The specialized pro-resolving lipid mediator Protectin D1 affects macrophages differentiation and activity in Adult-onset Still's disease and COVID-19, two hyperinflammatory diseases sharing similar transcriptomic profiles.

Introduction: COVID-19 and autoinflammatory diseases, such as Adult-onset Still's Disease (AOSD), are characterized by hyperinflammation, in which it is observed massive production and uncontrolled secretion of pro-inflammatory cytokines. The specialized pro-resolving lipid mediators (SPMs) family is one the most important processes counteracting hyperinflammation inducing tissue repair and homeostasis restoration. Among SPMs, Protectin D1 (PD1) is able to exert antiviral features, at least in animal models. The aim of this study was to compare the transcriptome of peripheral blood mononuclear cells (PBMCs) from patients with AOSD and COVID-19 and to evaluate the role of PD1 on those diseases, especially in modulating macrophages polarization. Methods: This study enrolled patients with AOSD, COVID-19, and healthy donors HDs, undergoing clinical assessment and blood sample collection. Next-generation deep sequencing was performed to identify differences in PBMCs transcripts profiles. Plasma levels of PD1 were assessed by commercial ELISA kits. Monocyte-derived macrophages were polarized into M1 and M2 phenotypes. We analyzed the effect of PD1 on macrophages differentiation. At 10 days, macrophages were analyzed for surface expression of subtypes markers by flow cytometry. Cytokines production was measured in supernatants by Bio-Plex Assays. Results: In the transcriptomes from AOSD patients and COVID-19 patients, genes involved in inflammation, lipid catabolism, and monocytes activation were specifically dysregulated in AOSD and COVID-19 patients when compared to HDs. Patients affected by COVID-19, hospitalized in intensive care unit (ICU), showed higher levels of PD1 when compared to not-ICU hospitalized patients and HDs (ICU COVID-19 vs not-ICU COVID-19, p= 0.02; HDs vs ICU COVID-19, p= 0.0006). PD1 levels were increased in AOSD patients with SS ≥1 compared to patients with SS=0 (p=0.028) and HDs (p=0.048). In vitro treatment with PD1 of monocytes-derived macrophages from AOSD and COVID-19 patients induced a significant increase of M2 polarization vs control (p<0.05). Furthermore, a significant release of IL-10 and MIP-1ß from M2 macrophages was observed when compared to controls (p<0.05). Discussion: PD1 is able to induce pro-resolutory programs in both AOSD and COVID-19 increasing M2 polarization and inducing their activity. In particular, PD1-treated M2 macrophages from AOSD and COVID-19 patients increased the production of IL-10 and enhanced homeostatic restoration through MIP-1ß production.

The similar expression of both ferritin and scavenger receptors activation genes in patients with COVID19 and AOSD support their role in the pathogenesis of these diseases and identify a common mechanism at the basis of the "hyperferritinemic syndromes".

A role for COVID19 in "hyperferritinemic syndromes" has been proposed based on its clinical and serological characteristics and its similarities with AOSD. To better understand the molecular pathways responsible of these similarities, we evaluated in the PBMCs of 4 active AOSD patients, 2 COVID19 patients with ARDS, and 2 HCs the expression of genes associated with iron metabolisms, with monocyte/macrophages activation, and finally with NETs formation.

Expanding the spectrum of the hyperferritinemic syndrome, from pathogenic mechanisms to clinical observations, and therapeutic implications.

From the introduction of hyperferritinemic syndrome concept, a growing body of evidence has suggested the role of ferritin as a pathogenic mediator and a relevant clinical feature in the management of patients with inflammatory diseases. From a pathogenic point of view, ferritin may directly stimulate the aberrant immune response by triggering the production of pro-inflammatory mediators in inducing a vicious pathogenic loop and contributing to the occurrence of cytokine storm syndrome. The latter has been recently defined as a clinical picture characterised by elevated circulating cytokine levels, acute systemic inflammatory symptoms, and secondary organ dysfunction beyond that which could be attributed to a normal response to a pathogen It is noteworthy that the occurrence of hyperferritinemia may be correlated with the development of the cytokine storm syndrome in the context of an inflammatory disease. In addition to adult onset Still's disease, macrophage activation syndrome, catastrophic anti-phospholipids syndrome, and septic shock, recent evidence has suggested this association between ferritin and life-threatening evolution in patients with systemic lupus erythematosus, with anti-MDA5 antibodies in the context of poly-dermatomyositis, with severe COVID-19, and with multisystem inflammatory syndrome. The possible underlying common inflammatory mechanisms, associated with hyperferritinemia, may led to the similar clinical picture observed in these patients. Furthermore, similar therapeutic strategies could be suggested inhibiting pro-inflammatory cytokines and improving long-term outcomes in these disorders. Thus, it could be possible to expand the spectrum of the hyperferritinemic syndrome to those diseases burdened by a dreadful clinical picture correlated with hyperferritinemia and the occurrence of the cytokine storm syndrome. In addition, the assessment of ferritin may provide useful information to the physicians in clinical practice to manage these patients. Therefore, ferritin may be considered a relevant clinical feature to be used as biomarker in dissecting the unmet needs in the management of these disorders. Novel evidence may thus support an expansion of the spectrum of the hyperferritinemic syndrome to these diseases burdened by a life-threatening clinical picture correlated with hyperferritinemia and the occurrence of the cytokine storm syndrome.

Pathogenic implications, incidence, and outcomes of COVID-19 in autoimmune inflammatory joint diseases and autoinflammatory disorders.

As the coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to spread rapidly, there are still many unresolved questions of how this virus would impact on autoimmune inflammatory joint diseases and autoinflammatory disorders. The main aim of this paper is to describe the main studies focusing their attention on COVID-19 incidence and outcomes of rheumatoid arthritis (RA), spondylarthritis (SpA), and autoinflammatory disease cohorts. We also revised possible pathogenic mechanisms associated with. Available data suggest that, in patients with RA and SpA, the immunosuppressive therapy, older age, male sex, and the presence of comorbidities (hypertension, lung disease, diabetes, CVD, and chronic renal insufficiency/end-stage renal disease) could be associated with an increased risk of infections and high rate of hospitalization. Other studies have shown that lower odds of hospitalization were associated with bDMARD or tsDMARDs monotherapy, driven largely by anti-TNF therapies. For autoinflammatory diseases, considering the possibility that COVID-19 could be associated with a cytokine storm syndrome, the question of the susceptibility and severity of SARS-CoV-2 infection in patients displaying innate immunity disorders has been raised. In this context, data are very scarce and studies available did not clarify if having an autoinflammatory disorder could be or not a risk factor to develop a more severe COVID-19. Taking together these observations, further studies are likely to be needed to fully characterize these specific patient groups and associated SARS-CoV-2 infection.

The Pathogenic Role of Interferons in the Hyperinflammatory Response on Adult-Onset Still's Disease and Macrophage Activation Syndrome: Paving the Way towards New Therapeutic Targets.

Adult-onset Still's disease (AOSD) is a systemic inflammatory disorder of unknown aetiology affecting young adults, which is burdened by life-threatening complications, mostly macrophage activation syndrome (MAS). Interferons (IFNs) are signalling molecules that mediate a variety of biological functions from defence against viral infections, to antitumor and immunomodulatory effects. These molecules have been classified into three major types: IFN I, IFN II, IFN III, presenting specific characteristics and functions. In this work, we reviewed the role of IFNs on AOSD and MAS, focusing on their pathogenic role in promoting the hyperinflammatory response and as new possible therapeutic targets. In fact, both preclinical and clinical observations suggested that these molecules could promote the hyperinflammatory response in MAS during AOSD. Furthermore, the positive results of inhibiting IFN-γ in primary hemophagocytic lymphohistiocytosis may provide a solid rationale to arrange further clinical studies, paving the way for reducing the high mortality rate in MAS during AOSD.

The wide spectrum of Kawasaki-like disease associated with SARS-CoV-2 infection.

Introduction: On June 2020, the first case of concurrent Covid-19 and Kawasaki disease (KD) was published. After this first description, further works reported new cases of children affected by KD and KD-like syndrome after SARS-CoV-2 infection. The clinical and biochemical features of these patients differed from the historical cohorts of KD, suggesting the possibility of a new multi-systemic inflammatory syndrome. Is still unclear if this new clinical entity, often referred as pediatric inflammatory multisystem syndrome (PIMS) or multi-system inflammatory syndrome in children (MIS-C), could be considered as part of the KD spectrum or is a new disease with different pathogenic mechanisms and uniquely linked to SARS-CoV-2 infection. The authors searched the available literature in MedLine (via Pubmed) with the terms ('coronaviruses' OR 'coronavirus') AND ('Kawasaki disease') for English studies without any temporal limit. Areas covered: This review aims to comprehensively describe multisystem inflammatory syndromes affecting children during Coronaviruses outbreak, and to evaluate the possible pathogenic role of human Coronaviridae in KD and KD-like syndromes. Expert opinion: An increased incidence of PIMS-TS, during the Covid-19 pandemic has been reported, suggesting that SARS-CoV-2 may trigger a severe hyper-inflammatory syndrome in childhood. The pathophysiological mechanisms of this disease are still unclear. Based on these findings, SARS-CoV-2 may be considered another trigger in the complex mosaic about the relationship among infectious agents and the occurrence of systemic hyper-inflammation related syndromes.

Mortality in tocilizumab-treated patients with COVID-19: a systematic review and meta-analysis.

OBJECTIVES: People who are exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) could develop a potentially fatal disease with lung involvement and severe cytokine storm syndrome (CSS) - coronavirus disease 2019 (hereafter, COVID-19). Tocilizumab (TCZ) was administered to these subjects, despite the lack of randomised clinical trial data. Hence, summarising data on the mortality rate and related risks factors may help physicians to correctly administer TCZ. METHODS: We performed a systematic review and meta-analysis on mortality rate in TCZ- treated patients with COVID-19 according to the PRISMA guidelines. The pooled mortality rate in TCZ-treated persons was calculated and meta-regressions were done to investigate associated factors. RESULTS: We included 22 studies and 1520 TCZ-treated patients (mean age: 61 years, 95% CI: 59-64; male: 71%, 95% CI: 64-78%). The mortality estimated pooled prevalence was 19% (95% CI: 13-25, I2=100%, p<0.00001) and improvement estimated pooled prevalence was 71% (95% CI: 62-81). Factors associated with the mortality are the number of patients in intensive care unit, the number of patients requiring invasive ventilation and the sera C-reactive protein value before TCZ administration. We observed a reduction in the odds of mortality in TCZ-treated patients when compared to those treated with other therapies (OR=0.47, 95% CI: 0.22-0.98, p=0.004). CONCLUSIONS: This study showed that the mortality pooled prevalence in TCZ-treated patients is lower than the overall mortality reported in patients with severe COVID-19.

Lung involvement in macrophage activation syndrome and severe COVID-19: results from a cross-sectional study to assess clinical, laboratory and artificial intelligence-radiological differences.

OBJECTIVES: To evaluate the clinical pictures, laboratory tests and imaging of patients with lung involvement, either from severe COVID-19 or macrophage activation syndrome (MAS), in order to assess how similar these two diseases are. METHODS: The present work has been designed as a cross-sectional single-centre study to compare characteristics of patients with lung involvement either from MAS or severe COVID-19. Chest CT scans were assessed by using an artificial intelligence (AI)-based software. RESULTS: Ten patients with MAS and 47 patients with severe COVID-19 with lung involvement were assessed. Although all patients showed fever and dyspnoea, patients with MAS were characterised by thrombocytopaenia, whereas patients with severe COVID-19 were characterised by lymphopaenia and neutrophilia. Higher values of H-score characterised patients with MAS when compared with severe COVID-19. AI-reconstructed images of chest CT scan showed that apical, basal, peripheral and bilateral distributions of ground-glass opacities (GGOs), as well as apical consolidations, were more represented in severe COVID-19 than in MAS. C reactive protein directly correlated with GGOs extension in both diseases. Furthermore, lymphopaenia inversely correlated with GGOs extension in severe COVID-19. CONCLUSIONS: Our data could suggest laboratory and radiological differences between MAS and severe COVID-19, paving the way for further hypotheses to be investigated in future confirmatory studies.

Severe COVID-19, Another Piece in the Puzzle of the Hyperferritinemic Syndrome. An Immunomodulatory Perspective to Alleviate the Storm.

The coronavirus disease 2019 (COVID-19), an acute respiratory disease caused by severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), has been declared as a worldwide public health emergency. Interestingly, severe COVID-19 is characterized by fever, hyperferritinemia, and a hyper-inflammatory process with a massive release of pro-inflammatory cytokines, which may be responsible for the high rate of mortality. These findings may advocate for a similarity between severe COVID-19 and some challenging rheumatic diseases, such as adult onset Still's disease, secondary hemophagocytic lymphohistiocytosis, and catastrophic anti-phospholipid syndrome, which have been included in the "hyperferritinemic syndrome" category. Furthermore, as performed in these hyper-inflammatory states, severe COVID-19 may benefit from immunomodulatory therapies.