Oncostatin M and Nivolumab Affect the Cytotoxic T-Cell Proportions and the Susceptibility to TRAIL-Induced Death in Non-Leukocyte Cell Subpopulations in Soft Tissue Sarcomas.

INTRODUCTION: Soft tissue sarcomas (STSs) are malignant tumors arising from mesenchymal tissues. Patients with advanced and metastatic STSs have low overall survival rates and relatively limited treatment options. Oncostatin M (OSM) is a pleiotropic cytokine that was shown to carry both pro- and anti-tumorigenic properties in various cancer types. However, the role of OSM in STSs has not yet been elucidated. Moreover, the potential additive effects of combining OSM and anti-PD-1 therapy have not been carried out so far. METHODS: The aim of this study was to determine the effects of in vitro OSM administration on liposarcoma, leiomyosarcoma, and myxofibrosarcoma immune cells isolated from peripheral blood and tumor tissues and the potential cooperative nature of OSM and nivolumab in treating these STSs. We designed a cohort study to explore novel histology-driven therapies in our target STSs. The immune cells were isolated from the peripheral blood and tumors of patients with STS, and the proportions and phenotypes of immune cells were evaluated with flow cytometry after cultivation with therapeutic monoclonal antibodies. RESULTS: The proportion of peripheral CD45+ cells was not affected by OSM but was significantly increased by nivolumab, whereas both treatments had an effect on CD8+ T cells. In tumor tissues, CD8+ T cell and CD45‒ TRAIL+ cell cultures were boosted by nivolumab and significantly enriched by OSM. Our data suggest that OSM may play a role in the treatment of leiomyosarcoma, myxofibrosarcoma, and liposarcoma. CONCLUSION: In conclusion, the biological efficacy of OSM is reflected in the tumor microenvironment rather than in the peripheral blood of the patients in our cohort, and nivolumab could potentiate its mechanism of action in selected cases. Nevertheless, more histotype-tailored studies are needed to fully understand the functions of OSM in STSs.

The role of interleukin 6 in the pathogenesis and therapy of Castleman disease - an immunologist's perspective.

Castleman disease (CD) is a heterogeneous group of diseases characterized by lymphadenopathy and systemic inflammatory manifestations. CD can be divided into uni- (UCD) and multicentric form (MCD) according to the disease extent. MCD is usually accompanied by the features of a systemic inflammatory response including fever, weight loss, hepatosplenomegaly, ascites, and edema. In these patients, we can also observe elevation of inflammatory parameters and anemia within the laboratory assessment. Based on etiological nature, the CD can be further divided into human herpesvirus-8-associated (HHV8-associated) and idiopathic form. Interleukin 6 (IL-6) plays a central role in the disease pathogenesis. Inhibition of IL-6 has been shown to be an effective treatment modality. Currently, siltuximab, a chimeric monoclonal antibody targeting IL-6, is the only approved treatment for MCD. Its short-term and long-term efficacy and safety have been demonstrated in a few clinical studies.

News in immunology.

The field of immunology has undergone a very significant development in recent decades, which has been reflected especially in the beginning of this millennium in significant advances in the understanding of the immune system and in the application of this knowledge in practice. The progress and acceleration of research and advances in the field of immunology was further prompt by the unexpected onset of the COVID-19 pandemic in 2020. The intense scientific work has not only led to the development of our understanding of the immune response to viruses, but also to the rapid conversion of this knowledge into practical pandemic management on a global scale, as exemplified by the development of vaccines against SARS-Cov-2 virus. The pandemic era has further contributed to the acceleration of the application of not only biological discoveries but also technological approaches into practical applications, such as use of advanced mathematics, computer science and, more recently, artificial intelligence which are all are adding to the advances that are significantly moving the field of immunology forward. In this communication, we present specific advances in particular areas of immunopathology, which are mainly allergy, immunodeficiency, immunity and infection, vaccination, autoimmune diseases and cancer immunology.

The expression profiles of CD47 in the tumor microenvironment of salivary gland cancers: a next step in histology-driven immunotherapy.

BACKGROUND: Salivary gland carcinomas (SGC) are extremely rare malignancies with only limited treatment options for the metastatic phase of the disease. Treatment with anti-CD47 antibodies could represent a potent therapy for SGCs by promoting the phagocytic clearance of tumor cells through various mechanisms. However, the efficacy of anti-CD47 therapy is largely dependent on the expression of CD47 within the tumor microenvironment (TME). MATERIALS AND METHODS: In 43 patients with SGC, we were the first to investigate the CD47 expression in both tumor cells and tumor-infiltrating immune cells (TIIC) in the center and periphery of primary tumors. We also correlated the data with the clinicopathological variables of the patients and offered novel insights into the potential effectiveness of anti-CD47 therapy in SGCs. RESULTS: We observed that the CD47+ tumor cells are outnumbered by CD47+ TIICs in mucoepidermoid carcinoma. In the tumor center, the proportion of CD47+ tumor cells was comparable to the proportion of CD47+ TIICs in most histological subtypes. In low-grade tumors, significantly higher expression of CD47 was observed in TIICs in the periphery of the tumor as compared to the center of the tumor. CONCLUSION: The reason for a high expression of 'don't eat me' signals in TIICs in the tumor periphery is unclear. However, we hypothesize that in the tumor periphery, upregulation of CD47 in TIICs could be a mechanism to protect newly recruited leukocytes from macrophage-mediated phagocytosis, while also allowing the removal of old or exhausted leukocytes in the tumor center.

Mast Cells and Dendritic Cells as Cellular Immune Checkpoints in Immunotherapy of Solid Tumors.

The immune checkpoint inhibitors have revolutionized cancer immunotherapy. These inhibitors are game changers in many cancers and for many patients, sometimes show unprecedented therapeutic efficacy. However, their therapeutic efficacy is largely limited in many solid tumors where the tumor-controlled immune microenvironment prevents the immune system from efficiently reaching, recognizing, and eliminating cancer cells. The tumor immune microenvironment is largely orchestrated by immune cells through which tumors gain resistance against the immune system. Among these cells are mast cells and dendritic cells. Both cell types possess enormous capabilities to shape the immune microenvironment. These capabilities stage these cells as cellular checkpoints in the immune microenvironment. Regaining control over these cells in the tumor microenvironment can open new avenues for breaking the resistance of solid tumors to immunotherapy. In this review, we will discuss mast cells and dendritic cells in the context of solid tumors and how these immune cells can, alone or in cooperation, modulate the solid tumor resistance to the immune system. We will also discuss how this modulation could be used in novel immunotherapeutic modalities to weaken the solid tumor resistance to the immune system. This weakening could then help other immunotherapeutic modalities engage against these tumors more efficiently.

Principles and Challenges in anti-COVID-19 Vaccine Development.

The number of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected patients keeps rising in most of the European countries despite the pandemic precaution measures. The current antiviral and anti-inflammatory therapeutic approaches are only supportive, have limited efficacy, and the prevention in reducing the transmission of SARS-CoV-2 virus is the best hope for public health. It is presumed that an effective vaccination against SARS-CoV-2 infection could mobilize the innate and adaptive immune responses and provide a protection against severe forms of coronavirus disease 2019 (COVID-19) disease. As the race for the effective and safe vaccine has begun, different strategies were introduced. To date, viral vector-based vaccines, genetic vaccines, attenuated vaccines, and protein-based vaccines are the major vaccine types tested in the clinical trials. Over 80 clinical trials have been initiated; however, only 18 vaccines have reached the clinical phase II/III or III, and 4 vaccine candidates are under consideration or have been approved for the use so far. In addition, the protective effect of the off-target vaccines, such as Bacillus Calmette-Guérin and measles vaccine, is being explored in randomized prospective clinical trials with SARS-CoV-2-infected patients. In this review, we discuss the most promising anti-COVID-19 vaccine clinical trials and different vaccination strategies in order to provide more clarity into the ongoing clinical trials.

Acquired Angioedema with C1 Inhibitor Deficiency: Occurrence, Clinical Features, and Management: A Nationwide Retrospective Study in the Czech Republic Patients.

INTRODUCTION: Acquired angioedema with C1 inhibitor deficiency (AAE-C1-INH) is rare but a potentially life-threatening disease. There are no official prevalence data, nor approved therapies for this condition. OBJECTIVE: In this study, we aimed to collect and analyze clinical data on patients with AAE-C1-INH in the Czech Republic. METHODS: We have conducted a retrospective analysis of AAE-C1-INH patients from Czech referral centers for the treatment of hereditary angioedema with C1 inhibitor deficiency. The inclusion criteria involved recurrent episodes of angioedema with the first manifestation at or after the age of 40, negative family history of angioedema, and C1 inhibitor function 50% or less. RESULTS: A total of 14 patients (7 males and 7 females) met the inclusion criteria for AAE-C1-INH. The median age of the symptom onset was 59.5 years, and the median diagnosis delay was 1 year. The most common clinical manifestation was facial edema (100%) and upper airway swelling (85.7%). All patients responded to the acute attack treatment with icatibant and plasma-derived or recombinant C1 inhibitor concentrate. Lymphoid malignancy was identified in 9 patients (64%), monoclonal gammopathy of uncertain significance in 3 (21%), and in 1 patient autoimmune disease (ulcerative colitis) was considered causative (7%). We were not able to identify any underlying disease only in 1 patient (7%). In 6 of 7 patients (86%) treated for lymphoma, either a reduction in the frequency of angioedema attacks or both angioedema symptoms' disappearance and complement parameter normalization was observed. CONCLUSIONS: The prevalence of AAE-C1-INH in the Czech Republic is about 1:760,000. This rare condition occurs in approximately 8% of the patients with angioedema with C1 inhibitor deficiency. AAE-C1-INH is strongly associated with lymphoproliferative disorders, and treating these conditions may improve the control of angioedema symptoms.

Dendritic cell-based immunotherapy (DCVAC/OvCa) combined with second-line chemotherapy in platinum-sensitive ovarian cancer (SOV02): A randomized, open-label, phase 2 trial.

OBJECTIVE: DCVAC/OvCa is an active cellular immunotherapy designed to stimulate an immune response against ovarian cancer. We explored the safety and efficacy of DCVAC/OvCa plus carboplatin and gemcitabine in platinum-sensitive ovarian cancer. METHODS: In this open-label, parallel-group, phase 2 trial (ClinicalTrials.gov number NCT02107950), patients with platinum-sensitive ovarian cancer relapsing after first-line chemotherapy were randomized to DCVAC/OvCa and chemotherapy or chemotherapy alone. DCVAC/OvCa was administered every 3-6 weeks (10 doses). Endpoints included safety, progression-free survival (PFS; primary efficacy endpoint) and overall survival (OS; secondary efficacy endpoint). RESULTS: Between November 2013 and May 2015, 71 patients were randomized to chemotherapy in combination with DCVAC/OvCa or to chemotherapy alone. Treatment-emergent adverse events related to DCVAC/OvCa, leukapheresis and chemotherapy occurred in six (16.2%), two (5.4%), and 35 (94.6%) patients in the DCVAC/OvCa group. Chemotherapy-related events occurred in all patients in the chemotherapy group. Seven patients in the DCVAC/OvCa group were excluded from primary efficacy analyses due to failure to receive ≥1 dose of DCVAC/OvCa. PFS was not improved (hazard ratio [HR] 0.73, 95% confidence interval [CI] 0.42-1.28, P = 0.274, data maturity 78.1%). Median OS was significantly prolonged (by 13.4 months) in the DCVAC/OvCa group (HR 0.38, 95% CI 0.20-0.74, P = 0.003; data maturity 56.3%). A signal for enhanced surrogate antigen-specific T-cell activity was seen with DCVAC/OvCa. CONCLUSIONS: DCVAC/OvCa combined with chemotherapy had a favorable safety profile in patients with platinum-sensitive ovarian cancer. DCVAC/OvCa did not improve PFS, but the exploratory analyses revealed OS prolongation and enhanced surrogate antigen-specific T-cell activity.

Thapsigargin-Stimulated LAD2 Human Mast Cell Line Is a Potent Cellular Adjuvant for the Maturation of Monocyte-Derived Dendritic Cells for Adoptive Cellular Immunotherapy.

The preparation of dendritic cells (DCs) for adoptive cellular immunotherapy (ACI) requires the maturation of ex vivo-produced immature(i) DCs. This maturation ensures that the antigen presentation triggers an immune response towards the antigen-expressing cells. Although there is a large number of maturation agents capable of inducing strong DC maturation, there is still only a very limited number of these agents approved for use in the production of DCs for ACI. In seeking novel DC maturation agents, we used differentially activated human mast cell (MC) line LAD2 as a cellular adjuvant to elicit or modulate the maturation of ex vivo-produced monocyte-derived iDCs. We found that co-culture of iDCs with differentially activated LAD2 MCs in serum-containing media significantly modulated polyinosinic:polycytidylic acid (poly I:C)-elicited DC maturation as determined through the surface expression of the maturation markers CD80, CD83, CD86, and human leukocyte antigen(HLA)-DR. Once iDCs were generated in serum-free conditions, they became refractory to the maturation with poly I:C, and the LAD2 MC modulatory potential was minimized. However, the maturation-refractory phenotype of the serum-free generated iDCs was largely overcome by co-culture with thapsigargin-stimulated LAD2 MCs. Our data suggest that differentially stimulated mast cells could be novel and highly potent cellular adjuvants for the maturation of DCs for ACI.

Can wearing face masks in public affect transmission route and viral load in COVID-19?

The mandatory face mask wearing was implemented in the Czech Republic and Slovakia shortly after the COVID-19 outbreak in Central Europe. So far, the number of COVID-19-associated deaths per 100,000 individuals is far lower in these countries as compared with other neighbouring or close countries. The use of face masks in public may not protect the general public from contracting the virus, however, presumptively decreases the viral load and contributes to a favourable clinical outcome in COVID-19 disease. A certain time is required for antigen-specific T cells and B cells to fully develop. Obligatory face mask wearing in public favours the virus transmission through oral mucosa and/or conjunctival epithelium, which enables the adaptive immune responses to evolve. In the case of inhalation of high loads of SARS-CoV-2, the time for the development of fully protective adaptive immune responses seems to be insufficient. Then, a less specific and more damaging innate immune response prevails.

COVID-19 from the perspective of an immunologist.

COVID-19 is an infectious disease caused by a coronavirus SARS-CoV-2. COVID-19 has a number of similarities to SARS and MERS diseases. Its highly contagious nature is particularly due to the rapid spread of the disease through asymptomatic individuals; however, the worlds most contagious infectious disease is still considered measles. Scientific data have revealed the interactions between COVID-19 and the immune system. These findings may contribute to the development of novel preventive and therapeutic approaches. Just as coronavirus itself the reports about the disease have massively spread through media and public contributing to overall public fear and stress. This promotion of non-scientific evidence and misinformation through social media might have also a devastating impact on the individuals immune system. Data regarding the mortality rates of COVID-19 have achieved unprecedented media and public engagements, however, the true facts about the disease prevention, immunomodulation and novel treatments are often left unsaid. We present the most recent facts about COVID-19 disease and its interactions with the immune system.

Principles and new perspectives in the vaccination against SARS-CoV-2 virus.

It has been a year since the first person on Earth became infected with a new type of coronavirus SARS-CoV-2, causing infectious acute respiratory disease COVID-19 with relatively high morbidity and mortality. The most endangered population by coronavirus SARS-CoV-2 are healthcare professionals, the elderly and people with associated comorbidities. Due to the fast community spread, governments of different European countries introduced precaution measures including limited socializing of people, closing of most public services and introducing mandatory facial protection. The hope for a return to the life before the pandemic is the development of an effective and safe vaccine against SARS-CoV-2 which would presumably reduce the incidence of severe forms of COVID-19 and prevent the massive spread of the disease. At the end of November, we have 13 clinical trials in phase III involving SARS-CoV-2 vaccines based on inactivated viruses, recombinant non-pathogenic viral vectors and proteins. The first mRNA-based vaccine is currently being evaluated in phase II/III clinical trial and is already being distributed and applied to high-risk population in the United Kingdom, the United States, and Israel, followed by the countries of the European Union, including the Czech Republic. In the review article we present currently ongoing clinical studies with a special focus on the phase III clinical trials and discuss the mechanisms of action of each type of vaccine.

The challenges of adoptive cell transfer in the treatment of human renal cell carcinoma.

Renal cell carcinoma (RCC) is one of the most lethal urologic malignancies. Its incidence continues to rise worldwide with a rate of 2% per year. Approximately, one-third of the RCC patients are diagnosed at advanced stages due to the asymptomatic nature of its early stages. This represents a great hurdle, since RCC is largely chemoresistant/radioresistant, and targeted therapy of mRCC still has limited efficacy. The 5-year survival rate of metastatic RCC (mRCC) is only around 10%. Adoptive cell transfer (ACT), a particular form of cell-based anticancer immunotherapy, is a promising approach in the treatment of mRCC. The vaccination principle, however, faces unique challenges that preclude the efficacy of ACT. In this article, we review the main challenges of ACT in the treatment of mRCC and describe multiple methods that can be used to overcome these challenges. In this respect, the ultimate purpose of this review is to provide a descriptive tool by which to improve the development of novel protocols for ACT of mRCC.

Bronchial Asthma and Bronchial Hyperresponsiveness and Their Characteristics in Patients with Common Variable Immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is one of the most frequent primary immunodeficiencies and is characterized by disturbed immunoglobulin production and dysregulation of the immune system. Results of previous studies suggest a higher prevalence of bronchial asthma (BA) in CVID patients than in the general population. We initiated this study to evaluate lung functions and identify risk factors for BA and bronchial hyperresponsiveness (BHR) in patients with CVID. METHODS: Twenty-three patients with CVID were included in this study. In all of them, spirometry and a metacholine bronchoprovocation test were performed. We also investigated the role of atopy, eosinophilic inflammation, and potential risk factors such as gender, age, or immunoglobulin levels at the time of diagnosis. RESULTS: BHR was confirmed in 12 patients (52%), all of whom had normal FEV1 and FEV1/FVC. However, BHR-positive patients had significantly decreased MEF25. BHR-positive patients had also more symptoms related to bronchial obstruction, with 8 of them (35%) being suspected of having BA at the end of the study. A higher prevalence of BHR was found in females, with a relative risk of 2.89. CONCLUSIONS: An increased prevalence of BHR and BA was detected in CVID patients compared to the general population. BA may develop despite the disturbed immunoglobulin production, and the majority of patients display nonatopic and noneosinophilic properties. These results suggest a limited role of atopy and eosinophilic inflammation in the pathogenesis of BA in CVID patients.

Current trends in immunosuppressive treatment.

Immunosuppressive agents represent a class of drugs that inhibits activity of the immune system. They are mostly used in autoimmune diseases and other inflammatory conditions treatment and in prevention of recipient´s immune response to donors antigens in transplantations. There is a broad spectrum of different immunosuppressive drugs with various mechanisms of action. This article provides an overview of drugs currently registered as immunosuppressive agents in the Czech Republic and provides some insights what we might expect regarding this group of drugs in the future.

Phase I/II trial of dendritic cell-based active cellular immunotherapy with DCVAC/PCa in patients with rising PSA after primary prostatectomy or salvage radiotherapy for the treatment of prostate cancer.

OBJECTIVE: Immunotherapy of cancer has the potential to be effective mostly in patients with a low tumour burden. Rising PSA (prostate-specific antigen) levels in patients with prostate cancer represents such a situation. We performed the present clinical study with dendritic cell (DC)-based immunotherapy in this patient population. MATERIALS AND METHODS: The single-arm phase I/II trial registered as EudraCT 2009-017259-91 involved 27 patients with rising PSA levels. The study medication consisted of autologous DCs pulsed with the killed LNCaP cell line (DCVAC/PCa). Twelve patients with a favourable PSA response continued with the second cycle of immunotherapy. The primary and secondary objectives of the study were to assess the safety and determine the PSA doubling time (PSADT), respectively. RESULTS: No significant side effects were recorded. The median PSADT in all treated patients increased from 5.67 months prior to immunotherapy to 18.85 months after 12 doses (p < 0.0018). Twelve patients who continued immunotherapy with the second cycle had a median PSADT of 58 months that remained stable after the second cycle. In the peripheral blood, specific PSA-reacting T lymphocytes were increased significantly already after the fourth dose, and a stable frequency was detected throughout the remainder of DCVAC/PCa treatment. Long-term immunotherapy of prostate cancer patients experiencing early signs of PSA recurrence using DCVAC/PCa was safe, induced an immune response and led to the significant prolongation of PSADT. Long-term follow-up may show whether the changes in PSADT might improve the clinical outcome in patients with biochemical recurrence of the prostate cancer.

High hydrostatic pressure induces immunogenic cell death in human tumor cells.

Recent studies have identified molecular events characteristic of immunogenic cell death (ICD), including surface exposure of calreticulin (CRT), the heat shock proteins HSP70 and HSP90, the release of high-mobility group box protein 1 (HMGB1) and the release of ATP from dying cells. We investigated the potential of high hydrostatic pressure (HHP) to induce ICD in human tumor cells. HHP induced the rapid expression of HSP70, HSP90 and CRT on the cell surface. HHP also induced the release of HMGB1 and ATP. The interaction of dendritic cells (DCs) with HHP-treated tumor cells led to a more rapid rate of DC phagocytosis, upregulation of CD83, CD86 and HLA-DR and the release of interleukin IL-6, IL-12p70 and TNF-α. DCs pulsed with tumor cells killed by HHP induced high numbers of tumor-specific T cells. DCs pulsed with HHP-treated tumor cells also induced the lowest number of regulatory T cells. In addition, we found that the key features of the endoplasmic reticulum stress-mediated apoptotic pathway, such as reactive oxygen species production, phosphorylation of the translation initiation factor eIF2α and activation of caspase-8, were activated by HHP treatment. Therefore, HHP acts as a reliable and potent inducer of ICD in human tumor cells.

Detection of Helicobacter pylori in oropharyngeal lymphatic tissue with real-time PCR and assessment of its carcinogenic potential.

Helicobacter pylori (HP) is considered a major gastric pathogen with oncogenic potential. The aim of this study was to determine whether HP is present in oropharyngeal lymphoid tissue and whether oropharyngeal HP strains carry virulence factor genes known to be involved in gastric carcinogenesis. The study included 104 subjects (41 patients with tonsillar carcinoma, 38 with chronic tonsillitis and 25 with obstructive sleep apnoea syndrome--OSAS). Detection of specific serum anti-HP antibodies was performed with an ELISA. The presence of HP in tissue was determined by culture and real-time PCR. Detection of virulence factors genes was also performed. Specific antibodies were found in 78.05% of tumour cases, 34.21% of chronic tonsillitis cases, and 72.0% of OSAS cases. The presence of HP in the tissue was detected in 73.91% of tonsillar tumours, 70.0% of tonsillitis cases, and 69.23% of OSAS specimens. The results of the virulence factor gene analysis showed the majority of the s1b (52.4%) and m2 (59.5%) alleles of vacA gene and limited abundance of cagA gene (12.5%). Results confirm that HP may colonise oropharyngeal lymphoid tissue. Oropharyngeal HP colonisation was frequently found in the oropharyngeal cancer group and in patients with benign oropharyngeal diseases. A virulence factor gene analysis showed differences from the predominant strains most commonly found in the stomach. The strains obtained from the oropharynx differed primarily by the lower abundance of the cagA gene and carried the less virulent vacA gene allele combination.

Distinct leukocyte populations and cytokine secretion profiles define tumoral and peritumoral areas in renal cell carcinoma.

Renal cell carcinoma (RCC) is a common malignancy frequently diagnosed at the metastatic stage. We performed a comprehensive analysis of the tumor immune microenvironment (TIME) in RCC patients, including the peritumoral tissue microenvironment, to characterize the phenotypic patterns and functional characteristics of infiltrating immune cells. T cells from various compartments (peripheral blood, tumor, peritumoral area, and adjacent healthy renal tissue) were assessed using flow cytometry and Luminex analyses, both before and after T cell-specific stimulation, to evaluate activation status and migratory potential. Our findings demonstrated that tumor-infiltrating lymphocytes (TILs) exhibited heightened cytokine production compared to peritumoral T cells (pTILs), acting as the primary source of cytotoxic markers (IFN-γ, granzyme B, and FasL). CD8+ T cells primarily employed Fas Ligand for cytotoxicity, while CD4+ T cells relied on CD107a. In addition, a statistically significant negative correlation between patient mortality and the presence of CD4+CD107+ pTILs was demonstrated. The engagement with the PD-1/PD-L1 pathway was also more evident in CD4+ and CD8+ pTILs as opposed to TILs. PD-L1 expression in the non-leukocyte fraction of the tumor tissue was relatively lower than in their leukocytic counterparts and upon stimulation, peripheral blood T cells displayed much stronger responses to stimulation than TILs and pTILs. Our results suggest that tumor and peritumoral T cells exhibit limited responsiveness to additional activation signals, while peripheral T cells retain their capacity to respond to stimulatory signals.

Dynamics of T-cell infiltration during the course of ovarian cancer: the gradual shift from a Th17 effector cell response to a predominant infiltration by regulatory T-cells.

The type of immune cells that are present within the tumor microenvironment can play a crucial role in the survival of patients. However, little is known about the dynamics of the tumor-infiltrating immune cells during disease progression. We studied the immune cells that infiltrated the tumor tissues of ovarian cancer patients at different stages of disease. The early stages of development of ovarian carcinomas were characterized by a strong Th17 immune response, whereas in stage II patients, recruitment of high numbers of Th1 cells was observed. In disseminated tumors (Stages III-IV), we detected a dominant population of Helios(+) activated regulatory T cells (Tregs) along with high numbers of monocytes/macrophages and myeloid dendritic cells (mDCs). Tumor-infiltrating Tregs had markedly lower expression of CCR4 than circulating Tregs, and the numbers of tumor-infiltrating Tregs significantly correlated with the levels of CCL22 in ovarian tumor cell culture supernatants, suggesting their recruitment via a CCR4/CCL22 interaction. CCL22 was mainly produced by tumor cells, monocytes/macrophages and mDCs in the primary ovarian tumors, and its expression markedly increased in response to IFNγ. Taken together, the specific recruitment of Tregs, probably triggered by inflammatory stimuli, leads to a significant immune suppression in the advanced stages of ovarian cancer.