Defect in recruiting effector memory CD8+ T-cells in malignant pleural effusions compared to normal pleural fluid

Immune modulation in malignant pleural effusion: from microenvironment to therapeutic implications

Immune microenvironment and immunotherapy have become the focus and frontier of tumor research, and the immune checkpoint inhibitors has provided novel strategies for tumor treatment. Malignant pleural effusion (MPE) is a common end-stage manifestation of lung cancer, malignant pleural mesothelioma and other thoracic malignancies, which is invasive and often accompanied by poor prognosis, affecting the quality of life of affected patients. Currently, clinical therapy for MPE is limited to pleural puncture, pleural fixation, catheter drainage, and other palliative therapies. Immunization is a new direction for rehabilitation and treatment of MPE. The effusion caused by cancer cells establishes its own immune microenvironment during its formation. Immune cells, cytokines, signal pathways of microenvironment affect the MPE progress and prognosis of patients. The interaction between them have been proved. The relevant studies were obtained through a systematic search of PubMed database according to keywords search method. Then through screening and sorting and reading full-text, 300 literatures were screened out. Exclude irrelevant and poor quality articles, 238 literatures were cited in the references. In this study, the mechanism of immune microenvironment affecting malignant pleural effusion was discussed from the perspectives of adaptive immune cells, innate immune cells, cytokines and molecular targets. Meanwhile, this study focused on the clinical value of microenvironmental components in the immunotherapy and prognosis of malignant pleural effusion.

C5a enhances inflammation and chemotaxis of γδ T cells in malignant pleural effusion

BACKGROUND

The inhibitory effect of γδT17 cells on the formation of murine malignant pleural effusions (MPE) has been established. However, there is limited understanding regarding the phenotypic characterization of γδ T cells in MPE patients and their recruitment to the pleural cavity.

METHODS

We quantified γδ T cell prevalence in pleural effusions and corresponding peripheral blood from malignant and benign patients using immunohistochemistry and flow cytometry. The expression of effector memory phenotype, stimulatory/inhibitory/chemokine receptors and cytokines on γδ T cells in MPE was analyzed using multicolor flow cytometry. The infiltration of γδ T cells in MPE was assessed through immunofluorescence, ELISA, flow cytometry and transwell migration assay.

RESULTS

We observed a significant infiltration of γδ T cells in MPE, surpassing the levels found in blood and benign pleural effusion. γδ T cells in MPE exhibited heightened expression of CD56 and an effector memory phenotype, while displaying lower levels of PD-1. Furthermore, γδ T cells in MPE showed higher levels of cytokines (IFN-γ, IL-17A and IL-22) and chemokine receptors (CCR2, CCR5 and CCR6). CCR2 expression was notably higher in the Vδ2 subtype compared to Vδ1 cells. Moreover, the complement C5a enhanced cytokine release by γδ T cells, upregulated CCR2 expression in Vδ2 subsets, and stimulated the production of chemokines (CCL2, CCL7 and CCL20) in MPE. In vitro utilizing CCR2 neutralising and C5aR antagonist significantly reduced the recruitment of γδ T cells.

CONCLUSIONS

γδ T cells infiltrate MPE by overexpressing CCR2 and exhibit hightened inflammation, which is further augmented by C5a.

Lymphocyte immunophenotyping and concentration of MMP-9 in transudates and exudates in horses

This study is the first to provide information on the lymphocyte subpopulations in peritoneal effusions in horses. Peritoneal transudates (n = 12), peritoneal exudates (n = 6) and a pleural exudate (n = 1) were analyzed. The total nucleated cell count (TNCC), total protein (TP) and matrix metalloproteinase-9 (MMP-9) concentration determined by ELISA were measured and routine cytological evaluation was performed. CD3, CD4, CD8 and CD21 positive cells were detected by flow cytometry. A higher percentage of neutrophils (P < 0.05) and higher MMP-9 (P < 0.01) levels were found in exudates. A higher percentage of macrophages (P < 0.05) and lymphocytes (P < 0.01) were found in transudates. CD4 + lymphocytes were the most common lymphocyte subpopulation in all samples. CD21 + lymphocytes were the least common in all samples. A large variability in the percentage of CD21 + lymphocytes was found in exudates. The percentage of CD21 + lymphocytes positively correlated with the level of total protein (r = 0.5704, P < 0.05). The correlation was even stronger in the group of exudates. The percentages of lymphocyte subpopulations did not correlate with the level of MMP-9 or with cytological findings. The level of MMP-9 positively correlated with the percentage of neutrophils (r = 0.4980, P < 0.05), the level of TP (r = 0.7855, P < 0.01) and TNCC (r = 0.6129, P < 0.01). A significantly higher level of MMP-9 was detected in euthanized horses than in horses that survived (P < 0.05). However, it was shown that the level of MMP-9 in the peritoneal fluid can change significantly in a short time. More studies on repeated abdominocentesis could contribute to elucidating the role of MMP-9 as a prognostic indicator.

Effect of chemotherapy, immunotherapy, and targeted therapies on removal of indwelling pleural catheters in non-small cell lung cancer patients with malignant pleural effusions

BACKGROUND

Indwelling pleural catheters (IPCs) are a mainstay therapy for malignant pleural effusions (MPEs). Many patients treated with IPCs achieve pleurodesis. We aimed to identify the effect of systemic therapies for non-small cell lung cancer (NSCLC) on IPC removal in patients with associated MPEs.

METHODS

We completed a retrospective cohort study of adult IPC recipients with metastatic NSCLC at the pleural effusion clinic at the Royal Alexandra Hospital from 2009 to 2020. We used logistic regression to assess the rates of IPC removal and Cox regression to assess the time to IPC removal.

RESULTS

232 patients met inclusion criteria with 248 IPCs reviewed. The overall pleurodesis rate was 42.7% with a median time to pleurodesis of 68 (IQR 38-140) days. In univariate analysis, chemotherapy (OR 1.86, CI 0.99-3.49) and epidermal growth factor receptor (EGFR) targeted therapy (OR 3.81, CI 1.86-7.79) were associated with higher rates of pleurodesis. In multivariate analysis, increased rates of pleurodesis were associated with an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of ≤2 (OR 4.82, CI 2.24-10.37) and EGFR targeted therapy (OR 3.87, CI 1.80-8.32). Earlier IPC removal was associated with EGFR targeted therapy in both univariate (HR 1.84, CI 1.20-2.83) and multivariate analysis (HR 1.86, CI 1.19-2.92).

CONCLUSIONS

Treatment with EGFR targeted therapy is associated with increased rates and earlier removal of IPC in patients with NSCLC in our cohort. Further large cohort studies are required to determine if this relationship persists.

IL-26 promotes the pathogenesis of malignant pleural effusion by enhancing CD4+ IL-22+ T-cell differentiation and inhibiting CD8+ T-cell cytotoxicity

IL-26 is a newly discovered IL-10 cytokine family member mainly secreted by Th17 cells. However, the relationship between IL-26 and lung cancer remains unclear. The present study reported that IL-26 is involved in the production and promotion of malignant pleural effusion (MPE) for the first time. The concentrations of IL-26 and several Th17-related cytokines in MPE and peripheral blood (PB) from MPE patients were measured. IL-26, IL-10, and IL-6 were elevated in MPE compared to PB. The cell resource of IL-26 was primary Th17 cells measured by flow cytometry, whereas Tc17 cells and macrophages could also contribute to higher concentration of IL-26 in MPE. Abundant IL-6 and IL-23 in MPE could promote the frequency of IL-26 expressed by CD4+ T cells through phosphorylating STAT3 signaling pathway and promoting the expression of a specific Th17 lineage marker RORγt subsequently. IL-26 could selectively increase Th22 proportion through up-regulating the percentage of Ki-67 expressed by CD4+ T cells and the expression of IL-22 secreted by memory CD4+ T cells. In addition, IL-26 could decrease secretion of granzyme B. The tumor-killing activity of CD8+ T cells were inhibited as well when cocultured with malignant cells. Furthermore, the accumulation of IL-26 protein in MPE predicted poor patient survival. In summary, our results indicated that IL-26 was involved in the pathogenesis of MPE by exerting its impacts on both CD4+ T cells and CD8+ T cells.

Higher CD4/CD8 ratio of pleural effusion predicts better survival for lung cancer patients receiving immune checkpoint inhibitors

Pleural effusion is a rare immune-related adverse event for lung cancer patients receiving immune checkpoint inhibitors (ICIs). We enrolled 281 lung cancer patients treated with ICIs and 17 were analyzed. We categorized the formation of pleural effusion into 3 patterns: type 1, rapid and massive; type 2, slow and indolent; and type 3, with disease progression. CD4/CD8 ratio of 1.93 was selected as the cutoff threshold to predict survival. Most patients of types 1 and 2 effusions possessed pleural effusion with CD4/CD8 ratios ≥ 1.93. The median OS time in type 1, 2, and 3 patients were not reached, 24.8, and 2.6 months, respectively. The median PFS time in type 1, 2, and 3 patients were 35.5, 30.2, and 1.4 months, respectively. The median OS for the group with pleural effusion CD4/CD8 ≥ 1.93 and < 1.93 were not reached and 2.6 months. The median PFS of those with pleural effusion CD4/CD8 ≥ 1.93 and < 1.93 were 18.4 and 1.2 months. In conclusion, patients with type 1 and 2 effusion patterns had better survival than those with type 3. Type 1 might be interpreted as pseudoprogression of malignant pleural effusion. CD4/CD8 ratio ≥ 1.93 in pleural effusion is a good predicting factor for PFS.

Malignant Pleural Effusions-A Window Into Local Anti-Tumor T Cell Immunity?

The success of immunotherapy that targets inhibitory T cell receptors for the treatment of multiple cancers has seen the anti-tumor immune response re-emerge as a promising biomarker of response to therapy. Longitudinal characterization of T cells in the tumor microenvironment (TME) helps us understand how to promote effective anti-tumor immunity. However, serial analyses at the tumor site are rarely feasible in clinical practice. Malignant pleural effusions (MPE) associated with thoracic cancers are an abnormal accumulation of fluid in the pleural space that is routinely drained for patient symptom control. This fluid contains tumor cells and immune cells, including lymphocytes, macrophages and dendritic cells, providing a window into the local tumor microenvironment. Recurrent MPE is common, and provides an opportunity for longitudinal analysis of the tumor site in a clinical setting. Here, we review the phenotype of MPE-derived T cells, comparing them to tumor and blood T cells. We discuss the benefits and limitations of their use as potential dynamic biomarkers of response to therapy.

CD4+ and CD8+ cell populations in HIV-positive women with cervical squamous intra-epithelial lesions and squamous cell carcinoma

INTRODUCTION

This study aimed to analyse cervical lymphocytic populations in HIV+ and HIV- patients and correlate different cervical lesions with HIV viral load and presence of high-risk HPV types.

MATERIAL AND METHODS

A total of 132 histological specimens from 40 HIV+ and 72 HIV- patients were evaluated for CD4⁺ and CD8⁺ T cell distribution, presence of high-risk HPV types, peripheral blood HIV viral load and CD4⁺/CD8⁺ ratio.

RESULTS

High-grade squamous intraepithelial lesions (HSIL) and squamous cell carcinoma (SCC) from HIV+ patients had lower CD4⁺ T cell scores compared with HIV- patients. In all lesion groups, HIV+ patients presented higher epithelial and stromal CD8⁺ T cell scores. HIV viral load was more often detectable in patients with SCC than in those with low-grade squamous intraepithelial lesion (LSIL) (p = 0.0409). HSIL HIV+ patients had lower circulating CD4⁺ T cell counts (p = 0.0434) and CD4⁺/CD8⁺ ratio (p = 0.0378) compared with LSIL HIV+ patients. High-risk HPV types other than 16 and 18/45 were more prevalent in the HIV+ group.

DISCUSSION

These results support an imbalance between cervical CD4⁺ and CD8⁺ T lymphocytes of HIV+ patients with SIL and SCC, with increased CD8+ infiltrate density with lesion severity, even in patients with immune system recovery under cART.

The NAD-dependent deacetylase SIRT2 regulates T cell differentiation involved in tumor immune response

Sirtuin 2 (SIRT2), an NAD+-dependent deacetylase, regulates multiple biologic and pathologic processes including mitosis, genomic integrity, cell homeostasis and tumorigenesis. However, the role of SIRT2 in the immune response to cancer remains largely elusive. In this study, we found significantly lower expression of SIRT2 in peripheral T lymphocytes from breast cancer patients when compared to normal individuals. Moreover, SIRT2 levels positively correlated with CD8⁺ effector memory T (T_EM) cells in breast cancer patients. In keeping with these findings, altered T cells differentiation manifested as decreased T_EM cells and increased naive T cells were observed in Sirt2 deficient mice. The upregulation of CD8⁺ T_EM by SIRT2 might attribute to the activation of aerobic oxidation as well as the inhibition of GSK3β acetylation in CD8⁺ T cells. Taken together, these results suggest that SIRT2 participate in tumor immune response by regulating T cell differentiation, which may provide novel insight for tumor prevention and immune therapy.

Characteristics of Malignant Pleural Effusion Resident CD8+ T Cells from a Heterogeneous Collection of Tumors

While T cell-based cancer immunotherapies have shown great promise, there remains a need to understand how individual metastatic tumor environments impart local T cell dysfunction. At advanced stages, cancers that metastasize to the pleural space can result in a malignant pleural effusion (MPE) that harbors abundant tumor and immune cells, often exceeding 10⁸ leukocytes per liter. Unlike other metastatic sites, MPEs are readily and repeatedly accessible via indwelling catheters, providing an opportunity to study the interface between tumor dynamics and immunity. In the current study, we examined CD8⁺ T cells within MPEs collected from patients with heterogeneous primary tumors and at various stages in treatment to determine (1) if these cells possess anti-tumor activity following removal from the MPE, (2) factors in the MPE that may contribute to their dysfunction, and (3) the phenotypic changes in T cell populations that occur following ex vivo expansion. Co-cultures of CD8⁺ T cells with autologous CD45^- tumor containing cells demonstrated cytotoxicity (p = 0.030) and IFNγ production (p = 0.003) that inversely correlated with percent of myeloid derived suppressor cells, lactate, and lactate dehydrogenase (LDH) within the MPE. Ex vivo expansion of CD8⁺ T cells resulted in progressive differentiation marked by distinct populations expressing decreased CD45RA, CCR7, CD127, and increased inhibitory receptors. These findings suggest that MPEs may be a source of tumor-reactive T cells and that the cellular and acellular components suppress optimal function.

Clinical efficacy of intra-cavitary infusions of autologous dendritic cell/cytokine-induced killer cell products for the treatment of refractory malignant pleural effusions and ascites

To explore the safety and efficacy of intra-cavitary infusions of autologous mixed dendritic cell (DC)-cytokine-induced killer (CIK) cell products in advanced cancer patients with malignant pleural effusions or ascites. DC-CIKs were expanded ex vivo (mean yield of 1.36×10⁹ cells (range, 0.74~4.98×10⁹)) from peripheral blood mononuclear cells obtained by repeated venipuncture or apheresis. Patients received at least 1 cycle of 3 infusions of the DC-CIKs administered by indwelling catheter into the pleural or peritoneal cavity every other day. The volume of malignant effusions was assessed radiologically. Peripheral blood lymphocyte populations were enumerated by flow cytometry. Quality of life (QoL) during the DC-CIK infusions was assessed by the EORTC QLQ-30 instrument. ctDNA sequencing was performed to analyze gene clonal load and molecular tumor burden during the infusion treatment. Thirty-seven patients with breast, lung and other malignancies were enrolled. The results showed that intra-cavitary DC-CIK infusions (16 intrapleural and 21 intraperitoneal) were well-tolerated with no grade 3/4 adverse events. There was one complete response with effusion disappearance (CR) (3%), 13 partial responses (PR) (35%), 12 with stable disease (SD) (32%) and 11 with progressive disease (PD) (30%), resulting in a clinical effusion control rate (CCR) of 70% (26/37). The total number of infused CIKs and the CD3+/CD8+ and CD8+/CD28+ T cell frequencies within the CIKs were associated with effusion control (P=0.013). Moreover, increased peripheral blood CD3+/CD8+ (P=0.035) and decreased CD4+/CD25+ T cell frequencies (P=0.041) following the DC-CIK infusions were associated with malignant effusion and ascites control. Reductions in ctDNA correlated with clinical benefit. In conclusion, intra-cavitary autologous cellular immunotherapy is an alternative method to effectively control malignant pleural effusions and ascites. The overall effusion control rate was associated with higher peripheral blood effector T cell frequencies.

Collection and Handling of Thoracic Small Biopsy and Cytology Specimens for Ancillary Studies: Guideline From the College of American Pathologists in Collaboration With the American College of Chest Physicians, Association for Molecular Pathology, American Society of Cytopathology, American Thoracic Society, Pulmonary Pathology Society, Papanicolaou Society of Cytopathology, Society of Interventional Radiology, and Society of Thoracic Radiology

CONTEXT.—

The need for appropriate specimen use for ancillary testing has become more commonplace in the practice of pathology. This, coupled with improvements in technology, often provides less invasive methods of testing, but presents new challenges to appropriate specimen collection and handling of these small specimens, including thoracic small biopsy and cytology samples.

OBJECTIVE.—

To develop a clinical practice guideline including recommendations on how to obtain, handle, and process thoracic small biopsy and cytology tissue specimens for diagnostic testing and ancillary studies.

METHODS.—

The College of American Pathologists convened an expert panel to perform a systematic review of the literature and develop recommendations. Core needle biopsy, touch preparation, fine-needle aspiration, and effusion specimens with thoracic diseases including malignancy, granulomatous process/sarcoidosis, and infection (eg, tuberculosis) were deemed within scope. Ancillary studies included immunohistochemistry and immunocytochemistry, fluorescence in situ hybridization, mutational analysis, flow cytometry, cytogenetics, and microbiologic studies routinely performed in the clinical pathology laboratory. The use of rapid on-site evaluation was also covered.

RESULTS.—

Sixteen guideline statements were developed to assist clinicians and pathologists in collecting and processing thoracic small biopsy and cytology tissue samples.

CONCLUSIONS.—

Based on the systematic review and expert panel consensus, thoracic small specimens can be handled and processed to perform downstream testing (eg, molecular markers, immunohistochemical biomarkers), core needle and fine-needle techniques can provide appropriate cytologic and histologic specimens for ancillary studies, and rapid on-site cytologic evaluation remains helpful in appropriate triage, handling, and processing of specimens.

IL-17A-Producing γδT Cells Inhibit the Formation of Malignant Pleural Effusions

γδT cells are an important source of IL-17A and play an anti- or protumor role depending on the surrounding microenvironment. The precise role of γδT cells in the development of malignant pleural effusions (MPE) remains unknown. Using flow cytometry, we analyzed the distribution and differentiation of γδT cells in wild-type (WT) and IL-10^-∕- mice. We carefully elucidated the influence of γδT cells on the formation of MPE by depleting γδT cells from WT, IL-10^-∕-, and IL-17a^-∕- mice. The distribution of γδT17 cells in human MPE and peripheral blood was also determined. Our data showed that both γδT cells and IL-17A-producing γδT (γδT17) cells accumulated in murine MPE, and IL-10 deficiency enhanced their accumulation. γδT cells were the main source of IL-17A in MPE for both WT and IL-10^-∕- mice. IL-10 inhibited the chemotactic response of γδT cells to MPE and the proliferation of these cells. IL-10 suppressed γδT cell secretion of IL-17A via RORγt. The ablation of γδT cells accelerated MPE accumulation in both WT and IL-10^-∕- mice, but it did not influence MPE accumulation in IL-17a^-∕- mice. Patients with higher frequencies of γδT17 cells had significantly longer survival times than patients with lower frequencies of γδT17 cells. Taken together, our data demonstrate that γδT17 cells play an inhibitory role in the progression of MPE, and the accumulation of γδT17 cells in MPE is suppressed by IL-10.

The Immune Microenvironment in Mesothelioma: Mechanisms of Resistance to Immunotherapy

Although mesothelioma is the consequence of a protracted immune response to asbestos fibers and characterized by a clear immune infiltrate, novel immunotherapy approaches show less convincing results as compared to those seen in melanoma and non-small cell lung cancer. The immune suppressive microenvironment in mesothelioma is likely contributing to this therapy resistance. Therefore, it is important to explore the characteristics of the tumor microenvironment for explanations for this recalcitrant behavior. This review describes the stromal, cytokine, metabolic, and cellular milieu of mesothelioma, and attempts to make connection with the outcome of immunotherapy trials.

Deficient glucose uptake is linked to impaired Glut1 expression upon CD3/CD28 stimulation in memory T cells from pleural effusions secondary to lung cancer

Glucose and nutrient uptake is essential in supporting T cell activation and is increased upon CD3/CD28 stimulation. As T cells from pleural effusions secondary to lung cancer show impaired function, we hypothesized that these cells might have altered expression of nutrient transporters. Here, we analysed by flow cytometry the expression of the transferrin receptor CD71, amino acid transporter CD98 and glucose transporter Glut1 and glucose uptake in pleural effusion-derived T cells from lung cancer patients, after stimulation via CD3/CD28 under normoxia or hypoxia (2% O₂ ). We compared the response of T cells from pleural effusions secondary to lung cancer with that of T cells from nonmalignant effusions. In memory T cells from both groups, anti-CD3/CD28-stimulation under normoxia upregulated CD98 and CD71 expression (measured as median fluorescence intensity, MFI) in comparison with anti-CD3-stimulation. Costimulation under hypoxia tended to increase CD98 expression compared to CD3-stimulation in memory T cells from both groups. Remarkably, in the cancer group, memory T cells stimulated via CD3/CD28 under hypoxia failed to increase CD71 and Glut1 expression levels compared to the cells receiving anti-CD3 stimulation, a phenomenon that contrasted with the behaviour of memory T cells from nonmalignant effusions. Consequently, glucose uptake by memory T cells from the cancer group was not increased after CD3/CD28 stimulation under hypoxia, implying that their glycolytic metabolism is defective. As this process is required for inducing an antitumoural response, our study suggests that memory T cells are rendered dysfunctional and are unable to eliminate lung tumour cells.

Potential Diagnostic and Prognostic Role of Microenvironment in Malignant Pleural Mesothelioma

INTRODUCTION

A comprehensive analysis of the immune cell infiltrate collected from pleural fluid and from biopsy specimens of malignant pleural mesothelioma (MPM) may contribute to understanding the immune-evasion mechanisms related to tumor progression, aiding in differential diagnosis and potential prognostic stratification. Until now such approach has not routinely been verified.

METHODS

We enrolled 275 patients with an initial clinical diagnosis of pleural effusion. Specimens of pleural fluids and pleural biopsy samples used for the pathologic diagnosis and the immune phenotype analyses were blindly investigated by multiparametric flow cytometry. The results were analyzed using the Kruskal-Wallis test. The Kaplan-Meier and log-rank tests were used to correlate immune phenotype data with patients' outcome.

RESULTS

The cutoffs of intratumor T-regulatory (>1.1%) cells, M2-macrophages (>36%), granulocytic and monocytic myeloid-derived suppressor cells (MDSC; >5.1% and 4.2%, respectively), CD4 molecule-positive (CD4⁺) programmed death 1-positive (PD-1⁺) (>5.2%) and CD8⁺PD-1⁺ (6.4%) cells, CD4⁺ lymphocyte activating 3-positive (LAG-3⁺) (>2.8% ) and CD8⁺LAG-3⁺ (>2.8%) cells, CD4⁺ T cell immunoglobulin and mucin domain 3-positive (TIM-3⁺) (>2.5%), and CD8⁺TIM-3⁺ (>2.6%) cells discriminated MPM from pleuritis with 100% sensitivity and 89% specificity. The presence of intratumor MDSC contributed to the anergy of tumor-infiltrating lymphocytes. The immune phenotype of pleural fluid cells had no prognostic significance. By contrast, the intratumor T-regulatory and MDSC levels significantly correlated with progression-free and overall survival, the PD-1⁺/LAG-3⁺/TIM-3⁺ CD4⁺ tumor-infiltrating lymphocytes correlated with overall survival.

CONCLUSIONS

A clear immune signature of pleural fluids and tissues of MPM patients may contribute to better predict patients' outcome.

Migrated T lymphocytes into malignant pleural effusions: an indicator of good prognosis in lung adenocarcinoma patients

The presence of leukocyte subpopulations in malignant pleural effusions (MPEs) can have a different impact on tumor cell proliferation and vascular leakiness, their analysis can help to understand the metastatic microenvironment. We analyzed the relationship between the leukocyte subpopulation counts per ml of pleural fluid and the tumor cell count, molecular phenotype of lung adenocarcinoma (LAC), time from cancer diagnosis and previous oncologic therapy. We also evaluated the leukocyte composition of MPEs as a biomarker of prognosis. We determined CD4+ T, CD8+ T and CD20+ B cells, monocytes and neutrophils per ml in pleural effusions of 22 LAC and 10 heart failure (HF) patients by flow cytometry. Tumor cells were identified by morphology and CD326 expression. IFNγ, IL-10 and IL-17, and chemokines were determined by ELISAs and migratory response to pleural fluids by transwell assays. MPEs from LAC patients had more CD8+ T lymphocytes and a tendency to more CD4+ T and CD20+ B lymphocytes than HF-related fluids. However, no correlation was found between lymphocytes and tumor cells. In those MPEs which were detected >1 month from LAC diagnosis, there was a negative correlation between pleural tumor cells and CD8+ T lymphocytes. CXCL10 was responsible for the attraction of CD20+ B, CD4+ T and CD8+ T lymphocytes in malignant fluids. Concentrations of IL-17 were higher in MPEs than in HF-related effusions. Survival after MPE diagnosis correlated positively with CD4+ T and CD8+ T lymphocytes, but negatively with neutrophils and IL-17 levels. In conclusion, lymphocyte enrichment in MPEs from LAC patients is mostly due to local migration and increases patient survival.

Making cold malignant pleural effusions hot: driving novel immunotherapies

Malignant pleural effusions, arising from either primary mesotheliomas or secondary malignancies, heralds advanced disease and poor prognosis. Current treatments, including therapeutic thoracentesis and tube thoracostomy, are largely palliative. The immunosuppressive environment within the pleural cavity includes myeloid derived suppressor cells, T-regulatory cells, and dysfunctional T cells. The advent of effective immunotherapy with checkpoint inhibitors and adoptive cell therapies for lung cancer and other malignancies suggests a renewed examination of local and systemic therapies for this malady. Prior strategies reporting remarkable success, including instillation of the cytokine interleukin-2, perhaps coupled with checkpoint inhibitors, should be further evaluated in the modern era.

Cytotoxic Natural Killer Subpopulations as a Prognostic Factor of Malignant Pleural Effusion

BACKGROUND

Malignant pleural effusion (MPE) is a sign of advanced disease of poor prognosis. As natural killer (NK) cells are involved in the first line of tumour defence, we aimed to validate a new diagnostic and prognostic indicator for MPE based on NK subpopulations of pleural fluid (PF) and peripheral blood (PB).

METHODS

NK subpopulations were determined in PF and PB in 71 patients with malignant, paramalignant or benign pleural effusion. The receiver operating characteristic (ROC) curves, Kaplan-Meier, multivariable Cox model and decision trees created with the CHAID (Chi-square automatic interaction detector) methodology were employed.

RESULTS

We demonstrated that the PF/PB ratios of the CD56 bright CD16- and CD56 dim CD16- NK subpopulations were higher (p = 0.013 and p = 0.003, respectively) in MPEs and paramalignant pleural effusions (PPEs) than in benign ones, with an AUC of 0.757 and 0.741, respectively. The PF/PB ratio of CD16+ NK and CD57+ NK obtained a higher hazard ratio (HR) in the crude Cox's regression analysis. In the adjusted Cox's regression analysis, the PF/PB ratio of CD16+ NK gave the highest HR (HR 6.1 [1.76-21.1]) (p = 0.004). In the decision tree created for the MPE prognosis, we observed that the main predictor variable among the studied clinical, radiological, and analytical variables was lung mass, and that 92.9% of the patients who survived had a PF/PB ratio of the CD56 dim CD16+ NK subpopulation ≤ 0.43.

CONCLUSIONS

Our data suggest that both the PF/PB ratios of cytotoxic subpopulations CD57+ NK and CD16+ NK are useful as a prognostic factor of MPE. Other subpopulations (CD56 bright CD16- and CD56 dim CD16- NK) could help to diagnose MPE.

Tumour associated lymphocytes in the pleural effusions of patients with mesothelioma express high levels of inhibitory receptors

OBJECTIVE

Pleural effusion (PE) is a common feature of malignant pleural mesothelioma. These effusions typically contain lymphocytes and malignant cells. We postulated that the PE would be a source of lymphocytes for analysis of tumor immune milieu. The aim of this study was to compare the phenotype and T cell receptor usage of pleural effusion T cells with paired concurrently drawn peripheral blood lymphocytes. We used multi-parameter flow cytometry and high-throughput T cell receptor sequencing to analyse peripheral blood and pleural effusion mononuclear cells.

RESULTS

Both CD8⁺ and CD4⁺ T cells from effusion showed increased expression of T cell inhibitory receptors PD-1, LAG-3 and Tim-3 compared to blood. Comprehensive T cell receptor sequencing on one of the patients showed a discordant distribution of clonotypes in the antigen-experienced (PD-1⁺) compartment between effusion and blood, suggesting an enrichment of antigen specific clonotypes in the effusion, with potential as an immunological response biomarker.

The era of immunogenomics/immunopharmacogenomics

Although germline alterations and somatic mutations in disease cells have been extensively analyzed, molecular changes in immune cells associated with disease conditions have not been characterized in depth. It is clear that our immune system has a critical role in various biological and pathological conditions, such as infectious diseases, autoimmune diseases, drug-induced skin and liver toxicity, food allergy, and rejection of transplanted organs. The recent development of cancer immunotherapies, particularly drugs modulating the immune checkpoint molecules, has clearly demonstrated the importance of host immune cells in cancer treatments. However, the molecular mechanisms by which these new therapies kill tumor cells are still not fully understood. In this regard, we have begun to explore the role of newly developed tools such as next-generation sequencing in the genetic characterization of both cancer cells and host immune cells, a field that is called immunogenomics/ immunopharmacogenomics. This new field has enormous potential to help us better understand changes in our immune system during the course of various disease conditions. Here we report the potential of deep sequencing of T-cell and B-cell receptors in capturing the molecular contribution of the immune system, which we believe plays critical roles in the pathogenesis of various human diseases.

Memory CD4+ T cell subsets in tumor draining lymph nodes of breast cancer patients: A focus on T stem cell memory cells

BACKGROUND

The compartments of memory T cells play a fundamental role in the immune system by substantiating specific and acquired immunity. A new subset of memory cells, T stem cell memory (T_SCM) cells, with stem cell-like properties, a high capacity to proliferate, a long survival, and an ability to differentiate into all effector and memory cells has recently been introduced. In the present study, we aimed to determine the frequency of CD4⁺ T_SCM and other T memory cell subsets in tumor draining lymph nodes of breast cancer patients.

MATERIALS AND METHODS

Mononuclear cells were obtained from axillary lymph nodes of 52 untreated patients with breast cancer (BC) and stained with fluorochrome conjugated anti-CD4, -CCR7, -CD45RO and -CD95 antibodies to detect different subtypes of memory cells in CD4⁺ lymphocyte populations. Data were acquired using a four-color FACSCalibur flow cytometer and analyzed using CellQuest Pro software.

RESULTS

We found that >70% of CD4⁺ lymphocytes in draining lymph nodes of BC patients exhibited a memory phenotype of which 7.04 ± 1.04% had a T_SCM phenotype (CD4⁺CCR7⁺CD45RO^-CD95⁺). The frequency of T_SCM cells was significantly higher in tumor positive lymph nodes compared to tumor negative lymph nodes (p = 0.026) as well as among those patients who had at least one affected lymph node (p = 0.012). Moreover, we found that the total frequency of central memory T cells (T_CM) with a low expression of CD45RO was significantly higher among these patients. The percentage of CD45RO^Low T_CM cells was also found to increase with tumor progression from stage I to stage III (p = 0.020). On the other hand, we found that the percentage of CD95^Hi effector memory T cells (T_EM) was significantly decreased in involved lymph nodes (p = 0.009).

CONCLUSION

Our data suggest that following long-term exposure to putative tumor antigens, T_SCM cells proliferate to generate a pool of committed memory and effector T cells. As the tumor progresses, the immunosuppressive milieu induced by tumor cells may slow down the differentiation of CD45RO^Low T_CM cells to more functional sub-populations.

Abundant expression of TIM-3, LAG-3, PD-1 and PD-L1 as immunotherapy checkpoint targets in effusions of mesothelioma patients

Malignant pleural mesothelioma (MPM) is an aggressive cancer with an increasing incidence, poor prognosis and limited effective treatment options. Hence, new treatment strategies are warranted which include immune checkpoint blockade approaches with encouraging preliminary data. Research on the immunological aspects of the easily accessible mesothelioma microenvironment could identify prognostic and/or predictive biomarkers and provide useful insights for developing effective immunotherapy. In this context, we investigated the immune cell composition of effusions (pleural and ascites fluids) from 11 different chemotherapy-treated MPM patients. We used multicolor flow cytometry to describe different subsets of immune cells and their expression of immune checkpoint molecules TIM-3, LAG-3, PD-1 and PD-L1. We demonstrate a patient-dependent inter- and intraspecific variation comparing pleural and ascites fluids in immune cell composition and immune checkpoint expression. We found CD4⁺ and CD8⁺ T cells, B cells, macrophages, natural killer cells, dendritic cells and tumor cells in the fluids. To the best of our knowledge, we are the first to report TIM-3 and LAG-3 expression and we confirm PD-1 and PD-L1 expression on different MPM effusion-resident immune cells. Moreover, we identified two MPM effusion-related factors with clinical value: CD4+ T cells were significantly correlated with better response to chemotherapy, while the percentage of PD-L1⁺ podoplanin (PDPN)⁺ tumor cells is a significant prognostic factor for worse outcome. Our data provide a basis for more elaborate research on MPM effusion material in the context of treatment follow-up and prognostic biomarkers and the development of immune checkpoint-targeted immunotherapy.

Malignant pleural effusion: from bench to bedside

Malignant pleural effusion (MPE) is a common but serious condition that is related with poor quality of life, morbidity and mortality. Its incidence and associated healthcare costs are rising and its management remains palliative, with median survival ranging from 3 to 12 months. During the last decade there has been significant progress in unravelling the pathophysiology of MPE, as well as its diagnostics, imaging, and management. Nowadays, formerly bed-ridden patients are genotyped, phenotyped, and treated on an ambulatory basis. This article attempts to provide a comprehensive overview of current advances in MPE from bench to bedside. In addition, it highlights unanswered questions in current clinical practice and suggests future directions for basic and clinical research in the field.

Interleukin-2 reverses CD8(+) T cell exhaustion in clinical malignant pleural effusion of lung cancer

Malignant pleural effusion (MPE) is a poor prognostic sign for cancer patients, whereas the functional condition of MPE CD8(+) T cells is unknown. Intracavitary immunotherapy with interleukin (IL)-2 has been proven effective in controlling MPE. To elucidate the underlying mechanism, 35 lung cancer (LC) patients with MPE and 12 healthy donors were included in this study. For the IL-2 therapy experiments, after draining partial MPE, we treated 14 patients by administrating IL-2 (3 or 5 × 10(6) U in 50 ml saline) into the thoracic cavity. Before and after IL-2 treatment (40-48 h), the MPE and peripheral blood (PB) were obtained from the subjects. PB from healthy volunteers was collected as control. The expression of programmed cell death 1 (PD-1), granzyme B (GzmB), interferon (IFN)-γ and the proliferation were analysed in CD8(+) T cells from MPE and PB. The CD8(+) T cells in the MPE of LC patients showed lowest GzmB, IFN-γ and proliferation but highest PD-1 expression, compared with that in PB of LC patients and healthy donors. IL-2 treatment reduced the expression of PD-1, increased the expression of GzmB and IFN-γ and enhanced the proliferation of CD8(+) T cells in MPE. In addition, IL-2 treatment reduced carcino-embryonic antigen (CEA) level in MPE. These results indicate that MPE CD8(+) T cells exhibit exhaustion phenotype which can be reversed by IL-2 therapy.

Malignant Nonhematological Effusion Characterization by Flow Cytometry

With the exception of hematological malignancies, flow cytometry (FC) is infrequently applied as an ancillary tool in the diagnosis of malignant effusions in most institutions. However, FC may be effectively used to differentiate between epithelial cells, mesothelial cells and leukocytes using antibodies against both cell surface and intracellular proteins, offering the advantage of quantitative analysis. Additionally, FC may be applied to the quantitative detection of cancer-associated molecules, including stem cell markers, as well as assessment of critical cellular processes, such as proliferation and apoptosis. Some of the latter tests may have relevance for monitoring treatment response in the presence of metastatic disease, although this does not constitute routine practice to date. This review summarizes current knowledge regarding the application of FC to serous effusions in the diagnostic setting, as well as in research into cancer biology focusing on clinical specimens. The studies published to date suggest a role for this method in the clinical setting in the context of diagnosis, prediction and prognosis.

Precision immunotherapy; dynamics in the cellular profile of pleural effusions in malignant mesothelioma patients

OBJECTIVES

Clinical studies have proven the potential of immunotherapy in malignancies. To increase efficacy, a prerequisite is that treatment is tailored, so precision immune-oncology is the logical next step. In order to tailor treatment, characterization of the patient's tumor environment is key. Pleural effusion (PE) often accompanies malignant pleural mesothelioma (MPM) and is an important part of the MPM environment. Furthermore, the composition of PE is used as surrogate for the tumor. In this study, we provide an insight in the dynamics of the MPM environment through characterization of PE composition over time and show that the immunological characteristics of PE do not necessarily mirror those of the tumor.

MATERIALS AND METHODS

From 5 MPM patients, PE and tumor biopsies were acquired at the same time point. From one of these patients multiple PEs were obtained. PEs were acquired performing thoracocenteses and total cell amounts were determined. Immunohistochemistry was performed to quantify immune cell composition (T cells, macrophages) and tumor cells in PE derived cytospins and tumor biopsies.

RESULTS

The PE amount and (immune) cellular composition varied considerably over time between multiple (n=10) thoracocenteses. These dynamics could in part be attributed to the treatment regimen consisting of standard chemotherapy and dendritic cell (DC)-based immunotherapy. In addition, the presence of T cells and macrophages in PE did not necessarily mirror the infiltration of these immune cells within tumor biopsies in 4 out of 5 patients.

CONCLUSIONS

In this proof-of-concept study with limited sample size, we demonstrate that the composition of PE is dynamic and influenced by treatment. Furthermore, the immune cell composition of PE does not automatically reflect the properties of tumor tissue. This has major consequences when applying precision immunotherapy based on PE findings in patients. Furthermore, it implies a regulated trafficking of immune regulating cells within the tumor environment.

Analysis of Lymphocyte Immunological Reactivity in Patients with Pleural Effusions of Different Aetiology

BACKGROUND

The proportion of T and B lymphocytes in pleural fluids and blood may point to the presence of local immunological phenomena in pleural disorders.

AIM

Aim of study was to evaluate the lymphocyte phenotype and the ratio between helper (CD4+) and cytotoxic/suppressor (CD8+) lymphocytes in malignant and non-malignant effusions.

MATERIAL AND METHODS

We studied 48 patients with pleural effusions. First group had 18 patients with tuberculosis pleural effusions; second group had 20 patients with malignant pleural fluids, third group had 10 patients with transudates and 30 healthy controls. We investigated the distribution of T and B lymphocytes, T cells with helper/inducer CD4 or suppresser/cytotoxic CD8 phenotypes and the CD16 subset.

RESULTS

Results showed decreases levels of CD3, CD4, and CD16 T cells in blood of patients versus healthy controls. There were increases in the percentage of the CD3 and CD4 T cells in the pleural fluid compared with values in the blood with statistical significance in tuberculous pleurisy. The values of CD8 were similar in the pleural fluid and in blood. Levels of CD16 were non-significantly higher in pleural fluid in all groups.

CONCLUSION

This study confirms the hypothesis that pleural cavity is compartment with immunological reactivity and results could be used in differential diagnosis together with other examinations.

Evaluation of imaging techniques for the assessment of tumour progression in an orthotopic rat model of malignant pleural mesothelioma†

OBJECTIVES

An orthotopic rat tumour recurrence model for malignant pleural mesothelioma (MPM) provides clinical similarity to patients and is useful for drug testing combined with surgical intervention. Importantly, a reliable imaging method is required allowing for noninvasive and repetitive evaluation of the tumour load. We compared the tumour load assessed by bioluminescence and magnetic resonance imaging (MRI) to the macroscopic tumour volume as a reference standard.

METHODS

A total of 500,000 syngeneic rat MPM cells transfected with luciferase were implanted underneath the parietal pleura of immunocompetent rats (n=13). From the second day after implantation, bioluminescence measurements of the tumour load expressed as the maximum bioluminescent intensity (photon/second) were performed daily after intraperitoneal injection of the luciferase substrate, d-luciferin, to observe the first occurrence of tumour. Six days after the first detection of tumour, bioluminescence, MRI and macroscopic tumour volume measurement were conducted. For MRI, a 4.7-Tesla small animal imager equipped with a 1H whole-body rat coil was employed using T2-weighted fast spin-echo sequences. Tumour burden (mm3) was quantified from magnetic resonance transverse images by two independent readers by manual segmentation. Finally, the tumour burden assessed by bioluminescence and MRI was correlated (Pearson's correlation) with the macroscopic measurement of tumour (ellipsoid) volume.

RESULTS

In all rats, a single tumour nodule was found at the inoculation site with a median macroscopic volume of 46 mm3 (18-377 mm3). For tumour burden quantification of MRIs, we observed good interobserver correlation (R2=0.81, P<0.0001) as well as significant association with the macroscopic tumour volume (R2=0.59, P=0.002). However, the signal intensity of bioluminescence did not correspond to the macroscopic tumour volume (R2=0.01, P=0.76).

CONCLUSIONS

MRI is a reliable and reproducible noninvasive in vivo imaging method for MPM tumour burden assessment for the present MPM model.