Prognostic impact of postoperative management by an intensive care unit intensivist after colonic perforation.

PURPOSE: Postoperative management for colonic perforation is an important prognostic factor, but whether intensivists perform postoperative management varies between institutions. METHODS: We investigated 291 patients with colonic perforation between 2018 and 2022. Patients were divided into those managed by an intensivists (ICU group; n = 40) and those not managed by an intensivists (non-ICU group; n = 251). We examined how management by intensivists affected prognosis using inverse probability weighting, and clarified which patients should consult an intensivists. RESULTS: The ICU group showed a significantly higher shock index (1.15 vs. 0.75, p < 0.01), higher APACHE II score (16.0 vs. 10.0, p < 0.001), and more severe comorbidities (Charlson Comorbidity Index 5.0 vs. 1.0, p < 0.001) and general peritonitis (85% vs. 38%, p < 0.001). Adjusted risk differences were - 24% (-34% to -13%) for 6-month mortality rate. Six-month mortality was improved by ICU intensivist management in patients with general peritonitis (risk difference - 22.8; 95% confidence interval - 34 to -11); APACHE II score ≥20 (-0.79; -1.06 to -0.52); lactate ≥1.6 (-0.38; -0.57 to -0.29); shock index ≥1.0 (-40.01; -54.87 to -25.16); and catecholamine index ≥10 (-41.16; -58.13 to -24.19). CONCLUSIONS: Intensivists were involved in treating patients in poor general condition, but prognosis was extremely good. Appropriate case consultation with intensivists is important.

Ebi3 Binding to IFN-γ and IL-10 Limits Their Function.

EBV-induced gene 3 (Ebi3) is a ß subunit within the IL-12 cytokine family that canonically binds to α subunits p19, p28, or p35 to form the heterodimeric cytokines IL-39, IL-27, and IL-35, respectively. In the last decade, the binding partners for Ebi3 have continued to expand to include IL-6 and the other IL-12 family ß subunit p40, revealing the possibility that Ebi3 may be able to bind to other cytokines and have distinct functions. We first explored this possibility utilizing an in vivo mouse model of regulatory T cell-restricted deletions of the subunits composing the cytokine IL-35, p35, and Ebi3, and we observed a differential impact on CD8+ T cell inhibitory receptor expression despite comparable reduction in tumor growth. We then screened the ability of Ebi3 to bind to different cytokines with varying structural resemblance to the IL-12 family α subunits. These in vitro screens revealed extracellular binding of Ebi3 to both IFN-γ and IL-10. Ebi3 bound to IFN-γ and IL-10 abrogated signal transduction and downstream functions of both cytokines. Lastly, we validated that extracellular complex formation after mixing native proteins resulted in loss of function. These data suggest that secreted partnerless Ebi3 may bind to cytokines within the extracellular microenvironment and act as a cytokine sink, further expanding the potential immunological impact of Ebi3.

In Situ Formation of Highly Durable Subnanometer Platinum Particle Electrocatalysts for Polymer Electrolyte Fuel Cells.

The durability of Pt nanoparticle catalysts is currently the most important factor limiting the widespread use of polymer electrolyte fuel cells (PEFCs). Specifically, the Pt nanoparticles in standard carbon black-supported Pt nanoparticle (Pt/CB) catalysts repeatedly aggregate on the CB surfaces during PEFC operation, thus, reducing the performance of the cell. Therefore, PEFCs must contain large quantities of Pt to maintain sufficient service lifetimes. This is the main factor hindering the reduction of the cost of PEFCs. The present research demonstrates that ultrafine Pt particles (Ptsubnanoes) having diameters of approximately 0.5 nm can be formed in situ from a platinum chloride complex (PtCl n ) on a carbon-based material doped with Fe and N via the dissolution and reprecipitation of Pt in the PtCl n during potential cycling in a 0.1 M HClO4 solution. The Ptsubnanoes are immobilized by both Fe and N in the support material. The mass-based catalytic activity of this material during the oxygen reduction reaction is eight times higher than that of a standard Pt/CB catalyst and is maintained even after 100,000 potential step cycles (0.6 ↔ 1.0 V). The present results provide guidelines for the development of highly durable yet active membrane electrode assemblies that minimize the use of Pt.

Procalcitonin, brain natriuretic peptide and albumin as markers to predict prognosis in hospitalized older Japanese patients with a risk of infection.

AIM: Whether serum concentration of procalcitonin (PCT), brain natriuretic peptide (BNP) and albumin (Alb) have an association with the outcome of hospitalized older patients is unclear. We investigated clinical outcomes and any predictive factors in hospitalized Japanese older patients with a risk of infection. METHODS: In the retrospective study, 820 Japanese patients were followed up for 30 days or until death. During the observation period, 656 patients survived and 164 patients died. The predictive factors of death were analyzed according to demographic and clinical variables. RESULTS: The survival rate was decreased as the serum PCT increased from <0.5 to ≥10 ng/mL, as was also the case with BNP from <300 to ≥300 pg./mL, whereas low Alb (<2.5 g/dL) showed a lower survival rate than high Alb (≥2.5 g/dL; P < 0.01). Using the Cox regression model, the multivariable-adjusted hazard ratios (95% confidence interval) were as follows: PCT 0.5-2 versus <0.5 ng/mL: 1.61(1.04-2.49), PCT 2-10 versus <0.5 ng/mL: 1.91(1.15-3.16), PCT ≥10 versus <0.5 ng/mL: 2.90(1.84-4.59), high BNP 1.26 (0.89-1.76) and low Alb 0.68 (0.52-0.87). The mortality rate increased as the number of scores (PCT + BNP + Alb) increased. CONCLUSIONS: Concentration-dependent high PCT, high BNP and low Alb were positive risk factors associated with poor prognosis in hospitalized older patients with a risk of infection. Geriatr Gerontol Int 2024; 24: 571-576.

Association between human epidermal growth factor receptor 2 status, namely low and zero expression, and prognosis in hormone receptor-positive breast cancer: a single-center retrospective study.

Background: The recently developed anti-human epidermal growth factor receptor 2 (HER2) therapy has substantially improved the prognosis of HER2-positive breast cancer. The DESTINY-Breast04 trial results showed that trastuzumab deruxtecan (T-DXd) significantly prolonged the survival of patients with HER2-low breast cancer, thus presenting a paradigm shift in anti-HER2 therapy. This may facilitate a change in the treatment strategy for HER2-low breast cancer. However, the implication of HER2-low in hormone receptor (HR)-positive breast cancer is unclear. In this retrospective study, we aimed to reveal the association between HER2 status, namely HER2-low and HER2-zero, and prognosis in HR-positive breast cancer. Methods: We collected the data of 247 patients with estrogen receptor (ER)-positive/HER2-negative breast cancer (159 with HER2-low and 88 with HER2-zero breast cancer) who underwent surgery. Patients were divided into HER2-low and HER2-zero groups. Univariate analysis was performed to evaluate the baseline characteristics using the Wilcoxon rank sum test and Fisher's exact test. Survival analysis of the HER2-low and HER2-zero groups was performed using the Kaplan-Meier method. Results: The median observation period was 2,706 days, and the median period until recurrence was 1,380 days; 25 patients (10%) had recurrences. Age (P=0.004) and menopausal status (P=0.04) were significant variables in the univariate analysis of baseline characteristics. In the subgroup analysis of luminal A- and B-like breast cancers, there was a significant difference in overall survival (OS) only in patients with luminal A-like breast cancer, but relapse-free survival (RFS) of the HER2-low luminal B-like cancer subgroups tended to be relatively short. Conclusions: We inferred that the HER2-low and HER2-zero statuses do not affect the RFS and OS of patients with ER-positive breast cancer. The prognostic significance of HER2-low or HER2-zero status in luminal A- and B-like breast cancers might differ, and a new treatment strategy is required for the HER2-low subgroup.

Dietary fiber is a critical determinant of pathologic ILC2 responses and intestinal inflammation.

Innate lymphoid cells (ILCs) can promote host defense, chronic inflammation, or tissue protection and are regulated by cytokines and neuropeptides. However, their regulation by diet and microbiota-derived signals remains unclear. We show that an inulin fiber diet promotes Tph1-expressing inflammatory ILC2s (ILC2INFLAM) in the colon, which produce IL-5 but not tissue-protective amphiregulin (AREG), resulting in the accumulation of eosinophils. This exacerbates inflammation in a murine model of intestinal damage and inflammation in an ILC2- and eosinophil-dependent manner. Mechanistically, the inulin fiber diet elevated microbiota-derived bile acids, including cholic acid (CA) that induced expression of ILC2-activating IL-33. In IBD patients, bile acids, their receptor farnesoid X receptor (FXR), IL-33, and eosinophils were all upregulated compared with controls, implicating this diet-microbiota-ILC2 axis in human IBD pathogenesis. Together, these data reveal that dietary fiber-induced changes in microbial metabolites operate as a rheostat that governs protective versus pathologic ILC2 responses with relevance to precision nutrition for inflammatory diseases.

Risk factors for infection of totally implantable central venous access ports among patients requiring port removal.

BACKGROUND: Totally implantable central venous access ports, are required for various purposes, ranging from chemotherapy to nutrition. Port infection is a common complication. In many patients with port infection, the ports are removed because antibiotics are ineffective. We evaluated the risk factors associated with port removal due to port infection. METHODS: By retrospective chart review, we collected data of 223 patients who underwent port removal for any reason. Port infection was defined as infection symptoms, such as fever; elevated white blood cell counts or C-reactive protein levels; or redness at the port site, in the absence of other infections, which improved with port removal. The characteristics of patients with or without port infection were compared using univariate (chi-squared test, t-test) and multivariate logistic regression analyses. RESULTS: We compared 172 patients without port infection to 51 patients with port infection. Univariate analysis identified sex (p = 0.01), body mass index (BMI) ⩽20 kg/m2 (p = 0.00004), diabetes mellitus (p = 0.04), and purpose of use (p = 0.0000003) as significant variables. However, male sex (p = 0.03, 95% confidence interval [CI]: 0.01-0.23), BMI ⩽20 kg m2 (p = 0.002, 95% CI: 0.06-0.29), and purpose of use (total parenteral nutrition (TPN); p = 0.000005, 95% CI: 0.31-0.76) remained significant using multivariate analysis. Moreover, the patients with short bowel syndrome and difficulty in oral intake tended to be infected easily. Additionally, Staphylococcus species were the most common microbes involved in port infection. CONCLUSIONS: Male sex, BMI ⩽20 kg/m2, and purpose of use as a TPN were risk factors for port infection. Ports should not be used for long duration of TPN or used only in exceptional cases.

Sensory neurons promote immune homeostasis in the lung.

Cytokines employ downstream Janus kinases (JAKs) to promote chronic inflammatory diseases. JAK1-dependent type 2 cytokines drive allergic inflammation, and patients with JAK1 gain-of-function (GoF) variants develop atopic dermatitis (AD) and asthma. To explore tissue-specific functions, we inserted a human JAK1 GoF variant (JAK1GoF) into mice and observed the development of spontaneous AD-like skin disease but unexpected resistance to lung inflammation when JAK1GoF expression was restricted to the stroma. We identified a previously unrecognized role for JAK1 in vagal sensory neurons in suppressing airway inflammation. Additionally, expression of Calcb/CGRPß was dependent on JAK1 in the vagus nerve, and CGRPß suppressed group 2 innate lymphoid cell function and allergic airway inflammation. Our findings reveal evolutionarily conserved but distinct functions of JAK1 in sensory neurons across tissues. This biology raises the possibility that therapeutic JAK inhibitors may be further optimized for tissue-specific efficacy to enhance precision medicine in the future.

EFFICACY AND SAFETY OF A DEXAMETHASONE-BASED MOUTHWASH TO PREVENT CHEMOTHERAPY-INDUCED STOMATITIS IN WOMEN WITH BREAST CANCER: A MULTICENTRE, OPEN-LABEL, RANDOMISED PHASE 2 STUDY.

PURPOSE: No standard approach other than oral care is available for preventing chemotherapy-induced stomatitis in patients with breast cancer. In this randomized, controlled phase 2 trial, we aimed to assess the efficacy and safety of a dexamethasone-based mouthwash in preventing chemotherapy-induced stomatitis in patients with early breast cancer. BASIC PROCEDURES: Patients with breast cancer scheduled for epirubicin and cyclophosphamide (EC) or docetaxel and cyclophosphamide (TC) therapy were selected and allocated in a 1:1 ratio to the intervention and control groups. The intervention group received chemotherapy, oral care, and a dexamethasone-based mouthwash, whereas the control group received chemotherapy and oral care. The primary endpoint was the incidence of stomatitis. This was a phase 2 study, and the significance level for the analysis of the primary endpoint was set a priori at 0.2. MAIN FINDINGS: Data pertaining to 58 patients in the control group and 59 patients in the intervention group were analyzed. Stomatitis incidence was 55% and 38% in the control and intervention groups, respectively (risk ratio, 0.68; 80% confidence interval, 0.52-0.88; P = .052). Stomatitis severity was lower in the intervention group than in the control group (P = .03). The proportion of patients who adhered to the mouthwash regimen was 87% (interquartile range, 67.8%-95.3%). No severe oral infections were observed. PRINCIPAL CONCLUSIONS: The dexamethasone-based mouthwash safely reduced stomatitis incidence and severity in patients receiving chemotherapy for early breast cancer. Phase 3 clinical trials are warranted for validating our results.

Respiratory support with nasal high flow without supplemental oxygen in patients undergoing endoscopic retrograde cholangiopancreatography under moderate sedation: a prospective, randomized, single-center clinical trial.

BACKGROUND: Nasal high flow (NHF) may reduce hypoxia and hypercapnia during an endoscopic retrograde cholangiopancreatography (ERCP) procedure under sedation. The authors tested a hypothesis that NHF with room air during ERCP may prevent intraoperative hypercapnia and hypoxemia. METHODS: In the prospective, open-label, single-center, clinical trial, 75 patients undergoing ERCP performed with moderate sedation were randomized to receive NHF with room air (40 to 60 L/min, n = 37) or low-flow O2 via a nasal cannula (1 to 2 L/min, n = 38) during the procedure. Transcutaneous CO2, peripheral arterial O2 saturation, a dose of administered sedative and analgesics were measured. RESULTS: The primary outcome was the incidence of marked hypercapnia during an ERCP procedure under sedation observed in 1 patient (2.7%) in the NHF group and in 7 patients (18.4%) in the LFO group; statistical significance was found in the risk difference (-15.7%, 95% CI -29.1 - -2.4, p = 0.021) but not in the risk ratio (0.15, 95% CI 0.02 - 1.13, p = 0.066). In secondary outcome analysis, the mean time-weighted total PtcCO2 was 47.2 mmHg in the NHF group and 48.2 mmHg in the LFO group, with no significant difference (-0.97, 95% CI -3.35 - 1.41, p = 0.421). The duration of hypercapnia did not differ markedly between the two groups either [median (range) in the NHF group: 7 (0 - 99); median (range) in the LFO group: 14.5 (0 - 206); p = 0.313] and the occurrence of hypoxemia during an ERCP procedure under sedation was observed in 3 patients (8.1%) in the NHF group and 2 patients (5.3%) in the LFO group, with no significant difference (p = 0.674). CONCLUSIONS: Respiratory support by NHF with room air did not reduce marked hypercapnia during ERCP under sedation relative to LFO. There was no significant difference in the occurrence of hypoxemia between the groups that may indicate an improvement of gas exchanges by NHF. TRIAL REGISTRATION: jRCTs072190021 . The full date of first registration on jRCT: August 26, 2019.

Impacts of trans-anal tube placement in patients with sigmoid colon cancer: Risk verification analysis using inverse probability weighting analysis.

Purpose: Anastomotic leakage (AL) is a serious postoperative complication that affects short- and long-term outcomes. The use of a trans-anal drainage tube (TDT) is reported to prevent AL in rectal cancer patients, but its value in sigmoid colon cancer patients is unknown. Methods: Admitted to the study were 379 patients who underwent surgery for sigmoid colon cancer between 2016 and 2020. Patients were divided into two groups according to the placement (n = 197) or nonplacement of a TDT (n = 182). To determine the factors affecting the association between TDT placement and AL, we estimated average treatment effects by stratifying each factor using the inverse probability of treatment weighting method. The association between prognosis and AL was evaluated in each identified factor. Results: Factors associated with postsurgical insertion of a TDT were advanced age, male sex, high body mass index (BMI), poor performance status, and presence of comorbidities. TDT placement was associated with a significantly lower AL in male patients (odds ratio [OR], 0.22; 95% confidence interval [CI], 0.07-0.73; P = .013) and for BMI ≥ 25 kg/m2 (OR, 0.13; 95% CI, 0.02-0.65; P = .013). In addition, there was a significant association of AL with poor prognosis in patients with BMI ≥ 25 kg/m2 (P = .043), age > 75 y (P = .021), and pathological node-positive disease (P = .015). Conclusion: Sigmoid colon cancer patients with BMI ≥ 25 kg/m2 are the most appropriate candidates for postoperative TDT insertion, in terms of reduced incidence of AL and improved prognosis.

Droplet-based forward genetic screening of astrocyte-microglia cross-talk.

Cell-cell interactions in the central nervous system play important roles in neurologic diseases. However, little is known about the specific molecular pathways involved, and methods for their systematic identification are limited. Here, we developed a forward genetic screening platform that combines CRISPR-Cas9 perturbations, cell coculture in picoliter droplets, and microfluidic-based fluorescence-activated droplet sorting to identify mechanisms of cell-cell communication. We used SPEAC-seq (systematic perturbation of encapsulated associated cells followed by sequencing), in combination with in vivo genetic perturbations, to identify microglia-produced amphiregulin as a suppressor of disease-promoting astrocyte responses in multiple sclerosis preclinical models and clinical samples. Thus, SPEAC-seq enables the high-throughput systematic identification of cell-cell communication mechanisms.

Evaluation of efficacy and safety of lascufloxacin for nursing and healthcare associated pneumonia: single-arm, open-label clinical trial: A study protocol.

BACKGROUND: Lascufloxacin hydrochloride (LSFX) is a quinolone antibiotic that inhibits DNA gyrase and topoisomerase IV of bacteria, it is anticipated to minimize antibiotic resistance in bacteria. It exhibits antibacterial activity against a relatively wide range of bacterial species, including anaerobic bacteria, and its efficacy and safety against community-acquired pneumonia have been shown; however, its efficacy and safety against nursing and healthcare associated pneumonia (NHCAP) have not been verified. METHODS/DESIGN: Here, a single-arm, open-label, uncontrolled study was conducted in which LSFX was administered to patients with NHCAP at 24 facilities. The research subjects (77 cases) were orally administered 75 mg of LSFX once a day for 7 days. The primary endpoint was the clinical efficacy at the time of test of cure (TOC) (TOC; 5-10 days after the end of LSFX administration), while the secondary endpoints were the efficacy at the time of end of treatment, early clinical efficacy, microbiological efficacy at the time of TOC and end of treatment, and safety evaluation of LSFX. DISCUSSION: NHCAP is a common pneumonia in clinical settings and a notable pneumonia whose mortality is high compared to community-acquired pneumonia. The present study showed the efficacy and safety of LSFX against NHCAP, which could lead to a larger number of therapeutic options for NHCAP.

A Survey of the Awareness and Educational Needs of Nurses in Nagasaki Prefecture Regarding Hereditary Breast and Ovarian Cancer.

The aim of this study was to evaluate the knowledge and educational needs with regard to hereditary breast and ovarian cancer among nurses working in breast cancer care in the Nagasaki Prefecture. In breast cancer care, the identification of patients at risk for hereditary breast and ovarian cancer is necessary for the implementation of genetic testing and counseling. Nurses should be involved in this process, since they play a crucial role in the care of patients with breast cancer. However, the knowledge regarding hereditary breast and ovarian cancer among nurses working in oncology care in Japan has not been assessed. The design of this study is cross-sectional design. We distributed 597 surveys to nurses working in breast cancer care. The surveys assessed the nurses' demographic data, their current knowledge and practices regarding cancer genetics and hereditary breast and ovarian cancer, and their attitude and preferences regarding learning about the condition. We received 317 valid replies. Nurses had limited knowledge about hereditary breast and ovarian cancer characteristics: 41.6% reported that they do not know about the condition, whereas less than 10% knew its characteristics. However, nurses were aware of hereditary breast and ovarian cancer significance and were willing to learn about it: 91% wished to learn about the condition, and 88.6% wanted to participate in study group meetings. Further, nurses' preferences regarding educational programs were clarified. Overall, our results show that educational programs should be implemented to advance nurses' knowledge of hereditary breast and ovarian cancer characteristics.

Adenoid Cystic Carcinoma, Solid-Basaloid Subtype of the Breast: A Case Report.

We present a rare tumor of adenoid cystic carcinoma, solid-basaloid subtype of the breast. Solid-basaloid adenoid cystic carcinoma may have a worse prognosis than classical adenoid cystic carcinoma. A 70-year-old woman presented with a mass in her left breast. Malignancy was suspected on imaging and confirmed via core needle biopsy. Left breast partial mastectomy and sentinel lymph node biopsy were performed. Histologically, the tumor was composed of basaloid cells with hyperchromatic nuclei and frequent mitotic figures, as are small-cell neuroendocrine carcinomas. Immunohistochemical analysis of the tumor cells showed high expression of KIT and CD10 and focal expression of keratin 7. Synaptophysin, chromogranin A, estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 were not expressed. This patient should be followed up carefully for distant metastases and recurrences.

Severe thrombocytopenia and anemia as an initial presentation of breast cancer: A case report.

Breast cancer patients with bone marrow metastasis (BMM) having profound thrombocytopenia and anemia are rare and there is no definitive treatment guideline. We present a case of successful initial treatment with anti-disseminated intravascular coagulation therapy and endocrine therapy, followed by chemotherapy to avoid deterioration of severe thrombocytopenia and anemia.

An Evaluation of the Efficacy of Compression Therapy Using Sleeves and Stockings to Prevent Docetaxel-induced Peripheral Neuropathy in Breast Cancer Patients.

Taxanes are key drugs for patients with breast cancer. A major adverse effect of taxanes is peripheral neuropathy (PN). To investigate the ability of compression therapy using sleeves and stockings to prevent PN due to the taxane docetaxel, we conducted a single-center historical control trial. Patients receiving docetaxel at 75 mg/m2 every 3 weeks for 4 cycles as first-line chemotherapy for breast cancer were eligible. PN was evaluated using the common terminology criteria for adverse events version 4.0. The primary endpoint was the incidence of allgrade PN until 3 weeks after the fourth docetaxel administration. We evaluated 26 patients in the intervention group and compared their data to those collected retrospectively from 52 patients treated with docetaxel without compression. Neither the incidence of all-grade PN until 3 weeks after the fourth docetaxel administration (63.5% in the control group vs. 76.9% in the intervention group, p=0.31) nor that of PN grade ≥ 2 (13.5% vs. 15.4%, p=0.99) differed between the groups. In this study, the efficacy of compression therapy using sleeves and stockings to prevent PN induced by docetaxel was not demonstrated. Further clinical studies including medications or intervention are needed to reduce the incidence and severity of PN induced by chemotherapy.

Inulin fibre promotes microbiota-derived bile acids and type 2 inflammation.

Dietary fibres can exert beneficial anti-inflammatory effects through microbially fermented short-chain fatty acid metabolites^1,2, although the immunoregulatory roles of most fibre diets and their microbiota-derived metabolites remain poorly defined. Here, using microbial sequencing and untargeted metabolomics, we show that a diet of inulin fibre alters the composition of the mouse microbiota and the levels of microbiota-derived metabolites, notably bile acids. This metabolomic shift is associated with type 2 inflammation in the intestine and lungs, characterized by IL-33 production, activation of group 2 innate lymphoid cells and eosinophilia. Delivery of cholic acid mimics inulin-induced type 2 inflammation, whereas deletion of the bile acid receptor farnesoid X receptor diminishes the effects of inulin. The effects of inulin are microbiota dependent and were reproduced in mice colonized with human-derived microbiota. Furthermore, genetic deletion of a bile-acid-metabolizing enzyme in one bacterial species abolishes the ability of inulin to trigger type 2 inflammation. Finally, we demonstrate that inulin enhances allergen- and helminth-induced type 2 inflammation. Taken together, these data reveal that dietary inulin fibre triggers microbiota-derived cholic acid and type 2 inflammation at barrier surfaces with implications for understanding the pathophysiology of allergic inflammation, tissue protection and host defence.

Neuropeptide regulation of non-redundant ILC2 responses at barrier surfaces.

Emerging studies indicate that cooperation between neurons and immune cells regulates antimicrobial immunity, inflammation and tissue homeostasis. For example, a neuronal rheostat provides excitatory or inhibitory signals that control the functions of tissue-resident group 2 innate lymphoid cells (ILC2s) at mucosal barrier surfaces1-4. ILC2s express NMUR1, a receptor for neuromedin U (NMU), which is a prominent cholinergic neuropeptide that promotes ILC2 responses5-7. However, many functions of ILC2s are shared with adaptive lymphocytes, including the production of type 2 cytokines8,9 and the release of tissue-protective amphiregulin (AREG)10-12. Consequently, there is controversy regarding whether innate lymphoid cells and adaptive lymphocytes perform redundant or non-redundant functions13-15. Here we generate a new genetic tool to target ILC2s for depletion or gene deletion in the presence of an intact adaptive immune system. Transgenic expression of iCre recombinase under the control of the mouse Nmur1 promoter enabled ILC2-specific deletion of AREG. This revealed that ILC2-derived AREG promotes non-redundant functions in the context of antiparasite immunity and tissue protection following intestinal damage and inflammation. Notably, NMU expression levels increased in inflamed intestinal tissues from both mice and humans, and NMU induced AREG production in mouse and human ILC2s. These results indicate that neuropeptide-mediated regulation of non-redundant functions of ILC2s is an evolutionarily conserved mechanism that integrates immunity and tissue protection.

Non-redundant functions of group 2 innate lymphoid cells.

Protective immunity relies on the interplay of innate and adaptive immune cells with complementary and redundant functions. Innate lymphoid cells (ILCs) have recently emerged as tissue-resident, innate mirror images of the T cell system, with which they share lineage-specifying transcription factors and effector machinery1. Located at barrier surfaces, ILCs are among the first responders against invading pathogens and thus could potentially determine the outcome of the immune response2. However, so far it has not been possible to dissect the unique contributions of ILCs to protective immunity owing to limitations in specific targeting of ILC subsets. Thus, all of the available data have been generated either in mice lacking the adaptive immune system or with tools that also affect other immune cell subsets. In addition, it has been proposed that ILCs might be dispensable for a proper immune response because other immune cells could compensate for their absence3-7. Here we report the generation of a mouse model based on the neuromedin U receptor 1 (Nmur1) promoter as a driver for simultaneous expression of Cre recombinase and green fluorescent protein, which enables gene targeting in group 2 ILCs (ILC2s) without affecting other innate and adaptive immune cells. Using Cre-mediated gene deletion of Id2 and Gata3 in Nmur1-expressing cells, we generated mice with a selective and specific deficiency in ILC2s. ILC2-deficient mice have decreased eosinophil counts at steady state and are unable to recruit eosinophils to the airways in models of allergic asthma. Further, ILC2-deficient mice do not mount an appropriate immune and epithelial type 2 response, resulting in a profound defect in worm expulsion and a non-protective type 3 immune response. In total, our data establish non-redundant functions for ILC2s in the presence of adaptive immune cells at steady state and during disease and argue for a multilayered organization of the immune system on the basis of a spatiotemporal division of labour.