Sensitive Detection and Analysis of Neoantigen-Specific T Cell Populations from Tumors and Blood

Neoantigen-specific T cells are increasingly viewed as important immunotherapy effectors, but physically isolating these rare cell populations is challenging. Here, we describe a sensitive method for the enumeration and isolation of neoantigen-specific CD8+ T cells from small samples of patient tumor or blood. The method relies on magnetic nanoparticles that present neoantigen-loaded major histocompatibility complex (MHC) tetramers at high avidity by barcoded DNA linkers. The magnetic particles provide a convenient handle to isolate the desired cell populations, and the barcoded DNA enables multiplexed analysis. The method exhibits superior recovery of antigen-specific T cell populations relative to literature approaches. We applied the method to profile neoantigen-specific T cell populations in the tumor and blood of patients with metastatic melanoma over the course of anti-PD1 checkpoint inhibitor therapy. We show that the method has value for monitoring clinical responses to cancer immunotherapy and might help guide the development of personalized mutational neoantigen-specific T cell therapies and cancer vaccines

Global patient outcomes after elective surgery: prospective cohort study in 27 low-, middle- and high-income countries.

BACKGROUND: As global initiatives increase patient access to surgical treatments, there remains a need to understand the adverse effects of surgery and define appropriate levels of perioperative care. METHODS: We designed a prospective international 7-day cohort study of outcomes following elective adult inpatient surgery in 27 countries. The primary outcome was in-hospital complications. Secondary outcomes were death following a complication (failure to rescue) and death in hospital. Process measures were admission to critical care immediately after surgery or to treat a complication and duration of hospital stay. A single definition of critical care was used for all countries. RESULTS: A total of 474 hospitals in 19 high-, 7 middle- and 1 low-income country were included in the primary analysis. Data included 44 814 patients with a median hospital stay of 4 (range 2-7) days. A total of 7508 patients (16.8%) developed one or more postoperative complication and 207 died (0.5%). The overall mortality among patients who developed complications was 2.8%. Mortality following complications ranged from 2.4% for pulmonary embolism to 43.9% for cardiac arrest. A total of 4360 (9.7%) patients were admitted to a critical care unit as routine immediately after surgery, of whom 2198 (50.4%) developed a complication, with 105 (2.4%) deaths. A total of 1233 patients (16.4%) were admitted to a critical care unit to treat complications, with 119 (9.7%) deaths. Despite lower baseline risk, outcomes were similar in low- and middle-income compared with high-income countries. CONCLUSIONS: Poor patient outcomes are common after inpatient surgery. Global initiatives to increase access to surgical treatments should also address the need for safe perioperative care. STUDY REGISTRATION: ISRCTN5181700

Tetrahydrobiopterin supplementation reduces atherosclerosis and vascular inflammation in apolipoprotein E-knockout mice.

BH4 (tetrahydrobiopterin) supplementation improves endothelial function in models of vascular disease by maintaining eNOS (endothelial nitric oxide synthase) coupling and NO (nitric oxide) bioavailability. However, the cellular mechanisms through which enhanced endothelial function leads to reduced atherosclerosis remain unclear. We have used a pharmaceutical BH4 formulation to investigate the effects of BH4 supplementation on atherosclerosis progression in ApoE-KO (apolipoprotein E-knockout) mice. Single oral dose pharmacokinetic studies revealed rapid BH4 uptake into plasma and organs. Plasma BH4 levels returned to baseline by 8 h after oral dosing, but remained markedly increased in aorta at 24 h. Daily oral BH4 supplementation in ApoE-KO mice from 8 weeks of age, for a period of 8 or 12 weeks, had no effect on plasma lipids or haemodynamic parameters, but significantly reduced aortic root atherosclerosis compared with placebo-treated animals. BH4 supplementation significantly reduced VCAM-1 (vascular cell adhesion molecule 1) mRNA levels in aortic endothelial cells, markedly reduced the infiltration of T-cells, macrophages and monocytes into plaques, and reduced T-cell infiltration in the adjacent adventitia, but importantly had no effect on circulating leucocytes. GCH (GTP cyclohydrolase I)-transgenic mice, with a specific increase in endothelial BH4 levels, exhibited a similar reduction in vascular immune cell infiltration compared with BH4-deficient controls, suggesting that BH4 reduces vascular inflammation via endothelial cell signalling. In conclusion, BH4 supplementation reduces vascular immune cell infiltration in atherosclerosis and may therefore be a rational therapeutic approach to reduce the progression of atherosclerosis