Persistent Autoimmune Activation and Proinflammatory State in Post-Coronavirus Disease 2019 Syndrome.

BACKGROUND: The immunopathological pathways enabling post-coronavirus disease 2019 (COVID-19) syndrome (PCS) development are not entirely known. We underwent a longitudinal analysis of patients with COVID-19 who developed PCS aiming to evaluate the autoimmune and immunological status associated with this condition. METHODS: Thirty-three patients were included for longitudinal clinical and autoantibody analyses, 12 of whom were assessed for cytokines and lymphocyte populations. Patients were followed for 7-11 months after acute COVID-19. Autoimmune profile and immunological statuses were evaluated mainly by enzyme-linked-immunosorbent assays and flow cytometry. RESULTS: Latent autoimmunity and overt autoimmunity persisted over time. A proinflammatory state was observed in patients with PCS characterized by up-regulated interferon-α, tumor necrosis factor-α, granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-17A, IL-6, IL-1ß, and IL-13, whereas interferon-γ-induced protein 10 (IP-10) was decreased. In addition, PCS was characterized by increased levels of Th9, CD8+ effector T cells, naive B cells, and CD4+ effector memory T cells. Total levels of immunoglobulin G S1-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies remained elevated over time. CONCLUSIONS: The clinical manifestations of PCS are associated with the persistence of a proinflammatory and effector phenotype induced by SARS-CoV-2 infection. This long-term persistent immune activation may contribute to the development of latent and overt autoimmunity. Results suggest the need to evaluate the role of immunomodulation in the treatment of PCS.

Autoimmunity is a hallmark of post-COVID syndrome.

Autoimmunity has emerged as a characteristic of the post-COVID syndrome (PCS), which may be related to sex. In order to further investigate the relationship between SARS-CoV-2 and autoimmunity in PCS, a clinical and serological assessment on 100 patients was done. Serum antibody profiles against self-antigens and infectious agents were evaluated by an antigen array chip for 116 IgG and 104 IgM antibodies. Thirty pre-pandemic healthy individuals were included as a control group. The median age of patients was 49 years (IQR: 37.8 to 55.3). There were 47 males. The median post-COVID time was 219 (IQR: 143 to 258) days. Latent autoimmunity and polyautoimmunity were found in 83% and 62% of patients, respectively. Three patients developed an overt autoimmune disease. IgG antibodies against IL-2, CD8B, and thyroglobulin were found in more than 10% of the patients. Other IgG autoantibodies, such as anti-interferons, were positive in 5-10% of patients. Anti-SARS-CoV-2 IgG antibodies were found in > 85% of patients and were positively correlated with autoantibodies, age, and body mass index (BMI). Few autoantibodies were influenced by age and BMI. There was no effect of gender on the over- or under-expression of autoantibodies. IgG anti-IFN-λ antibodies were associated with the persistence of respiratory symptoms. In summary, autoimmunity is characteristic of PCS, and latent autoimmunity correlates with humoral response to SARS-CoV-2.

New insights into the taxonomy of autoimmune diseases based on polyautoimmunity.

OBJECTIVE: The clinical coexistence of two or more autoimmune diseases (ADs) fulfilling classification criteria is termed "overt polyautoimmunity" (PolyA), whereas the presence of autoantibodies unrelated to an index AD, without clinical criteria fulfillment, is known as "latent PolyA". We aimed to explore a new taxonomy of ADs based on PolyA. METHODS: In a cross-sectional study of 292 subjects, we evaluated the presence of PolyA in 146, 45, 29, 17, and 17 patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Sjögren's syndrome (SS), autoimmune thyroid disease (AITD) and systemic sclerosis (SSc), respectively, and 38 healthy controls. Clinical assessment, autoantibody profile (by autoantigen array chip), lymphocytes immunophenotype and cytokine profile (by flow cytometry) were evaluated simultaneously. A mixed cluster methodology was used to classify ADs. RESULTS: Latent PolyA was more frequent than overt PolyA, ranging from 69.9% in RA to 100% in SSc. Nevertheless, both latent and overt PolyA clustered together. Over-expressed IgG autoantibodies were found to be hallmarks for the identification of index ADs. The combination of autoantibodies allowed high accuracy in the classification of ADs. Three well-defined clusters based on PolyA were observed with distinctive clinical and immunological phenotypes. CONCLUSIONS: This proof-of-concept study indicates that ADs can be classified according to PolyA. PolyA should be considered in all studies dealing with ADs, including epidemiological, genetic, and clinical trials.

Safety and efficacy of convalescent plasma for severe COVID-19: a randomized, single blinded, parallel, controlled clinical study.

BACKGROUND: Convalescent plasma (CP) has been widely used to treat COVID-19 and is under study. However, the variability in the current clinical trials has averted its wide use in the current pandemic. We aimed to evaluate the safety and efficacy of CP in severe coronavirus disease 2019 (COVID-19) in the early stages of the disease. METHODS: A randomized controlled clinical study was conducted on 101 patients admitted to the hospital with confirmed severe COVID-19. Most participants had less than 14 days from symptoms onset and less than seven days from hospitalization. Fifty patients were assigned to receive CP plus standard therapy (ST), and 51 were assigned to receive ST alone. Participants in the CP arm received two doses of 250 mL each, transfused 24 h apart. All transfused plasma was obtained from "super donors" that fulfilled the following criteria: titers of anti-SARS-CoV-2 S1 IgG ≥ 1:3200 and IgA ≥ 1:800 antibodies. The effect of transfused anti-IFN antibodies and the SARS-CoV-2 variants at the entry of the study on the overall CP efficacy was evaluated. The primary outcomes were the reduction in viral load and the increase in IgG and IgA antibodies at 28 days of follow-up. The per-protocol analysis included 91 patients. RESULTS: An early but transient increase in IgG anti-S1-SARS-CoV-2 antibody levels at day 4 post-transfusion was observed (Estimated difference [ED], - 1.36; 95% CI, - 2.33 to - 0.39; P = 0.04). However, CP was not associated with viral load reduction in any of the points evaluated. Analysis of secondary outcomes revealed that those patients in the CP arm disclosed a shorter time to discharge (ED adjusted for mortality, 3.1 days; 95% CI, 0.20 to 5.94; P = 0.0361) or a reduction of 2 points on the WHO scale when compared with the ST group (HR adjusted for mortality, 1.6; 95% CI, 1.03 to 2.5; P = 0.0376). There were no benefits from CP on the rates of intensive care unit admission (HR, 0.82; 95% CI, 0.35 to 1.9; P = 0.6399), mechanical ventilation (HR, 0.66; 95% CI, 0.25 to 1.7; P = 0.4039), or mortality (HR, 3.2; 95% CI, 0.64 to 16; P = 0.1584). Anti-IFN antibodies and SARS-CoV-2 variants did not influence these results. CONCLUSION: CP was not associated with viral load reduction, despite the early increase in IgG anti-SARS-CoV-2 antibodies. However, CP is safe and could be a therapeutic option to reduce the hospital length of stay. Trial registration NCT04332835.

COVID-19 convalescent plasma composition and immunological effects in severe patients.

Convalescent plasma (CP) has emerged as a treatment for COVID-19. However, the composition and mechanism of action are not fully known. Therefore, we undertook a two-phase controlled study in which, first the immunological and metabolomic status of recovered and severe patients were evaluated. Secondly, the 28-day effect of CP on the immune response in severe patients was assessed. Nineteen recovered COVID-19 patients, 18 hospitalized patients with severe disease, and 16 pre-pandemic controls were included. Patients with severe disease were treated with CP transfusion and standard therapy (i.e., plasma recipients, n = 9) or standard therapy alone (n = 9). Clinical and biological assessments were done on day 0 and during follow-up on days 4, 7, 14, and 28. Clinical parameters, viral load, total immunoglobulin (Ig) G and IgA anti-S1-SARS-CoV-2 antibodies, neutralizing antibodies (NAbs), autoantibodies, cytokines, T and B cells, and metabolomic and lipidomic profiles were examined. Total IgG and IgA anti-S1-SARS-CoV-2 antibodies were key factors for CP selection and correlated with NAbs. In severe COVID-19 patients, mostly interleukin (IL)-6 (P = <0.0001), IL-10 (P = <0.0001), IP-10 (P = <0.0001), fatty acyls and glycerophospholipids were higher than in recovered patients. Latent autoimmunity and anti-IFN-α antibodies were observed in both recovered and severe patients. COVID-19 CP induced an early but transient cytokine profile modification and increases IgG anti-S1-SARS-CoV-2 antibodies. At day 28 post-transfusion, a decrease in activated, effector and effector memory CD4+ (P < 0.05) and activated and effector CD8+ (P < 0.01) T cells and naïve B cells (P = 0.001), and an increase in non-classical memory B cells (P=<0.0001) and central memory CD4+ T cells (P = 0.0252) were observed. Moreover, IL-6/IFN-γ (P = 0.0089) and IL-6/IL-10 (P = 0.0180) ratios decreased in plasma recipients compared to those who received standard therapy alone. These results may have therapeutic implications and justify further post-COVID-19 studies.

Ebola virus disease: An emerging and re-emerging viral threat.

The genus Ebolavirus from the family Filoviridae is composed of five species including Sudan ebolavirus, Reston ebolavirus, Bundibugyo ebolavirus, Taï Forest ebolavirus, and Ebola virus (previously known as Zaire ebolavirus). These viruses have a large non-segmented, negative-strand RNA of approximately 19 kb that encodes for glycoproteins (i.e., GP, sGP, ssGP), nucleoproteins, virion proteins (i.e., VP 24, 30,40) and an RNA dependent RNA polymerase. These viruses have become a global health concern because of mortality, their rapid dissemination, new outbreaks in West-Africa, and the emergence of a new condition known as "Post-Ebola virus disease syndrome" that resembles inflammatory and autoimmune conditions such as rheumatoid arthritis, systemic lupus erythematosus and spondyloarthritis with uveitis. However, there are many gaps in the understanding of the mechanisms that may induce the development of such autoimmune-like syndromes. Some of these mechanisms may include a high formation of neutrophil extracellular traps, an uncontrolled "cytokine storm", and the possible formation of auto-antibodies. The likely appearance of autoimmune phenomena in Ebola survivors suppose a new challenge in the management and control of this disease and opens a new field of research in a special subgroup of patients. Herein, the molecular biology, pathogenesis, clinical manifestations, and treatment of Ebola virus disease are reviewed and some strategies for control of disease are discussed.

Autoinflammatory and autoimmune conditions at the crossroad of COVID-19.

Coronavirus disease 2019 (COVID-19) has been categorized as evolving in overlapping phases. First, there is a viral phase that may well be asymptomatic or mild in the majority, perhaps 80% of patients. The pathophysiological mechanisms resulting in minimal disease in this initial phase are not well known. In the remaining 20% of cases, the disease may become severe and/or critical. In most patients of this latter group, there is a phase characterized by the hyperresponsiveness of the immune system. A third phase corresponds to a state of hypercoagulability. Finally, in the fourth stage organ injury and failure occur. Appearance of autoinflammatory/autoimmune phenomena in patients with COVID-19 calls attention for the development of new strategies for the management of life-threatening conditions in critically ill patients. Antiphospholipid syndrome, autoimmune cytopenia, Guillain-Barré syndrome and Kawasaki disease have each been reported in patients with COVID-19. Here we present a scoping review of the relevant immunological findings in COVID-19 as well as the current reports about autoinflammatory/autoimmune conditions associated with the disease. These observations have crucial therapeutic implications since immunomodulatory drugs are at present the most likely best candidates for COVID-19 therapy. Clinicians should be aware of these conditions in patients with COVID-19, and these observations should be considered in the current development of vaccines.

Bystander activation and autoimmunity.

The interaction over time of genetic, epigenetic and environmental factors (i.e., autoimmune ecology) increases or decreases the liability an individual would have to develop an autoimmune disease (AD) depending on the misbalance between risk and protective effects. Pathogens have been the most common antecedent events studied, but multiple other environmental factors including xenobiotic chemicals, drugs, vaccines, and nutritional factors have been implicated into the development of ADs. Three main mechanisms have been offered to explain the development of autoimmunity: molecular mimicry, epitope spreading, and bystander activation. The latter is characterized by auto-reactive B and T cells that undergo activation in an antigen-independent manner, influencing the development and course of autoimmunity. Activation occurs due to a combination of an inflammatory milieu, co-signaling ligands, and interactions with neighboring cells. In this review, we will discuss the studies performed seeking to define the role of bystander activation in systemic and organ-specific ADs. In all cases, we are cognizant of individual differences between hosts and the variable latency time for clinical expression of disease, all of which have made our understanding of the etiology of loss of immune tolerance difficult and enigmatic.

Cluster analysis of autoimmune rheumatic diseases based on autoantibodies. New insights for polyautoimmunity.

Autoimmune diseases (ADs) are a chronic and clinically heterogeneous group of diseases characterized by share common immunopathogenic mechanisms and risk factors (i.e., the autoimmune tautology), which explain the fact that one AD may coexist with others (i.e., polyautoimmunity - PolyA). In the present exploratory study, a mixed-cluster analysis of the most common autoimmune rheumatic diseases (ARDs) was done. A total of 187 consecutive women with established systemic lupus erythematosus (n = 70), rheumatoid arthritis (n = 51), systemic sclerosis (n = 35) and Sjögren's syndrome (n = 31) were included. A comprehensive clinical, autoantibody and cytokine assessment was simultaneously done. Total PolyA was registered in 142 (75.9%) patients. Six clusters were obtained, built mainly on autoantibodies: PolyA-I to -VI. The PolyA-III cluster showed the highest frequency of overt PolyA (p = 0.01), and the PolyA-I, -III, and -IV clusters exhibited the highest positivity for IL-12/23p40 (p = 0.015). These results provide new insights into the pathophysiology of PolyA and warrant prospective validation to enable development of a more accurate taxonomy of ARDs.

Cytokine imbalance in patients with systemic sclerosis and resilience: the key role of interleukin-6.

OBJECTIVES: Resilience, the ability to respond positively to adverse events, may be influenced by long-term stressors and autoimmune/inflammatory conditions such as systemic sclerosis (SSc). Since the immune system plays a role in the development of resilience, we aimed to evaluate the relationship between a panel of cytokines and resilience in patients with SSc. METHODS: Thirty-five consecutive women with established SSc were involved in this exploratory study. Clinical characteristics, including severity of symptoms and resilience, a panel of 15 serum cytokines and 17 autoantibodies were assessed simultaneously. Multivariate methods were used to analyse the data. RESULTS: Interleukin-6 (IL-6) levels were associated with severity of symptoms (ß=1.8395, p=0.04), and low resilience scores (ß= -0.581120, p=0.02). Furthermore, resilience was not associated with clinical manifestations nor polyautoimmunity. Cytokine levels did not significantly differ between groups based on regular physical activity. CONCLUSIONS: The results highlight the importance of IL-6 as a key mediator in the altered cytokine network of SSc.

Molecular mimicry and autoimmunity.

Molecular mimicry is one of the leading mechanisms by which infectious or chemical agents may induce autoimmunity. It occurs when similarities between foreign and self-peptides favor an activation of autoreactive T or B cells by a foreign-derived antigen in a susceptible individual. However, molecular mimicry is unlikely to be the only underlying mechanism for autoimmune responses; other factors such as breach in central tolerance, non-specific bystander activation, or persistent antigenic stimuli (amongst others) may also contribute to the development of autoimmune diseases. Host genetics, exposure to microbiota and environmental chemicals are additional links to our understanding of molecular mimicry. Our current knowledge of the detailed mechanisms of molecular mimicry is limited by the issues of prolonged periods of latency before the appearance of disease, the lack of enough statistical power in epidemiological studies, the limitations of the potential role of genetics in human studies, the relevance of inbred murine models to the diverse human population and especially the limited technology to systematically dissect the human T-cell repertoire and B-cell responses. Nevertheless, studies on the role of autoreactive T-cells that are generated secondary to molecular mimicry, the diversity of the T-cell receptor repertoires of auto-reactive T-cells, the role of exposure to cryptic antigens, the generation of autoimmune B-cell responses, the interaction of microbiota and chemical adjuvants with the host immune systems all provide clues in advancing our understanding of the molecular mechanisms involved in the evolving concept of molecular mimicry and also may potentially aid in the prevention and treatment of autoimmune diseases.

Autonomic symptoms following Zika virus infection.

PURPOSE: To determine if autonomic symptoms are associated with previous Zika virus infection. METHODS: Case-control study including 35 patients with Zika virus infection without evidence of neurological disease and 105 controls. Symptoms of autonomic dysfunction were assessed with the composite autonomic symptom scale 31 (COMPASS-31). RESULTS: Patients with previous Zika virus infection had significantly higher COMPASS-31 score than controls regardless of age and sex (p = 0.007). The main drivers for the higher scores where orthostatic intolerance (p = 0.003), secretomotor (p = 0.04) and bladder symptoms (p < 0.001). CONCLUSION: Zika virus infection is associated with autonomic dysfunction. The mechanisms remain to be elucidated.

VRK1 phosphorylates and protects NBS1 from ubiquitination and proteasomal degradation in response to DNA damage.

NBS1 is an early component in DNA-Damage Response (DDR) that participates in the initiation of the responses aiming to repair double-strand breaks caused by different mechanisms. Early steps in DDR have to react to local alterations in chromatin that are induced by DNA damage. NBS1 participates in the early detection of DNA damage and functions as a platform for the recruitment and assembly of components that are sequentially required for the repair process. In this work we have studied whether the VRK1 chromatin kinase can affect the activation of NBS1 in response to DNA damage induced by ionizing radiation. VRK1 is forming a basal preassembled complex with NBS1 in non-damaged cells. Knockdown of VRK1 resulted in the loss of NBS1 foci induced by ionizing radiation, an effect that was also detected in cell-cycle arrested cells and in ATM (-/-) cells. The phosphorylation of NBS1 in Ser343 by VRK1 is induced by either doxorubicin or IR in ATM (-/-) cells. Phosphorylated NBS1 is also complexed with VRK1. NBS1 phosphorylation by VRK1 cooperates with ATM. This phosphorylation of NBS1 by VRK1 contributes to the stability of NBS1 in ATM (-/-) cells, and the consequence of its loss can be prevented by treatment with the MG132 proteasome inhibitor of RNF8. We conclude that VRK1 regulation of NBS1 contributes to the stability of the repair complex and permits the sequential steps in DDR.

Cytokine and autoantibody clusters interaction in systemic lupus erythematosus.

BACKGROUND: Evidence supports the existence of different subphenotypes in systemic lupus erythematosus (SLE) and the pivotal role of cytokines and autoantibodies, which interact in a highly complex network. Thus, understanding how these complex nonlinear processes are connected and observed in real-life settings is a major challenge. Cluster approaches may assist in the identification of these subphenotypes, which represent such a phenomenon, and may contribute to the development of personalized medicine. Therefore, the relationship between autoantibody and cytokine clusters in SLE was analyzed. METHODS: This was an exploratory study in which 67 consecutive women with established SLE were assessed. Clinical characteristics including disease activity, a 14-autoantibody profile, and a panel of 15 serum cytokines were measured simultaneously. Mixed-cluster methodology and bivariate analyses were used to define autoantibody and cytokine clusters and to identify associations between them and related variables. RESULTS: First, three clusters of autoantibodies were defined: (1) neutral, (2) antiphospholipid antibodies (APLA)-dominant, and (3) anti-dsDNA/ENA-dominant. Second, eight cytokines showed levels above the threshold thus making possible to find 4 clusters: (1) neutral, (2) chemotactic, (3) G-CSF dominant, and (4) IFNα/Pro-inflammatory. Furthermore, the disease activity was associated with cytokine clusters, which, in turn, were associated with autoantibody clusters. Finally, when all biomarkers were included, three clusters were found: (1) neutral, (2) chemotactic/APLA, and (3) IFN/dsDNA, which were also associated with disease activity. CONCLUSION: These results support the existence of three SLE cytokine-autoantibody driven subphenotypes. They encourage the practice of personalized medicine, and support proof-of-concept studies.

Original antigenic sin: A comprehensive review.

The concept of "original antigenic sin" was first proposed by Thomas Francis, Jr. in 1960. This phenomenon has the potential to rewrite what we understand about how the immune system responds to infections and its mechanistic implications on how vaccines should be designed. Antigenic sin has been demonstrated to occur in several infectious diseases in both animals and humans, including human influenza infection and dengue fever. The basis of "original antigenic sin" requires immunological memory, and our immune system ability to autocorrect. In the context of viral infections, it is expected that if we are exposed to a native strain of a pathogen, we should be able to mount a secondary immune response on subsequent exposure to the same pathogen. "Original antigenic sin" will not contradict this well-established immunological process, as long as the subsequent infectious antigen is identical to the original one. But "original antigenic sin" implies that when the epitope varies slightly, then the immune system relies on memory of the earlier infection, rather than mount another primary or secondary response to the new epitope which would allow faster and stronger responses. The result is that the immunological response may be inadequate against the new strain, because the immune system does not adapt and instead relies on its memory to mount a response. In the case of vaccines, if we only immunize to a single strain or epitope, and if that strain/epitope changes over time, then the immune system is unable to mount an accurate secondary response. In addition, depending of the first viral exposure the secondary immune response can result in an antibody-dependent enhancement of the disease or at the opposite, it could induce anergy. Both of them triggering loss of pathogen control and inducing aberrant clinical consequences.

A comprehensive analysis and immunobiology of autoimmune neurological syndromes during the Zika virus outbreak in Cúcuta, Colombia.

We have focused on the epidemiology and immunobiology of Zika virus (ZIKV) infection and factors associated with the development of Guillain-Barré syndrome (GBS) and other neurological syndromes in Cúcuta, the capital of North Santander department, Colombia. Data of patients with ZIKV disease reported to the national population-based surveillance system were used to calculate the basic reproduction number (R0) and the attack rates (ARs) as well as to develop epidemiological maps. Patients with neurological syndromes were contacted and their diagnoses were confirmed. A case-control study in which 29 patients with GBS associated with ZIKV compared with 74-matched control patients with ZIKV infection alone was undertaken. Antibodies against arboviruses and other infections that may trigger GBS were evaluated. The estimated value of R0 ranged between 2.68 (95% CI 2.54-2.67) to 4.57 (95% CI 4.18-5.01). The sex-specific ARs were 1306 per 100,000 females, and 552 per 100,000 males. A non-linear interaction between age and gender on the ARs was observed. The incidence of GBS in Cúcuta increased 4.41 times secondary to ZIKV infection. The lag time between ZIKV infection and neurological symptoms was 7 days (interquartile range 2-14.5). Patients with GBS appeared to represent a lower socioeconomic status and were living near to environmentally contaminated areas. All GBS patients were positive for IgG antibodies against both ZIKV and Dengue virus, and 69% were positive for Chikungunya virus. Noteworthy, GBS was associated with a previous infection with M. pneumoniae (OR: 3.95; 95% CI 1.44-13.01; p = 0.006). No differences in antibody levels against C. jejuni, Epstein-Barr virus and cytomegalovirus were observed. High rates of cranial nerves involvement and dysautonomia were present in 82% and 75.9%, respectively. Intensive care unit (ICU) admission was necessary in 69% of the GBS patients. Most of the patients disclosed a high disability condition (Hughes grade 4). Dysautonomia was the main risk factor of poor GBS prognosis (i.e., ICU admission and disability). Thirteen patients were diagnosed with other neurological syndromes different to GBS (6 with transverse myelitis, 3 with encephalitis, 3 with peripheral facial palsy and one with thoraco-lumbosacral myelopathy). Our data confirm an increased transmission of ZIKV in Cúcuta, and provide support to the view that severe neurological syndromes are related to ZIKV disease. The complex ways by which previous infections and socioeconomic status interact to increase the risk of GBS in people infected by ZIKV should be further investigated.

Predictors of mortality in hospitalised patients with COVID-19: a 1-year case-control study.

BACKGROUND: A paucity of predictive models assessing risk factors for COVID-19 mortality that extend beyond age and gender in Latino population is evident in the current academic literature. OBJECTIVES: To determine the associated factors with mortality, in addition to age and sex during the first year of the pandemic. DESIGN: A case-control study with retrospective revision of clinical and paraclinical variables by systematic revision of clinical records was conducted. Multiple imputations by chained equation were implemented to account for missing variables. Classification and regression trees (CART) were estimated to evaluate the interaction of associated factors on admission and their role in predicting mortality during hospitalisation. No intervention was performed. SETTING: High-complexity centre above 2640 m above sea level (masl) in Colombia. PARTICIPANTS: A population sample of 564 patients admitted to the hospital with confirmed COVID-19 by PCR. Deceased patients (n=282) and a control group (n=282), matched by age, sex and month of admission, were included. MAIN OUTCOME MEASURE: Mortality during hospitalisation. MAIN RESULTS: After the imputation of datasets, CART analysis estimated 11 clinical profiles based on respiratory distress, haemoglobin, lactate dehydrogenase, partial pressure of oxygen to inspired partial pressure of oxygen ratio, chronic kidney disease, ferritin, creatinine and leucocytes on admission. The accuracy model for prediction was 80.4% (95% CI 71.8% to 87.3%), with an area under the curve of 78.8% (95% CI 69.63% to 87.93%). CONCLUSIONS: This study discloses new interactions between clinical and paraclinical features beyond age and sex influencing mortality in COVID-19 patients. Furthermore, the predictive model could offer new clues for the personalised management of this condition in clinical settings.

Vaccinia-related kinase 1 (VRK1) is an upstream nucleosomal kinase required for the assembly of 53BP1 foci in response to ionizing radiation-induced DNA damage.

Cellular responses to DNA damage require the formation of protein complexes in a highly organized fashion. The complete molecular components that participate in the sequential signaling response to DNA damage remain unknown. Here we demonstrate that vaccinia-related kinase 1 (VRK1) in resting cells plays an important role in the formation of ionizing radiation-induced foci that assemble on the 53BP1 scaffold protein during the DNA damage response. The kinase VRK1 is activated by DNA double strand breaks induced by ionizing radiation (IR) and specifically phosphorylates 53BP1 in serum-starved cells. VRK1 knockdown resulted in the defective formation of 53BP1 foci in response to IR both in number and size. This observed effect on 53BP1 foci is p53- and ataxia-telangiectasia mutated (ATM)-independent and can be rescued with VRK1 mutants resistant to siRNA. VRK1 knockdown also prevented the activating phosphorylation of ATM, CHK2, and DNA-dependent protein kinase in response to IR. VRK1 activation in response to DNA damage is a novel and early step in the signaling of mammalian DNA damage responses.