Citations

Sweat out the fat with TSLP! Thymic stromal lymphopoietin (TSLP) is a cytokine that can promote immune responses that characterize allergic diseases. Choa et al . found that mice engineered to produce elevated TSLP displayed selective white adipose tissue loss that protected them from obesity, insulin resistance, and steatohepatitis (see the Perspective by Schneider). Protection was not mediated by eosinophils, regulatory T cells, or innate lymphoid cells. Rather, TLSP induced the migration of conventional T cells to sebaceous glands in the skin. Once there, these T cells promoted white adipose tissue loss by the hypersecretion of sebum, a lipid-rich substance that augments the skin’s barrier function. This mechanism, which likely evolved to enhance cutaneous antimicrobial defenses, could be possibly targeted in future treatments for obesity. —STS

0024 Background: There is evidence for the role of inflammation in the pathogenesis of coronary disease. Relative lymphocytopenia was reported for the diagnosis of myocardial infarction (MI), but little is known about its prognostic value. This study was undertaken to test the hypothesis that relative lymphocytopenia was associated with cardiac events (defined as recurrent MI, congestive heart failure or cardiac death) after MI among Olmsted County residents. Methods: MIs were validated using standard epidemiological criteria using enzymes, chest pain and Minnesota coding of the ECG. The entire community medical record, available via the Rochester Epidemiology Project, was reviewed to determine incident status and ascertain outcomes. Relative lymphocytopenia was defined as percent lymphocytes<20, 3%. Results: Between 1979 and 1994, an incidence cohort of 1653 validated MIs (mean age 67 ± 14, 43% women) was assembled. At the time of index MI, relative lymphocytopenia was present in 51% of the cases. After a mean follow-up of 6.9 ± 5.4 years, 471 pts had experienced recurrent MIs, 849 pts CHF and 602 cardiac deaths occurred. The 5-year event-free survival was 35% for cases with relative lymphocytopenia vs 52% for those without(p<0.001). After adjustment for age and current smoking, relative lymphocytopenia was associated with a 21% increase in the risk of cardiac event (RR 1.21, 95% CI 1.1-1.4; p=0.003). Conclusion: Relative lymphocytopenia is associated with cardiac events after incident MI. These data support the role of inflammation in the outcome of coronary disease.

P46 While heart failure (HF), an emerging epidemic, complicates myocardial infarction (MI), little is known on the predictors of HF post-MI, in particular the impact of reperfusion therapy. This population-based study was undertaken to examine the association between clinical characteristics and post-MI HF between 1979 and 1994. Hospitalized incident MIs were validated using enzymes, chest pain, and Minnesota coding of the ECG. Framingham criteria were used to ascertain both in- and outpatient HF. Proportional hazard regression was used to identify predictors of CHF. In the study period, 1657 patients (pts.) (mean age 67.2 ± 13.9 years, 43% women) had an incident MI. History of diabetes, hypertension and prior HF was found in 19%, 54% and 11% of pts respectively. After 5 years, 43% of pts had experienced HF. Factors independently associated with HF were (see table). There was a 2% decline per year in occurrence of HF. Adding reperfusion therapy in the model attenuated the association between year and HF (adjusted RR for reperfusion 0.67, 95% CI 0.53, 0.84, p=0.006; adjusted for year 0.99; 95% CI 0.97, 1.01, p=0.37). Thus, while remaining frequent post-MI CHF has declined over time. Reperfusion therapy accounted for most of the effect of year. Table 1.

AbstractBackgroundMucosal‐associated invariant T (MAIT) cells are unconventional T cells which recognize microbial metabolites presented by the major histocompatibility complex class I‐related molecule MR1. Although MAIT cells have been shown to reside in human and murine skin, their contribution to atopic dermatitis (AD), an inflammatory skin disease associated with barrier dysfunction and microbial translocation, has not yet been determined.MethodsGenetic deletion of MR1 and topical treatment with inhibitory MR1 ligands, which result in the absence and functional inhibition of MAIT cells, respectively, were used to investigate the role of MR1‐dependent immune surveillance in a MC903‐driven murine model of AD.ResultsThe absence or inhibition of MR1 arrested AD disease progression through the blockade of both eosinophil activation and recruitment of IL‐4‐ and IL‐13‐producing cells. In addition, the therapeutic efficacy of phototherapy against MC903‐driven AD could be increased with prior application of folate, which photodegrades into the inhibitory MR1 ligand 6‐formylpterin.ConclusionWe identified MAIT cells as sentinels and mediators of cutaneous type 2 immunity. Their pathogenic activity can be inhibited by topical application or endogenous generation, via phototherapy, of inhibitory MR1 ligands.

Introduction: Practice guidelines recommend use of subcutaneous implantable cardioverter-defibrillators (ICD) in patients (pts) at risk of sudden cardiac death and high risk for infection. This has prompted a need to better identify pts at high risk of infection to assist in de novo device selection. The objective of this study is to estimate infection incidence in de novo transvenous (TV) ICD implants and assess risk factors associated with infection in a large Medicare population. Methods: A retrospective cohort study was conducted using 100% Medicare administrative and claims data to identify pts who underwent de novo TV-ICD implantation between 7/2016 and 1/2018. Device-related infection within 2 years of implantation was identified using ICD-10 diagnosis and procedure codes. Baseline pt factors associated with infection were identified by univariable logistic regression analysis of all variables of interest, including factors in Charlson and Elixhauser comorbidity indices, followed by stepwise selection criteria with a p≤0.25 for inclusion in a multivariable model and a backwards, stepwise elimination process with p≤0.1 to remain in the model. A time-to-event analysis was also conducted. Results: Among 26,742 pts with de novo TV-ICD, 519 (1.9%) had a device-related infection over 2 years. The mean pt age with and without infection was 68 and 71 years, respectively. While more than half (54%) of infections occurred within 90 days post implant, infections continued to be diagnosed with 16% of infections occurring between years 1 and 2. Multivariable analysis revealed several significant predictors of infection (Figure) including age <70 years, end stage renal disease with chronic dialysis and diabetes with complications. Conclusion: The rate of de novo TV-ICD infection in a large real-world Medicare population is clinically significant. The factors associated with increased infection risk identified here can be used to help determine device selection.

The enigmatic eosinophil has emerged as an exciting component of the immune system, involved in a plethora of homeostatic and inflammatory responses. Substantial progress has been achieved through experimental systems manipulating eosinophils in vivo, initially in mice and more recently in humans. Researchers using eosinophil knockout mice have identified a contributory role for eosinophils in basal and inflammatory processes and protective immunity. Primarily fueled by the purported proinflammatory role of eosinophils in eosinophil-associated diseases, a series of anti-eosinophil therapeutics have emerged as a new class of drugs. These agents, which dramatically deplete eosinophils, provide a valuable opportunity to characterize the consequences of eosinophil knockout humans. Herein, we comparatively describe mouse and human eosinophil knockouts. We put forth the view that human eosinophils negatively contribute to a variety of diseases and, unlike mouse eosinophils, do not yet have an identified role in physiological health; thus, clarifying all roles of eosinophils remains an ongoing pursuit.

Eosinophils protect against liver injury during orthotopic liver transplantation and other conditions of hepatic ischemia-reperfusion injury in mice.

AbstractBackgroundMagnetic Resonance Spectroscopy (MRS) is a non‐invasive technique assessing the concentration of various metabolites within the brain, both cross‐sectionally to characterize disease type and severity, and longitudinally to assess disease progression and potential treatment efficacy in the context of disease‐modifying interventions. In such context, the involvement of multiple imaging facilities inevitably introduces variability, whose amount must be known to inform on comparability between sites and sensitivity to change. Our objective is to study variability in the concentration of various brain metabolites using a dedicated MRS phantom and assess impact of field strength.Methods30 sites are being considered to participate in an on‐going clinical trial in metachromatic leukodystrophy. Site qualification mandates the scanning of a dedicated MRS phantom. 30 of these HD‐polyethylene spheres were simultaneously manufactured and filled with the same mixture of chemicals mimicking main metabolite concentrations. To date, 14 sites provided data (5 1.5T scanners and 9 3T). All sites implemented a standardized single‐voxel MRS sequence. MRS voxel was placed within the phantom and acquisition repeated 3 times. Spectra were centrally analyzed using LCModel v6.3 and quality controlled by Bioclinica. Repeat acquisitions were requested for parameter deviations, voxel positioning and/or shimming issues. Results only include passing datasets. Coefficient of Variation (CV) was calculated for NAA/Cr, Cho/Cr, mI/Cr, Glx/Cr and Lac/Cr ratios for each site and overall. LCModel quality metrics (FHWM and S/N) were also extracted to assess spectra quality. Comparison between field strengths was carried out using t‐tests.ResultsAverage CV by site was 2.0% for NAA/Cr (2.5% at 1.5T and 1.8% at 3T), 2.4% for Cho/Cr, 3.0% for mI/Cr, 4.5% for Glx/Cr and 6.1% for Lac/Cr. CVs were generally lower at 3T (except for Lac/Cr) although difference was not significant. As expected, Signal‐to‐Noise was higher at 3T (p=0.05). Overall CV by metabolite across scanners was much higher (ranging from 4.6% for Cho/Cr up to 12.1% for Lac/Cr).ConclusionMRS measures of metabolite concentrations have low variability at scanner‐level, insensitive to field strength. Nevertheless, variability across sites is much higher and would require, if possible, cross‐calibration. These phantom data make such calibration possible and will improve sensitivity of subject data analyses.