Germline homozygosity and allelic imbalance of HLA-I are common in esophagogastric adenocarcinoma and impair the repertoire of immunogenic peptides.

BACKGROUND: The individual HLA-I genotype is associated with cancer, autoimmune diseases and infections. This study elucidates the role of germline homozygosity or allelic imbalance of HLA-I loci in esophago-gastric adenocarcinoma (EGA) and determines the resulting repertoires of potentially immunogenic peptides. METHODS: HLA genotypes and sequences of either (1) 10 relevant tumor-associated antigens (TAAs) or (2) patient-specific mutation-associated neoantigens (MANAs) were used to predict good-affinity binders using an in silico approach for MHC-binding (www.iedb.org). Imbalanced or lost expression of HLA-I-A/B/C alleles was analyzed by transcriptome sequencing. FluoroSpot assays and TCR sequencing were used to determine peptide-specific T-cell responses. RESULTS: We show that germline homozygosity of HLA-I genes is significantly enriched in EGA patients (n=80) compared with an HLA-matched reference cohort (n=7605). Whereas the overall mutational burden is similar, the repertoire of potentially immunogenic peptides derived from TAAs and MANAs was lower in homozygous patients. Promiscuity of peptides binding to different HLA-I molecules was low for most TAAs and MANAs and in silico modeling of the homozygous to a heterozygous HLA genotype revealed normalized peptide repertoires. Transcriptome sequencing showed imbalanced expression of HLA-I alleles in 75% of heterozygous patients. Out of these, 33% showed complete loss of heterozygosity, whereas 66% had altered expression of only one or two HLA-I molecules. In a FluoroSpot assay, we determined that peptide-specific T-cell responses against NY-ESO-1 are derived from multiple peptides, which often exclusively bind only one HLA-I allele. CONCLUSION: The high frequency of germline homozygosity in EGA patients suggests reduced cancer immunosurveillance leading to an increased cancer risk. Therapeutic targeting of allelic imbalance of HLA-I molecules should be considered in EGA.

Resultados intrahospitalarios tras tratamiento percutáneo frente a quirúrgico en pacientes con estenosis aórtica y enfermedad arterial coronaria concomitante / In-hospital outcomes following percutaneous versus surgical intervention in the treatment of aortic stenosis and concomitant coronary artery disease

Introducción y objetivos: La enfermedad coronaria (EC) es frecuente en pacientes con estenosis aórtica; sin embargo, la estrategia terapéutica óptima sigue siendo objeto de debate. Investigamos los resultados periprocedimiento en pacientes sometidos a implante percutáneo de válvula aórtica con intervención coronaria percutánea (TAVI/ICP) frente al recambio valvular aórtico con injerto de derivación de arteria coronaria (RVAo/CABG) en pacientes con estenosis aórtica con EC.Métodos: Con los datos de alta del Sistema Nacional de Salud Español, se identificaron 6.194 pacientes (5.217 RVAo/CABG y 977 TAVI/ICP) entre 2016 y 2019. Se realizó un análisis emparejado por puntuación de propensión ajustado por características basales. El objetivo primario fue la mortalidad hospitalaria, Los objetivos secundarios fueron las complicaciones hospitalarias y rehospitalización cardiovascular a 30 días.Resultados: Tras el emparejamiento, se seleccionaron 774 parejas de pacientes. La mortalidad total hospitalaria fue más frecuente en el grupo quirúrgico (3,4 frente a 9,4%, p <0,001), al igual que el ictus periprocedimiento (0,9 frente a 2,2%, p=0,004), fallo renal agudo (4,3 frente a 16,0%, p <0,002), transfusión (9,6 frente a 21,1%, p <0,001) y neumonía intrahospitalaria (0,1 frente a 1,7%, p=0,001). La implantación de marcapasos permanente fue más frecuente en el tratamiento percutáneo (12,0 frente a 5,7%, p <0,001). Los centros de menor volumen (< 130 procedimientos por año) tuvieron mayor mortalidad hospitalaria para ambos procedimientos: TAVI/ICP (3,6 frente a 2,9%, p <0,001) y RVAo/CABG (9,3 frente a 6,8%, p <0,001). La rehospitalización cardiovascular a 30 días no difirió entre los grupos.(AU)

Introduction and objectives: Concomitant coronary artery disease (CAD) is prevalent among aortic stenosis patients; however the optimal therapeutic strategy remains debated. We investigated periprocedural outcomes among patients undergoing transcatheter aortic valve implantation with percutaneous coronary intervention (TAVI/PCI) vs surgical aortic valve replacement with coronary artery bypass grafting (SAVR/CABG) for aortic stenosis with CAD.Methods: Using discharge data from the Spanish National Health System, we identified 6194 patients (5217 SAVR/CABG and 977 TAVI/PCI) between 2016 and 2019. Propensity score matching was adjusted for baseline characteristics. The primary outcome was in-hospital all-cause mortality. Secondary outcomes were in-hospital complications and 30-day cardiovascular readmission.Results: Matching resulted in 774 pairs. In-hospital all-cause mortality was more common in the SAVR/CABG group (3.4% vs 9.4%, P <.001) as was periprocedural stroke (0.9% vs 2.2%; P=.004), acute kidney injury (4.3% vs 16.0%, P <.001), blood transfusion (9.6% vs 21.1%, P <.001), and hospital-acquired pneumonia (0.1% vs 1.7%, P=.001). Permanent pacemaker implantation was higher for matched TAVI/PCI (12.0% vs 5.7%, P <.001). Lower volume centers (< 130 procedures/y) had higher in-hospital all-cause mortality for both procedures: TAVI/PCI (3.6% vs 2.9%, P <.001) and SAVR/CABG (8.3 vs 6.8%, P <.001). Thirty-day cardiovascular readmission did not differ between groups.Conclusions: In this large contemporary nationwide study, percutaneous management of aortic stenosis and CAD with TAVI/PCI had lower in-hospital mortality and morbidity than surgical intervention. Higher volume centers had less in-hospital mortality in both groups. Dedicated national high-volume heart centers warrant further investigation.(AU)

Low B-cell content is associated with a CD73-low tumour microenvironment and unfavourable prognosis in classic Hodgkin lymphoma.

B-cell content in the tumour microenvironment (TME) of classic Hodgkin lymphoma (HL) is known to be associated with prognosis. Here we demonstrate that whole slide image analysis using routinely available slides predicts outcomes in patients treated with ABVD in a prospective trial with a high B-cell content being associated with a favourable prognosis. B cells in the TME did not correlate with B cells in peripheral blood. In the TME maturation, stages of B cells (naive and memory) were consistent. However, we detected down-regulation of CD73 in HL with low B cells suggestive of an antibody-independent function of B cells in the TME of HL.

In-hospital outcomes following percutaneous versus surgical intervention in the treatment of aortic stenosis and concomitant coronary artery disease.

INTRODUCTION AND OBJECTIVES: Concomitant coronary artery disease (CAD) is prevalent among aortic stenosis patients; however the optimal therapeutic strategy remains debated. We investigated periprocedural outcomes among patients undergoing transcatheter aortic valve implantation with percutaneous coronary intervention (TAVI/PCI) vs surgical aortic valve replacement with coronary artery bypass grafting (SAVR/CABG) for aortic stenosis with CAD. METHODS: Using discharge data from the Spanish National Health System, we identified 6194 patients (5217 SAVR/CABG and 977 TAVI/PCI) between 2016 and 2019. Propensity score matching was adjusted for baseline characteristics. The primary outcome was in-hospital all-cause mortality. Secondary outcomes were in-hospital complications and 30-day cardiovascular readmission. RESULTS: Matching resulted in 774 pairs. In-hospital all-cause mortality was more common in the SAVR/CABG group (3.4% vs 9.4%, P <.001) as was periprocedural stroke (0.9% vs 2.2%; P=.004), acute kidney injury (4.3% vs 16.0%, P <.001), blood transfusion (9.6% vs 21.1%, P <.001), and hospital-acquired pneumonia (0.1% vs 1.7%, P=.001). Permanent pacemaker implantation was higher for matched TAVI/PCI (12.0% vs 5.7%, P <.001). Lower volume centers (< 130 procedures/y) had higher in-hospital all-cause mortality for both procedures: TAVI/PCI (3.6% vs 2.9%, P <.001) and SAVR/CABG (8.3 vs 6.8%, P <.001). Thirty-day cardiovascular readmission did not differ between groups. CONCLUSIONS: In this large contemporary nationwide study, percutaneous management of aortic stenosis and CAD with TAVI/PCI had lower in-hospital mortality and morbidity than surgical intervention. Higher volume centers had less in-hospital mortality in both groups. Dedicated national high-volume heart centers warrant further investigation.

Characteristics and outcomes of percutaneous coronary interventions in patients with spontaneous coronary artery dissection. A study from the administrative minimum data set of the Spanish National Health System.

Background: Coronary revascularization in patients with spontaneous coronary artery dissection (SCAD) is challenging. Indications and results of percutaneous coronary interventions (PCI) in SCAD patients are not well established. Aim: To assess indications and results of PCI in SCAD. Methods: The minimum basic data set of the Spanish National Health System (years 2016-2019) was used to identify 804 episodes of acute myocardial infarction (AMI) and SCAD, with a crude in-hospital mortality rate of 3%. Of these, 368 (46.8%) patients were revascularized with PCI during admission whereas 436 (54.2%) were managed conservatively. Results: Revascularization and in-hospital mortality rates both declined over the study period (p for trend both < 0.05). SCAD patients treated with PCI were older, more frequently male, and had higher frequency of diabetes, ST-segment elevation AMI and cardiogenic shock, compared to patients managed conservatively. The crude in-hospital mortality rate was higher in patients treated with PCI (4.9% vs. 1.4%; p = 0.004). However, after adjusting by propensity score (223 pairs) the in-hospital mortality rate was similar in the two groups (Adj OR: 1.21; 95%CI: 0.30-1.57; p = 0.76). Readmissions at 30-days were higher in patients managed conservatively (7.1 vs. 1.6%, p < 0.001) and this difference was maintained after propensity score adjustment (Adj average treatment effect: 2% vs. 12.2%; OR: 0.15; 95%CI: 0.04-0.45; p < 0.001). Conclusion: Revascularization is frequently used in unselected patients with AMI and SCAD but its use is declining. Patients with SCAD treated with PCI have a higher in-hospital mortality but this appears to be explained by their adverse baseline clinical characteristics.

Heart failure and in-hospital mortality in elderly patients after elective noncardiac surgery in Spain

Background: Patients with heart failure (HF) undergoing noncardiac surgical procedures is rising worldwide. This study was aiming at analyzing the impact of heart failure (HF) on the outcomes (mortality, complications, readmissions, and length of stay) of elderly patients undergoing elective major noncardiac surgical procedures in Spain.MethodsA retrospective observational study of patients undergoing noncardiac surgery was conducted. The Minimum Basic Data Set (MBDS) was used to collect information about the demographic characteristics of patients discharged from hospitals of the Spanish National Health System (SNHS), variables related to patients’ medical conditions and surgeries conducted during the episode.ResultsA total of 996,986 selected procedures in the discharge record were identified in the period 2007–2015. HF was recorded as a secondary diagnosis in 22,367 discharges (2.24%). The mean age of patients was 76.6±7.27 years, with a difference in patients without and with HF: 76.5 (95% CI: 76.47–76.50) vs 82.8 (95% CI: 82.71–82.90). The number of selected surgical procedures increased by 13.2% (117,487 in 2015 vs. 103,744 in 2007), and the proportion of presence HF as a comorbidity increased by 24.4% (2.4% in 2015 v 1.9% in 2007). The proportion of women was higher in the HF group: 53.2% (95% CI: 53.18–53.22) vs 64.3% (95% CI: 64.20–64.44), with a longer average length of stay: 7.9 (95% CI: 7.9–7.9) vs 14.9 (95% CI 14.7–15.0) days, and women had a higher proportion of comorbidities. HF was found to be an independent risk factor in-hospital mortality in the multilevel risk adjustment model (OR=2.3; 95% CI: 2.2–2.4). (AU)

Antecedentes: El número de pacientes con insuficiencia cardíaca (IC) que se someten a procedimientos quirúrgicos no cardíacos está aumentando en todo el mundo. El objetivo de este estudio es analizar el impacto de la IC en los resultados (mortalidad, complicaciones, reingresos y duración de la estancia) de los pacientes de edad avanzada sometidos a procedimientos quirúrgicos mayores electivos no cardíacos en España.MétodosSe realizó un estudio observacional retrospectivo de pacientes sometidos a cirugía no cardíaca. Se utilizó el Conjunto Mínimo Básico de Datos (CMBD) para recoger información sobre las características demográficas de los pacientes dados de alta en los hospitales del Sistema Nacional de Salud (SNS), variables relacionadas con las condiciones médicas de los pacientes y las cirugías realizadas durante el episodio.ResultadosSe identificaron un total de 996.986 procedimientos seleccionados en el registro de altas en el periodo 2007-2015. La IC se registró como diagnóstico secundario en 22.367 altas (2,24%). La edad media de los pacientes fue de 76,6 ± 7,27 años, con una diferencia en los pacientes sin y con IC: 76,5 IC 95%: 76,47 - 76,50) vs. 82,8 (IC 95%: 82,71 – 82,90). El número de procedimientos quirúrgicos seleccionados aumentó un 13,2% (117.487 en 2015 vs. 103.744 en 2007), y la proporción de presencia de IC como comorbilidad aumentó un 24,4% (2,4% en 2015 vs. 1,9% en 2007). La proporción de mujeres fue mayor en el grupo de IC: 53,2% (IC 95%: 53,18 – 53,22) vs. 64,3% (IC 95%: 64,20 – 64,44), con una duración media de la estancia mayor 7,9 (IC 95%: 7,9 – 7,9) vs. 14,9 (IC 95%: 14,7 – 15,0), y las mujeres tenían una mayor proporción de comorbilidades. La IC resultó ser un factor de riesgo independiente de mortalidad intrahospitalaria en el modelo de ajuste de riesgo multinivel (OR = 2,3; IC 95%: 2,2-2,4). (AU)

Spontaneous coronary artery dissection in Spain: a study using the minimum data set of the Spanish National Health System.

INTRODUCTION AND OBJECTIVES: Spontaneous coronary artery dissection (SCAD) is a rare cause of acute myocardial infarction (AMI). We sought to compare the results on in-hospital mortality and 30-day readmission rates among patients with AMI-SCAD vs AMI due to other causes (AMI-non-SCAD). METHODS: Risk-standardized in-hospital mortality (rIMR) and risk-standardized 30-day readmission ratios (rRAR) were calculated using the minimum dataset of the Spanish National Health System (2016-2019). RESULTS: A total of 806 episodes of AMI-SCAD were compared with 119 425 episodes of AMI-non-SCAD. Patients with AMI-SCAD were younger and more frequently female than those with AMI-non-SCAD. Crude in-hospital mortality was lower (3% vs 7.6%; P<.001) and rIMR higher (7.6±1.7% vs 7.4±1.7%; P=.019) in AMI-SCAD. However, after propensity score adjustment (806 pairs), the mortality rate was similar in the 2 groups (AdjOR, 1.15; 95%CI, 0.61-2,2; P=.653). Crude 30-day readmission rates were also similar in the 2 groups (4.6% vs 5%, P=.67) whereas rRAR were lower (4.7±1% vs 4.8%±1%; P=.015) in patients with AMI-SCAD. Again, after propensity score adjustment (715 pairs) readmission rates were similar in the 2 groups (AdjOR, 1.14; 95%CI, 0.67-1.98; P=.603). CONCLUSIONS: In-hospital mortality and readmission rates are similar in patients with AMI-SCAD and AMI-non-SCAD when adjusted for the differences in baseline characteristics. These findings underscore the need to optimize the management, treatment, and clinical follow-up of patients with SCAD.

Post-transplant Malignancies Show Reduced T-cell Abundance and Tertiary Lymphoid Structures as Correlates of Impaired Cancer Immunosurveillance.

PURPOSE: An increased risk to develop cancer is one of the most challenging negative side effects of long-term immunosuppression in organ transplant recipients and impaired cancer immunosurveillance is assumed as underlying mechanism. This study aims to elucidate transplant-related changes in the tumor immune microenvironment (TME) of cancer. EXPERIMENTAL DESIGN: Data from 123 organ transplant recipients (kidney, heart, lung, and liver) were compared with historic data from non-immunosuppressed patients. Digital image analysis of whole-section slides was used to assess abundance and spatial distribution of T cells and tertiary lymphoid structures (TLS) in the TME of 117 tumor samples. Expression of programmed cell death 1 ligand 1 (PD-L1) and human-leucocyte-antigen class I (HLA-I) was assessed on tissue microarrays. RESULTS: We found a remarkably reduced immune infiltrate in the center tumor (CT) regions as well as the invasive margins (IM) of post-transplant cancers. These differences were more pronounced in the IM than in the CT and larger for CD8+ T cells than for CD3+ T cells. The Immune-score integrating results from CT and IM was also lower in transplant recipients. Density of TLS was lower in cancer samples of transplant recipients. The fraction of samples with PD-L1 expression was higher in controls whereas decreased expression of HLA-I was more common in transplant recipients. CONCLUSIONS: Our study demonstrates the impact of immunosuppression on the TME and supports impaired cancer immunosurveillance as important cause of post-transplant cancer. Modern immunosuppressive protocols and cancer therapies should consider the distinct immune microenvironment of post-transplant malignancies.

The effect of weekends and public holidays on the care of acute coronary syndrome in the Spanish National Health System.

INTRODUCTION AND OBJECTIVES: To analyze whether admission on weekends or public holidays (WHA) influences the management (performance of angioplasty, percutaneous coronary intervention [PCI]) and outcomes (in-hospital mortality) of patients hospitalized for acute coronary syndrome in the Spanish National Health System compared with admission on weekdays. METHODS: Retrospective observational study of patients admitted for ST-segment elevation myocardial infarction (STEMI) or for non-ST-segment elevation acute coronary syndrome (NSTEACS) in hospitals of the Spanish National Health system from 2003 to 2018. RESULTS: A total of 438 987 episodes of STEMI and 486 565 of NSTEACS were selected, of which 28.8% and 26.1% were WHA, respectively. Risk-adjusted models showed that WHA was a risk factor for in-hospital mortality in STEMI (OR, 1.05; 95%CI,1.03-1.08; P < .001) and in NSTEACS (OR, 1.08; 95%CI, 1.05-1.12; P < .001). The rate of PCI performance in STEMI was more than 2 percentage points higher in patients admitted on weekdays from 2003 to 2011 and was similar or even lower from 2012 to 2018, with no significant changes in NSTEACS. WHA was a statistically significant risk factor for both STEMI and NSTEACS. CONCLUSIONS: WHA can increase the risk of in-hospital death by 5% (STEMI) and 8% (NSTEACS). The persistence of the risk of higher in-hospital mortality, after adjustment for the performance of PCI and other explanatory variables, probably indicates deficiencies in management during the weekend compared with weekdays.

Immune responses against shared antigens are common in esophago-gastric cancer and can be enhanced using CD40-activated B cells.

BACKGROUND: Specific immune response is a hallmark of cancer immunotherapy and shared tumor-associated antigens (TAAs) are important targets. Recent advances using combined cellular therapy against multiple TAAs renewed the interest in this class of antigens. Our study aims to determine the role of TAAs in esophago-gastric adenocarcinoma (EGA). METHODS: RNA expression was assessed by NanoString in tumor samples of 41 treatment-naïve EGA patients. Endogenous T cell and antibody responses against the 10 most relevant TAAs were determined by FluoroSpot and protein-bound bead assays. Digital image analysis was used to evaluate the correlation of TAAs and T-cell abundance. T-cell receptor sequencing, in vitro expansion with autologous CD40-activated B cells (CD40Bs) and in vitro cytotoxicity assays were applied to determine specific expansion, clonality and cytotoxic activity of expanded T cells. RESULTS: 68.3% of patients expressed ≥5 TAAs simultaneously with coregulated clusters, which were similar to data from The Cancer Genome Atlas (n=505). Endogenous cellular or humoral responses against ≥1 TAA were detectable in 75.0% and 53.7% of patients, respectively. We found a correlation of T-cell abundance and the expression of TAAs and genes related to antigen presentation. TAA-specific T-cell responses were polyclonal, could be induced or enhanced using autologous CD40Bs and were cytotoxic in vitro. Despite the frequent expression of TAAs co-occurrence with immune responses was rare. CONCLUSIONS: We identified the most relevant TAAs in EGA for monitoring of clinical trials and as therapeutic targets. Antigen-escape rather than missing immune response should be considered as mechanism underlying immunotherapy resistance of EGA.

Reverted exhaustion phenotype of circulating lymphocytes as immune correlate of anti-PD1 first-line treatment in Hodgkin lymphoma.

While classical Hodgkin lymphoma (HL) is highly susceptible to anti-programmed death protein 1 (PD1) antibodies, the exact modes of action remain controversial. To elucidate the circulating lymphocyte phenotype and systemic effects during anti-PD1 1st-line HL treatment we applied multicolor flow cytometry, FluoroSpot and NanoString to sequential samples of 81 HL patients from the NIVAHL trial (NCT03004833) compared to healthy controls. HL patients showed a decreased CD4 T-cell fraction, a higher percentage of effector-memory T cells and higher expression of activation markers at baseline. Strikingly, and in contrast to solid cancers, expression for 10 out of 16 analyzed co-inhibitory molecules on T cells (e.g., PD1, LAG3, Tim3) was higher in HL. Overall, we observed a sustained decrease of the exhausted T-cell phenotype during anti-PD1 treatment. FluoroSpot of 42.3% of patients revealed T-cell responses against ≥1 of five analyzed tumor-associated antigens. Importantly, these responses were more frequently observed in samples from patients with early excellent response to anti-PD1 therapy. In summary, an initially exhausted lymphocyte phenotype rapidly reverted during anti-PD1 1st-line treatment. The frequently observed IFN-y responses against shared tumor-associated antigens indicate T-cell-mediated cytotoxicity and could represent an important resource for immune monitoring and cellular therapy of HL.

T-cells of invasive candidiasis patients show patterns of T-cell-exhaustion suggesting checkpoint blockade as treatment option.

OBJECTIVE: Recent data imply that strengthening host immunity by checkpoint inhibition improves outcome in invasive fungal infections (IFI), particularly in candidiasis. METHODS: To assess T-cell exhaustion in this context, we compared peripheral blood mononuclear cells (PBMCs) and serum samples of patients with invasive Candida albicans infection (IC, n = 21) to PBMCs or tumor-infiltrating lymphocytes (TILs) from cancer patients (n = 14) and PBMCs of healthy controls (n = 20). Type and differentiation of lymphocytes and expression of 29 immune-regulatory molecules were analyzed by flow cytometry. C. albicans specific responses were assessed by FluoroSpot (n = 8) and antibody measurement (n = 14). RESULTS: Fractions and phenotypes of lymphocyte subsets in PBMCs of IC patients were similar compared to PBMCs of controls, while they were different in TILs. PBMCs of patients with IC showed increased expression of immune-checkpoint molecules. The pattern of upregulated molecules was similar to TILs, but not present in PBMCs of control cancer patients. Fractions of T-cells expressing PD-1 and TIGIT were higher in IC patients that died. FluoroSpot analysis showed a Candida-specific IFN-y or IL-2 response in 5/8 patients, enhanced by addition of nivolumab in vitro. CONCLUSIONS: Together with preclinical data and preliminary evidence of clinical efficacy in mucormycosis, our results support clinical evaluation of immune-checkpoint inhibition in IFI treatment. TRIAL REGISTRATION: NCT04533087; retrospectively registered on August 31, 2020.

Cancer-specific immune evasion and substantial heterogeneity within cancer types provide evidence for personalized immunotherapy.

The immune response against cancer is orchestrated by various parameters and site-dependent specificities have been poorly investigated. In our analyses of ten different cancer types, we describe elevated infiltration by regulatory T cells as the most common feature, while other lymphocyte subsets and also expression of immune-regulatory molecules on tumor-infiltrating lymphocytes showed site-specific variation. Multiparametric analyses of these data identified similarities of renal and liver or lung with head and neck cancer. Co-expression of immune-inhibitory ligands on tumor cells was most frequent in colorectal, lung and ovarian cancer. Genes related to antigen presentation were frequently dysregulated in liver and lung cancer. Expression of co-inhibitory molecules on tumor-infiltrating T cells accumulated in advanced stages while T-cell abundance was related to enhanced expression of genes related to antigen presentation. Our results promote evaluation of cancer-specific or even personalized immunotherapeutic combinations to overcome primary or secondary resistance as major limitation of immune-checkpoint inhibition.

CD86+ Antigen-Presenting B Cells Are Increased in Cancer, Localize in Tertiary Lymphoid Structures, and Induce Specific T-cell Responses.

The role of B cells in antitumor immunity and their impact on emerging immunotherapies is increasingly gaining attention. B-cell effector functions include not only secretion of antibodies, but also presentation of antigens to T cells. A physiologic B-cell subset with immunostimulatory properties was described in humans, defined by a high expression of CD86 and downregulation of CD21. We used multicolor flow cytometry and IHC to elucidate abundance and spatial distribution of these antigen-presenting B cells (BAPC) in blood (peripheral blood mononuclear cells, PBMC) and tumor samples of 237 patients with cancer. Antigen-specific T-cell responses to cancer testis antigens were determined using tetramer staining and sorted BAPCs in FluoroSpot assays for selected patients. We found that BAPCs were increased in the tumor microenvironment of 9 of 10 analyzed cancer types with site-specific variation. BAPCs were not increased in renal cell carcinoma, whereas we found a systemic increase with elevated fractions in tumor-infiltrating lymphocytes (TIL) and PBMCs of patients with colorectal cancer and gastroesophageal adenocarcinoma. BAPCs were localized in lymphoid follicles of tertiary lymphoid structures (TLS) and were enriched in tumors with increased numbers of TLSs. BAPCs isolated from tumor-draining lymph nodes of patients with cancer showed increased percentages of tumor antigen-specific B cells and induced responses of autologous T cells in vitro. Our results highlight the relevance of BAPCs as professional antigen-presenting cells in tumor immunity and provide a mechanistic rationale for the observed correlation of B-cell abundance and response to immune checkpoint inhibition.

Microwave ablation enhances tumor-specific immune response in patients with hepatocellular carcinoma.

Thermal ablative therapies are standard treatments for localized hepatocellular carcinoma (HCC). In addition to local tumor destruction, ablation leads to abscopal effects in distant lesions most likely mediated by an anti-tumor immune response. Although microwave ablation (MWA) is increasingly substituting other ablative techniques, its systemic immunostimulatory effects are poorly studied. We analyzed tumor-specific immune responses in peripheral blood of HCC patients after thermal ablation with regard to T cell responses and disease outcome. While comprehensive flow cytometric analyses in sequential samples of a prospective patient cohort (n = 23) demonstrated only moderate effects of MWA on circulating immune cell subsets, fluorospot analyses of specific T cell responses against seven tumor-associated antigens (TTAs) revealed de-novo or enhanced tumor-specific immune responses in 30% of patients. This anti-tumor immune response was related to tumor control as Interferon-y and Interleukin-5 T cell responses against TAAs were more frequent in patients with a long-time remission (> 1 year) after MWA (7/16) compared to patients suffering from an early relapse (0/13 patients) and presence of tumor-specific T cell response (IFN-y and/or IL-5) was associated to longer progression-free survival (27.5 vs. 10.0 months). Digital image analysis of immunohistochemically stained archival HCC samples (n = 18) of patients receiving combined MWA and resection revealed a superior disease-free survival of patients with high T cell abundance at the time of thermal ablation (37.4 vs. 13.1 months). Our data demonstrates remarkable immune-related effects of MWA in HCC patients and provides additional evidence for a combination of local ablation and immunotherapy in this challenging disease.