Search Results (150)

The COVID-19 pandemic, caused by SARS-CoV-2, has led to a wide range of acute and chronic disease manifestations. While most infections are mild, a significant number of patients develop severe illness marked by respiratory failure, thromboinflammation, and multi-organ dysfunction. In addition, post-acute sequelae—commonly known as long-COVID—can persist for months. Recent studies have identified the emergence of diverse autoantibodies in COVID-19, including those targeting nuclear antigens, phospholipids, type I interferons, cytokines, endothelial components, and G-protein-coupled receptors. These autoantibodies are more frequently detected in patients with moderate to severe disease and have been implicated in immune dysregulation, vascular injury, and persistent symptoms. This review examines the underlying immunological mechanisms driving autoantibody production during SARS-CoV-2 infection—including molecular mimicry, epitope spreading, and bystander activation—and discusses their functional roles in acute and post-acute disease. We further explore the relevance of autoantibodies in maternal–fetal immunity and comorbid conditions such as autoimmunity and cancer, and we summarize current and emerging therapeutic strategies. A comprehensive understanding of SARS-CoV-2-induced autoantibodies may improve risk stratification, inform clinical management, and guide the development of targeted immunomodulatory therapies. Full article

Objectives: COVID-19, caused by the SARS-CoV-2 virus, has infected over 777 million individuals and led to approximately 7 million deaths worldwide. Despite significant efforts to develop effective therapies, treatment remains largely supportive, especially for severe complications like acute respiratory distress syndrome (ARDS). Numerous compounds from diverse pharmacological classes are currently undergoing preclinical and clinical evaluation, targeting both the virus and the host immune response. Methods: Despite the large number of articles published and after a preliminary attempt was published, we discarded the option of a systematic review. Instead, we have done a description of therapies with these results and a tentative mechanism of action. Results: Preliminary studies and early-phase clinical trials have demonstrated the potential of Mesenchymal Stem Cells (MSCs) in mitigating severe lung damage in COVID-19 patients. Previous research has shown MSCs to be effective in treating various pulmonary conditions, including acute lung injury, idiopathic pulmonary fibrosis, ARDS, asthma, chronic obstructive pulmonary disease, and lung cancer. Their ability to reduce inflammation and promote tissue repair supports their potential role in managing COVID-19-related complications. This review demonstrates the utility of MSCs in the acute phase of COVID-19 and postulates the etiopathogenic role of mitochondria in Long-COVID. Even more, their combination with other therapies is also analyzed. Conclusions: While the therapeutic application of MSCs in COVID-19 is still in early stages, emerging evidence suggests promising outcomes. As research advances, MSCs may become an integral part of treatment strategies for severe COVID-19, particularly in addressing immune-related lung injury and promoting recovery. However, a full pathogenic mechanism may explain or unify the complexity of signs and symptoms of Long COVID and Post-Acute Sequelae (PASC). Full article

Background/Objectives: To investigate the incidence of new-onset diabetic retinopathy (DR) in individuals with pre-existing type 2 diabetes (T2D) up to 3 years post SARS-CoV-2 infection. Methods: This retrospective study consisted of 5151 COVID-19 and 5151 propensity-matched non-COVID-19 patients with T2D in the Montefiore Health System between 1 March 2020 and 17 January 2023. The primary outcome was new-onset DR at least 2 months after the index date up to 17 January 2023. Matching for index date between groups was also used to ensure the same follow-up duration. Hazard ratios (HRs) were computed, adjusted for competing risks. Results: T2D patients with COVID-19 had a higher cumulative incidence of DR than T2D patients. The unadjusted HR for COVID-19 status for developing new DR was 2.44 [1.60, 3.73], p < 0.001. The adjusted HR was 1.70 [1.08, 2.70], p < 0.05, and the adjusted HR for prior insulin use was 3.28 [2.10, 5.12], p < 0.001. Sex, ethnicity, and major comorbidities had no significant association with outcome. Conclusions: T2D patients who contracted COVID-19 exhibited a significantly higher risk of developing DR within three years post infection compared to propensity-matched controls. The increased incidence was primarily driven by greater pre-existing insulin usage and SARS-CoV-2 infection in the COVID-19 positive cohort. Full article

Narrative review synthesizes the most current literature on the SARS-CoV-2 XEC variant, focusing on its genomic evolution, immune evasion characteristics, epidemiological dynamics, and public health implications. To achieve this, we conducted a structured search of the literature of peer-reviewed articles, preprints, and official surveillance data from 2023 to early 2025, prioritizing virological, clinical, and immunological reports related to XEC and its parent lineages. Defined by the distinctive spike protein mutations, T22N and Q493E, XEC exhibits modest reductions in neutralization in vitro, although current evidence suggests that mRNA booster vaccines, including those targeting JN.1 and KP.2, retain cross-protective efficacy against symptomatic and severe disease. The XEC strain of SARS-CoV-2 has drawn particular attention due to its increasing prevalence in multiple regions and its potential to displace other Omicron subvariants, although direct evidence of enhanced replicative fitness is currently lacking. Preliminary analyses also indicated that glycosylation changes at the N-terminal domain enhance infectivity and immunological evasion, which is expected to underpin the increasing prevalence of XEC. The XEC variant, while still emerging, is marked by a unique recombination pattern and a set of spike protein mutations (T22N and Q493E) that collectively demonstrate increased immune evasion potential and epidemiological expansion across Europe and North America. Current evidence does not conclusively associate XEC with greater disease severity, although additional research is required to determine its clinical relevance. Key knowledge gaps include the precise role of recombination events in XEC evolution and the duration of cross-protective T-cell responses. New research priorities include genomic surveillance in undersampled regions, updated vaccine formulations against novel spike epitopes, and long-term longitudinal studies to monitor post-acute sequelae. These efforts can be augmented by computational modeling and the One Health approach, which combines human and veterinary sciences. Recent computational findings (GISAID, 2024) point to the potential of XEC for further mutations in under-surveilled reservoirs, enhancing containment challenges and risks. Addressing the potential risks associated with the XEC variant is expected to benefit from interdisciplinary coordination, particularly in regions where genomic surveillance indicates a measurable increase in prevalence. Full article

Defibrotide, which is approved for treating hepatic veno-occlusive disease (VOD)/sinusoidal obstruction syndrome (SOS), exhibits pleiotropic anti-inflammatory, anti-thrombotic, and fibrinolytic properties, conferring broad endothelial protective effects. Given these mechanisms, defibrotide has potential utility in various conditions involving endothelial injury or activation. In this review we outline the endothelial-protective mechanisms of defibrotide and comprehensively summarize current evidence supporting its applications in hematologic malignancies, including the prevention and treatment of hepatic VOD/SOS, graft-versus-host disease, and transplant-associated thrombotic microangiopathy. Additionally, we discuss its role in mitigating key toxicities linked to chimeric antigen receptor (CAR) T-cell therapies and bispecific antibodies, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). We also explore emerging evidence on defibrotide’s potential in SARS-CoV-2 infection-associated endotheliopathies, including acute COVID-19 and post-acute sequelae of SARS-CoV-2 infection (“long-COVID”), and the endothelial protective activity of defibrotide in these settings. Finally, we highlight potential future applications of defibrotide in hematologic malignancies and viral infections, emphasizing its multimodal mechanism of action. Full article

The COVID-19 pandemic has revealed the profound and lasting impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on the nervous system. Beyond acute infection, SARS-CoV-2 acts as a potent immunomodulatory agent, disrupting immune homeostasis and contributing to persistent inflammation, autoimmunity, and neurodegeneration. Long COVID, or post-acute sequelae of SARS-CoV-2 infection (PASC), is characterized by a spectrum of neurological symptoms, including cognitive dysfunction, fatigue, neuropathy, and mood disturbances. These are linked to immune dysregulation involving cytokine imbalance, blood–brain barrier (BBB) disruption, glial activation, and T-cell exhaustion. Key biomarkers such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), glial fibrillary acidic protein (GFAP), and neurofilament light chain (NFL) correlate with disease severity and chronicity. This narrative review examines the immunopathological mechanisms underpinning the neurological sequelae of long COVID, focusing on neuroinflammation, endothelial dysfunction, and molecular mimicry. We also assess the role of viral variants in shaping neuroimmune outcomes and explore emerging diagnostic and therapeutic strategies, including biomarker-guided and immune-targeted interventions. By delineating how SARS-CoV-2 reshapes neuroimmune interactions, this review aims to support the development of precision-based diagnostics and targeted therapies for long COVID-related neurological dysfunction. Emerging approaches include immune-modulatory agents (e.g., anti-IL-6), neuroprotective drugs, and strategies for repurposing antiviral or anti-inflammatory compounds in neuro-COVID. Given the high prevalence of comorbidities, personalized therapies guided by biomarkers and patient-specific immune profiles may be essential. Advancements in vaccine technologies and targeted biologics may also hold promise for prevention and disease modification. Finally, continued interdisciplinary research is needed to clarify the complex virus–immune–brain axis in long COVID and inform effective clinical management. Full article

While there are many postulates for the etiology of post-viral chronic fatigue and other symptomatology, little is known. We draw on our past experience of these syndromes to devise means which can expose the primary players of this malady in terms of a panoply participating biomolecules and the state of the stool microbiome. Using databases established from a large dataset of patients at risk of colorectal cancer who were followed longitudinally over 3 decades, and a smaller database dedicated to building a Long PASC cohort (Post-Acute Sequelae of COVID-19), we were able to ascertain factors that predisposed patients to (and resulted in) significant changes in various biomarkers, i.e., the stool microbiome and serum cytokine levels, which we verified by collecting stool and serum samples. There were significant changes in the stool microbiome with an inversion from the usual Bacillota and Bacteroidota species. Serum cytokines showed significant differences in MIP-1β versus TARC (CC chemokine ligand 17) in patients with either PASC or COVID-19 (p < 0.02); IL10 versus IL-12p70a (p < 0.02); IL-1b versus IL-6 (p < 0.01); MCP1 versus TARC (p < 0.03); IL-8 versus TARC (p < 0.002); and Eotaxin3 versus TARC (p < 0.004) in PASC. Some changes were seen solely in COVID-19, including MDC versus MIP-1α (p < 0.01); TNF-α versus IL-1-β (p < 0.06); MCP4 versus TARC (p < 0.0001). We also show correlates with chronic fatigue where an etiology was not identified. These findings in patients with positive criteria for PASC show profound changes in the microbiome and serum cytokine expression. Patients with chronic fatigue without clear viral etiologies also have common associations, including a history of tonsillectomy, which evokes a likely immune etiology. Full article

Background/Objectives: Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a debilitating condition with not fully understood causes, though evidence points to immune system involvement and possible autoimmunity. ME/CFS could be triggered by various infectious pathogens, like SARS-CoV-2; furthermore, a subset of the post-COVID-19 condition (PCC) patients fulfill the diagnostic criteria of ME/CFS. According to the Canadian Consensus Criteria (CCC), the presence of specific symptoms such as fatigue, post-exertional malaise, sleep dysfunction, pain, neurological/cognitive manifestations, and symptoms from at least two of the following categories lead to the diagnosis of ME/CFS: autonomic, neuroendocrine, and immune manifestation. In this study, the patient selection was based on the identification of ME/CFS patients with elevated autoantibodies, regardless of the triggering factor of their condition. Methods: The aim of this study was to identify ME/CFS patients among long COVID patients with elevated autoantibodies. In seven cases, plasmapheresis (PE) and intravenous immunoglobulins (IVIGs) with repetitive autoantibody measurements were applied: four PE sessions on days 1, 5, 30, and 60, and a low-dose IVIG therapy after each treatment. Antibodies were measured before the first PE and two weeks after the last PE session. To monitor clinical outcomes, the following somatic and psychometric follow-up assessments were conducted before the first PE, 2 weeks after the second, and 2 weeks after the last PE: the Schellong test, ISI (insomnia), FSS (fatigue), HADS (depression and anxiety), and EQ-5D-5L (quality of life) questionnaires. Results: There was a negative association between both the β2-adrenergic and M3-muscarinic receptor autoantibody concentration and the quality of life measurements assessed with the EQ-5D-5L questionnaire. Per 1 U/mL increase in the concentration levels of β2-adrenergic receptor antibodies or M3-muscarinic acetylcholine receptor antibodies, the EQ-5D-5L index score [−0.59 to 1] decreased by 0.01 (0.63%) or 0.02 (1.26%), respectively. There were no significant associations between the ISI, HADS, and FSS questionnaires and the β1-adrenergic and M4-muscarinic receptor antibodies titers. Conclusions: After a thorough selection of patients with present autoantibodies, this pilot study found negative associations concerning autoantibody concentration and somatic, as well as psychological wellbeing. To validate these promising feasibility study results—indicating the potential therapeutic potential of antibody-lowering methods—further investigation with larger sample sizes is needed. Full article

Background/Objectives: SARS-CoV-2 can affect the central nervous system directly or indirectly. AD shares several similarities with long COVID cognitive impairment on a molecular and imaging level, as well as common risk factors. The objective of this review is to evaluate the incidence of post-acute COVID-19 cognitive impairment. Secondarily, we aim to determine if neuroinflammation in COVID-19 survivors may be associated with the onset of neurological disease, with a focus on Alzheimer’s disease (AD). Methods: literature search up to March 2025 on the prevalence of cognitive deficits in COVID-19 survivors, underlying pathophysiology and associations with neurological disorders. Results: a wide array of neuropsychiatric manifestations is associated with COVID-19; executive function, memory, and attention are the most frequently reported neurocognitive deficits, regardless of COVID-19 severity. There are associations between the risks for cognitive deficits post-infection with the age of the patients and the severity of the disease. Increasing evidence suggests that neurocognitive deficits are associated with the onset of neurological and neuropsychiatric disease in COVID-19 survivors. Conclusions: clinicians caring for COVID-19 survivors should actively investigate neurocognitive sequelae, particularly for patients with increased risk for cognitive deficits. Full article

Background: Long COVID can develop in individuals who have had COVID-19, regardless of the severity of their initial infection or the treatment they received. Several studies have examined the prevalence and manifestation of symptom phenotypes to comprehend the pathophysiological mechanisms associated with these symptoms. Numerous articles outlined specific approaches for multidisciplinary management and treatment of these patients, focusing primarily on those with mild acute illness. The various management models implemented focused on a patient-centered approach, where the specialists were positioned around the patient. On the other hand, the created pathways do not consider the possibility of symptom clusters when determining how to define diagnostic algorithms. Methods: This retrospective longitudinal study took place at the “Fondazione IRCCS Policlinico San Matteo”, Pavia, Italy (SMATTEO) and at the “Ospedale di Cremona”, ASST Cremona, Italy (CREMONA). Information was retrieved from the administrative data warehouse and from two dedicated registries. We included patients discharged with a diagnosis of severe COVID-19, systematically invited for a 3-month follow-up visit. Unsupervised machine learning was used to identify potential patient phenotypes. Results: Three hundred and eighty-two patients were included in these analyses. About one-third of patients were older than 65 years; a quarter were female; more than 80% of patients had multi-morbidities. Diagnoses related to the circulatory system were the most frequent, comprising 46% of cases, followed by endocrinopathies at 20%. PCA (principal component analysis) had no clustering tendency, which was comparable to the PCA plot of a random dataset. The unsupervised machine learning approach confirms these findings. Indeed, while dendrograms for the hierarchical clustering approach may visually indicate some clusters, this is not the case for the PAM method. Notably, most patients were concentrated in one cluster. Conclusions: The extreme heterogeneity of patients affected by post-acute sequelae of SARS-CoV-2 infection (PASC) has not allowed for the identification of specific symptom clusters with the most recent statistical techniques, thus preventing the generation of common diagnostic-therapeutic pathways. Full article

Cardiovascular complications are a hallmark of Post-Acute Sequelae of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection (PASC), yet the mechanisms driving persistent cardiac dysfunction remain poorly understood. Emerging evidence implicates mitochondrial dysfunction in immune cells as a key contributor. This study investigated whether CD14⁺⁺ monocytes from long COVID patients exhibit bioenergetic impairment, mitochondrial DNA (mtDNA) damage, and defective oxidative stress adaptation, which may underlie cardiovascular symptoms in PASC. CD14⁺⁺ monocytes were isolated from 14 long COVID patients with cardiovascular symptoms (e.g., dyspnea, angina) and 10 age-matched controls with similar cardiovascular risk profiles. Mitochondrial function was assessed using a Seahorse Agilent Analyzer under basal conditions and after oxidative stress induction with buthionine sulfoximine (BSO). Mitochondrial membrane potential was measured via Tetramethylrhodamine Ethyl Ester (TMRE) assay, mtDNA integrity via qPCR, and reactive oxygen species (ROS) dynamics via Fluorescence-Activated Cell Sorting (FACS). Parallel experiments exposed healthy monocytes to SARS-CoV-2 spike protein to evaluate direct viral effects. CD14⁺⁺ monocytes from long COVID patients with cardiovascular symptoms (n = 14) exhibited profound mitochondrial dysfunction compared to age-matched controls (n = 10). Under oxidative stress induced by buthionine sulfoximine (BSO), long COVID monocytes failed to upregulate basal respiration (9.5 vs. 30.4 pmol/min in controls, p = 0.0043), showed a 65% reduction in maximal respiration (p = 0.4035, ns) and demonstrated a 70% loss of spare respiratory capacity (p = 0.4143, ns) with significantly impaired adaptation to BSO challenge (long COVID + BSO: 9.9 vs. control + BSO: 54 pmol/min, p = 0.0091). Proton leak, a protective mechanism against ROS overproduction, was blunted in long COVID monocytes (3-fold vs. 13-fold elevation in controls, p = 0.0294). Paradoxically, long COVID monocytes showed reduced ROS accumulation after BSO treatment (6% decrease vs. 1.2-fold increase in controls, p = 0.0015) and elevated mitochondrial membrane potential (157 vs. 113.7 TMRE fluorescence, p = 0.0179), which remained stable under oxidative stress. mtDNA analysis revealed severe depletion (80% reduction, p < 0.001) and region-specific damage, with 75% and 70% reductions in amplification efficiency for regions C and D (p < 0.05), respectively. In contrast, exposure of healthy monocytes to SARS-CoV-2 spike protein did not recapitulate these defects, with preserved basal respiration, ATP production, and spare respiratory capacity, though coupling efficiency under oxidative stress was reduced (p < 0.05). These findings suggest that mitochondrial dysfunction in long COVID syndrome arises from maladaptive host responses rather than direct viral toxicity, characterized by bioenergetic failure, impaired stress adaptation, and mitochondrial genomic instability. This study identifies persistent mitochondrial dysfunction in long COVID monocytes as a critical driver of cardiovascular complications in PASC. Key defects—bioenergetic failure, impaired stress adaptation and mtDNA damage—correlate with clinical symptoms like heart failure and exercise intolerance. The stable elevation of mitochondrial membrane potential and resistance to ROS induction suggest maladaptive remodeling of mitochondrial physiology. These findings position mitochondrial resilience as a therapeutic target, with potential strategies including antioxidants, mtDNA repair agents or metabolic modulators. The dissociation between spike protein exposure and mitochondrial dysfunction highlights the need to explore host-directed mechanisms in PASC pathophysiology. This work advances our understanding of long COVID cardiovascular sequelae and provides a foundation for biomarker development and targeted interventions to mitigate long-term morbidity. Full article

Background: Despite the multiple waves of the COVID-19 pandemic, follow-up strategies for recovered patients remain inconclusive. This study aimed to evaluate chest computed tomography (CT) and pulmonary function test (PFT) abnormalities in convalescents six months after COVID-19 and to compare these findings with those from a representative population cohort. The goal was to support more individualized pulmonary management of post-COVID-19 sequelae. Methods: This study population consisted of 2 groups: I—232 post-COVID-19 patients and II—543 patients from a population cohort. Chest CT was performed during the acute phase of COVID-19 and six months after. The PFTs were conducted six months after COVID-19. Results: There were no significant differences in FEV1, FVC, TLC, and DLCO in the two study groups. A singular GGO in 24 patients (20%), a crazy paving pattern in 1 patient (0.8%), thickening of interlobular septa in 4 patients (3.5%), consolidations in 4 patients (3.5%), traction bronchiectasis in 6 patients (5%), fibrosis in 6 patients (5%), and singular nodular densities in 68 patients (58%) were observed in chest CT 6 months after COVID-19. Most radiological abnormalities were clinically insignificant and did not require further diagnostic evaluation. No significant differences in chest CT and PFT six months after infection were observed between patients differing in the severity of inflammation during the acute disease or SARS-CoV-2 variant. Conclusions: The majority of chest CT abnormalities resolved within six months of recovery, regardless of SARS-CoV-2 variant or initial disease severity. Pulmonary function tests should be prioritized in post-COVID-19 follow-up, as PFT results in convalescents were comparable to those observed in the general population. Full article

SARS-CoV-2 infection has had a significant impact on global health through both acute illness, referred to as coronavirus disease 2019 (COVID-19), and chronic conditions (long COVID or post-acute sequelae of COVID-19, PASC). Despite substantial advancements in preventing severe COVID-19 cases through vaccination, the rise in the prevalence of long COVID syndrome and a notable degree of genomic mutation, primarily in the S protein, underscores the necessity for a deeper understanding of the underlying pathophysiological mechanisms related to the S protein of SARS-CoV-2. In this review, the latest part of this series, we investigate the potential pathophysiological molecular mechanisms triggered by the interaction between the spike protein and cellular receptors. Therefore, this review aims to provide a differential and focused view on the mechanisms potentially activated by the binding of the spike protein to canonical and non-canonical receptors for SARS-CoV-2, together with their possible interactions and effects on the pathogenesis of long COVID. Full article

SARS-CoV-2 infection has resulted in more than 700 million cases and nearly 7 million deaths worldwide. Although vaccination efforts have effectively reduced mortality and transmission rates, a significant proportion of recovered patients—up to 40%—develop long COVID syndrome (LC) or post-acute sequelae of COVID-19 infection (PASC). LC is characterized by the persistence or emergence of new symptoms following initial SARS-CoV-2 infection, affecting the cardiovascular, neurological, respiratory, gastrointestinal, reproductive, and immune systems. Despite the broad range of clinical symptoms that have been described, the risk factors and pathogenic mechanisms behind LC remain unclear. This review, the first of a two-part series, is distinguished by the discussion of the role of the SARS-CoV-2 spike protein in the primary mechanisms underlying the pathophysiology of LC. Full article

Although the acute phase of the COVID-19 pandemic has subsided, the emergence of the post-COVID-19 condition presents a new and complex public health challenge, characterized by persistent, multisystem symptoms that can endure for weeks or months after the initial infection with the SARS-CoV-2 virus, significantly affecting survivors’ quality of life. Among the most concerning sequelae are cardiovascular complications, which encompass a broad spectrum of conditions, including arrhythmias, myocardial damage, or postural orthostatic tachycardia syndrome. This narrative review explores the burden of the SARS-CoV-2 infection on cardiovascular health by reviewing the latest and most relevant findings in the literature and highlighting different aspects of COVID-19’s cardiovascular involvement. This review investigates the pathophysiological mechanisms underlying cardiovascular involvement in the post-COVID-19 condition, with a focus on direct viral invasion via ACE2 receptors, immune-mediated cardiovascular injury, cytokine storm, systemic inflammation, endothelial dysfunction, and mitochondrial injury. The interplay between pre-existing cardiovascular diseases, such as hypertension, atherosclerosis, diabetes, and atrial fibrillation, and COVID-19 is also explored, revealing that individuals with such conditions are at heightened risk for both severe acute illness and long-term complications. Long-term immune activation and the persistence of viral antigens are increasingly recognized as contributors to ongoing cardiovascular damage, even in individuals with mild or asymptomatic initial infections. As the healthcare system continues to adapt to the long-term consequences of the SARS-CoV-2 pandemic, a deeper understanding of these cardiovascular manifestations is essential. This knowledge will inform the development of targeted strategies for prevention, clinical management, and rehabilitation of affected patients. Furthermore, the insights gained from the intersection of COVID-19 and cardiovascular health will be instrumental in shaping responses to future viral epidemics, highlighting the necessity for multidisciplinary approaches to patient care and public health preparedness. Full article