^low, CD163⁺). Differentiation with M-CSF produces macrophages that are highly phagocytic, HIV-1-infectable, and upon activation produce a pro-inflammatory cytokine profile similar to blood monocyte-derived macrophages. Macrophages are notoriously hard to genetically manipulate, as they recognise foreign nucleic acids; the lentivector system described here overcomes this, as pluripotent stem cells can be relatively simply genetically manipulated for efficient transgene expression in the differentiated cells, surmounting issues of transgene silencing. Overall, the method we describe here is an efficient, effective, scalable system for the reproducible production and genetic modification of human macrophages, facilitating the interrogation of human macrophage biology.

Diagnostic value of interleukin 21 and carcinoembryonic antigen levels in malignant pleural effusions

The aim of this study was to evaluate the diagnostic value of interleukin 21 (IL-21) and carcinoembryonic antigen (CEA) in tuberculous pleural effusions (TPEs) and malignant pleural effusions (MPEs). Pleural effusion samples from 103 patients were classified on the basis of diagnosis as TPE (n=51) and MPE (n=52). The concentration of IL-21 was determined by ELISA. Lactate dehydrogenase (LDH), adenosine dehydrogenase (ADA) and CEA levels were also determined in all patients. A significant difference was observed in the levels of ADA and CEA (P<0.01), but not in the levels of LDH (P>0.05) between TPE and MPE. The concentration of IL-21 in MPE was significantly higher compared to TPE (P<0.01). With a threshold value of 4.32 pg/ml, IL-21 had a sensitivity of 76.9% (40/52) and a specificity of 80.4% (41/51). Combined detection of IL-21 and CEA had a sensitivity of 69.2% (36/52) and a specificity of 92.2% (47/51). These two markers can contribute to the differential diagnosis of MPEs.

Subpopulations of helper T lymphocytes in tuberculous pleurisy

Although it is curable, tuberculosis continues to be is a major global public health problem, especially in developing countries. Tuberculous pleural effusion (TPE) is one of the most common forms of extrapulmonary tuberculosis. It has been well documented that CD4(+) T lymphocytes are dominant leukocytes present in TPE. Traditionally, CD4(+) T cells have been classified into two functionally distinct subsets, helper T-cell type 1 (Th1) and Th2 cells, based on their cytokine production profiles. Recently, regulatory T cells, Th17 cells, Th9 cells, and Th22 cells have been added to the 'portfolio' of Th cells. In this review, we summarize recent findings regarding the phenotypic characteristics of the above Th cells, the mechanisms of differentiation and recruitment of Th cells into pleural space, and the immune regulation of Th cells in TPE environment. We also describe the interplay between different Th cells, as well as between Th cells and other type of cells, such as pleural mesothelial cells in TPE. Further studies should be directed at identifying the mediators and mechanisms involved in the immunoregulatory properties of pleural Th cells in tuberculosis infection.

The responses of multiple cytokines following incubation of whole blood from TB patients, latently infected individuals and controls with the TB antigens ESAT-6, CFP-10 and TB7.7

The development of clinically relevant biomarkers is important for diagnosing latent tuberculosis infection (LTBI) and active tuberculosis (TB) and predicting their prognoses. This study examined whether the responses of multiple cytokines can be used as a biomarker to distinguish the TB infection status and mycobacterial load. We analysed the responses of multiple cytokines (IFN-γ, IL-2, IL-10, IL-13, IL-17 and TNF-α) in the supernatant from the QuantiFERON-TB Gold In-Tube assay following stimulation of whole blood from the TB group (n = 32), LTBI group (n = 19) and healthy controls (n = 30) with TB antigens (ESAT-6, CFP-10 and TB7.7). The median responses of IFN-γ, IL-2, IL-10 and IL-13 were higher in the LTBI and active TB groups than in the non-TB control group (IFN-γ, P < 0.001; IL-2, P < 0.001; IL-10, P = 0.012; IL-13, P < 0.001). The median IL-2/IFN-γ ratio of the LTBI group was higher than that of the active TB group (P = 0.014) and differed significantly between patients with LTBI, patients with smear-negative TB and patients with smear-positive TB (P = 0.027). This difference was especially evident between the patients with LTBI and patients with smear-positive TB (P = 0.047). In conclusion, IFN-γ, IL-2, IL-10 and IL-13 can serve as biomarkers for distinguishing TB infection. In addition, the IL-2/IFN-γ ratio appears to be a biomarker for diagnosing LTBI and may be useful as a prognostic factor and for evaluating treatment responses.

Reduced frequency of memory T cells and increased Th17 responses in patients with active tuberculosis

Phenotypic and functional alterations in Mycobacterium tuberculosis T cell subsets have been reported in patients with active tuberculosis. A better understanding of these alterations will increase the knowledge about immunopathogenesis and also may contribute to the development of new diagnostics and prophylactic strategies. Here, the ex vivo phenotype of CD4(+) and CD8(+) T cells and the frequency and phenotype of gamma interferon (IFN-γ)- and interleukin 17 (IL-17)-producing cells elicited in short-term and long-term cultures following CFP-10 and purified protein derivative (PPD) stimulation were determined in noninfected persons (non-TBi), latently infected persons (LTBi), and patients with active tuberculosis (ATB). Phenotypic characterization of T cells was done based on the expression of CD45RO and CD27. Results show that ATB had a reduced frequency of circulating CD4(+) CD45RO(+) CD27(+) T cells and an increased frequency of CD4(+) CD45RO(-) CD27(+) T cells. ATB also had a higher frequency of circulating IL-17-producing CD4(+) T cells than did LTBi after PPD stimulation, whereas LTBi had more IFN-γ-producing CD4(+) T cells than did non-TBi. The phenotype of IFN-γ-producing cells at 24 h differs from the phenotype of IL-17-producing cells with no differences between LTBi and ATB. At 144 h, IFN-γ- and IL-17-producing cells were mainly CD45RO(+) CD27(+) T cells and they were more frequent in ATB. These results suggest that M. tuberculosis infection induces alterations in T cells which interfere with an adequate specific immune response.

Differentiation and recruitment of IL-22-producing helper T cells stimulated by pleural mesothelial cells in tuberculous pleurisy

RATIONALE

IL-22-producing helper T cells (Th22 cells) have been reported to be involved in tuberculosis infection. However, differentiation and immune regulation of Th22 cells in tuberculous pleural effusion (TPE) remain unknown.

OBJECTIVES

To elucidate the mechanism by which Th22 cells differentiate and recruit into the pleural space.

METHODS

The distribution and phenotypic features of Th22 cells in both TPE and blood were determined. The impacts of proinflammatory cytokines and antigen presentation by pleural mesothelial cells (PMCs) on Th22-cell differentiation were explored. The chemoattractant activity of chemokines produced by PMCs for Th22 cells was observed.

MEASUREMENTS AND MAIN RESULTS

Th22 cells were significantly higher in TPE than in blood. IL-1β, IL-6, and/or tumor necrosis factor-α promoted Th22-cell differentiation from CD4(+) T cells. It was found that PMCs expressed CCL20, CCL22, and CCL27, and that TPE and PMC supernatants were chemotactic for Th22 cells. This activity was partly blocked by anti-CCL20, anti-CCL22, and anti-CCL27 antibodies. IL-22 and IL-17 significantly improved PMC wound healing. Moreover, PMCs were able to stimulate CD4(+) T-cell proliferation and Th22-cell differentiation by presenting tuberculosis-specific antigen.

CONCLUSIONS

The overrepresentation of Th22 cells in TPE may be due to pleural cytokines and to PMC-produced chemokines. Our data suggest a collaborative loop between PMCs and Th22 cells in TPE. In particular, PMCs were able to function as antigen-presenting cells to stimulate CD4(+) T-cell proliferation and Th22-cell differentiation.

Differentiation and recruitment of Th9 cells stimulated by pleural mesothelial cells in human Mycobacterium tuberculosis infection

Newly discovered IL-9–producing CD4⁺ helper T cells (Th9 cells) have been reported to contribute to tissue inflammation and immune responses, however, differentiation and immune regulation of Th9 cells in tuberculosis remain unknown. In the present study, our data showed that increased Th9 cells with the phenotype of effector memory cells were found to be in tuberculous pleural effusion as compared with blood. TGF-β was essential for Th9 cell differentiation from naïve CD4⁺ T cells stimulated with PMA and ionomycin in vitro for 5 h, and addition of IL-1β, IL-4 or IL-6 further augmented Th9 cell differentiation. Tuberculous pleural effusion and supernatants of cultured pleural mesothelial cells were chemotactic for Th9 cells, and this activity was partly blocked by anti-CCL20 antibody. IL-9 promoted the pleural mesothelial cell repairing and inhibited IFN-γ-induced pleural mesothelial cell apoptosis. Moreover, pleural mesothelial cells promoted Th9 cell differentiation by presenting antigen. Collectively, these data provide new information concerning Th9 cells, in particular the collaborative immune regulation between Th9 cells and pleural mesothelial cells in human M. tuberculosis infection. In particular, pleural mesothelial cells were able to function as antigen-presenting cells to stimulate Th9 cell differentiation.

Diagnostic value of interleukin 22 and carcinoembryonic antigen in tuberculous and malignant pleural effusions

The aim of this study was to investigate the diagnostic value of interleukin 22 (IL-22) and carcinoembryonic antigen (CEA) in tuberculous pleural effusions (TPEs) and malignant pleural effusions (MPEs). Pleural effusion samples from 56 patients were classified on the basis of diagnosis as TPE (n=28) and MPE (n=28). The concentration of IL-22 was determined by ELISA. Lactate dehydrogenase (LDH), adenosine dehydrogenase (ADA) and CEA levels were also determined in all patients. A significant difference was observed in the levels of ADA and CEA (P<0.01), but not in the levels of LDH (P>0.05) between TPE and MPE. The concentration of IL-22 in TPE was significantly higher compared to MPE (P<0.01). With a threshold value of 49 pg/ml, IL-22 had a sensitivity of 82.14% (23/28) and a specificity of 96.43% (27/28) for differential diagnosis. The combined detection of IL-22 and CEA had a sensitivity of 100% (28/28) and a specificity of 96.43% (27/28) to distinguish TPE from MPE. TPEs showed significantly higher levels of IL-22 compared to MPEs. The combined detection of IL-22 and CEA may be more valuable in the differential diagnosis between TPE and MPE.

Imbalance of Th17 cells and regulatory T cells in tuberculous pleural effusion

Both T helper interleukin 17 (IL-17)-producing cells (Th17 cells) and regulatory T cells (Tregs) have been found to be increased in human tuberculous pleural effusion (TPE); however, the possible interaction between Th17 cells and Tregs in TPE remains to be elucidated. The objective of the present study was to investigate the distribution of Th17 cells in relation to Tregs, as well as the mechanism of Tregs in regulating generation and differentiation of Th17 cells in TPE. In the present study, the numbers of Th17 cells and Tregs in TPE and blood were determined by flow cytometry. The regulation and mechanism of CD39(+) Tregs on generation and differentiation of Th17 cells were explored. Our data demonstrated that the numbers of Th17 cells and CD39(+) Tregs were both increased in TPE compared with blood. Th17 cell numbers were correlated negatively with Tregs in TPE but not in blood. When naïve CD4(+) T cells were cultured with CD39(+) Tregs, Th17 cell numbers decreased as CD39(+) Treg numbers increased, and the addition of the anti-latency-associated peptide monoclonal antibody to the coculture reversed the inhibitory effect exerted by CD39(+) Tregs. This study shows that Th17/Treg imbalance exists in TPE and that pleural CD39(+) Tregs inhibit generation and differentiation of Th17 cells via a latency-associated peptide-dependent mechanism.