PD-L1 engagement on T cells promotes self-tolerance and suppression of neighboring macrophages and effector T cells in cancer.

Programmed cell death protein 1 (PD-1) ligation delimits immunogenic responses in T cells. However, the consequences of programmed cell death 1 ligand 1 (PD-L1) ligation in T cells are uncertain. We found that T cell expression of PD-L1 in cancer was regulated by tumor antigen and sterile inflammatory cues. PD-L1+ T cells exerted tumor-promoting tolerance via three distinct mechanisms: (1) binding of PD-L1 induced STAT3-dependent 'back-signaling' in CD4+ T cells, which prevented activation, reduced TH1-polarization and directed TH17-differentiation. PD-L1 signaling also induced an anergic T-bet-IFN-γ- phenotype in CD8+ T cells and was equally suppressive compared to PD-1 signaling; (2) PD-L1+ T cells restrained effector T cells via the canonical PD-L1-PD-1 axis and were sufficient to accelerate tumorigenesis, even in the absence of endogenous PD-L1; (3) PD-L1+ T cells engaged PD-1+ macrophages, inducing an alternative M2-like program, which had crippling effects on adaptive antitumor immunity. Collectively, we demonstrate that PD-L1+ T cells have diverse tolerogenic effects on tumor immunity.

One Anastomosis Gastric Bypass for Revisional Bariatric Surgery: Assessment of Short-Term Safety.

PURPOSE: With the continued increase in bariatric procedures being performed in the USA, a growing percentage are revisions for weight regain after sleeve gastrectomy (SG) and gastric banding (LAGB). Standard practice in the USA involves conversion to Roux-en-Y gastric bypass (RYGB). Internationally, one anastomosis gastric bypass (OAGB) has become a popular and effective alternative. Without the jejuno-jejunal anastomosis, OAGB has reduced potential related long-term complications. The purpose of this study is to compare the short-term safety of revision to OAGB versus RYGB. MATERIALS AND METHODS: Patients who underwent conversion to OAGB from LAGB or SG for weight regain from January 2019 to October 2021 were compared to BMI, sex, and age-matched patients who underwent conversion to RYGB. RESULTS: In our study, 82 patients were included, 41 in each cohort (41 OAGB vs. 41 RYGB). The majority in both groups underwent conversion from SG (71% vs. 78%). Operative time, estimated blood loss, and length of stay were comparable. There was no difference in 30-day complications (9.8% vs. 12.2%, p = .99) or reoperation (4.9% vs. 4.9%, p = .99). Mean weight loss at 1 month was also comparable (7.91 lbs vs 6.36 lbs). CONCLUSIONS: Patients undergoing conversion to OAGB for weight regain had similar operative times, post-operative complication rates, and 1-month weight loss compared to those who underwent RYGB. While more research is needed, this early data suggests that OAGB and RYGB provide comparable outcomes when used as conversion procedures for to failed weight loss. Therefore, OAGB may present a safe alternative to RYGB.

BTLA+CD200+ B cells dictate the divergent immune landscape and immunotherapeutic resistance in metastatic vs. primary pancreatic cancer.

Response to cancer immunotherapy in primary versus metastatic disease has not been well-studied. We found primary pancreatic ductal adenocarcinoma (PDA) is responsive to diverse immunotherapies whereas liver metastases are resistant. We discovered divergent immune landscapes in each compartment. Compared to primary tumor, liver metastases in both mice and humans are infiltrated by highly anergic T cells and MHCIIloIL10+ macrophages that are unable to present tumor-antigen. Moreover, a distinctive population of CD24+CD44-CD40- B cells dominate liver metastases. These B cells are recruited to the metastatic milieu by Muc1hiIL18hi tumor cells, which are enriched >10-fold in liver metastases. Recruited B cells drive macrophage-mediated adaptive immune-tolerance via CD200 and BTLA. Depleting B cells or targeting CD200/BTLA enhanced macrophage and T-cell immunogenicity and enabled immunotherapeutic efficacy of liver metastases. Our data detail the mechanistic underpinnings for compartment-specific immunotherapy-responsiveness and suggest that primary PDA models are poor surrogates for evaluating immunity in advanced disease.

The emergency surgery score (ESS) and outcomes in elderly patients undergoing emergency laparotomy: A post-hoc analysis of an EAST multicenter study.

INTRODUCTION: We sought to evaluate whether the Emergency Surgery Score (ESS) can accurately predict outcomes in elderly patients undergoing emergent laparotomy (EL). METHODS: This is a post-hoc analysis of an EAST multicenter study. Between April 2018 and June 2019, all adult patients undergoing EL in 19 participating hospitals were prospectively enrolled, and ESS was calculated for each patient. Using the c-statistic, the correlation between ESS and mortality, morbidity, and need for ICU admission was assessed in three patient age cohorts (65-74, 75-84, ≥85 years old). RESULTS: 715 patients were included, of which 52% were 65-74, 34% were 75-84, and 14% were ≥85 years old; 51% were female, and 77% were white. ESS strongly correlated with postoperative mortality (c-statistic:0.81). Mortality gradually increased from 0% to 20%-60% at ESS of 2, 10 and 16 points, respectively. ESS predicted mortality, morbidity, and need for ICU best in patients 65-74 years old (c-statistic:0.81, 0.75, 0.83 respectively), but its performance significantly decreased in patients ≥85 years (c-statistic:0.72, 0.64, 0.67 respectively). CONCLUSION: ESS is an accurate predictor of outcome in the elderly EL patient 65-85 years old, but its performance decreases for patients ≥85. Consideration should be given to modify ESS to better predict outcomes in the very elderly patient population.

The Emergency Surgery Score accurately predicts the need for postdischarge respiratory and renal support after emergent laparotomies: A prospective EAST multicenter study.

BACKGROUND: The Emergency Surgery Score (ESS) was recently validated as an accurate mortality risk calculator for emergency general surgery. We sought to prospectively evaluate whether ESS can predict the need for respiratory and/or renal support (RRS) at discharge after emergent laparotomies (EL). METHODS: This is a post hoc analysis of a 19-center prospective observational study. Between April 2018 and June 2019, all adult patients undergoing EL were enrolled. Preoperative, intraoperative, and postoperative variables were systematically collected. In this analysis, patients were excluded if they died during the index hospitalization, were discharged to hospice, or transferred to other hospitals. A composite variable, the need for RRS, was defined as the need for one or more of the following at hospital discharge: tracheostomy, ventilator dependence, or dialysis. Emergency Surgery Score was calculated for all patients, and the correlation between ESS and RRS was examined using the c-statistics method. RESULTS: From a total of 1,649 patients, 1,347 were included. Median age was 60 years, 49.4% were men, and 70.9% were White. The most common diagnoses were hollow viscus organ perforation (28.1%) and small bowel obstruction (24.5%); 87 patients (6.5%) had a need for RRS (4.7% tracheostomy, 2.7% dialysis, and 1.3% ventilator dependence). Emergency Surgery Score predicted the need for RRS in a stepwise fashion; for example, 0.7%, 26.2%, and 85.7% of patients required RRS at an ESS of 2, 12, and 16, respectively. The c-statistics for the need for RRS, the need for tracheostomy, ventilator dependence, or dialysis at discharge were 0.84, 0.82, 0.79, and 0.88, respectively. CONCLUSION: Emergency Surgery Score accurately predicts the need for RRS at discharge in EL patients and could be used for preoperative patient counseling and for quality of care benchmarking. LEVEL OF EVIDENCE: Prognostic and epidemiological, level III.

Early Anti-Xa Assay-Guided Low Molecular Weight Heparin Chemoprophylaxis Is Safe in Adult Patients with Acute Traumatic Brain Injury.

This study evaluated the safety of early anti-factor Xa assay-guided enoxaparin dosing for chemoprophylaxis in patients with TBI. We hypothesized that assay-guided chemoprophylaxis would be comparable in the risk of intracranial hemorrhage (ICH) progression to fixed dosing. An observational analysis of adult patients with blunt traumatic brain injury (TBI) was performed at a Level I trauma center from August 2016 to September 2017. Patients in the assay-guided group were treated with an initial enoxaparin dose of 0.5 mg/kg, with peak anti-factor Xa activity measured four hours after the third dose. Prophylactic range was defined as 0.2 to 0.5 IU/mL with a dose adjustment of ± 10 mg based on the assay result. The assay-guided group was compared with historical fixed-dose controls and to a TBI cohort from the most recent Trauma Quality Improvement Project dataset. Of 179 patients included in the study, 85 were in the assay-guided group and 94 were in the fixed-dose group. Compared with the fixed-dose group, the assay-guided group had a lower Glasgow Coma Score and higher Injury Severity Score. The proportion of severe (Abbreviated Injury Score, head ≥3) TBI, ICH progression, and venous thromboembolism rates were similar between all groups. The assay-guided and fixed-dose groups had chemoprophylaxis initiated earlier than the Trauma Quality Improvement Project group. The assay-guided group had the highest percentage of low molecular weight heparin use. Early initiation of enoxaparin anti-factor Xa assay-guided venous thromboembolism chemoprophylaxis has a comparable risk of ICH progression to fixed dosing in patients with TBI. These findings should be validated prospectively in a multicenter study.

Prospective validation of the Emergency Surgery Score in emergency general surgery: An Eastern Association for the Surgery of Trauma multicenter study.

BACKGROUND: The Emergency Surgery Score (ESS) was recently developed and retrospectively validated as an accurate mortality risk calculator for emergency general surgery. We sought to prospectively validate ESS, specifically in the high-risk nontrauma emergency laparotomy (EL) patient. METHODS: This is an Eastern Association for the Surgery of Trauma multicenter prospective observational study. Between April 2018 and June 2019, 19 centers enrolled all adults (aged >18 years) undergoing EL. Preoperative, intraoperative, and postoperative variables were prospectively and systematically collected. Emergency Surgery Score was calculated for each patient and validated using c-statistic methodology by correlating it with three postoperative outcomes: (1) 30-day mortality, (2) 30-day complications (e.g., respiratory/renal failure, infection), and (3) postoperative intensive care unit (ICU) admission. RESULTS: A total of 1,649 patients were included. The mean age was 60.5 years, 50.3% were female, and 71.4% were white. The mean ESS was 6, and the most common indication for EL was hollow viscus perforation. The 30-day mortality and complication rates were 14.8% and 53.3%; 57.0% of patients required ICU admission. Emergency Surgery Score gradually and accurately predicted 30-day mortality; 3.5%, 50.0%, and 85.7% of patients with ESS of 3, 12, and 17 died after surgery, respectively, with a c-statistic of 0.84. Similarly, ESS gradually and accurately predicted complications; 21.0%, 57.1%, and 88.9% of patients with ESS of 1, 6, and 13 developed postoperative complications, with a c-statistic of 0.74. Emergency Surgery Score also accurately predicted which patients required intensive care unit admission (c-statistic, 0.80). CONCLUSION: This is the first prospective multicenter study to validate ESS as an accurate predictor of outcome in the EL patient. Emergency Surgery Score can prove useful for (1) perioperative patient and family counseling, (2) triaging patients to the intensive care unit, and (3) benchmarking the quality of emergency general surgery care. LEVEL OF EVIDENCE: Prognostic study, level III.

Re-programing Chromatin with a Bifunctional LSD1/HDAC Inhibitor Induces Therapeutic Differentiation in DIPG.

H3K27M mutations resulting in epigenetic dysfunction are frequently observed in diffuse intrinsic pontine glioma (DIPGs), an incurable pediatric cancer. We conduct a CRISPR screen revealing that knockout of KDM1A encoding lysine-specific demethylase 1 (LSD1) sensitizes DIPG cells to histone deacetylase (HDAC) inhibitors. Consistently, Corin, a bifunctional inhibitor of HDACs and LSD1, potently inhibits DIPG growth in vitro and in xenografts. Mechanistically, Corin increases H3K27me3 levels suppressed by H3K27M histones, and simultaneously increases HDAC-targeted H3K27ac and LSD1-targeted H3K4me1 at differentiation-associated genes. Corin treatment induces cell death, cell-cycle arrest, and a cellular differentiation phenotype and drives transcriptional changes correlating with increased survival time in DIPG patients. These data suggest a strategy for treating DIPG by simultaneously inhibiting LSD1 and HDACs.

Innate αß T Cells Mediate Antitumor Immunity by Orchestrating Immunogenic Macrophage Programming.

Unconventional T-lymphocyte populations are emerging as important regulators of tumor immunity. Despite this, the role of TCRαß+CD4-CD8-NK1.1- innate αß T cells (iαßT) in pancreatic ductal adenocarcinoma (PDA) has not been explored. We found that iαßTs represent ∼10% of T lymphocytes infiltrating PDA in mice and humans. Intratumoral iαßTs express a distinct T-cell receptor repertoire and profoundly immunogenic phenotype compared with their peripheral counterparts and conventional lymphocytes. iαßTs comprised ∼75% of the total intratumoral IL17+ cells. Moreover, iαßT-cell adoptive transfer is protective in both murine models of PDA and human organotypic systems. We show that iαßT cells induce a CCR5-dependent immunogenic macrophage reprogramming, thereby enabling marked CD4+ and CD8+ T-cell expansion/activation and tumor protection. Collectively, iαßTs govern fundamental intratumoral cross-talk between innate and adaptive immune populations and are attractive therapeutic targets. SIGNIFICANCE: We found that iαßTs are a profoundly activated T-cell subset in PDA that slow tumor growth in murine and human models of disease. iαßTs induce a CCR5-dependent immunogenic tumor-associated macrophage program, T-cell activation and expansion, and should be considered as novel targets for immunotherapy.See related commentary by Banerjee et al., p. 1164.This article is highlighted in the In This Issue feature, p. 1143.