Dynamics of host immune responses and a potential function of Trem2hi interstitial macrophages in Pneumocystis pneumonia.

BACKGROUND: Pneumocystis pneumonia (PCP) is a life-threatening opportunistic fungal infection with a high mortality rate in immunocompromised patients, ranging from 20 to 80%. However, current understanding of the variation in host immune response against Pneumocystis across different timepoints is limited. METHODS: In this study, we conducted a time-resolved single-cell RNA sequencing analysis of CD45+ cells sorted from lung tissues of mice infected with Pneumocystis. The dynamically changes of the number, transcriptome and interaction of multiply immune cell subsets in the process of Pneumocystis pneumonia were identified according to bioinformatic analysis. Then, the accumulation of Trem2hi interstitial macrophages after Pneumocystis infection was verified by flow cytometry and immunofluorescence. We also investigate the role of Trem2 in resolving the Pneumocystis infection by depletion of Trem2 in mouse models. RESULTS: Our results characterized the CD45+ cell composition of lung in mice infected with Pneumocystis from 0 to 5 weeks, which revealed a dramatic reconstitution of myeloid compartments and an emergence of PCP-associated macrophage (PAM) following Pneumocystis infection. PAM was marked by the high expression of Trem2. We also predicted that PAMs were differentiated from Ly6C+ monocytes and interacted with effector CD4+ T cell subsets via multiple ligand and receptor pairs. Furthermore, we determine the surface markers of PAMs and validated the presence and expansion of Trem2hi interstitial macrophages in PCP by flow cytometry. PAMs secreted abundant pro-inflammation cytokines, including IL-6, TNF-α, GM-CSF, and IP-10. Moreover, PAMs inhibited the proliferation of T cells, and depletion of Trem2 in mouse lead to reduced fungal burden and decreased lung injury in PCP. CONCLUSION: Our study delineated the dynamic transcriptional changes in immune cells and suggests a role for PAMs in PCP, providing a framework for further investigation into PCP's cellular and molecular basis, which could provide a resource for further discovery of novel therapeutic targets.

MiR-150 levels are related to in-hospital mortality in non-HIV Pneumocystis pneumonia patients.

Pneumocystis pneumonia (PCP) is a common opportunistic infection that occurs in immunocompromised patients. Compared with HIV patients, PCP in non-HIV patients tends to follow up a more urgent course and poorer prognosis. Therefore, markers that could predict survival of PCP patients in non-HIV population are of great value. MiRNA-150 has been widely studied in many diseases since it has been identified as a vital regulator of immune cell differentiation and activation. We thus conduct this study aiming to evaluate the prognostic value of miR-150 level in non-HIV PCP. First, the expression levels of miR-150 were compared between PCP patients and healthy volunteers. The miR-150 levels in immune cells were also detected in PCP mouse models. Then the prognostic value of miR-150 was further assessed in another PCP population (n = 72). The expression levels of miR-150 were measured by reverse transcription real-time PCR (RT-PCR) technique. Our data demonstrated significantly decreased miR-150 expression levels in PCP patients and mouse models compared to controls. The miR-150 levels also decreased in various immune cells of PCP mouse models. With a cut-off value of 3.48, the area under the curve, sensitivity, specificity of miR-150 to predicate PCP mortality were 0.845, 68.2% and 96.0%, respectively. In conclusion, miR-150 expression value might serve as a potential biomarker to identify PCP patients at high risk of death.

Pneumocystis pneumonia (PCP) remains a fatal risk for immunosuppressed patients. MiR-150 takes part in immune regulation, and thus is involved in infection control. Our study indicated that the miR-150 expression may act as a potential biomarker for predicting mortality of PCP patients.

Psittacosis caused severe community-acquired pneumonia accompanied by acute hypoxic respiratory failure: a multicenter retrospective cohort study from China.

INTRODUCTION: Psittacosis can cause severe community-acquired pneumonia (CAP). The clinical manifestations of psittacosis range from subclinical to fulminant psittacosis with multi-organ failure. It is essential to summarize the clinical characteristic of patients with severe psittacosis accompanied by acute hypoxic respiratory failure (AHRF). METHODS: This retrospective study included patients with severe psittacosis caused CAP accompanied by AHRF from 19 tertiary hospitals of China. We recorded the clinical data, antimicrobial therapy, respiratory support, complications, and outcomes. Chlamydia psittaci was detected on the basis of metagenomic next-generation sequencing performed on bronchoalveolar lavage fluid samples. Patient outcomes were compared between the treatment methods. RESULTS: This study included 45 patients with severe CAP and AHRF caused by psittacosis from April 2018 to May 2021. The highest incidence of these infections was between September and April. There was a history of poultry contact in 64.4% of the patients. The median PaO2/FiO2 of the patients was 119.8 (interquartile range, 73.2 to 183.6) mmHg. Four of 45 patients (8.9%) died in the ICU, and the median ICU duration was 12 days (interquartile range, 8 to 21) days. There were no significant differences between patients treated with fluoroquinolone initially and continued after the diagnosis, fluoroquinolone initially followed by tetracycline, and fluoroquinolone combined with tetracycline. CONCLUSION: Psittacosis caused severe CAP seems not rare, especially in the patients with the history of exposure to poultry or birds. Empirical treatment that covers atypical pathogens may benefit such patients, which fluoroquinolones might be considered as an alternative.

Characteristics and prognostic implications of peripheral blood lymphocyte subsets in patients with anti-MDA5 antibody positive dermatomyositis-interstitial lung disease.

OBJECTIVES: To examine the characteristics of blood lymphocyte subsets in dermatomyositis-interstitial lung disease (DM-ILD) inflicted patients with positive anti-melanoma differentiation-associated gene 5 (anti-MDA5), as well as its prognosis value in this set of patients. METHODS: Data were retrospectively collected from 253 DM-ILD patients from three hospitals in China between January 2016 to January 2021. Patients were grouped into anti-MDA5 antibody positive group (MDA5+ DM-ILD) and anti-MDA5 antibody negative group (MDA5- DM-ILD) based on myositis-specific autoantibody test results. Demographic characteristics, lymphocyte subsets patterns and other clinical features were compared between the two groups. The association of lymphocyte subsets with 180-day mortality was investigated using survival analysis in MDA5+ DM-ILD. RESULTS: Out of 253 eligible patients with DM-ILD, 59 patients were anti-MDA5+ and 194 were anti-MDA5-. Peripheral blood lymphocyte count, CD3+ count, percentage of CD3+, CD3+CD4+ count, and CD3+CD8+ count was lower in MDA5+ DM-ILD than in MDA5- DM-ILD- (all P < 0.001) as well as CD3-CD19+ count (P = 0.04). In MDA5+ DM-ILD, CD3+CD8+ count ≤ 49.22 cell/µL (HR = 3.81, 95%CI [1.20,12.14]) and CD3-CD19+ count ≤ 137.64 cell/µL (HR = 3.43, 95%CI [1.15,10.24]) were independent predictors of mortality. CD3+CD8+ count ≤ 31.38 cell/µL was associated with a higher mortality risk in all DM-ILD patients (HR = 8.6, 95%CI [2.12,31.44]) after adjusting for anti-MDA5 and other clinical characteristics. CONCLUSION: Significant lymphocytes decrease was observed in MDA5+ DM-ILD patients. CD3+CD8+ cell count was associated with worse prognosis in both MDA5+ DM-ILD and all DM-ILD patients.

Modern thromboprophylaxis protocol based on guidelines applied in a respiratory intensive care unit: a single-center prospective cohort study.

BACKGROUND: Critically ill patients in intensive care units (ICUs) are at high risk of venous thromboembolism (VTE). This study aimed to explore the prophylaxis effect under a guideline-based thromboprophylaxis protocol among critically ill patients in a respiratory ICU. METHODS: For this single-center prospective cohort study, we followed the thromboprophylaxis protocol, which was drawn up based on relevant guidelines and Chinese experts' advice. Clinical data were entered into an electronic case report form and analyzed. Multivariate logistic regression was conducted to explore independent risk factors of VTE event under this protocol. RESULTS: From August 1, 2014, to December 31, 2020, 884 patients underwent thromboprophylaxis according to this protocol; 10.5% of them received mechanical prophylaxis, 43.8% received pharmacological prophylaxis, and 45.7% received pharmacological combined with mechanical prophylaxis. The proportion of VTE events was 14.3% for patients who received the thromboprophylaxis protocol, of which 0.1% had pulmonary thromboembolism (PTE), 2.0% had proximal deep vein thrombosis (DVT), and 12.1% had isolated distal DVT. There was no significant difference between different thromboprophylaxis measures. Cirrhosis (OR 5.789, 95% CI [1.402, 23.894], P = 0.015), acute asthma exacerbation (OR 39.999, 95% CI [4.704, 340.083], P = 0.001), and extracorporeal membrane oxygenation treatment (OR 22.237, 95%CI [4.824, 102.502], P < 0.001) were independent risk factors for proximal DVT under thromboprophylaxis. CONCLUSIONS: The thromboprophylaxis protocol based on guidelines applied in the ICU was practicable and could help decrease the proportion of PTE and proximal DVT events. The risk factors of VTE events happening under the thromboprophylaxis protocol require more attention. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02213978.

Modified high-flow nasal cannula oxygen therapy versus conventional oxygen therapy in patients undergoing bronchoscopy: a randomized clinical trial.

BACKGROUND: Hypoxemia frequently occurs during bronchoscopy. High-flow nasal cannula (HFNC) oxygen therapy may be a feasible alternative to prevent the deterioration of gas exchange during bronchoscopy. With the convenience of clinical use in mind, we modified an HFNC using a single cannula. This clinical trial was designed to test the hypothesis that a modified HFNC would decrease the proportion of patients with a single moment of peripheral arterial oxygen saturation (SpO2) < 90% during bronchoscopy. METHODS: In this single-center, prospective randomized controlled trial, hospitalized patients in the respiratory department in need of diagnostic bronchoscopy were randomly assigned to a modified HFNC oxygen therapy group or a conventional oxygen therapy (COT) group. The primary outcome was the proportion of patients with a single moment of SpO2 < 90% during bronchoscopy. RESULTS: Eight hundred and twelve patients were randomized to the modified HFNC (n = 406) or COT (n = 406) group. Twenty-four patients were unable to cooperate or comply with bronchoscopy. Thus, 788 patients were included in the analysis. The proportion of patients with a single moment of SpO2 < 90% during bronchoscopy in the modified HFNC group was significantly lower than that in the COT group (12.5% vs. 28.8%, p < 0.001). There were no significant differences in the fraction of inspired oxygen between the two groups. The lowest SpO2 during bronchoscopy and 5 min after bronchoscopy in the modified HFNC group was significantly higher than that in the COT group. Multivariate analysis showed that a baseline forced vital capacity (FVC) < 2.7 L (OR, 0.276; 95% CI, 0.083-0.919, p = 0.036) and a volume of fluid instilled > 60 ml (OR, 1.034; 95% CI, 1.002-1.067, p = 0.036) were independent risk factors for hypoxemia during bronchoscopy in the modified HFNC group. CONCLUSIONS: A modified HFNC could decrease the proportion of patients with a single moment of SpO2 < 90% during bronchoscopy. A lower baseline FVC and large-volume bronchoalveolar lavage may predict desaturation during bronchoscopy when using a modified HFNC. Trial registration ClinicalTrials. Gov: NCT02606188. Registered 17 November 2015.

An update of the long-term outcome of patients with nonspecific pleurisy at medical thoracoscopy.

BACKGROUND: Medical thoracoscopy (MT) is recommended in patients with undiagnosed exudative pleural effusion and offers a degree of diagnostic sensitivity for pleural malignancy. However, not all patients who undergo MT receive an exact diagnosis. Our previous investigation from 2014 summarized the long-term outcomes of these patients with nonspecific pleurisy (NSP); now, we offer updated data with the goal of refining our conclusions. METHODS: Between July 2005 and August 2018, MT with pleural biopsies were performed in a total of 1,254 patients with undiagnosed pleural effusions. One hundred fifty-four patients diagnosed with NSP with available follow-up data were included in the present study, and their medical records were reviewed. RESULTS: A total of 154 patients were included in this study with a mean follow-up duration of 61.5 ± 43.7 months (range: 1-180 months). No specific diagnosis was established in 67 (43.5%) of the patients. Nineteen patients (12.3%) were subsequently diagnosed with pleural malignancies. Sixty-eight patients (44.2%) were diagnosed with benign diseases. Findings of pleural nodules or plaques during MT and the recurrence of pleural effusion were associated with malignant disease. CONCLUSIONS: Although most NSP patients received a diagnosis of a benign disease, malignant disease was still a possibility, especially in those patients with nodules or plaques as noted on the MT and a recurrence of pleural effusion. One year of clinical follow-up for NSP patients is likely sufficient. These updated results further confirm our previous study's conclusions.

PD-1 Deficiency Promotes Macrophage Activation and T-Helper Cell Type 1/T-Helper Cell Type 17 Response in Pneumocystis Pneumonia.

Pneumocystis is an unusual, opportunistic fungal pathogen capable of causing Pneumocystis pneumonia (PCP) in immunocompromised hosts. Although PCP was discovered >100 years ago, its pathogenesis remains unclear. The inhibitory receptor PD-1 (programmed death 1), a negative regulator of activated T cells, has been reported to take part in tumor escape, immune tolerance, and infection immunity. In this study, we examined the role of the PD-1/PD-L1 (programmed death-ligand 1) pathway in patients with PCP and in mice. The expression levels of PD-1/PD-L1 in patients with PCP and in mice were measured by real-time PCR and flow cytometry. The effects of PD-1 deficiency are demonstrated using wild-type and PD-1-/- mice. Our data show that Pneumocystis infection promotes PD-1/PD-L1 expression; PD-1 deficiency enhances the phagocytic function of macrophages and the pulmonary T-helper cell type 1 (Th1)/Th17 response, which might contribute to Pneumocystis clearance; and PD-1 deficiency affects the polarization of macrophages. PCP mice treated with anti-PD-1 antibody showed improved pulmonary clearance of Pneumocystis. Collectively, our results demonstrate that the PD-1/PD-L1 pathway plays a role in regulating the innate and adaptive immune responses, suggesting that manipulation of this pathway may constitute an immunotherapeutic strategy for PCP.

Application of metagenomic next-generation sequencing for bronchoalveolar lavage diagnostics in critically ill patients.

The purpose of this study was to assess the value of metagenomic next-generation sequencing (mNGS) of bronchoalveolar lavage fluid (BALF) for the diagnosis of severe respiratory diseases based on interpretation of sequencing results. BALF samples were harvested and used for mNGS as well as microbiological detection. Infectious bacteria or fungi were defined according to relative abundance and number of unique reads. We performed mNGS on 35 BALF samples from 32 patients. The positive rate reached 100% in the mNGS analysis of nine immunocompromised patients. Compared with the culture method, mNGS had a diagnostic sensitivity of 88.89% and a specificity of 74.07% with an agreement rate of 77.78% between these two methods. Compared with the smear method and PCR, mNGS had a diagnostic sensitivity of 77.78% and a specificity of 70.00%. In 13 cases, detection results were positive by mNGS but negative by culture/smear and PCR. The mNGS findings in 11/32 (34.4%) cases led to changes in treatment strategies. Linear regression analysis showed that diversity was significantly correlated with interval between disease onset and sampling. Dynamic changes in reads could indirectly reflect therapeutic effectiveness. BALF mNGS improves sensitivity of pathogen detection and provides guidance in clinical practice. Potential pathogens can be identified based on relative abundance and number of unique reads.

IL-10-producing B cells regulate Th1/Th17-cell immune responses in Pneumocystis pneumonia.

Pneumocystis pneumonia (PCP) is a common opportunistic infectious disease that is prevalent in immunosuppressed hosts. Accumulating evidence shows that B cells play an important role in infectious diseases. In the present study, the immune regulatory role of mature B cells in host defense to Pneumocystis was evaluated. Pneumocystis infection resulted in a decrease in B cells in patients and mice, and the Pneumocystis burden in B cell-deficient mice also progressively increased from weeks 1 to 7 after infection. The clearance of Pneumocystis was delayed in B cell-activating factor receptor (BAFF-R)-deficient mice (BAFF-R-/- mice), which had few B cells and Pneumocystis-specific IgG and IgM antibodies, compared with clearance in wild-type (WT) mice. There were fewer effector CD4+ T cells and higher percentages of T helper (Th)1/Th17 cells in BAFF-R-/- mice than in WT mice. Adoptive transfer of naive B cells, mRNA sequencing, and IL-1ß neutralization experiments indicated that IL-1ß is a likely determinant of the IL-10-producing B cell-mediated suppression of Th1/Th17-cell immune responses in BAFF-R-/- PCP mice. Our data indicated that B cells play a vital role in the regulation of Th cells in response to Pneumocystis infection.

Development and validation of the PET-CT score for diagnosis of malignant pleural effusion.

PURPOSE: Although some parameters of positron emission tomography with 18F-fluorodeoxyglucose (18F-FDG) and computed tomography (PET-CT) are somehow helpful in differentiating malignant pleural effusion (MPE) from benign effusions, no individual parameter offers sufficient evidence for its implementation in the clinical practice. The aim of this study was to establish the diagnostic accuracy of a scoring system based on PET-CT (the PET-CT score) in diagnosing MPE. METHODS: One prospective derivation cohort of patients with pleural effusions (84 malignant and 115 benign) was used to develop the PET-CT score for the differential diagnosis of malignant pleural effusion. The PET-CT score was then validated in another independent prospective cohort (n = 74). RESULTS: The PET-CT parameters developed for discriminating MPE included unilateral lung nodules and/or masses with increased 18F-FDG uptake (3 points); extrapulmonary malignancies (3 points); pleural thickening with increased 18F-FDG uptake (2 points); multiple nodules or masses (uni- or bilateral lungs) with increased 18F-FDG uptake (1 point); and increased pleural effusion 18F-FDG uptake (1 point). With a cut-off value of 4 points in the derivation cohort, the area under the curve, sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of the PET-CT score to diagnose MPE were 0.949 (95% CI: 0.908-0.975), 83.3% (73.6%-90.6%), 92.2% (85.7%-96.4%), 10.7 (5.6-20.1), and 0.2 (0.1-0.3), respectively. CONCLUSIONS: A simple-to-use PET-CT score that uses PET-CT parameters was developed and validated. The PET-CT score can help physicians to differentiate MPE from benign pleural effusions.

IL-17 Inversely Correlated with IL-10 via the STAT3 Gene in Pneumocystis-Infected Mice.

BACKGROUND: Pneumocystis pneumonia (PCP) remains a common opportunistic infection in immunosuppressed individuals. Current studies showed that multiple immune cells and cytokines took part in the host defense against Pneumocystis (PC). However, the roles of IL-17 and IL-10 in the development of PCP have not been elucidated. METHODS: IL-10 and IL-17 levels in serum from PCP mice were detected via ELISA. The percentages of B10 cells, IL-10+ macrophages, and IL-10+ T cells in the lung from IL-17-/- PCP mice and Th17 cells and IL-17+ γδT cells in IL-10-/- PCP mice were examined via flow cytometry. Also, antibody neutralization examination was also performed to elucidate the relationship of IL-17 and IL-10 in the PCP model. RESULTS: We noted the increase of IL-17 and IL-10 levels in serum from mice infected with Pneumocystis. Furthermore, deficiency of IL-17 or IL-10 could lead to the delayed clearance of Pneumocystis and more severed lung damage. Our data also demonstrated that IL-17 deficiency enhanced the serum IL-10 level and the percentages of B10 cells, IL-10+ macrophages, and IL-10+ T cells in the lung from PCP mice. Interestingly, we also noted an increase of the IL-17 level in serum and Th17 cell and IL-17+ γδT cell percentages in the lung from IL-10-/- PCP mice. Using antibody neutralization experiments, we found that the STAT3 gene might play a critical role in the interplay of IL-17 and IL-10 in PCP. CONCLUSION: Taken together, our results demonstrated that IL-17 and IL-10 could play the protective roles in the progression of PCP and the inverse correlation of them might be mediated by STAT3.

Diagnostic accuracy of interleukin 27 for tuberculous pleural effusion: two prospective studies and one meta-analysis.

BACKGROUND: Accurate differentiating diagnosis is essential for choosing treatment for exudative pleural effusions. OBJECTIVE: To establish the diagnostic accuracy of interleukin 27 for tuberculous pleural effusion (TPE). METHODS: First, the concentrations of pleural interleukin 27, interferon-gamma and adenosine deaminase were compared between 51 patients with TPE and 103 with non-TPEs (Beijing cohort), and their diagnostic values were evaluated. These were further verified in another independent population (Wuhan cohort, n=120). In the second part of the study, we performed a meta-analysis. RESULTS: With a cut-off value of 591.4 ng/L in the Beijing cohort, the area under the curve, sensitivity, specificity, positive predictive value and negative predictive value of interleukin 27 to diagnose TPE were 0.983 (95% CI 0.947 to 0.997), 96.1% (86.5% to 99.5%), 99.0% (94.7% to 100%), 98.0 (89.4 to 99.9) and 98.1 (93.3 to 99.8), respectively. Excellent diagnostic accuracy of interleukin 27 was also found in the Wuhan cohort and was further confirmed in the meta-analysis. The diagnostic performance of interleukin 27 was comparable to that of interferon-gamma and was more accurate than that of adenosine deaminase. Since the post-test probability of a negative result was always <0.1%, a negative test was considered to exclude TPE in all tuberculosis prevalence settings. CONCLUSIONS: Interleukin 27 can be used to diagnose TPE in a high prevalence setting, and a negative result can also be reliably used to rule out TPE in all prevalence settings.

Malignant pleural mesothelioma: diagnostic value of medical thoracoscopy and long-term prognostic analysis.

BACKGROUND: Malignant pleural mesothelioma (MPM) is marked by its difficult diagnosis and poor prognosis. Medical thoracoscopy (MT) is an effective and safe procedure for the diagnosis of exudative pleural effusions and many factors associated with poor prognosis of MPM. We conducted this study to investigate the value of MT for diagnosing of MPM and to identify prognostic factors for MPM patients. METHODS: From July 2005 through June 2014, a total of 833 patients with undiagnosed pleural effusions underwent MT and pleural biopsies were taken. Clinical data of all patients with MPM were retrospectively analyzed, and those with complete follow-up data were analyzed for prognostic factors. RESULTS: Eventually, MPM was the final diagnosis in 40 patients. Diagnostic efficiency of MT for MPM was 87.5%, since diagnosis of MPM failed to be established in 5 patients during the initial MT. Median survival was 17.1 mo (95% confidence interval: 13.6-20.7 mo). MT findings of pleural adhesion and plaques were adverse prognostic factors for MPM. In addition, old age, male gender, smoking history, histological type, poor staging, no treatment, low total protein level in pleural fluid, and computed tomographic findings such as pulmonary consolidation or infiltration, mediastinal lymphopathy, pulmonary mass or nodules, and pleural nodularity were also poor prognostic factors for MPM. CONCLUSIONS: MT is safe with a high positive rate in the diagnosis of MPM, and pleural adhesion and plaques seen under MT may be the adverse prognostic factors for MPM. Multiple clinical characteristics can affect the survival of MPM patients.

Diagnostic value of medical thoracoscopy in malignant pleural effusion.

BACKGROUND: Medical thoracoscopy has been shown to be an efficacious procedure in diagnosing unexplained exudative pleural effusions with excellent safety. This study aimed to assess the diagnostic significance of thoracoscopy in the management of patients with malignant pleural effusion (MPE). METHODS: Consecutive patients with malignant pleural effusion were retrospectively reviewed, and their demographic, radiographic, thoracoscopic and histological data were collected. RESULTS: Between July 2005 and June 2014, 342 of 833 patients undergoing thoracoscopy were finally confirmed to suffer from MPE. The top three frequent causes of MPE were metastatic carcinoma (79.5%), malignant mesothelioma (10.2%), and lymphoma (2.9%). Among metastatic malignancies, the most common cancer was lung cancer (85.2%), followed by breast cancer (4.4%), ovarian cancer (2.2%), pancreatic cancer (1.8%), etc. No serious adverse events associated with thoracoscopy were recorded. CONCLUSIONS: Medical thoracoscopy is a valuable and safe tool in diagnosing malignant pleural effusion with minimal complication rates.

Toll-like receptor 4 signaling inhibits malignant pleural effusion by altering Th1/Th17 responses.

Toll-like receptor 4 (TLR4) is involved in multiple malignancies; however, the role of TLR4 in the pathogenesis of malignant pleural effusion (MPE) remains unknown. The objectives of this study were to explore the impact of TLR4 signaling on the development of MPE in a murine model and to define the underline mechanisms by which TLR works. Development of MPE as well as proliferation and angiogenesis of pleural tumor were determined in TLR4(-/-) and wild type mice. Differentiation of Th1 and Th17 cells as well as their signal transductions was explored. The effects of TLR4 signaling on survival of mice bearing MPE were also investigated. Compared with wild type mice, Th1 cells were augmented, and Th17 cells were suppressed in MPE from TLR4(-/-) mice. The in vitro experiments showed that TLR4 deficiency promoted Th1 cell differentiation via enhancing STAT1 pathway and inhibited Th17 cell differentiation via suppressing STAT3 pathway. TLR4 deficiency promoted MPE formation and, thus, accelerated the death of mice bearing MPE, whereas intraperitoneal injection of anti-IFN-γ mAb or recombinant mouse IL-17 protein into TLR4(-/-) mice was associated with improved survival. Our data provides the first definitive evidence of a role for TLR4 signaling in protective immunity in the development of MPE. Our findings also demonstrate that TLR4 deficiency promotes MPE formation and accelerates mouse death by enhancing Th1 and suppressing Th17 response.

Efficacy and safety of diagnostic thoracoscopy in undiagnosed pleural effusions.

BACKGROUND: The differential diagnosis of pleural effusions can present a considerable challenge, and the etiology of pleural effusions varies depending on the population studied. OBJECTIVE: This study aimed to assess the efficacy and safety of medical thoracoscopy in the diagnosis of patients with undiagnosed pleural effusions in a Chinese population. METHODS: Between July 2005 and June 2014, medical thoracoscopy (MT) using the semirigid instrument was performed in 833 patients with pleural effusions of unknown etiology in our Institute, where diagnostic thoracocentesis or/and blind pleural biopsy had failed to yield an answer. Demographic, radiographic, procedural, and histological data were recorded and analyzed. RESULTS: During this 9-year study, satisfactory pleural biopsy samples were obtained in 833 patients, and MT revealed malignant pleural effusion in 342 (41.1%) patients, benign pleural effusion in 429 (51.5%) patients, and 62 (7.4%) patients could not get definite diagnoses. The overall diagnostic efficiency of MT was 92.6% (771/833). After MT, the only severe complication was empyema, seen in 3 patients (0.4%). The most common minor complication was transient chest pain (44.1%) from the indwelling chest tube. CONCLUSIONS: MT is an effective and safe procedure for diagnosing pleural effusions of undetermined causes. In areas with high tuberculosis prevalence, MT should be particularly helpful in the differential diagnosis of tuberculous pleural effusion.

Recruitment of IL-27-Producing CD4(+) T Cells and Effect of IL-27 on Pleural Mesothelial Cells in Tuberculous Pleurisy.

BACKGROUND: The numbers of IL-27-producing CD4(+) T cells and the concentration of soluble IL-27 have been found to be increased in tuberculous pleural effusion (TPE). The objective of the present study was to explore the mechanism by which IL-27(+)CD4(+) T cells are recruited into the pleural space, and to explore the impact of IL-27 on pleural mesothelial cells (PMCs). METHODS: The expression profiles of chemokine receptor (CCR) were determined by flow cytometry. The chemoattractant activity of chemokines CCL20 and CCL22 for IL-27(+)CD4(+) T cells in vitro was observed. Effects of IL-27 on wound healing, proliferation and apoptosis of PMCs were also investigated. RESULTS: IL-27(+)CD4(+) T cells in TPE expressed high level of CCR6, medium level of CCR4, and low levels of CCR2, CCR3, CCR5, CCR7, CCR10, and CXCR3. Recruitment of IL-27(+)CD4(+) T cells into TPE could be induced by pleural CCL20 and CCL22. By activating STAT3 signaling, IL-27 significantly improved wound healing and promoted proliferation of PMCs, and completely prevented apoptosis of PMCs induced by IFN-γ. CONCLUSIONS: After being recruited into pleural space by CCL20 or/and CCL22, these pleural IL-27-producing CD4(+) T cells may play important roles in tuberculosis immunity by affecting PMC functions.

Interplay of Th1 and Th17 cells in murine models of malignant pleural effusion.

RATIONALE: IFN-γ-producing CD4(+) T (Th1) cells and IL-17-producing CD4(+) T (Th17) cells have been found to be involved in multiple malignancies; however, the reciprocal relationship between Th1 and Th17 cells in malignant pleural effusion (MPE) remains to be elucidated. OBJECTIVES: To explore the differentiation and immune regulation of Th1 and Th17 cells in the development of MPE in murine models. METHODS: The distribution and differentiation of Th1 and Th17 cells in MPE were investigated in IFN-γ(-/-), IL-17(-/-), and wild-type mice. The effects of Th1 and Th17 cells on the development of MPE and the survival of mice bearing MPE were also investigated. MEASUREMENTS AND MAIN RESULTS: We have demonstrated that increased Th1 and Th17 cells could be found in MPE as compared with blood and spleen. Compared with wild-type mice, Th17 cells were markedly augmented in MPE from IFN-γ(-/-) mice, and improved survival could be seen in IFN-γ(-/-) mice. Th1 cell numbers were elevated in MPE from IL-17(-/-) mice, and decreased survival could be seen in IL-17(-/-) mice. The in vitro experiments showed that IFN-γ deficiency promoted Th17-cell differentiation by suppressing the STAT3 pathway and that IL-17 deficiency promoted Th1-cell differentiation by suppressing the STAT1 pathway. CONCLUSIONS: In mouse models of MPE, IFN-γ inhibited Th17-cell differentiation, whereas IL-17 inhibited Th1-cell differentiation. IL-17 inhibited the formation of MPE and improved the survival of mice bearing MPE; in contrast, IFN-γ promoted MPE formation and mouse death.