An IL-4 signalling axis in bone marrow drives pro-tumorigenic myelopoiesis.

Myeloid cells are known to suppress antitumour immunity1. However, the molecular drivers of immunosuppressive myeloid cell states are not well defined. Here we used single-cell RNA sequencing of human and mouse non-small cell lung cancer (NSCLC) lesions, and found that in both species the type 2 cytokine interleukin-4 (IL-4) was predicted to be the primary driver of the tumour-infiltrating monocyte-derived macrophage phenotype. Using a panel of conditional knockout mice, we found that only deletion of the IL-4 receptor IL-4Rα in early myeloid progenitors in bone marrow reduced tumour burden, whereas deletion of IL-4Rα in downstream mature myeloid cells had no effect. Mechanistically, IL-4 derived from bone marrow basophils and eosinophils acted on granulocyte-monocyte progenitors to transcriptionally programme the development of immunosuppressive tumour-promoting myeloid cells. Consequentially, depletion of basophils profoundly reduced tumour burden and normalized myelopoiesis. We subsequently initiated a clinical trial of the IL-4Rα blocking antibody dupilumab2-5 given in conjunction with PD-1/PD-L1 checkpoint blockade in patients with relapsed or refractory NSCLC who had progressed on PD-1/PD-L1 blockade alone (ClinicalTrials.gov identifier NCT05013450 ). Dupilumab supplementation reduced circulating monocytes, expanded tumour-infiltrating CD8 T cells, and in one out of six patients, drove a near-complete clinical response two months after treatment. Our study defines a central role for IL-4 in controlling immunosuppressive myelopoiesis in cancer, identifies a novel combination therapy for immune checkpoint blockade in humans, and highlights cancer as a systemic malady that requires therapeutic strategies beyond the primary disease site.

Incidence and outcomes of uterine rupture in women with unscarred, preterm or prelabour uteri: data from the international network of obstetric survey systems.

OBJECTIVE: Analysis of atypical cases of uterine rupture, namely, uterine rupture occurring in unscarred, preterm or prelabour uteri. DESIGN: Descriptive multi-country population-based study. SETTING: Ten high-income countries within the International Network of Obstetric Survey Systems. POPULATION: Women with unscarred, preterm or prelabour ruptured uteri. METHODS: We merged prospectively collected individual patient data in ten population-based studies of women with complete uterine rupture. In this analysis, we focused on women with uterine rupture of unscarred, preterm or prelabour ruptured uteri. MAIN OUTCOME MEASURES: Incidence, women's characteristics, presentation and maternal and perinatal outcome. RESULTS: We identified 357 atypical uterine ruptures in 3 064 923 women giving birth. Estimated incidence was 0.2 per 10 000 women (95% CI 0.2-0.3) in the unscarred uteri, 0.5 (95% CI 0.5-0.6) in the preterm uteri, 0.7 (95% CI 0.6-0.8) in the prelabour uteri, and 0.5 (95% CI 0.4-0.5) in the group with no previous caesarean. Atypical uterine rupture resulted in peripartum hysterectomy in 66 women (18.5%, 95% CI 14.3-23.5%), three maternal deaths (0.84%, 95% CI 0.17-2.5%) and perinatal death in 62 infants (19.7%, 95% CI 15.1-25.3%). CONCLUSIONS: Uterine rupture in preterm, prelabour or unscarred uteri are extremely uncommon but were associated with severe maternal and perinatal outcome. We found a mix of risk factors in unscarred uteri, most preterm uterine ruptures occurred in caesarean-scarred uteri and most prelabour uterine ruptures in 'otherwise' scarred uteri. This study may increase awareness among clinicians and raise suspicion of the possibility of uterine rupture under these less expected conditions.

TREM2 macrophages drive NK cell paucity and dysfunction in lung cancer.

Natural killer (NK) cells are commonly reduced in human tumors, enabling many to evade surveillance. Here, we sought to identify cues that alter NK cell activity in tumors. We found that, in human lung cancer, the presence of NK cells inversely correlated with that of monocyte-derived macrophages (mo-macs). In a murine model of lung adenocarcinoma, we show that engulfment of tumor debris by mo-macs triggers a pro-tumorigenic program governed by triggering receptor expressed on myeloid cells 2 (TREM2). Genetic deletion of Trem2 rescued NK cell accumulation and enabled an NK cell-mediated regression of lung tumors. TREM2+ mo-macs reduced NK cell activity by modulating interleukin (IL)-18/IL-18BP decoy interactions and IL-15 production. Notably, TREM2 blockade synergized with an NK cell-activating agent to further inhibit tumor growth. Altogether, our findings identify a new axis, in which TREM2+ mo-macs suppress NK cell accumulation and cytolytic activity. Dual targeting of macrophages and NK cells represents a new strategy to boost antitumor immunity.

A progressive T cell exhaustion program mapped across tissues in patients with lung cancer on immune checkpoint blockade.

Immune checkpoint blockade has reached the standard of care for patients with lung cancer. However, its mode of action in patients is still incompletely understood. In this issue, Pai et al. present a temporally and spatially resolved differentiation map of tumor-directed T cells in patients with lung cancer on PD-1 blockade.

Network analysis of large-scale ImmGen and Tabula Muris datasets highlights metabolic diversity of tissue mononuclear phagocytes.

The diversity of mononuclear phagocyte (MNP) subpopulations across tissues is one of the key physiological characteristics of the immune system. Here, we focus on understanding the metabolic variability of MNPs through metabolic network analysis applied to three large-scale transcriptional datasets: we introduce (1) an ImmGen MNP open-source dataset of 337 samples across 26 tissues; (2) a myeloid subset of ImmGen Phase I dataset (202 MNP samples); and (3) a myeloid mouse single-cell RNA sequencing (scRNA-seq) dataset (51,364 cells) assembled based on Tabula Muris Senis. To analyze such large-scale datasets, we develop a network-based computational approach, genes and metabolites (GAM) clustering, for unbiased identification of the key metabolic subnetworks based on transcriptional profiles. We define 9 metabolic subnetworks that encapsulate the metabolic differences within MNP from 38 different tissues. Obtained modules reveal that cholesterol synthesis appears particularly active within the migratory dendritic cells, while glutathione synthesis is essential for cysteinyl leukotriene production by peritoneal and lung macrophages.

Platelet p110ß mediates platelet-leukocyte interaction and curtails bacterial dissemination in pneumococcal pneumonia.

Phosphatidylinositol 3-kinase catalytic subunit p110ß is involved in tumorigenesis and hemostasis. However, it remains unclear if p110ß also regulates platelet-mediated immune responses, which could have important consequences for immune modulation during anti-cancer treatment with p110ß inhibitors. Thus, we investigate how platelet p110ß affects inflammation and infection. Using a mouse model of Streptococcus pneumoniae-induced pneumonia, we find that both platelet-specific p110ß deficiency and pharmacologic inhibition of p110ß with TGX-221 exacerbate disease pathogenesis by preventing platelet-monocyte and neutrophil interactions, diminishing their infiltration and enhancing bacterial dissemination. Platelet p110ß mediates neutrophil phagocytosis of S. pneumoniae in vitro and curtails bacteremia in vivo. Genetic deficiency or inhibition of platelet p110ß also impairs macrophage recruitment in an independent model of sterile peritonitis. Our results demonstrate that platelet p110ß dysfunction exacerbates pulmonary infection by impeding leukocyte functions. Thereby, our findings provide important insights into the immunomodulatory potential of PI3K inhibitors in bacterial infection.

A neutrophil-B-cell axis impacts tissue damage control in a mouse model of intraabdominal bacterial infection via Cxcr4.

Sepsis is a life-threatening condition characterized by uncontrolled systemic inflammation and coagulation, leading to multiorgan failure. Therapeutic options to prevent sepsis-associated immunopathology remain scarce. Here, we established a mouse model of long-lasting disease tolerance during severe sepsis, manifested by diminished immunothrombosis and organ damage in spite of a high pathogen burden. We found that both neutrophils and B cells emerged as key regulators of tissue integrity. Enduring changes in the transcriptional profile of neutrophils include upregulated Cxcr4 expression in protected, tolerant hosts. Neutrophil Cxcr4 upregulation required the presence of B cells, suggesting that B cells promoted disease tolerance by improving tissue damage control via the suppression of neutrophils' tissue-damaging properties. Finally, therapeutic administration of a Cxcr4 agonist successfully promoted tissue damage control and prevented liver damage during sepsis. Our findings highlight the importance of a critical B-cell/neutrophil interaction during sepsis and establish neutrophil Cxcr4 activation as a potential means to promote disease tolerance during sepsis.

The interaction of CD4+ helper T cells with dendritic cells shapes the tumor microenvironment and immune checkpoint blockade response.

Despite their key regulatory role and therapeutic potency, the molecular signatures of interactions between T cells and antigen-presenting myeloid cells within the tumor microenvironment remain poorly characterized. Here, we systematically characterize these interactions using RNA sequencing of physically interacting cells (PIC-seq) and find that CD4+PD-1+CXCL13+ T cells are a major interacting hub with antigen-presenting cells in the tumor microenvironment of human non-small cell lung carcinoma. We define this clonally expanded, tumor-specific and conserved T-cell subset as T-helper tumor (Tht) cells. Reconstitution of Tht cells in vitro and in an ovalbumin-specific αß TCR CD4+ T-cell mouse model, shows that the Tht program is primed in tumor-draining lymph nodes by dendritic cells presenting tumor antigens, and that their function is important for harnessing the antitumor response of anti-PD-1 treatment. Our molecular and functional findings support the modulation of Tht-dendritic cell interaction checkpoints as a major interventional strategy in immunotherapy.

One year into the SARS-CoV-2 pandemic: perinatal outcome and data on the transmission of 116 pregnant women.

OBJECTIVES: Report of clinical data on maternal outcomes, mode of delivery and immediate neonatal outcome in women infected with COVID-19, as well as clarifying whether the transmission of SARS-CoV-2 could occur in utero (congenital), intrapartum, and/or postnatally through breastmilk, amniotic fluid or cord blood. METHODS: Retrospective data collection. Evidence of vertical transmission was assessed by testing for SARS-CoV-2 in amniotic fluid, cord blood, maternal liquor, breast milk and neonatal pharyngeal swab samples. RESULTS: 8.9% (n=8) of the total population of hospitalized SARS-CoV-2 positive pregnant women were admitted to a critical care unit, one (0.9%) needed extracorporal membrane oxygenation (ECMO) and one woman died (0.9%). The premature birth rate before 34+0 weeks of gestational age of 8.2% (n=8) among pregnant women who tested positive for SARS-CoV-2, was almost four times higher than among the total population of pregnant women in Austria. Two newborns (2%) were tested positive for SARS-CoV-2 after birth. No SARS-CoV-2 was found in amniotic fluid, cord blood, maternal liquor or breast milk using polymerase chain reaction (PCR). CONCLUSIONS: Pregnant women with COVID-19 seem to be at a higher risk of invasive ventilation, admission to a critical care unit and pre-term birth and therefore they should be considered as a high-risk population. The risk of congenital or intrapartal infection seems to be insignificant.

Single-cell analysis of human non-small cell lung cancer lesions refines tumor classification and patient stratification.

Immunotherapy is a mainstay of non-small cell lung cancer (NSCLC) management. While tumor mutational burden (TMB) correlates with response to immunotherapy, little is known about the relationship between the baseline immune response and tumor genotype. Using single-cell RNA sequencing, we profiled 361,929 cells from 35 early-stage NSCLC lesions. We identified a cellular module consisting of PDCD1+CXCL13+ activated T cells, IgG+ plasma cells, and SPP1+ macrophages, referred to as the lung cancer activation module (LCAMhi). We confirmed LCAMhi enrichment in multiple NSCLC cohorts, and paired CITE-seq established an antibody panel to identify LCAMhi lesions. LCAM presence was found to be independent of overall immune cell content and correlated with TMB, cancer testis antigens, and TP53 mutations. High baseline LCAM scores correlated with enhanced NSCLC response to immunotherapy even in patients with above median TMB, suggesting that immune cell composition, while correlated with TMB, may be a nonredundant biomarker of response to immunotherapy.

Supporting the Next Generation of Scientists to Lead Cancer Immunology Research.

Recent success in the use of immunotherapy for a broad range of cancers has propelled the field of cancer immunology to the forefront of cancer research. As more and more young investigators join the community of cancer immunologists, the Arthur L. Irving Family Foundation Cancer Immunology Symposium provided a platform to bring this expanding and vibrant community together and support the development of the future leaders in the field. This commentary outlines the lessons that emerged from the inaugural symposium highlighting the areas of scientific and career development that are essential for professional growth in the field of cancer immunology and beyond. Leading scientists and clinicians in the field provided their experience on the topics of scientific trajectory, career trajectory, publishing, fundraising, leadership, mentoring, and collaboration. Herein, we provide a conceptual and practical framework for career development to the broader scientific community.

Caesarean Section. Guideline of the DGGG, OEGGG and SGGG (S3-Level, AWMF Registry No. 015/084, June 2020).

Purpose This is an official S3-guideline of the German Society of Gynaecology and Obstetrics (DGGG), the Austrian Society of Gynaecology and Obstetrics (ÖGGG) and the Swiss Society of Gynaecology and Obstetrics (SGGG). The guideline contains evidence-based information and recommendations on indications, complications, methods and care associated with delivery by caesarean section for all medical specialties involved as well as for pregnant women. Methods This guideline has adapted information and recommendations issued in the NICE Caesarean Birth guideline. This guideline also considers additional issues prioritised by the Cochrane Institute and the Institute for Research in Operative Medicine (IFOM). The evaluation of evidence was based on the system developed by the Scottish Intercollegiate Guidelines Network (SIGN). A multi-part nominal group process moderated by the AWMF was used to compile this S3-level guideline. Recommendations Recommendations on consultations, indications and the process of performing a caesarean section as well as the care provided to the mother and neonate were drawn up.

[Pain management during pregnancy : An expert-based interdisciplinary consensus recommendation]. / Schmerztherapie in der Schwangerschaft : Eine expertInnenbasierte interdisziplinäre Konsensus-Empfehlung.

BACKGROUND: Pregnancy and pain of different origins is an unfavorable combination that presents all practitioners with special challenges. Pain negatively affects the homeostasis of humans. Patient compliance and in-depth knowledge of the fetotoxicity and teratogenicity of the substances are necessary to maintain a balance between therapy for the mother and safety of the unborn child. OBJECTIVES: Experts from various disciplines who are entrusted with the care of pregnant patients with pain have come together to develop drug and nondrug therapy concepts with the aim of providing adequate analgesia for pregnant pain patients. MATERIALS AND METHODS: Relevant questions were formulated by experts and subjected to a literature search. Combined with further national and international recommendations, treatment concepts were developed and discussed in an interdisciplinary manner. Core statements were then drawn up and given recommendation grades. RESULTS: Depending on the trimester, paracetamol, ibuprofen, diclofenac, metamizole, and opioids can be administered carefully in the event of pain; special care is required with nonsteroidal anti-inflammatory drugs (NSAIDs ) in the last trimester. COX­2 inhibitors are not recommended. For neuropathic pain, amitriptyline, duloxetine, and venlafaxine are considered safe. Non-pharmacological treatment concepts are also available, namely transcutaneous electrical nerve stimulation (TENS therapy), kinesio tapes, and acupuncture. Lymphatic drainage is recommended in cases of edema, if not caused by preeclampsia. CONCLUSIONS: A deliberated concept for pain therapy during pregnancy should be initiated with a non-pharmacological intervention and, if necessary, supplemented with pharmacological agents.

Tissue-resident macrophages provide a pro-tumorigenic niche to early NSCLC cells.

Macrophages have a key role in shaping the tumour microenvironment (TME), tumour immunity and response to immunotherapy, which makes them an important target for cancer treatment1,2. However, modulating macrophages has proved extremely difficult, as we still lack a complete understanding of the molecular and functional diversity of the tumour macrophage compartment. Macrophages arise from two distinct lineages. Tissue-resident macrophages self-renew locally, independent of adult haematopoiesis3-5, whereas short-lived monocyte-derived macrophages arise from adult haematopoietic stem cells, and accumulate mostly in inflamed lesions1. How these macrophage lineages contribute to the TME and cancer progression remains unclear. To explore the diversity of the macrophage compartment in human non-small cell lung carcinoma (NSCLC) lesions, here we performed single-cell RNA sequencing of tumour-associated leukocytes. We identified distinct populations of macrophages that were enriched in human and mouse lung tumours. Using lineage tracing, we discovered that these macrophage populations differ in origin and have a distinct temporal and spatial distribution in the TME. Tissue-resident macrophages accumulate close to tumour cells early during tumour formation to promote epithelial-mesenchymal transition and invasiveness in tumour cells, and they also induce a potent regulatory T cell response that protects tumour cells from adaptive immunity. Depletion of tissue-resident macrophages reduced the numbers and altered the phenotype of regulatory T cells, promoted the accumulation of CD8+ T cells and reduced tumour invasiveness and growth. During tumour growth, tissue-resident macrophages became redistributed at the periphery of the TME, which becomes dominated by monocyte-derived macrophages in both mouse and human NSCLC. This study identifies the contribution of tissue-resident macrophages to early lung cancer and establishes them as a target for the prevention and treatment of early lung cancer lesions.

SARS-CoV-2 in pregnancy: maternal and perinatal outcome data of 34 pregnant women hospitalised between May and October 2020.

OBJECTIVES: To report clinical data on maternal outcome, mode of delivery and immediate neonatal outcome in women infected with COVID-19. METHODS: Retrospective data collection. RESULTS: A total of 8.6% of the total population of hospitalised SARS-CoV-2 positive pregnant women were admitted to a critical care unit. The premature birth rate for births before 34+0 weeks of gestation among pregnant women who tested positive for SARS-CoV-2 was 7.1%. One newborn (3.6%) tested positive for SARS-CoV-2 two days after birth and showed symptoms. CONCLUSIONS: Pregnant women with COVID-19 seem to be at higher risk of invasive ventilation, admission to a critical care unit and preterm birth, and should therefore be considered a high-risk-population.

Squalene emulsion-based vaccine adjuvants stimulate CD8 T cell, but not antibody responses, through a RIPK3-dependent pathway.

The squalene-based oil-in-water emulsion (SE) vaccine adjuvant MF59 has been administered to more than 100 million people in more than 30 countries, in both seasonal and pandemic influenza vaccines. Despite its wide use and efficacy, its mechanisms of action remain unclear. In this study we demonstrate that immunization of mice with MF59 or its mimetic AddaVax (AV) plus soluble antigen results in robust antigen-specific antibody and CD8 T cell responses in lymph nodes and non-lymphoid tissues. Immunization triggered rapid RIPK3-kinase dependent necroptosis in the lymph node which peaked at 6 hr, followed by a sequential wave of apoptosis. Immunization with alum plus antigen did not induce RIPK3-dependent signaling. RIPK3-dependent signaling induced by MF59 or AV was essential for cross-presentation of antigen to CD8 T cells by Batf3-dependent CD8+ DCs. Consistent with this, RIPK3 deficient or Batf3 deficient mice were impaired in their ability to mount adjuvant-enhanced CD8 T cell responses. However, CD8 T cell responses were unaffected in mice deficient in MLKL, a downstream mediator of necroptosis. Surprisingly, antibody responses were unaffected in RIPK3-kinase or Batf3 deficient mice. In contrast, antibody responses were impaired by in vivo administration of the pan-caspase inhibitor Z-VAD-FMK, but normal in caspase-1 deficient mice, suggesting a contribution from apoptotic caspases, in the induction of antibody responses. These results demonstrate that squalene emulsion-based vaccine adjuvants induce antigen-specific CD8 T cell and antibody responses, through RIPK3-dependent and-independent pathways, respectively.

Author Correction: A conserved dendritic-cell regulatory program limits antitumour immunity.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

A conserved dendritic-cell regulatory program limits antitumour immunity.

Checkpoint blockade therapies have improved cancer treatment, but such immunotherapy regimens fail in a large subset of patients. Conventional type 1 dendritic cells (DC1s) control the response to checkpoint blockade in preclinical models and are associated with better overall survival in patients with cancer, reflecting the specialized ability of these cells to prime the responses of CD8+ T cells1-3. Paradoxically, however, DC1s can be found in tumours that resist checkpoint blockade, suggesting that the functions of these cells may be altered in some lesions. Here, using single-cell RNA sequencing in human and mouse non-small-cell lung cancers, we identify a cluster of dendritic cells (DCs) that we name 'mature DCs enriched in immunoregulatory molecules' (mregDCs), owing to their coexpression of immunoregulatory genes (Cd274, Pdcd1lg2 and Cd200) and maturation genes (Cd40, Ccr7 and Il12b). We find that the mregDC program is expressed by canonical DC1s and DC2s upon uptake of tumour antigens. We further find that upregulation of the programmed death ligand 1 protein-a key checkpoint molecule-in mregDCs is induced by the receptor tyrosine kinase AXL, while upregulation of interleukin (IL)-12 depends strictly on interferon-γ and is controlled negatively by IL-4 signalling. Blocking IL-4 enhances IL-12 production by tumour-antigen-bearing mregDC1s, expands the pool of tumour-infiltrating effector T cells and reduces tumour burden. We have therefore uncovered a regulatory module associated with tumour-antigen uptake that reduces DC1 functionality in human and mouse cancers.