OBJECTIVE:To determine the association of cardiovascular atherosclerotic plaque monosodium urate deposits with the occurrence of major cardiovascular events in gout and hyperuricemia patients. METHODS:This retrospective cohort study included patients with clinically suspicion of gout, who performed a dual energy computed tomography of the affected limb and thorax between 1 June 2012 and 5 December 2019. Clinical and laboratory parameters were retrieved from patients' charts. Established cardiovascular risk factors were evaluated. Medical history review identified the presence of major adverse cardiac events with a median follow-up time of 33 months (range 0-108 months) after the performed computed tomography scan. RESULTS:Full data sets were available for 189 patients: 131 (69.3%) gout patients, 40 (21.2%) hyperuricemia patients and 18 (9.5%) controls. Patients with cardiovascular monosodium urate deposits (n = 85/189, 45%) revealed increased serum acute phase reactants, uric acid levels and calcium scores in computed tomography compared with patients without cardiovascular monosodium urate deposits. Major adverse cardiac events were observed in 35 patients (18.5%) with a higher prevalence in those patients revealing cardiovascular monosodium urate deposits (n = 22/85, 25.9%) compared with those without cardiovascular monosodium urate deposits (n = 13/104, 12.5%, OR 2.4, P = 0.018). CONCLUSION:This is the first study demonstrating the higher hazard of major adverse cardiac events in patients with dual energy computed tomography-verified cardiovascular monosodium urate deposits. The higher prevalence of cardiac events in patients with cardiovascular monosodium urate deposits may facilitate risk stratification of gout patients, as classical cardiovascular risk scores or laboratory markers fail in their proper identification.

A hyperinflammatory state with highly elevated concentrations of inflammatory biomarkers such as C-reactive protein (CRP) is a characteristic feature of severe coronavirus disease 2019 (COVID-19). To examine a potential role of common genetic factors that may influence COVID-19 outcomes, we investigated whether individuals with a polygenic predisposition for a pro-inflammatory response (in the form of Polygenic Scores) are more likely to develop severe COVID-19. The innovative approach of polygenic scores to investigate genetic factors in COVID-19 severity should provide a comprehensive approach beyond single-gene studies. In our cohort of 156 patients of European ancestry, two overlapping Polygenic Scores (PGS) predicting a genetic predisposition to basal CRP concentrations were significantly different between non-severe and severe COVID-19 cases and were associated with less severe COVID-19 outcomes. Furthermore, specific single nucleotide polymorphisms (SNPs) that contribute to either of the two Polygenic Scores predicting basal CRP levels are associated with different traits that represent risk factors for COVID-19 disease initiation (ACE2 receptor, viral replication) and progression (CRP). We suggest that genetically determined enforced CRP formation may contribute to strengthening of innate immune responses and better initial pathogen control thereby reducing the risk of subsequent hyperinflammation and adverse course of COVID-19.

Abstract Aims Iron is essential to maintain cellular energy metabolism in the myocardium. Impaired cellular iron availability negatively affects myocardial physiology and can aggravate heart failure (HF). Iron deficiency (ID) is frequently found in patients with acute and chronic HF (AHF, CHF) and associated with clinical outcome. The aim of this analysis was to assess the true ID prevalence in HF patients on the basis of different ID definitions. Methods We performed a retrospective analysis of 329 AHF and 613 CHF patients, recruited between 02/2021 and 05/2022 at the Innsbruck Medical University (47%/32% female, median age 81/64 years). ID was defined according to a general definition, gastroenterology and cardiology guidelines as ferritin <30 or <45 ng/mL or <100/ng/mL (absolute ID), ferritin 30–100 or 45–150 or 100–299 ng/mL plus TSAT <20% (combined ID), and ferritin >100 or >150 or ≥300 ng/mL plus TSAT <20% (functional ID). Results ID prevalence was significantly higher in AHF compared with CHF patients: general definition (74.8% vs. 32.6%, P < 0.001), gastroenterology guidelines (75.7% vs. 34.7%, P < 0.001), cardiology guidelines (79.9% vs. 47.3%, P < 0.001). We found distinctive differences in prevalence of ID types between the three definitions. Absolute ID prevalence was highest when applying cardiology compared with gastroenterology guidelines and general definition (AHF: 44.7% vs. 20.4% vs. 7.0%; CHF: 34.1% vs. 13.4% vs. 7.2%), while frequency of combined ID was almost equally distributed. Functional ID prevalence was highest when applying general definition compared with gastroenterology and cardiology guidelines (AHF: 34.7% vs. 23.4% vs. 11.6%; CHF: 13.1% vs. 9.0% vs. 3.4%). Out of 494 patients classified as having absolute or combined ID according to the cardiology guidelines, only 252 patients received the same classification while 107 and 135 patients were classified having no and functional ID when applying the general definition. Conclusions We show that ID prevalence is higher in AHF versus CHF patients in a continuous cohort of HF patients managed at the same institution over the same period of time. There were distinctive differences in detection of ID and the type of ID when applying several recommended definitions thus affecting sensitivity and specificity for absolute and functional ID detection. This may result in exclusion of patients, which may benefit from iron supplementation and inclusion of those who may not respond or even anticipate site effects. Our study calls for the urgent need of prospective trials for redefinition of ID and identification of biomarkers associated with therapeutic response to optimize patient outcomes.

BackgroundEarly studies in cellular models suggested an iron accumulation in Friedreich's ataxia (FA), yet findings from patients are lacking. ObjectivesThe objective is to characterize systemic iron metabolism, body iron storages, and intracellular iron regulation in FA patients. MethodsIn FA patients and matched healthy controls, we assessed serum iron parameters, regulatory hormones as well as the expression of regulatory proteins and iron distribution in peripheral blood mononuclear cells (PBMCs). We applied magnetic resonance imaging with R2*-relaxometry to quantify iron storages in the liver, spleen, and pancreas. Across all evaluations, we assessed the influence of the genetic severity as expressed by the length of the shorter GAA-expansion (GAA1). ResultsWe recruited 40 FA patients (19 women). Compared to controls, FA patients displayed lower serum iron and transferrin saturation. Serum ferritin, hepcidin, mean corpuscular hemoglobin and mean corpuscular volume in FA inversely correlated with the GAA1-repeat length, indicating iron deficiency and restricted availability for erythropoiesis with increasing genetic severity. R2*-relaxometry revealed a reduction of splenic and hepatic iron stores in FA. Liver and spleen R2* values inversely correlated with the GAA1-repeat length. FA PBMCs displayed downregulation of ferritin and upregulation of transferrin receptor and divalent metal transporter-1 mRNA, particularly in patients with >500 GAA1-repeats. In FA PBMCs, intracellular iron was not increased, but shifted toward mitochondria. ConclusionsWe provide evidence for a previously unrecognized iron starvation signature at systemic and cellular levels in FA patients, which is related to the underlying genetic severity. These findings challenge the use of systemic iron lowering therapies in FA. (c) 2024 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

BACKGROUND AND AIMS:The interaction of serum uric acid (SUA) with atherogenesis is incompletely understood. Aim of our study was to investigate the association of SUA levels with coronary plaque composition including high-risk-plaque (HRP) features by coronary computed tomography angiography (CTA) and for the prediction of major adverse cardiac events (MACE). METHODS AND RESULTS:1242 patients (age 66.17 ± 11.03; 56 % males) referred to coronary CTA were included. SUA>6.5 mg/dl was defined as hyperuricemia. CTA-image analysis included: Coronary stenosis severity (CADRADS), plaque burden (SIS/G-score weighted for non-calcifying plaque), plaques types (1 = calcifying; 2 = mixed (predominantly calcifying); 3 = mixed (predominantly noncalcifying), 4 = noncalcifying."High-risk-plaque"(HRP)-features were quantified: Low-attenuation plaque (LAP) density, Spotty calcification, Napkin-Ring Sign (NRS), Remodeling Index. Coronary Artery Calcium Score (CAC) was measured. Primary outcome was MACE. HRP-features were more prevalent in patients with hyperuricemia (p = 0.005, p = 0.0002, p = 0.0004). SUA level was associated with LAP<30HU (HR:1.23; p = 0.04). Plaque burden and CAC-score were higher in the hyperuricemia group (G-score:p = 0.022 and CAC:p = 0.027). After a mean follow-up of mean 8,32 years, MACE rate was 2.9 %. There was no difference in the MACE rate between subjects with elevated SUA and normals (HR 1.221:95%CI:0.817-2.563; p = 0.597). Low-attenuation-plaque density/LAP<30HU was the strongest prognosticator for MACE (p = 0.033 and p = 0.013); stenosis severity, plaque types and G-score were also predictive, but not SUA, CAC and the other conventional cardiovascular risk factors (except smoking). CONCLUSION:SUA is associated with HRP-features and coronary plaque burden. Low attenuation plaque is the strongest predictor of MACE, but not SUA level and other major CVRF. CTA imaging biomarkers may improve CV-risk stratification in patients with hyperuricemia.

Background/Objectives: Anemia is a frequent multifactorial co-morbidity in end-stage kidney disease (ESKD) associated with morbidity and poor QoL. Apart from insufficient erythropoietin formation, iron deficiency (ID) contributes to anemia development. Identifying patients in need of iron supplementation with current ID definitions is difficult since no good biomarker is available to detect actual iron needs. Therefore, new diagnostic tools to guide therapy are needed. Methods: We performed a prospective cohort study analyzing tissue iron content with MRI-based R2*-relaxometry in 20 anemic ESKD patients and linked it with iron biomarkers in comparison to 20 otherwise healthy individuals. Results: ESKD patients had significantly higher liver (90.1 s−1 vs. 36.1 s−1, p < 0.001) and spleen R2* values (119.8 s−1 vs. 19.3 s−1, p < 0.001) compared to otherwise healthy individuals, while their pancreas and heart R2* values did not significantly differ. Out of the 20 ESKD patients, 17 had elevated spleen and 12 had elevated liver R2* values. KDIGO guidelines (focusing on serum iron parameters) would recommend iron supplementation in seven patients with elevated spleen and four patients with elevated liver R2* values. Conclusions: These findings highlight that liver and especially spleen iron concentrations are significantly higher in ESKD patients compared to controls. Tissue iron overload diverged from classical iron parameters suggesting need of iron supplementation. Measurement of MRI-guided tissue iron distribution might help guide treatment of anemic ESKD patients.

Background: Recently, monosodium urate (MSU) deposits were demonstrated in coronary arteries of 86.4% of gout patients by dual energy computed tomography (DECT).[1] Cardiovascular (CV) MSU deposits were associated with major adverse cardiac events (MACE) [2], but also the presence of peripheral MSU deposits increased the risk for CV disease and death.[3] Objectives: The aim of this retrospective analysis was to evaluate the possible association of 1) peripheral MSU deposits with CV MSU deposits and 2) the presence of MSU deposits with MACE. Methods: We included all patients, recruited at the radiology department of medical university Innsbruck with clinically or ultrasound-based suspicion of gout, who performed ultrasound and DECT of the affected limb as well as of the thorax between 01.05.2012 and 01.09.2019. Clinical and laboratory parameters were retrieved from patients´ charts. Gout was defined according to the ACR/EULAR classification criteria, uric acid levels over 6 mg/dl or ongoing uric acid lowering treatment without clinical signs of gout specified hyperuricemia patients and control group definition was achieved when uric acid levels were normal without concomitant uric acid lowering therapy and absence of gout symptoms. Peripheral MSU deposits and tophi were identified using DECT. A tophus was arbitrarily defined as MSU deposit >1cm diameter. If present, the maximum diameter of the tophus was measured. Medical history review identified the presence of MACE, defined as myocardial infarction and/or stroke. For statistical appraisal, χ2 statistic based on a 2 × 2 tabulation, and Mann–Whitney U tests were performed using IBM SPSS (version 27). P < 0.05 was used as the cut-off for statistical significance. Results: Out of the 189 patients recruited, peripheral MSU deposits were present in 126 (66.7%) cases. 103 (103/131, 78.6%) were gout patients and 23 (23/40, 57.5%) were hyperuricemia patients. Of those 126, 55 patients (50 gout, 5 hyperuricemia patients) were tophaceous. Median peripheral tophus size was 2 cm (range 1-8cm). 62.7% (n=79) of our patients with peripheral MSU deposits revealed CV MSU positive plaques (61 gout, 18 hyperuricemia patients). Tophaceous patients showed higher serum uric acid levels [mean 7.8 (SD 2.7) vs 6.5 (SD 2.2) mg/dl, p=0.002] but inflammatory parameters [C-reactive protein (CRP): median 1.5 (range 0.1-25.2) vs 0.6 (range 0.1-31.8), p=0.095] were equally distributed in tophaceous and non-tophaceous patients. When comparing age, coronary calcium score, uric acid, CRP, presence of tophi and MACE between patients with and without peripheral and CV MSU deposits, significant differences were shown in age, coronary calcium score, CRP-levels as well as tophi and MACE (see Table 1). Both, non-tophaceous peripheral MSU deposits as well as tophi were associated with CV MSU deposits (p<0.001, respectively). Only tophi, but not peripheral MSU deposits, were associated with the presence of MACE (p=0.047). Overall 35 MACE occurred, in tophaceous patients 15 MACE (27.3%) were documented. Tophus size/diameter showed no difference in patients with MACE [median 2cm (range 1-5)] when compared to those without MACE [median 2cm (range 1-8cm), p=0.933]. Conclusion: To our knowledge, this is the first study demonstrating the association of peripheral MSU deposits and tophi with the presence of CV MSU plaques. MACE was more prevalent in patients with peripheral tophaceous MSU deposits. In contrast to previous published data, peripheral tophus size was not related to the occurrence of MACE in our cohort. REFERENCES: [1] Klauser, A.S., et al., Dual-Energy Computed Tomography Detection of Cardiovascular Monosodium Urate Deposits in Patients With Gout. JAMA Cardiol, 2019. [2] Held, J., et al., OP0155 CLINICAL IMPACT OF CARDIOVASCULAR MONOSODIUM URATE DEPOSITS MEASURED BY DUAL ENERGY COMPUTED TOMOGRAPHY: A RETROSPECTIVE EVALUATION. Annals of the Rheumatic Diseases, 2023. 82(Suppl 1): p. 102-103. [3] Marty-Ané, A., et al., Crystal deposition measured with dual-energy computed tomography: association with mortality and cardiovascular risks in gout. Rheumatology (Oxford), 2021. 60(10): p. 4855-4860. Acknowledgements: NIL. Disclosure of Interests: None declared.

Purpose of Review To highlight novel findings in the detection of monosodium urate deposits in vessels using dual energy computed tomography, and to discuss the potential clinical implications for gout and hyperuricemia patients.Recent Findings Gout is an independent risk factor for cardiovascular disease. However, classical risk calculators do not take into account these hazards, and parameters to identify patients at risk are lacking. Monosodium urate measured by dual energy computed tomography is a well-established technology for the detection and quantification of monosodium urate deposits in peripheral joints and tendons. Recent findings also suggest its applicability to identify vascular urate deposits.Summary Dual energy computed tomography is a promising tool for detection of cardiovascular monosodium urate deposits in gout patients, to better delineate individuals at increased risk for cardiovascular disease.

Severe coronavirus disease 19 (COVID‐19) manifests with systemic immediate proinflammatory innate immune activation and altered iron turnover. Iron homeostasis, differentiation, and function of myeloid leukocytes are interconnected. Therefore, we characterized the cellularity, surface marker expression, and iron transporter phenotype of neutrophils and monocyte subsets in COVID‐19 patients within 72 h from hospital admission, and analyzed how these parameters relate to infection severity. Between March and November 2020, blood leukocyte samples from hospitalized COVID‐19 patients (n = 48) and healthy individuals (n = 7) were analyzed by flow cytometry enabling comparative analysis of 40 features. Inflammation‐driven neutrophil expansion, depletion of CD16 + nonclassical monocytes, and changes in surface expression of neutrophil and monocyte CD64 and CD86 were associated with COVID‐19 severity. By unsupervised self‐organizing map clustering, four patterns of innate myeloid response were identified and linked to varying levels of systemic inflammation, altered cellular iron trafficking and the severity of disease. These alterations of the myeloid leukocyte compartment during acute COVID‐19 may be hallmarks of inefficient viral control and immune hyperactivation and may help at risk prediction and treatment optimization.

The CovILD study is a prospective, multicenter, observational cohort study to systematically follow up patients after coronavirus disease-2019 (COVID-19). We extensively evaluated 145 COVID-19 patients at 3 follow-up visits scheduled for 60, 100, and 180 days after initial confirmed diagnosis based on typical symptoms and a positive reverse transcription-polymerase chain reaction (RT-PCR) for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). We employed comprehensive pulmonary function and laboratory tests, including serum concentrations of IgG against the viral spike (S) glycoprotein, and compared the results to clinical data and chest computed tomography (CT). We found that at the 60 day follow-up, 131 of 145 (90.3%) participants displayed S-specific serum IgG levels above the cut-off threshold. Notably, the highly elevated IgG levels against S glycoprotein positively correlated with biomarkers of immune activation and negatively correlated with pulmonary function and the extent of pulmonary CT abnormalities. Based on the association between serum S glycoprotein-specific IgG and clinical outcome, we generated an S-specific IgG-based recovery score that, when applied in the early convalescent phase, accurately predicted delayed pulmonary recovery after COVID-19. Therefore, we propose that S-specific IgG levels serve as a useful immunological surrogate marker for identifying at-risk individuals with persistent pulmonary injury who may require intensive follow-up care after COVID-19.

ABSTRACT Given the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), a deeper analysis of the host genetic contribution to severe COVID-19 is important to improve our understanding of underlying disease mechanisms. Here, we describe an extended GWAS meta-analysis of a well-characterized cohort of 3,260 COVID-19 patients with respiratory failure and 12,483 population controls from Italy, Spain, Norway and Germany/Austria, including stratified analyses based on age, sex and disease severity, as well as targeted analyses of chromosome Y haplotypes, the human leukocyte antigen (HLA) region and the SARS-CoV-2 peptidome. By inversion imputation, we traced a reported association at 17q21.31 to a highly pleiotropic ∼0.9-Mb inversion polymorphism and characterized the potential effects of the inversion in detail. Our data, together with the 5 th release of summary statistics from the COVID-19 Host Genetics Initiative, also identified a new locus at 19q13.33, including NAPSA , a gene which is expressed primarily in alveolar cells responsible for gas exchange in the lung.

Macrophages are at the center of innate pathogen control and iron recycling. Divalent metal transporter 1 (DMT1) is essential for the uptake of non-transferrin-bound iron (NTBI) into macrophages and for the transfer of transferrin-bound iron from the endosome to the cytoplasm. As the control of cellular iron trafficking is central for the control of infection with siderophilic pathogens such as Salmonella Typhimurium, a Gram-negative bacterium residing within the phagosome of macrophages, we examined the potential role of DMT1 for infection control. Bone marrow derived macrophages lacking DMT1 (DMT1fl/flLysMCre(+)) present with reduced NTBI uptake and reduced levels of the iron storage protein ferritin, the iron exporter ferroportin and, surprisingly, of the iron uptake protein transferrin receptor. Further, DMT1-deficient macrophages have an impaired control of Salmonella Typhimurium infection, paralleled by reduced levels of the peptide lipocalin-2 (LCN2). LCN2 exerts anti-bacterial activity upon binding of microbial siderophores but also facilitates systemic and cellular hypoferremia. Remarkably, nifedipine, a pharmacological DMT1 activator, stimulates LCN2 expression in RAW264.7 macrophages, confirming its DMT1-dependent regulation. In addition, the absence of DMT1 increases the availability of iron for Salmonella upon infection and leads to increased bacterial proliferation and persistence within macrophages. Accordingly, mice harboring a macrophage-selective DMT1 disruption demonstrate reduced survival following Salmonella infection. This study highlights the importance of DMT1 in nutritional immunity and the significance of iron delivery for the control of infection with siderophilic bacteria.

Due to the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), deepening the host genetic contribution to severe COVID-19 may further improve our understanding about underlying disease mechanisms. Here, we describe an extended GWAS meta-analysis of 3,260 COVID-19 patients with respiratory failure and 12,483 population controls from Italy, Spain, Norway and Germany, as well as hypothesis-driven targeted analysis of the human leukocyte antigen (HLA) region and chromosome Y haplotypes. We include detailed stratified analyses based on age, sex and disease severity. In addition to already established risk loci, our data identify and replicate two genome-wide significant loci at 17q21.31 and 19q13.33 associated with severe COVID-19 with respiratory failure. These associations implicate a highly pleiotropic ~0.9-Mb 17q21.31 inversion polymorphism, which affects lung function and immune and blood cell counts, and the NAPSA gene, involved in lung surfactant protein production, in COVID-19 pathogenesis.

Background: Iron deficiency anaemia (IDA) is a major health concern. However, preventive iron supplementation in regions with high burden of infectious diseases resulted in an increase of infection related morbidity and mortality. Methods: We fed male C57BL/6N mice with either an iron deficient or an iron adequate diet. Next, they received oral iron supplementation or placebo followed by intraperitoneal infection with Salmonella Typhimurium (S.Tm). Findings: We found that mice with IDA had a poorer clinical outcome than mice on an iron adequate diet. Interestingly, iron supplementation of IDA mice resulted in higher bacterial burden in organs and shortened survival. Increased transferrin saturation and non-transferrin bound iron in the circulation together with low expression of ferroportin facilitated the access of the pathogen to iron and promoted bacterial growth. Anaemia, independent of iron supplementation, was correlated with reduced neutrophil counts and cytotoxic T cells. With iron supplementation, anaemia additionally correlated with increased splenic levels of the cytokine IL-10, which is suggestive for a weakened immune control to S.Tm infection. Interpretation: Supplementing iron to anaemic mice worsens the clinical course of bacterial infection. This can be traced back to increased iron delivery to bacteria along with an impaired anti-microbial immune response. Our findings may have important implications for iron supplementation strategies in areas with high endemic burden of infections, putting those individuals, who potentially profit most from iron supplementation for anaemia, at the highest risk for infections. Funding: Financial support by the Christian Doppler Laboratory for Iron Metabolism and Anemia Research.

The control over iron availability is crucial under homeostatic conditions and even more in the case of an infection. This results from diverse properties of iron: first, iron is an important trace element for the host as well as for the pathogen for various cellular and metabolic processes, second, free iron catalyzes Fenton reaction and is therefore producing reactive oxygen species as a part of the host defense machinery, third, iron exhibits important effects on immune cell function and differentiation and fourth almost every immune activation in turn impacts on iron metabolism and spatio-temporal iron distribution. The central importance of iron in the host and microbe interplay and thus for the course of infections led to diverse strategies to restrict iron for invading pathogens. In this review, we focus on how iron restriction to the pathogen is a powerful innate immune defense mechanism of the host called "nutritional immunity". Important proteins in the iron-host-pathogen interplay will be discussed as well as the influence of iron on the efficacy of innate and adaptive immunity. Recently described processes like ferritinophagy and ferroptosis are further covered in respect to their impact on inflammation and infection control and how they impact on our understanding of the interaction of host and pathogen.

The calcium channel blocker nifedipine induces cellular iron export, thereby limiting the availability of the essential nutrient iron for intracellular pathogens, resulting in bacteriostatic activity. To study if nifedipine may exert a synergistic anti-microbial activity when combined with antibiotics, we used the mouse macrophage cell line RAW267.4, infected with the intracellular bacterium Salmonella Typhimurium, and exposed the cells to varying concentrations of nifedipine and/or ampicillin, azithromycin and ceftriaxone. We observed a significant additive effect of nifedipine in combination with various antibiotics, which was not observed when using Salmonella, with defects in iron uptake. Of interest, increasing intracellular iron levels increased the bacterial resistance to treatment with antibiotics or nifedipine or their combination. We further showed that nifedipine increases the expression of the siderophore-binding peptide lipocalin-2 and promotes iron storage within ferritin, where the metal is less accessible for bacteria. Our data provide evidence for an additive effect of nifedipine with conventional antibiotics against Salmonella, which is partly linked to reduced bacterial access to iron.

Iron is an essential nutrient for mammals as well as for pathogens. Inflammation-driven changes in systemic and cellular iron homeostasis are central for host-mediated antimicrobial strategies. Here, we studied the role of the iron storage protein ferritin H (FTH) for the control of infections with the intracellular pathogen Salmonella enterica serovar Typhimurium by macrophages. Mice lacking FTH in the myeloid lineage (LysM-Cre+/+Fthfl/fl mice) displayed impaired iron storage capacities in the tissue leukocyte compartment, increased levels of labile iron in macrophages, and an accelerated macrophage-mediated iron turnover. While under steady-state conditions, LysM-Cre+/+Fth+/+ and LysM-Cre+/+Fthfl/fl animals showed comparable susceptibility to Salmonella infection, i.v. iron supplementation drastically shortened survival of LysM-Cre+/+Fthfl/fl mice. Mechanistically, these animals displayed increased bacterial burden, which contributed to uncontrolled triggering of NF-κB and inflammasome signaling and development of cytokine storm and death. Importantly, pharmacologic inhibition of the inflammasome and IL-1β pathways reduced cytokine levels and mortality and partly restored infection control in iron-treated ferritin-deficient mice. These findings uncover incompletely characterized roles of ferritin and cellular iron turnover in myeloid cells in controlling bacterial spread and for modulating NF-κB and inflammasome-mediated cytokine activation, which may be of vital importance in iron-overloaded individuals suffering from severe infections and sepsis.

To the Editor: The strength of host immune reaction to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) determines the severity of corona virus disease 2019 (Covid-19). While a basic antiviral immune response involving innate immune mechanisms and an induction of adaptive immunity is needed to resolve the disease, particularly innate myeloid cells can also induce a dysregulated, excessive, aberrant and non-effective host immune response in severe Covid-19. The latter is termed “hyperinflammation,” “cytokine storm,” “macrophage activation syndrome” or “cytokine release syndrome.” Hyperinflammation contributes to the pathogenesis of Covid-19 related acute respiratory distress syndrome (ARDS), which is associated with a fatal outcome in the majority of patients, but may also induce multi-organ damage, which is the second most common cause of death in Covid-19. Thus, a better understanding of underlying host-intrinsic factors driving immune dysfunction is warranted for the immediate identification of patients at risk and eventually also for selecting novel targeted therapies. Thus, SARS-CoV-2 has been found to infect multiple cells expression ACE-2 receptors including human monocytes, macrophages and dendritic cells, emphasizing their contribution to disease pathology. Of relevance, clonal hematopoiesis (CH; defined as somatic variants in the peripheral blood at a variant allele frequency ≥2%) is considered to imprint inflammation in myeloid cells, which may perpetuate acute (e.g., infectious-triggered) and chronic inflammatory processes. Moreover, CH is associated with some of the comorbidities relevant for higher risk of severe Covid-19, especially age and cardiovascular disease. Augmented injury in cardiovascular tissues was attributed to increased inflammatory tension in clonal myeloid and T cells, which drive pro-inflammatory circuits via NLRP3-inflammasome activation and subsequent IL-1β production. Moreover, while published data regarding the risk of patients with hematological malignancies to acquire Covid-19 are discordant, these papers consistently show that these patients have a higher case fatality rate. In addition, case reports of acute leukemia and concomitant Covid-19 are increasingly reported. Especially newly diagnosed, refractory or relapsed cases pose a challenge, as these patients often need immediate therapy. However, diagnostic work-up prior to therapy initiation is essential for the selection of the optimal patienttailored therapy. For example, for acute myeloid leukemia, besides a complete blood count, flow cytometric analysis and a bone marrow smear, genetic work-up including molecular genetics is indispensable for proper classification and risk assessment. Indeed, the American Society of Hematology recommends starting with induction chemotherapy in eligible patients regardless of Covid-19 status. Thus, knowledge about the influence of viral infections in general and Covid-19 specifically, on molecular analyses and their dynamics during fulminant infection would help to better manage and interpret findings of such newly diagnosed/relapsed/refractory leukemia patients. However, to the best of our knowledge there are currently no reports on the dynamics of aberrations detected during acute (viral) infections. Against this background, we herein investigated the prevalence and clinical impact of CH in Covid-19. Moreover, we analyzed clonal size during the disease and upon its resolution. In total, 169 patients were screened for participation in this study. Nine patients turned out to be SARS-CoV-2 PCR negative, and thus were excluded from further analysis. Of the remaining 160 patients, 43 patients were included during hospitalization due to Covid-19 (median time to blood test for CH analysis: 24 days; range: 0– 57 days), 117 patients, who were either treated as outpatients or also being hospitalized during the acute phase, were included when they came for follow-up evaluation performed between 31–119 days (median: 56 days) after initial diagnosis of Covid-19 (Figure S1). Eight patients were analyzed at two or more time points. Both trial protocols were approved by the institutional review board at Innsbruck Medical University (EK-Nb: 1091/2020 and 1103/2020). Informed consent was obtained from each patient. Laboratory analyses and complete blood count were assessed by standard methods as part of patient care at the Medical University of Innsbruck. Detection of CH variants was performed by next generation sequencing on MiSeq devices using the TrueSight Myeloid sequencing panel from Illumina. For data analysis, the SeqNext software of JSI Medical Systems was utilized. Only coding variants not frequent in the general population with a variant allele frequency (VAF) between 2% and 45% were included in the dataset. Further details on genetic analysis are given in the supplemental file. Statistical analysis was performed using GraphPad Prism software. In order to assess correlation between disease groups and CH, chi-square test was used. For comparison between disease groups, two-sided Mann–Whitney U test was used, because of non-normal Received: 16 April 2021 Revised: 18 May 2021 Accepted: 20 May 2021