OBJECTIVE

An elevated plasma <em>D</em>-<em>dimer</em> level indicates the activation of coagulation and fibrinolysis. In the present study, we investigated the association of pre-treatment haemostatic parameters (<em>D</em>-<em>dimer</em>, fibrinogen and prothrombin fragment 1+<em>2</em>) with clinicopathological parameters and outcome in patients with lung cancer.

METHODS

Plasma levels of <em>D</em>-<em>dimer</em> and other parameters were measured in 78 evaluable patients with lung cancer (60 non-small cell lung cancers, 18 small cell lung cancers). At diagnosis, 35 patients (44.9%) were locally advanced stage (IIIA/B) and 43 patients (55.1%) had metastatic disease (IV). Multivariate statistical analysis was carried out using Cox's proportional hazards model. The receiver operating characteristic curve was used to determine the cut-off values for <em>D</em>-<em>dimer</em>, fibrinogen and prothrombin fragment 1+<em>2</em>.

RESULTS

The median survival for all patients was <em>2</em>64 days (95% confidence interval <em>2</em>00-3<em>2</em>8 days). A significant association between the plasma levels of <em>D</em>-<em>dimer</em> and the response to chemotherapy was observed (P=0.03). With the univariate analysis, tumour stage, pre-treatment plasma levels of <em>D</em>-<em>dimer</em>, fibrinogen, platelet count, lactate dehydrogenase concentration and Karnofsky performance status were predictive for survival. With the multivariate analysis (P< or =0.1), the plasma level of <em>D</em>-<em>dimer</em> (P<0.001), tumour stage (P=0.01) and Karnofsky performance status (P=0.0<em>2</em>) were identified as independent predictive factors. The median survival times were 405 days (95% confidence interval 165-644 days) and <em>2</em>07 days (95% confidence interval 146-<em>2</em>67 days, P<0.001), respectively, for patients with a low <em>D</em>-<em>dimer</em> level (< or =0.65 microg/ml) and a high <em>D</em>-<em>dimer</em> level (>0.65 microg/ml).

CONCLUSIONS

Elevated plasma levels of D-dimer in patients with lung cancer are associated with decreased survival and a poor response to treatment. Pre-treatment for the D-dimer level may be useful in the prediction of survival and the response to treatment.

Chronic HIV infection is characterized by chronic immune activation and dysfunctional T cells with elevated intracellular cyclic AMP (cAMP), which inhibits the T cell activation capability. cAMP may be induced by prostaglandin E(<em>2</em>) following lipopolysaccharide (LPS)-induced upregulation of cyclooxygenase type <em>2</em> (COX-<em>2</em>) in monocytes due to the elevated LPS levels in patients with chronic HIV infection. This hypothesis was tested using celecoxib, a COX-<em>2</em> inhibitor, for 1<em>2</em> weeks in HIV-infected patients without antiretroviral treatment in a prospective, open, randomized exploratory trial. Thirty-one patients were randomized in the trial; <em>2</em>7 completed the study, including 13 patients on celecoxib. Celecoxib reduced chronic immune activation in terms of C<em>D</em>38 density on C<em>D</em>8(+) T cells (-<em>2</em>4%; P = 0.04), IgA levels (P = 0.04), and a combined score for inflammatory markers (P < 0.05). Celecoxib further reduced the inhibitory surface receptor programmed death 1 (P<em>D</em>-1) on C<em>D</em>8(+) T cells (P = 0.01), including P<em>D</em>-1 on the HIV Gag-specific subset (P = 0.0<em>2</em>), enhanced the number of C<em>D</em>3(+) C<em>D</em>4(+) C<em>D</em><em>2</em>5(+) C<em>D</em>1<em>2</em>7(lo/-) Treg or activated cells (P = 0.0<em>2</em>), and improved humoral memory recall responses to a T cell-dependent vaccine (P = 0.04). HIV RNA (P = 0.06) and <em>D</em> <em>dimers</em> (P = 0.07) tended to increase in the controls, whereas interleukin-6 (IL-6) possibly decreased in the treatment arm (P = 0.10). In conclusion, celecoxib downmodulated the immune activation related to clinical progression of chronic HIV infection and improved T cell-dependent functions in vivo.

BACKGROUND

Clinical probability assessment is combined with d-dimer testing to exclude pulmonary embolism (PE).

OBJECTIVE

To compare the test characteristics of gestalt (a physician's unstructured estimate) and clinical decision rules for evaluating adults with suspected PE and assess the failure rate of gestalt and rules when used in combination with d-dimer testing.

METHODS

Articles in MEDLINE and EMBASE in English, French, German, Italian, Spanish, or Dutch that were published between 1966 and June 2011.

METHODS

3 reviewers, working in pairs, selected prospective studies in consecutive patients suspected of having PE. Studies had to estimate the probability of PE by using gestalt or a decision rule and verify the diagnosis by using an appropriate reference standard.

METHODS

Data on study characteristics, test performance, and prevalence were extracted. Reviewers constructed 2 × 2 tables and assessed the methodological quality of the studies.

RESULTS

52 studies, comprising 55 268 patients, were selected. Meta-analysis was performed on studies that used gestalt (15 studies; sensitivity, 0.85; specificity, 0.51), the Wells rule with a cutoff value less than 2 (19 studies; sensitivity, 0.84; specificity, 0.58) or 4 or less (11 studies; sensitivity, 0.60; specificity, 0.80), the Geneva rule (5 studies; sensitivity, 0.84; specificity, 0.50), and the revised Geneva rule (4 studies; sensitivity, 0.91; specificity, 0.37). An increased prevalence of PE was associated with higher sensitivity and lower specificity. Combining a decision rule or gestalt with d-dimer testing seemed safe for all strategies, except when the less-sensitive Wells rule (cutoff value ≤4) was combined with less-sensitive qualitative d-dimer testing.

CONCLUSIONS

Studies had substantial heterogeneity due to prevalence of PE and differences in threshold. Many studies (63%) had potential bias due to differential disease verification.

CONCLUSIONS

Clinical decision rules and gestalt can safely exclude PE when combined with sensitive d-dimer testing. The authors recommend standardized rules because gestalt has lower specificity, but the choice of a particular rule and d-dimer test depend on both prevalence and setting.

Granulocyte colony-stimulating factor (G-CSF) enhances neutrophil functions in vitro an<em>d</em> in vivo. It is known that neutrophil-<em>d</em>erive<em>d</em> pro<em>d</em>ucts can alter the hemostatic balance. To un<em>d</em>erstan<em>d</em> whether polymorphonuclear leukocyte (PMN) activation, measure<em>d</em> as PMN <em>d</em>egranulation an<em>d</em> phenotypical change, may be associate<em>d</em> to hemostatic alterations in vivo, we have stu<em>d</em>ie<em>d</em> the effect of recombinant human G-CSF (rHuG-CSF) a<em>d</em>ministration on leukocyte parameters an<em>d</em> hemostatic variables in healthy <em>d</em>onors of hematopoietic progenitor cells (HPCs). Twenty-six consecutive healthy <em>d</em>onors receiving 10 micrograms/kg/<em>d</em> rHuG-CSF subcutaneously for 5 to 7 <em>d</em>ays to mobilize HPCs for allogeneic transplants were inclu<em>d</em>e<em>d</em> in the stu<em>d</em>y. All of them respon<em>d</em>e<em>d</em> to rHuG-CSF with a significant white bloo<em>d</em> cell count increase. Bloo<em>d</em> samples were <em>d</em>rawn before therapy on <em>d</em>ays <em>2</em> an<em>d</em> 5 an<em>d</em> 1 week after stopping rHuG-CSF treatment. The following parameters were evaluate<em>d</em>: (1) PMN activation parameters, ie, surface C<em>D</em>11b/C<em>D</em>18 antigen expression, plasma elastase antigen levels an<em>d</em> cellular elastase activity; (<em>2</em>) plasma markers of en<em>d</em>othelium activation, ie, thrombomo<em>d</em>ulin (TM) an<em>d</em> von Willebran<em>d</em> factor (vWF) antigens; (3) plasma markers of bloo<em>d</em> coagulation activation, ie, F1+<em>2</em>, TAT complex, <em>D</em>-<em>dimer</em>; an<em>d</em> (4) mononuclear cell (MNC) procoagulant activity (PCA) expression. The results show that, after starting rHuG-CSF, an in vivo PMN activation occurre<em>d</em>, as <em>d</em>emonstrate<em>d</em> by the significant increment of surface C<em>D</em>11b/C<em>D</em>18 an<em>d</em> plasma elastase antigen levels. Moreover, PMN cellular elastase activity, which was significantly increase<em>d</em> at 1 <em>d</em>ay of treatment, returne<em>d</em> to baseline at <em>d</em>ay 5 to 6, in correspon<em>d</em>ence with the elastase antigen peak in the circulation. This change was accompanie<em>d</em> by a parallel significant increase in plasma levels of the two en<em>d</em>othelial an<em>d</em> the three coagulation markers. The PCA generate<em>d</em> in vitro by unstimulate<em>d</em> MNC isolate<em>d</em> from rHuG-CSF-treate<em>d</em> subjects was not <em>d</em>ifferent from that of control cells from untreate<em>d</em> subjects. However, en<em>d</em>otoxin-stimulate<em>d</em> MNC isolate<em>d</em> from on-treatment in<em>d</em>ivi<em>d</em>uals pro<em>d</em>uce<em>d</em> significantly more PCA compare<em>d</em> with both baseline an<em>d</em> control samples. All of the parameters were <em>d</em>ecrease<em>d</em> or normal 1 week after stopping treatment. These <em>d</em>ata show that rHuG-CSF in<em>d</em>uces PMN activation an<em>d</em> transiently affects some hemostatic variables in healthy HPC <em>d</em>onor subjects. The clinical significance of these fin<em>d</em>ings remains to be establishe<em>d</em>.

Human dipeptidyl peptidase I was expressed in the insect cell/baculovirus system and purified in its active (rh<em>D</em>PPI) and precursor (pro-rh<em>D</em>PPI) forms. Rh<em>D</em>PPI was very similar to the purified enzyme (h<em>D</em>PPI) with respect to glycosylation, enzymatic processing, oligomeric structure, C<em>D</em> spectra, and catalytic activity. The precursor, which was a <em>dimer</em>, could be activated approximately <em>2</em>000-fold with papain. Cathepsin L efficiently activated pro-rh<em>D</em>PPI in vitro at pH 4.5 (k(app) approximately <em>2</em> x 10(3) min(-)(1) M(-)(1)), and two cleavage pathways were characterized. The initial cleavage was within the pro region between the residual pro part and the activation peptide. Subsequently, the activation peptide was cleaved from the catalytic region, and the latter was cleaved into the heavy and light chains. Alternatively, the pro region was first separated from the catalytic region. Cathepsin S was a less efficient activating enzyme. Cathepsin B and rh<em>D</em>PPI did not activate pro-rh<em>D</em>PPI, and the proenzyme was incapable of autoactivation. Incubation of both pro-rh<em>D</em>PPI and rh<em>D</em>PPI with cathepsin <em>D</em> resulted in degradation. Cystatin C and stefins A and B inhibited rh<em>D</em>PPI with K(i) values in the nanomolar range (K(i) = 0.5-1.1 nM). The results suggest that cathepsin L could be an important activator of <em>D</em>PPI in vivo and that cathepsin <em>D</em> and possibly the cystatins may contribute to <em>D</em>PPI downregulation.

BACKGROUND

The genetic modification of pigs is a powerful strategy that may ultimately enable successful xenotransplantation of porcine organs into humans.

METHODS

Transgenic pigs were produced by microinjection of gene constructs for human complement regulatory proteins C<em>D</em>55 and C<em>D</em>59 and the enzyme alpha1,<em>2</em>-fucosyltransferase (H-transferase, HT), which reduces expression of the major xenoepitope galactose-alpha1,3-galactose (alphaGal). Kidneys from C<em>D</em>55/HT and C<em>D</em>55/C<em>D</em>59/HT transgenic pigs were transplanted into nephrectomised, nonimmunosuppressed adult baboons.

RESULTS

In several lines of transgenic pigs, C<em>D</em>55 and C<em>D</em>59 were expressed strongly in all tissues examined, whereas HT expression was relatively weak and did not significantly reduce alphaGal. Control nontransgenic kidneys (n=4) grafted into baboons were hyperacutely rejected within 1 hr. In contrast, kidneys from C<em>D</em>55/HT pigs (n=<em>2</em>) were rejected after 30 hr, although kidneys from C<em>D</em>55/C<em>D</em>59/HT pigs (n=6) maintained function for up to 5 days. In the latter grafts, infiltration by macrophages, T cells, and B cells was observed at days 3 and 5 posttransplantation. The recipients developed thrombocytopenia and abnormalities in coagulation, manifested in increased clotting times and an elevation in the plasma level of the fibrin degradation product <em>D</em>-<em>dimer</em>, within <em>2</em> days of transplantation. Treatment with low molecular weight heparin prevented profound thrombocytopenia but not the other aspects of coagulopathy.

CONCLUSIONS

Strong expression of C<em>D</em>55 and C<em>D</em>59 completely protected porcine kidneys from hyperacute rejection and allowed a detailed analysis of xenograft rejection in the absence of immunosuppression. Coagulopathy appears to be a common feature of pig-to-baboon renal transplantation and represents yet another major barrier to its clinical application.

<em>D</em>evelopmental studies of oncogene expression implicate the Fos and Jun family of transcription factors in the regulation of bone growth and differentiation. Promoters of many developmentally regulated genes, including osteocalcin, a marker of osteoblast differentiation, contain AP-1 sites that bind Fos/Jun <em>dimers</em>. Here, we demonstrate that the selective expression of fos- and jun-related genes is functionally related to the stage of osteoblast growth and differentiation in vitro. <em>D</em>uring osteoblast proliferation, nuclear protein levels of all seven activating protein-1 (AP-1) members are maximal. Subsequently, during the period of extracellular matrix maturation, levels decline. In fully differentiated osteoblasts, Fra-<em>2</em> and (to a lesser extent) Jun <em>D</em> are the principal AP-1 members detectable by Western blot analysis. AP-1 complex composition and binding activity also exhibit developmental changes. All Fos and Jun family members are involved in AP-1 complex formation in proliferating cells, whereas Fra-<em>2</em> and Jun <em>D</em> predominate in AP-1 complexes in differentiated osteoblasts. Overexpression of Fos and Jun family members in ROS 17/<em>2</em>.8 cells markedly affects the expression of an osteocalcin promoter-chloramphenicol acetyltransferase construct. Coexpression of only one AP-1 pair, Fra-<em>2</em> and Jun <em>D</em>, stimulated reporter expression, whereas coexpression of other AP-1 pairs down-regulated expression (i.e. c-jun and any Fos family member) or had no effect (i.e. Fra-1 and Jun B). Promoter deletion analyses indicate that these effects are site specific. Consequential effects of Fra-<em>2</em> on osteoblast differentiation are further demonstrated by antisense studies in which osteoblast differentiation and the development of a bone tissue-like organization were suppressed. Consistent with recent findings suggesting that AP-1 complex composition can selectively regulate gene transcription, our findings demonstrate that differential expression of Fos and Jun family members could play a role in the developmental regulation of bone-specific gene expression and, as a result, may be functionally significant for osteoblast differentiation.

Previously, we pro<em>d</em>uce<em>d</em> the whole extracellular region of metabotropic glutamate receptor subtype 1 (mGluR1) in a soluble form. The soluble receptor retaine<em>d</em> a ligan<em>d</em> affinity comparable with that of the full-length membrane-boun<em>d</em> receptor an<em>d</em> forme<em>d</em> a <em>d</em>isulfi<em>d</em>e-linke<em>d</em> <em>dimer</em>. Here, we have i<em>d</em>entifie<em>d</em> a cysteine resi<em>d</em>ue responsible for the intermolecular <em>d</em>isulfi<em>d</em>e bon<em>d</em> an<em>d</em> <em>d</em>etermine<em>d</em> <em>d</em>omain organization of the extracellular region of mGluR1. A mutant, C140A, was a monomer un<em>d</em>er nonre<em>d</em>uce<em>d</em> con<em>d</em>itions by SDS-polyacrylami<em>d</em>e gel electrophoresis; however, C140A was elute<em>d</em> at the position similar to that of mGluR113, the wil<em>d</em> type soluble receptor, by size exclusion column chromatography. Furthermore, C140A boun<em>d</em> a ligan<em>d</em>, [(3)H]quisqualate, with an affinity similar to that obtaine<em>d</em> by mGluR113. Oocytes injecte<em>d</em> with RNA for full-length mGluR1 containing C140A mutation showe<em>d</em> responses to ligan<em>d</em>s at magnitu<em>d</em>es similar to those with wil<em>d</em> type full-length RNA. Thus, elimination of the <em>d</em>isulfi<em>d</em>e linkage <em>d</em>i<em>d</em> not perturb the <em>dimer</em> formation an<em>d</em> ligan<em>d</em> signaling, suggesting that cryptic <em>dimer</em> interface(s) possibly exist in mGluR1. Limite<em>d</em> proteolysis of the whole extracellular fragment (resi<em>d</em>ue 33-59<em>2</em>) reveale<em>d</em> two trypsin-sensitive sites, after the resi<em>d</em>ues Arg(139) an<em>d</em> Arg(5<em>2</em>1). A 15-kDa NH(<em>2</em>)-terminal proteolytic fragment (resi<em>d</em>ue 33-139) was associate<em>d</em> with the <em>d</em>ownstream part after the <em>d</em>igestion. Arg(5<em>2</em>1) was locate<em>d</em> before a cysteine-rich stretch prece<em>d</em>ing the transmembrane region. A new shorter soluble receptor (resi<em>d</em>ue 33-5<em>2</em><em>2</em>) lacking the cysteine-rich region was <em>d</em>esigne<em>d</em> base<em>d</em> on the protease-sensitive boun<em>d</em>ary. The purifie<em>d</em> receptor protein gave a K(<em>d</em>) value of 58.1 +/- 0.84 nm, which is compatible to a reporte<em>d</em> value of the full-length receptor. The B(max) value was 7.06 +/- 0. 8<em>2</em> nmol/mg of protein. These results in<em>d</em>icate<em>d</em> that the ligan<em>d</em>-bin<em>d</em>ing specificity of mGluR1 is confine<em>d</em> to the NH(<em>2</em>)-terminal 490-amino aci<em>d</em> region of the mature protein.

BACKGROUND

Efforts to achieve tolerance to transplanted pig organs in nonhuman primates by the induction of a state of mixed hematopoietic chimerism have been associated with disorders of coagulation and thrombosis. Activation of recipient vascular endothelium and platelets by porcine hematopoietic cells and/or activation of donor organ vascular endothelium and/or molecular differences between the species may play roles. Irradiation or drug therapy could possibly potentiate endothelial cell activation and/or injury.

METHODS

We have investigated parameters of coagulation and platelet activation in nonhuman primates after (1) a regimen aimed at inducing mixed hematopoietic chimerism and tolerance (TIR that included total body irradiation, T cell depletion, and splenectomy; (<em>2</em>) pig bone marrow or pig peripheral blood mobilized progenitor cell transplantation (PCTx); and/or (3) pig organ transplantation (POTx). Five experimental groups were studied. Baboons were the recipient subjects in all groups except Group 1. Gp 1 Cynomolgus monkeys (n=6) underwent TIR + allotransplantation of hematopoietic cells and a kidney or heart or TIR + concordant xenotransplantation (using baboons as donors) of cells and a kidney; Gp <em>2</em> Baboons (n=4) underwent TIR with or without (+/-) autologous hematopoietic cell infusion; Gp 3 (n=1<em>2</em>) PCTx+/-TIR; Gp 4 (n=5) POTx+/-TIR; Gp 5 (n=4) TIR + PCTx + POTx. Platelet counts, with plasma prothrombin time, partial thromboplastin time, fibrinogen levels, fibrin split products and/or <em>D</em>-<em>dimer</em> were measured.

RESULTS

In the absence of a discordant (porcine) cellular or organ transplant (Groups 1 and <em>2</em>), TIR resulted in transient thrombocytopenia only, in keeping with bone marrow depression from irradiation. PCTx alone (Group 3) was associated with the rapid development of a thrombotic thrombocytopenic (TTP)-like microangiopathic state, that persisted longer when PCTx was combined with TIR. POTx (+/-TIR) (Group 4) was associated with a gradual fall (over several days) in platelet counts and fibrinogen with disseminated intravascular coagulation (<em>D</em>IC); after graft excision, the <em>D</em>IC generally resolved. When TIR, PCTx and POTx were combined (Group 5), an initial TTP-like state was superseded by a consumptive picture of <em>D</em>IC within the first week, necessitating graft removal.

CONCLUSIONS

Both PCTx and POTx lead to profound alterations in hemostasis and coagulation parameters that must be overcome if discordant xenotransplantation of hematopoietic cells and organs is to be fully successful. Disordered thromboregulation could exacerbate vascular damage and potentiate activation of coagulation pathways after exposure to xenogeneic cells or a vascularized xenograft.

We have measured the lateral diffusion coefficient (<em>D</em>), of active dansyl-labeled gramicidin C (<em>D</em>GC), using the technique of fluorescence photobleaching recovery, under conditions in which the cylindrical <em>dimer</em> channel of <em>D</em>GC predominates. In pure, hydrated, dimyristoylphosphatidylcholine (<em>D</em>MPC) multibilayers (MBL), <em>D</em> decreases from 6 X 10(-8) cm<em>2</em>/s at 40 degrees C to 3 X 10(-8) cm<em>2</em>/s at <em>2</em>5 degrees C, and drops 100-fold at <em>2</em>3 degrees C, the phase transition temperature (Tm) of <em>D</em>MPC. Above Tm, addition of cholesterol decreases <em>D</em>; a threefold stepwise drop occurs between 10 and <em>2</em>0 mol %. Below Tm, increasing cholesterol increases <em>D</em>; a 10-fold increase occurs between 10 and <em>2</em>0 mol % at <em>2</em>1 degrees C, between <em>2</em>0 and <em>2</em>5 mol % at 15 degrees C, and between <em>2</em>5 and 30 mol % at 5 degrees C. In egg phosphatidylcholine (EPC) MBL, <em>D</em> decreases linearly from 5 X 10(-8) cm<em>2</em>/s at 35 degrees C to <em>2</em> X 10(-8) cm<em>2</em>/s at 5 degrees C; addition of equimolar cholesterol reduces <em>D</em> by a factor of <em>2</em>. Thus this transmembrane polypeptide at low membrane concentrations diffuses quite like a lipid molecule. Its diffusivity in lipid mixtures appears to reflect predicted changes of lateral composition. Increasing gramicidin C (GC) in <em>D</em>MPC/GC MBL broadened the phase transition, and the diffusion coefficient of the lipid probe N-4-nitrobenzo-<em>2</em>-diazole phosphatidylethanolamine (NB<em>D</em>-PE) at 30 degrees C decreases from 8 X 10(-8) cm<em>2</em>/s below 5 mol % GC to <em>2</em> X 10(-8) cm<em>2</em>/s at 14 mol % GC; <em>D</em> for <em>D</em>GC similarly decreases from 4 X 10(-8) cm<em>2</em>/s at <em>2</em> mol % GC to 1.4 X 10(-8) cm<em>2</em>/s at 14 mol % GC. Hence, above Tm, high concentrations of this polypeptide restrict the lateral mobility of membrane components.

BfiI is a novel type IIs restriction endonuclease that, unlike all other restriction enzymes characterised to date, cleaves <em>D</em>NA in the absence of Mg(<em>2</em>+). The amino acid sequence of the N-terminal part of BfiI has some similarities to Nuc of Salmonella typhimurium, an E<em>D</em>TA-resistant nuclease akin to phospholipase <em>D</em>. The <em>dimer</em>ic form of Nuc contains a single active site composed of residues from both subunits. To examine the roles of the amino acid residues of BfiI that align with the catalytic residues in Nuc, a set of alanine replacement mutants was generated by site-directed mutagenesis. The mutationally altered forms of BfiI were all catalytically inactive but were still able to bind <em>D</em>NA specifically. The active site of BfiI is thus likely to be similar to that of Nuc. BfiI was also found by gel-filtration to be a <em>dimer</em> in solution. Both gel-shift and pull-down assays indicated that the <em>dimer</em>ic form of BfiI binds two copies of its recognition sequence. In reactions on plasmids with either one or two copies of its recognition sequence, BfiI cleaved the <em>D</em>NA with two sites more rapidly than that with one site. Yet, when bound to two copies of its recognition sequence, the BfiI <em>dimer</em> cleaved only one phosphodiester bond at a time. The <em>dimer</em> thus seems to contain two <em>D</em>NA-binding domains but only one active site.

Background: A subset of patients with COVID-19 develops a hyperinflammatory syndrome that has similarities with other hyperinflammatory disorders. However, clinical criteria specifically to define COVID-19-associated hyperinflammatory syndrome (cHIS) have not been established. We aimed to develop and validate diagnostic criteria for cHIS in a cohort of inpatients with COVID-19.

Methods: We searched for clinical research articles published between Jan 1, 1990, and Aug 20, 2020, on features and diagnostic criteria for secondary haemophagocytic lymphohistiocytosis, macrophage activation syndrome, macrophage activation-like syndrome of sepsis, cytokine release syndrome, and COVID-19. We compared published clinical data for COVID-19 with clinical features of other hyperinflammatory or cytokine storm syndromes. Based on a framework of conserved clinical characteristics, we developed a six-criterion additive scale for cHIS: fever, macrophage activation (hyperferritinaemia), haematological dysfunction (neutrophil to lymphocyte ratio), hepatic injury (lactate dehydrogenase or asparate aminotransferase), coagulopathy (D-dimer), and cytokinaemia (C-reactive protein, interleukin-6, or triglycerides). We then validated the association of the cHIS scale with in-hospital mortality and need for mechanical ventilation in consecutive patients in the Intermountain Prospective Observational COVID-19 (IPOC) registry who were admitted to hospital with PCR-confirmed COVID-19. We used a multistate model to estimate the temporal implications of cHIS.

Findings: We included 299 patients admitted to hospital with COVID-19 between March 13 and May 5, 2020, in analyses. Unadjusted discrimination of the maximum daily cHIS score was 0·81 (95% CI 0·74-0·88) for in-hospital mortality and 0·92 (0·88-0·96) for mechanical ventilation; these results remained significant in multivariable analysis (odds ratio 1·6 [95% CI 1·2-2·1], p=0·0020, for mortality and 4·3 [3·0-6·0], p<0·0001, for mechanical ventilation). 161 (54%) of 299 patients met two or more cHIS criteria during their hospital admission; these patients had higher risk of mortality than patients with a score of less than 2 (24 [15%] of 138 vs one [1%] of 161) and for mechanical ventilation (73 [45%] vs three [2%]). In the multistate model, using daily cHIS score as a time-dependent variable, the cHIS hazard ratio for worsening from low to moderate oxygen requirement was 1·4 (95% CI 1·2-1·6), from moderate oxygen to high-flow oxygen 2·2 (1·1-4·4), and to mechanical ventilation 4·0 (1·9-8·2).

Interpretation: We proposed and validated criteria for hyperinflammation in COVID-19. This hyperinflammatory state, cHIS, is commonly associated with progression to mechanical ventilation and death. External validation is needed. The cHIS scale might be helpful in defining target populations for trials and immunomodulatory therapies.

Funding: Intermountain Research and Medical Foundation.

BACKGROUND

Although diabetes mellitus is implicated in susceptibility to infection, the association of diabetes with the subsequent course and outcome is unclear.

METHODS

A retrospective analysis of two multicentre cohorts was carried out. The effect of pre-existing diabetes on the host immune response, acute organ function and mortality in patients hospitalised with community-acquired pneumonia (CAP) in the GenIMS study (n=1895) and on mortality following either CAP or non-infectious hospitalisations in the population-based cohort study, Health ABC (n=1639) was determined. Measurements included the mortality rate within the first year, risk of organ dysfunction, and immune responses, including circulating inflammatory (tumour necrosis factor, interleukin 6, interleukin 10), coagulation (Factor IX, thrombin-antithrombin complexes, antithrombin), fibrinolysis (plasminogen-activator inhibitor-1 and <em>D</em>-<em>dimer</em>) and cell surface markers (C<em>D</em>1<em>2</em>0a, C<em>D</em>1<em>2</em>0b, human leucocyte antigen (HLA)-<em>D</em>R, Toll-like receptor-<em>2</em> and Toll-like receptor-4).

RESULTS

In GenIMS, diabetes increased the mortality rate within the first year after CAP (unadjusted HR 1.41, 95% CI 1.1<em>2</em> to 1.76, p=0.00<em>2</em>), even after adjusting for pre-existing cardiovascular and renal disease (adjusted HR 1.3, 95% CI 1.03 to 1.65, p=0.0<em>2</em>). In Health ABC, diabetes increased the mortality rate within the first year following CAP hospitalisation, but not after hospitalisation for non-infectious illnesses (significant interaction for diabetes and reason for hospitalisation (p=0.04); HR for diabetes on mortality over the first year after CAP 1.87, 95% CI 0.76 to 4.6, p=0.16, and after non-infectious hospitalisation 1.16, 95% CI 0.8 to 1.6, p=0.37). In GenIMS, immediate immune response was similar, as evidenced by similar circulating immune marker levels, in the emergency department and during the first week. Those with diabetes had a higher risk of acute kidney injury during hospitalisation (39.3% vs 31.7%, p=0.005) and they were more likely to die due to cardiovascular and kidney disease (34.4% vs <em>2</em>6.8% and 10.4% vs 4.5%, p=0.03).

CONCLUSIONS

Pre-existing diabetes was associated with a higher risk of death following CAP. The mechanism is not due to an altered immune response, at least as measured by a broad panel of circulating and cell surface markers, but may be due to worsening of pre-existing cardiovascular and kidney disease.

The effect of increased expression or reconstitution of the mitochondrial inhibitor protein (IF1) on the <em>dimer</em>/monomer ratio (<em>D</em>/M) of the rat liver and bovine heart F1F0-ATP synthase was studied. The <em>2</em>-fold increased expression of IF1 in AS-30<em>D</em> hepatoma mitochondria correlated with a 1.4-fold increase in the <em>D</em>/M ratio of the ATP synthase extracted with digitonin as determined by blue native electrophoresis and averaged densitometry analyses. Removal of IF1 from rat liver or bovine heart submitochondrial particles increased the F1F0-ATPase activity and decreased the <em>D</em>/M ratio of the ATP synthase. Reconstitution of recombinant IF1 into submitochondrial particles devoid of IF1 inhibited the F1F0-ATPase activity by 90% and restored partially the <em>D</em>/M ratio of the whole F1F0 complex as revealed by blue native electrophoresis and subsequent S<em>D</em>S-PAGE or glycerol density gradient centrifugation. Thus, the inhibitor protein promotes or stabilizes the <em>dimer</em>ic form of the intact F1F0-ATP synthase. A possible location of the IF1 protein in the <em>dimer</em>ic structure of the rat liver F1F0 complex is proposed. According to crystallographic and electron microscopy analyses, <em>dimer</em>ic IF1 could bridge the F1-F1 part of the <em>dimer</em>ic F1F0-ATP synthase in the inner mitochondrial membrane.

Overuse of the <em>d</em>-<em>dimer</em> to screen for possible pulmonary embolism (PE) can have negative consequences. This stu<em>d</em>y <em>d</em>erives an<em>d</em> tests clinical criteria to justify not or<em>d</em>ering a <em>d</em>-<em>dimer</em>. The test threshol<em>d</em> was estimate<em>d</em> at 1.8% using the metho<em>d</em> of Pauker an<em>d</em> Kassirer. The PE rule-out criteria were <em>d</em>erive<em>d</em> from logistic regression analysis with stepwise backwar<em>d</em> elimination of <em>2</em>1 variables collecte<em>d</em> on 3148 emergency <em>d</em>epartment patients evaluate<em>d</em> for PE at 10 US hospitals. Eight variables were inclu<em>d</em>e<em>d</em> in a block rule: Age < 50 years, pulse < 100 bpm, SaO(<em>2</em>)>> 94%, no unilateral leg swelling, no hemoptysis, no recent trauma or surgery, no prior PE or DVT, no hormone use. The rule was then prospectively teste<em>d</em> in a low-risk group (14<em>2</em>7 patients from two hospitals initially teste<em>d</em> for PE with a <em>d</em>-<em>dimer</em>) an<em>d</em> a very low-risk group (convenience sample of 38<em>2</em> patients with chief complaint of <em>d</em>yspnea, PE not suspecte<em>d</em>). The prevalence of PE was 8% (95% confi<em>d</em>ence interval: 7-9%) in the low-risk group an<em>d</em> <em>2</em>% (1-4%) in the very low-risk group on longitu<em>d</em>inal follow-up. Application of the rule in the low-risk an<em>d</em> very low-risk populations yiel<em>d</em>e<em>d</em> sensitivities of 96% an<em>d</em> 100% an<em>d</em> specificities of <em>2</em>7% an<em>d</em> 15%, respectively. The prevalence of PE in those who met the rule criteria was 1.4% (0.5-3.0%) an<em>d</em> 0% (0-6.<em>2</em>%), respectively. The <em>d</em>erive<em>d</em> eight-factor block rule re<em>d</em>uce<em>d</em> the pretest probability below the test threshol<em>d</em> for <em>d</em>-<em>dimer</em> in two vali<em>d</em>ation populations, but the rule's utility was limite<em>d</em> by low specificity.

BACKGROUND

Air pollution is associated with cardiovascular disease, and systemic inflammation may mediate this effect. We assessed associations between long- and short-term concentrations of air pollution and markers of inflammation, coagulation, and endothelial activation.

METHODS

We studied participants from the Multi-Ethnic Study of Atherosclerosis from <em>2</em>000 to <em>2</em>01<em>2</em> with repeat measures of serum C-reactive protein (CRP), interleukin-6 (IL-6), fibrinogen, <em>D</em>-<em>dimer</em>, soluble E-selectin, and soluble Intercellular Adhesion Molecule-1. Annual average concentrations of ambient fine particulate matter (PM<em>2</em>.5), individual-level ambient PM<em>2</em>.5 (integrating indoor concentrations and time-location data), oxides of nitrogen (NOx), nitrogen dioxide (NO<em>2</em>), and black carbon were evaluated. Short-term concentrations of PM<em>2</em>.5 reflected the day of blood draw, day prior, and averages of prior <em>2</em>-, 3-, 4-, and 5-day periods. Random-effects models were used for long-term exposures and fixed effects for short-term exposures. The sample size was between 9,000 and 10,000 observations for CRP, IL-6, fibrinogen, and <em>D</em>-<em>dimer</em>; approximately <em>2</em>,100 for E-selectin; and 3,300 for soluble Intercellular Adhesion Molecule-1.

RESULTS

After controlling for confounders, 5 µg/m increase in long-term ambient PM<em>2</em>.5 was associated with 6% higher IL-6 (95% confidence interval = <em>2</em>%, 9%), and 40 parts per billion increase in long-term NOx was associated with 7% (95% confidence interval = <em>2</em>%, 13%) higher level of <em>D</em>-<em>dimer</em>. PM<em>2</em>.5 measured at day of blood draw was associated with CRP, fibrinogen, and E-selectin. There were no other positive associations between blood markers and short- or long-term air pollution.

CONCLUSIONS

These data are consistent with the hypothesis that long-term exposure to air pollution is related to some markers of inflammation and fibrinolysis.

As the result of a high prevalence of fixed airways obstruction in workers at a microwave popcorn manufacturing plant, we examined the hypothesis that vapors of butter flavoring used in the manufacture of microwave popcorn and other foods can produce airway injury in rats. Rats were exposed to vapors liberated from heated butter flavoring. Rats were exposed for 6 h by inhalation and were necropsied 1 day after exposure. The exposure was found by GC-MS analysis to be a complex mixture of various organic gases with the major peaks consisting of diacetyl (<em>2</em>,3-butanedione), acetic acid, acetoin (3-hydroxy-<em>2</em>-butanone), butyric acid, acetoin <em>dimers</em>, <em>2</em>-nonanone, and <em>delta</em>-alkyl lactones. Diacetyl was used as a marker of exposure concentration. In the lung, butter flavoring vapors containing <em>2</em>85-371 ppm diacetyl caused multifocal, necrotizing bronchitis, which was most consistently present in the mainstem bronchus. Alveoli were unaffected. Butter flavoring vapors containing <em>2</em>03-371 ppm diacetyl caused necrosuppurative rhinitis, which affected all four levels of the nose. Within the posterior two nasal levels (T3 and T4), necrosis and inflammation was principally localized to the nasopharyngeal duct. Control rats were unaffected. Therefore, concentrations of butter flavoring vapors that can occur during the manufacture of foods are associated with epithelial injury in the nasal passages and pulmonary airways of rats.

Background: Obesity was recently identified as a major risk factor for worse COVID-19 severity, especially among the young. The reason why its impact seems to be less pronounced in the elderly may be due to the concomitant presence of other comorbidities. However, all reports only focus on BMI, an indirect marker of body fat. Aim To explore the impact on COVID-19 severity of abdominal fat as a marker of body composition easily collected in patients undergoing a chest CT scan.

<strong class="sub-title"> Methods: </strong> Patients included in this retrospective study were consecutively enrolled among those admitted to an Emergency Department in Rome, Italy, who tested positive for SARS-Cov-<em>2</em> and underwent a chest CT scan in March <em>2</em>0<em>2</em>0. Data were extracted from electronic medical records.

<strong class="sub-title"> Results: </strong> 150 patients were included (64.7% male, mean age 64 ± 16 years). Visceral fat (VAT) was significantly higher in patients requiring intensive care (p = .03<em>2</em>), together with age (p = .009), inflammation markers CRP and LDH (p < .0001, p = .003, respectively), and interstitial pneumonia severity as assessed by a Lung Severity Score (LSS) (p < .0001). Increasing age, lymphocytes, CRP, LDH, D-Dimer, LSS, total abdominal fat as well as VAT were found to have a significant univariate association with the need of intensive care. A multivariate analysis showed that LSS and VAT were independently associated with the need of intensive care (OR: 1.<em>2</em>6<em>2</em>; 95%CI: 1.0171-1.488; p = .005 and OR: <em>2</em>.474; 95%CI: 1.017-6.019; p = .046, respectively).

Conclusions: VAT is a marker of worse clinical outcomes in patients with COVID-19. Given the exploratory nature of our study, further investigation is needed to confirm our findings and elucidate the mechanisms underlying such association.

<strong class="sub-title"> Keywords: </strong> Body composition; Covid-19; Fat; Obesity; Risk factor; SARS-CoV-<em>2</em>.

Potassium channels are particularly important in <em>d</em>etermining the shape an<em>d</em> <em>d</em>uration of the action potential, controlling the membrane potential, mo<em>d</em>ulating hormone secretion, epithelial function an<em>d</em>, in the case of those K(+) channels activate<em>d</em> by Ca(<em>2</em>+), <em>d</em>amping excitatory signals. The multiplicity of roles playe<em>d</em> by K(+) channels is only possible to their mammoth <em>d</em>iversity that inclu<em>d</em>es at present 70 K(+) channels enco<em>d</em>ing genes in mammals. To<em>d</em>ay, thanks to the use of cloning, mutagenesis, an<em>d</em> the more recent structural stu<em>d</em>ies using x-ray crystallography, we are in a unique position to un<em>d</em>erstan<em>d</em> the origins of the enormous <em>d</em>iversity of this superfamily of ion channels, the roles they play in <em>d</em>ifferent cell types, an<em>d</em> the relations that exist between structure an<em>d</em> function. With the exception of two-pore K(+) channels that are <em>dimers</em>, voltage-<em>d</em>epen<em>d</em>ent K(+) channels are tetrameric assemblies an<em>d</em> share an extremely well conserve<em>d</em> pore region, in which the ion-selectivity filter resi<em>d</em>es. In the present overview, we <em>d</em>iscuss in the function, localization, an<em>d</em> the relations between function an<em>d</em> structure of the five <em>d</em>ifferent subfamilies of K(+) channels: (a) inwar<em>d</em> rectifiers, Kir; (b) four transmembrane segments-<em>2</em> pores, K<em>2</em>P; (c) voltage-gate<em>d</em>, Kv; (<em>d</em>) the Slo family; an<em>d</em> (e) Ca(<em>2</em>+)-activate<em>d</em> SK family, SKCa.

Reactive oxygen species (ROS) play important roles in multiple physiological processes such as cellular signalling an<em>d</em> stress responses, whereas, the hy<em>d</em>rogen peroxi<em>d</em>e (H(<em>2</em>)O(<em>2</em>)) scavenging enzyme ascorbate peroxi<em>d</em>ase (APX) participates in the regulation of intracellular ROS levels. Here, a cotton (Gossypium hirsutum) cytosolic APX1 (GhAPX1) was i<em>d</em>entifie<em>d</em> to be highly accumulate<em>d</em> <em>d</em>uring cotton fibre elongation by proteomic analysis. GhAPX1 cDNA containe<em>d</em> an open rea<em>d</em>ing frame of 753-bp enco<em>d</em>ing a protein of <em>2</em>50 amino aci<em>d</em> resi<em>d</em>ues. When GhAPX1 was expresse<em>d</em> in Escherichia coli, the purifie<em>d</em> GhAPX1 was a <em>dimer</em> consisting of two i<em>d</em>entical subunits with a molecular mass of <em>2</em>8 kDa. GhAPX1 showe<em>d</em> the highest substrate specificity for ascorbate. Quantitative real-time polymerase chain reaction (PCR) analyses showe<em>d</em> that GhAPX1 was highly expresse<em>d</em> in wil<em>d</em>-type 5-<em>d</em> postanthesis fibres with much lower transcript levels in the fuzzless-lintless mutant ovules. Treating in vitro culture<em>d</em> wil<em>d</em>-type cotton ovules with exogenous H(<em>2</em>)O(<em>2</em>) or ethylene in<em>d</em>uce<em>d</em> the expression of GhAPX1 an<em>d</em> hence increase<em>d</em> total APX activity proportionally, followe<em>d</em> by exten<em>d</em>e<em>d</em> fibre cell elongation. These <em>d</em>ata suggest that GhAPX1 expression is upregulate<em>d</em> in response to an increase in cellular H(<em>2</em>)O(<em>2</em>) an<em>d</em> ethylene. GhAPX1 enco<em>d</em>es a functional enzyme that is involve<em>d</em> in hy<em>d</em>rogen peroxi<em>d</em>e homeostasis <em>d</em>uring cotton fibre <em>d</em>evelopment.

An ongoing global pandemic of viral pneumonia (coronavirus disease [COVI<em>D</em>-19]), due to the virus SARS-CoV-<em>2</em>, has infected millions of people and remains a threat to many more. Most critically ill patients have respiratory failure and there is an international effort to understand mechanisms and predictors of disease severity. Coagulopathy, characterized by elevations in <em>D</em>-<em>dimer</em> and fibrin(ogen) degradation products (F<em>D</em>Ps), is associated with critical illness and mortality in patients with COVI<em>D</em>-19. Furthermore, increasing reports of microvascular and macrovascular thrombi suggest that hemostatic imbalances may contribute to the pathophysiology of SARS-CoV-<em>2</em> infection. We review the laboratory and clinical findings of patients with COVI<em>D</em>-19-associated coagulopathy, and prior studies of hemostasis in other viral infections and acute respiratory distress syndrome. We hypothesize that an imbalance between coagulation and inflammation may result in a hypercoagulable state. Although thrombosis initiated by the innate immune system is hypothesized to limit SARS-CoV-<em>2</em> dissemination, aberrant activation of this system can cause endothelial injury resulting in loss of thromboprotective mechanisms, excess thrombin generation, and dysregulation of fibrinolysis and thrombosis. The role various components including neutrophils, neutrophil extracellular traps, activated platelets, microparticles, clotting factors, inflammatory cytokines, and complement play in this process remains an area of active investigation and ongoing clinical trials target these different pathways in COVI<em>D</em>-19.

Keywords: COVID-19; NETs; anticoagulation; antiplatelet; coagulation; coronavirus; inflammation; neutrophils; thrombosis; vascular endothelium; venous thromboembolism (VTE).

<AbstractText>Coronavirus disease <em>2</em>019 (COVI<em>D</em>-19) caused by severe acute respiratory syndrome coronavirus <em>2</em> (SARS-CoV-<em>2</em>) infection has been spread worldwide.</AbstractText><AbstractText>To identify the clinical characteristics and risk factors associated with the severe incidence of SARS-CoV-<em>2</em> infection.</AbstractText><AbstractText>All adult patients (≥18 years old) consecutively admitted in <em>D</em>abieshan Medical Center from January 30, <em>2</em>0<em>2</em>0 to February 11, <em>2</em>0<em>2</em>0 were collected and reviewed. Only patients diagnosed with COVI<em>D</em>-19 according to WHO interim guidance were included in this retrospective cohort study.</AbstractText><AbstractText>A total of 108 patients with COVI<em>D</em>-19 were retrospectively analyzed. Twenty-five patients (<em>2</em>3.1%, <em>2</em>5/108) developed severe disease, and of those 1<em>2</em> (48%, 1<em>2</em>/<em>2</em>5) patients died. Advanced age, co-morbidities with hypertension, higher blood leukocyte count, neutrophil count, higher sensitive C-reactive protein level, <em>D</em>-<em>dimer</em> level, Acute Physiology and Chronic Health Evaluation Ⅱ (APECHE Ⅱ) score and Sequential Organ Failure Assessment (SOFA) score were associated with greater risk of development of severe COVI<em>D</em>-19, and so were lower lymphocyte count and albumin level. Multivariable regression showed increasing odds of severe COVI<em>D</em>-19 associated with higher SOFA score (OR <em>2</em>.450, 1.30<em>2</em>-4.608; p = 0.005), and lymphocyte count less than 0.8×109 per L (OR 9.017, <em>2</em>.808-<em>2</em>8.857; p <0.001) on admission. The higher SOFA score (OR <em>2</em>.40<em>2</em>, 1.313-4.395; p = 0.004) on admission was identified as risk factor for in-hospital death.</AbstractText><AbstractText>Lymphocytopenia and the higher SOFA score on admission could help clinicians to identify patients with high risk for developing severe COVI<em>D</em>-19. More related studies are needed in the future.</AbstractText>

Maize bran contains phenolic acids [approximately 4% dry matter; mainly ferulic acid (Fe) and also diferulic acid], heteroxylans (approximately 50%), and cellulose (approximately <em>2</em>0%), but is devoid of lignin. Treatment of maize pericarp with 0.05 M trifluoroacetic acid at 100 degrees C for <em>2</em> h released approximately 90% of the heteroxylans and approximately 90% of the ferulic acid and its esters. After fractionation of the products with Amberlite XA<em>D</em>-<em>2</em> and Sephadex LH-<em>2</em>0 three main feruloylated oligosaccharides (F3-F7) were isolated. They represented approximately 30% of the ferulic acid, and approximately <em>2</em>% of the neutral sugars contained in the hydrolysis supernatant. The compositions of F7, F6, and F3 were Fe-Ara (1:1), Fe-Ara-Xyl (1:1:1), and Fe-Ara-Xyl-Gal (1:1:1:1), respectively. The structures of the three oligomers were determined using chemical methods (methylation, acetalation, reduction) and 13C NMR spectroscopy: F7 was 5-O-(trans-feruloyl)-L-Araf;F6 was O-beta-<em>D</em>-Xyl p-(1->><em>2</em>)-[5-O-(trans-feruloyl)-L-Araf]; and F3 was O-L-Gal p-(1-->4)-O-<em>D</em>-Xyl p-(1->><em>2</em>)-[5-O-(trans-feruloyl)-L- Araf]. F7 has been previously isolated from other monocots especially from wheat bran and soluble arabinoxylans from wheat flour; this is the first report of feruloylated oligosaccharides F6 and F3. Our results suggest that these oligomers are side-chain constituents of heteroxylans in maize bran. Ferulic acid is probably partly responsible for the insolubility of heteroxylans by coupling polysaccharide chains through ferulic acid <em>dimers</em>.

<strong class="sub-title"> Background: </strong> COVID-19 can course with respiratory and extrapulmonary disease. SARS-CoV-<em>2</em> RNA is detected in respiratory samples but also in blood, stool and urine. Severe COVID-19 is characterized by a dysregulated host response to this virus. We studied whether viral RNAemia or viral RNA load in plasma is associated with severe COVID-19 and also to this dysregulated response.

<strong class="sub-title"> Methods: </strong> A total of <em>2</em>50 patients with COVID-19 were recruited (50 outpatients, 100 hospitalized ward patients and 100 critically ill). Viral RNA detection and quantification in plasma was performed using droplet digital PCR, targeting the N1 and N<em>2</em> regions of the SARS-CoV-<em>2</em> nucleoprotein gene. The association between SARS-CoV-<em>2</em> RNAemia and viral RNA load in plasma with severity was evaluated by multivariate logistic regression. Correlations between viral RNA load and biomarkers evidencing dysregulation of host response were evaluated by calculating the Spearman correlation coefficients.

<strong class="sub-title"> Results: </strong> The frequency of viral RNAemia was higher in the critically ill patients (78%) compared to ward patients (<em>2</em>7%) and outpatients (<em>2</em>%) (p < 0.001). Critical patients had higher viral RNA loads in plasma than non-critically ill patients, with non-survivors showing the highest values. When outpatients and ward patients were compared, viral RNAemia did not show significant associations in the multivariate analysis. In contrast, when ward patients were compared with ICU patients, both viral RNAemia and viral RNA load in plasma were associated with critical illness (OR [CI 95%], p): RNAemia (3.9<em>2</em> [1.183-1<em>2</em>.968], 0.0<em>2</em>5), viral RNA load (N1) (1.96<em>2</em> [1.<em>2</em>44-3.096], 0.004); viral RNA load (N<em>2</em>) (<em>2</em>.<em>2</em><em>2</em>9 [1.38<em>2</em>-3.595], 0.001). Viral RNA load in plasma correlated with higher levels of chemokines (CXCL10, CCL<em>2</em>), biomarkers indicative of a systemic inflammatory response (IL-6, CRP, ferritin), activation of NK cells (IL-15), endothelial dysfunction (VCAM-1, angiopoietin-<em>2</em>, ICAM-1), coagulation activation (D-Dimer and INR), tissue damage (LDH, GPT), neutrophil response (neutrophils counts, myeloperoxidase, GM-CSF) and immunodepression (PD-L1, IL-10, lymphopenia and monocytopenia).

<strong class="sub-title"> Conclusions: </strong> SARS-CoV-<em>2</em> RNAemia and viral RNA load in plasma are associated with critical illness in COVID-19. Viral RNA load in plasma correlates with key signatures of dysregulated host responses, suggesting a major role of uncontrolled viral replication in the pathogenesis of this disease.

<strong class="sub-title"> Keywords: </strong> COVID-19; Cytokine; ICU; Plasma; Rnaemia; SARS-CoV-<em>2</em>; Sepsis; Viral RNA load.