DNGR-1-mediated cross-presentation of dead cell-associated antigens.

Conventional dendritic cells type 1 (cDC1) are critical for inducing protective CD8+ T cell responses to tumour and viral antigens. In many instances, cDC1 access those antigens in the form of material internalised from dying tumour or virally-infected cells. How cDC1 extract dead cell-associated antigens and cross-present them in the form of peptides bound to MHC class I molecules to CD8+ T cells remains unclear. Here we review the biology of dendritic cell natural killer group receptor-1 (DNGR-1; also known as CLEC9A), a C-type lectin receptor highly expressed on cDC1 that plays a key role in this process. We highlight recent advances that support a function for DNGR-1 signalling in promoting inducible rupture of phagocytic or endocytic compartments containing dead cell debris, thereby making dead cell-associated antigens accessible to the endogenous MHC class I processing and presentation machinery of cDC1. We further review how DNGR-1 detects dead cells, as well as the functions of the receptor in anti-viral and anti-tumour immunity. Finally, we highlight how the study of DNGR-1 has opened new perspectives into cross-presentation, some of which may have applications in immunotherapy of cancer and vaccination against viral diseases.

N-acetyl-cysteine in Intensive Care Unit Patients with Acute Respiratory Distress Syndrome due to COVID-19: A Retrospective Cohort Study.

PURPOSE: We assessed the potential association between N-acetyl-cysteine (NAC) and clinical outcomes in critically ill subjects with COVID-19-related ARDS. MATERIAL AND METHODS: We included subjects with confirmed COVID-19 who were admitted to our ICU between March 1, 2020, and January 31, 2021, due to ARDS and necessitating invasive mechanical ventilation (IMV). Subjects who received standard of care (SOC) were compared with subjects who additionally received NAC 600 mg bid orally. RESULTS: A total of 243 subjects were included in this study. The results indicate significantly improved survival rates in the NAC plus SOC group, both in the unadjusted analysis and after adjusting for confounding factors such as ARDS severity (HR 0.48, 95% CI 0.32-0.70). CONCLUSIONS: We found that oral administration of NAC was associated with reduced mortality in critically ill patients with COVID-19 related ARDS.

Procalcitonin and High APACHE (Acute Physiological and Chronic Health Evaluation) Level Are Associated with the Course of Acute Kidney Injury in Patients with SARS-CoV-2.

Background: Acute kidney injury (AKI) is associated with poor outcomes in patients infected with SARS-CoV-2. Sepsis, direct injury to kidney cells by the virus, and severe systemic inflammation are mechanisms implicated in its development. We investigated the association between inflammatory markers (C-reactive protein, procalcitonin, D-dimer, lactate dehydrogenase, and ferritin) in patients infected with SARS-CoV-2 and the development of AKI. Methods: A prospective cohort study performed at the Civil Hospital (Dr. Juan I. Menchaca) Guadalajara, Mexico, included patients aged >18 years with a diagnosis of SARS-CoV-2 pneumonia confirmed by RT-PCR and who did or did not present with AKI (KDIGO) while hospitalized. Biomarkers of inflammation were recorded, and kidney function was estimated using the CKD-EPI formula. Results: 291 patients were included (68% males; average age, 57 years). The incidence of AKI was 40.5% (118 patients); 21% developed stage 1 AKI, 6% developed stage 2 AKI, and 14% developed stage 3 AKI. The development of AKI was associated with higher phosphate (p = 0.002) (RR 1.39, CI 95% 1.13-1.72), high procalcitonin levels at hospital admission (p = 0.005) (RR 2.09, CI 95% 1.26-3.50), and high APACHE scores (p = 0.011) (RR 2.0, CI 95% 1.17-3.40). The survival analysis free of AKI according to procalcitonin levels and APACHE scores demonstrated a lower survival in patients with procalcitonin >0.5 ng/ml (p = 0.001) and APACHE >15 points (p = 0.004). Conclusions: Phosphate, high procalcitonin levels, and APACHE levels >15 were predictors of AKI development in patients hospitalized with COVID-19.

Subcutaneous rapid-acting insulin analogues for diabetic ketoacidosis.

BACKGROUND: Diabetic ketoacidosis (DKA) is an acute, life-threatening complication of uncontrolled diabetes that mainly occurs in individuals with autoimmune type 1 diabetes, but it is not uncommon in some people with type 2 diabetes. The treatment of DKA is traditionally accomplished by the administration of intravenous infusion of regular insulin that is initiated in the emergency department and continued in an intensive care unit or a high-dependency unit environment. It is unclear whether people with DKA should be treated with other treatment modalities such as subcutaneous rapid-acting insulin analogues. OBJECTIVES: To assess the effects of subcutaneous rapid-acting insulin analogues for the treatment of diabetic ketoacidosis. SEARCH METHODS: We identified eligible trials by searching MEDLINE, PubMed, EMBASE, LILACS, CINAHL, and the Cochrane Library. We searched the trials registers WHO ICTRP Search Portal and ClinicalTrials.gov. The date of last search for all databases was 27 October 2015. We also examined reference lists of included randomised controlled trials (RCTs) and systematic reviews, and contacted trial authors. SELECTION CRITERIA: We included trials if they were RCTs comparing subcutaneous rapid-acting insulin analogues versus standard intravenous infusion in participants with DKA of any age or sex with type 1 or type 2 diabetes, and in pregnant women. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data, assessed studies for risk of bias, and evaluated overall study quality utilising the GRADE instrument. We assessed the statistical heterogeneity of included studies by visually inspecting forest plots and quantifying the diversity using the I² statistic. We synthesised data using random-effects model meta-analysis or descriptive analysis, as appropriate. MAIN RESULTS: Five trials randomised 201 participants (110 participants to subcutaneous rapid-acting insulin analogues and 91 to intravenous regular insulin). The criteria for DKA were consistent with the American Diabetes Association criteria for mild or moderate DKA. The underlying cause of DKA was mostly poor compliance with diabetes therapy. Most trials did not report on type of diabetes. Younger diabetic participants and children were underrepresented in our included trials (one trial only). Four trials evaluated the effects of the rapid-acting insulin analogue lispro, and one the effects of the rapid-acting insulin analogue aspart. The mean follow-up period as measured by mean hospital stay ranged between two and seven days. Overall, risk of bias of the evaluated trials was unclear in many domains and high for performance bias for the outcome measure time to resolution of DKA.No deaths were reported in the included trials (186 participants; 3 trials; moderate- (insulin lispro) to low-quality evidence (insulin aspart)). There was very low-quality evidence to evaluate the effects of subcutaneous insulin lispro versus intravenous regular insulin on the time to resolution of DKA: mean difference (MD) 0.2 h (95% CI -1.7 to 2.1); P = 0.81; 90 participants; 2 trials. In one trial involving children with DKA, the time to reach a glucose level of 250 mg/dL was similar between insulin lispro and intravenous regular insulin. There was very low-quality evidence to evaluate the effects of subcutaneous insulin aspart versus intravenous regular insulin on the time to resolution of DKA: MD -1 h (95% CI -3.2 to 1.2); P = 0.36; 30 participants; 1 trial. There was low-quality evidence to evaluate the effects of subcutaneous rapid-acting insulin analogues versus intravenous regular insulin on hypoglycaemic episodes: 6 of 80 insulin lispro-treated participants compared with 9 of 76 regular insulin-treated participants reported hypoglycaemic events; risk ratio (RR) 0.59 (95% CI 0.23 to 1.52); P = 0.28; 156 participants; 4 trials. For insulin aspart compared with regular insulin, RR for hypoglycaemic episodes was 1.00 (95% CI 0.07 to 14.55); P = 1.0; 30 participants; 1 trial; low-quality evidence. Socioeconomic effects as measured by length of mean hospital stay for insulin lispro compared with regular insulin showed a MD of -0.4 days (95% CI -1 to 0.2); P = 0.22; 90 participants; 2 trials; low-quality evidence and for insulin aspart compared with regular insulin 1.1 days (95% CI -3.3 to 1.1); P = 0.32; low-quality evidence. Data on morbidity were limited, but no specific events were reported for the comparison of insulin lispro with regular insulin. No trial reported on adverse events other than hypoglycaemic episodes, and no trial investigated patient satisfaction. AUTHORS' CONCLUSIONS: Our review, which provided mainly data on adults, suggests on the basis of mostly low- to very low-quality evidence that there are neither advantages nor disadvantages when comparing the effects of subcutaneous rapid-acting insulin analogues versus intravenous regular insulin for treating mild or moderate DKA.

Heparin versus placebo for non-ST elevation acute coronary syndromes.

BACKGROUND: Non-ST elevation acute coronary syndromes (NSTEACS) represent a spectrum of disease including unstable angina and non-ST segment myocardial infarction (NSTEMI). Despite treatment with aspirin, beta-blockers and nitroglycerin, unstable angina/NSTEMI is still associated with significant morbidity and mortality. Although evidence suggests that low molecular weight heparin (LMWH) is more efficacious compared to unfractionated heparin (UFH), there is limited data to support the role of heparins as a drug class in the treatment of NSTEACS. This is an update of a review last published in 2008. OBJECTIVES: To determine the effect of heparins (UFH and LMWH) compared with placebo for the treatment of patients with non-ST elevation acute coronary syndromes (unstable angina or NSTEMI). SEARCH METHODS: For this update the Cochrane Heart Group Trials Search Co-ordinator searched the Cochrane Central Register of Controlled Trials on The Cochrane Library (2013, Issue 12), MEDLINE (OVID, 1946 to January week 1 2014), EMBASE (OVID, 1947 to 2014 week 02), CINAHL (1937 to 15 January 2014) and LILACS (1982 to 15 January 2014). We applied no language restrictions. SELECTION CRITERIA: Randomized controlled trials of parenteral UFH or LMWH versus placebo in people with non-ST elevation acute coronary syndromes (unstable angina or NSTEMI). DATA COLLECTION AND ANALYSIS: Two review authors independently assessed quality of studies and independently extracted data. MAIN RESULTS: There were no new included studies for this update. Eight studies (3118 participants) were included in this review. We found no evidence for difference in overall mortality between the groups treated with heparin and placebo (risk ratio (RR) = 0.84, 95% confidence interval (CI) 0.36 to 1.98). Heparins compared with placebo, reduced the occurrence of myocardial infarction in patients with unstable angina and NSTEMI (RR = 0.40, 95% CI 0.25 to 0.63, number needed to benefit (NNTB) = 33). There was a trend towards more major bleeds in the heparin studies compared to control studies (RR = 2.05, 95% CI 0.91 to 4.60). From a limited data set, there appeared to be no difference between patients treated with heparins compared to control in the occurrence of thrombocytopenia (RR = 0.20, 95% CI 0.01 to 4.24). Assessment of overall risk of bias in these studies was limited as most of the studies did not give sufficient detail to allow assessment of potential risk of bias. AUTHORS' CONCLUSIONS: Compared with placebo, patients treated with heparins had a similar risk of mortality, revascularization, recurrent angina, and thrombocytopenia. However, those treated with heparins had a decreased risk of myocardial infarction and a higher incidence of minor bleeding. Overall, the evidence assessed in this review was classified as low quality according to the GRADE approach. The results presented in this review must therefore be interpreted with caution.

Low-Dose Thymoglobulin versus Basiliximab Induction Therapy in Low-Risk Living Related Kidney Transplant Recipients: Three-Year Follow-Up Study.

BACKGROUND: The optimal dose of rabbit anti-thymocyte globulin (r-ATG) in renal transplantation is still under debate. We previously reported that a low-dose r-ATG induction of 3 mg/kg can be used safely and effectively in low-risk kidney transplants with good results in the first year after transplantation compared to basiliximab induction. AIMS: The purpose of this study is to evaluate the long-term impact of this trial of low-dose r-ATG versus basiliximab on post-transplant outcomes (patient and graft survival, biopsy-proven acute rejection incidence [BPAR], infectious complications, and side effects). METHODS: Observational study (three-year follow-up) of a 12-month single-center, open-label RCT in de novo kidney allograft recipients assigned to receive either thymoglobulin or basiliximab before transplantation. RESULTS: Patients in the basiliximab group (BG) underwent more kidney transplant biopsies than patients in the low-dose r-ATG group (TG) (50 vs. 31.8%, p = 0.07). Although the 12-month cumulative incidence of BPAR was lower in BG, by the end of the three-year follow-up period this incidence was higher (22%) than in the low-dose TG (15%) (p = ns). Steroids were withdrawn more frequently in the TG group and sirolimus was most frequently indicated. Graft function and graft survival were higher in the low-dose TG than in the BG at three-year follow-up but not statistically significant. Patient survival was similar between groups (>90%). CONCLUSIONS: These three-year follow-up data confirm the efficacy and favorable safety aspects of the low-dose r-ATG (3 mg/kg) in low-risk kidney transplantation.

Hyperstabilization of T cell microvilli contacts by chimeric antigen receptors.

T cells typically recognize their ligands using a defined cell biology-the scanning of their membrane microvilli (MV) to palpate their environment-while that same membrane scaffolds T cell receptors (TCRs) that can signal upon ligand binding. Chimeric antigen receptors (CARs) present both a therapeutic promise and a tractable means to study the interplay between receptor affinity, MV dynamics and T cell function. CARs are often built using single-chain variable fragments (scFvs) with far greater affinity than that of natural TCRs. We used high-resolution lattice lightsheet (LLS) and total internal reflection fluorescence (TIRF) imaging to visualize MV scanning in the context of variations in CAR design. This demonstrated that conventional CARs hyper-stabilized microvillar contacts relative to TCRs. Reducing receptor affinity, antigen density, and/or multiplicity of receptor binding sites normalized microvillar dynamics and synapse resolution, and effector functions improved with reduced affinity and/or antigen density, highlighting the importance of understanding the underlying cell biology when designing receptors for optimal antigen engagement.

SYK ubiquitination by CBL E3 ligases restrains cross-presentation of dead cell-associated antigens by type 1 dendritic cells.

Cross-presentation of dead cell-associated antigens by conventional dendritic cells type 1 (cDC1s) is critical for CD8+ T cells response against many tumors and viral infections. It is facilitated by DNGR-1 (CLEC9A), an SYK-coupled cDC1 receptor that detects dead cell debris. Here, we report that DNGR-1 engagement leads to rapid activation of CBL and CBL-B E3 ligases to cause K63-linked ubiquitination of SYK and terminate signaling. Genetic deletion of CBL E3 ligases or charge-conserved mutation of target lysines within SYK abolishes SYK ubiquitination and results in enhanced DNGR-1-dependent antigen cross-presentation. We also find that cDC1 deficient in CBL E3 ligases are more efficient at cross-priming CD8+ T cells to dead cell-associated antigens and promoting host resistance to tumors. Our findings reveal a role for CBL-dependent ubiquitination in limiting cross-presentation of dead cell-associated antigens and highlight an axis of negative regulation of cDC1 activity that could be exploited to increase anti-tumor immunity.

IL-31-dependent neurogenic inflammation restrains cutaneous type 2 immune response in allergic dermatitis.

Despite robust literature associating IL-31 with pruritic inflammatory skin diseases, its influence on cutaneous inflammation and the interplay between inflammatory and neurosensory pathways remain unmapped. Here, we examined the consequences of disrupting Il31 and its receptor Il31ra in a mouse model of house dust mite (HDM)-induced allergic dermatitis. Il31-deficient mice displayed a deficit in HDM dermatitis-associated scratching, consistent with its well-established role as a pruritogen. In contrast, Il31 deficiency increased the number and proportion of cutaneous type 2 cytokine-producing CD4+ T cells and serum IgE in response to HDM. Furthermore, Il4ra+ monocytes and macrophages capable of fueling a feedforward type 2 inflammatory loop were selectively enriched in Il31ra-deficient HDM dermatitis skin. Thus, IL-31 is not strictly a proinflammatory cytokine but rather an immunoregulatory factor that limits the magnitude of type 2 inflammatory responses in skin. Our data support a model wherein IL-31 activation of IL31RA+ pruritoceptors triggers release of calcitonin gene-related protein (CGRP), which can mediate neurogenic inflammation, inhibit CD4+ T cell proliferation, and reduce T cell production of the type 2 cytokine IL-13. Together, these results illustrate a previously unrecognized neuroimmune pathway that constrains type 2 tissue inflammation in the setting of chronic cutaneous allergen exposure and may explain paradoxical dermatitis flares in atopic patients treated with anti-IL31RA therapy.