Since the emergence of COVID-19 in December 2019, the novel SARS-CoV-2 virus has primarily affected adults, with children representing a smaller proportion of cases. However, the escalation of the pandemic has led to a notable increase in pediatric cases of Multisystem Inflammatory Syndrome in Children (MIS-C). The pathogenesis of MIS-C is largely attributed to immune-mediated mechanisms, such as cytokine storms and endothelial damage, following SARS-CoV-2 infection. In this review, we comprehensively describe MIS-C, including its definitions as proposed by the CDC, WHO, and RCPCH, which emphasize persistent fever, excessive inflammatory responses, and multi-organ involvement. Additionally, we summarize current treatment approaches, prioritizing immunotherapy with intravenous immunoglobulin and corticosteroids, along with anticoagulation therapy, and monoclonal antibodies in severe cases.

Coronavirus disease 2019 (COVID-19) causes pulmonary edema, which disrupts the lung alveoli-capillary barrier and leads to pulmonary cell apoptosis, the main cause of death. However, the molecular mechanism behind SARS-CoV-2's apoptotic activity remains unknown. Here, we revealed that SARS-CoV-2-ORF-3a mediates the pulmonary pathology associated with SARS-CoV-2, which is demonstrated by the fact that it causes lung tissue damage. The in vitro results showed that SARS-CoV-2-ORF-3a triggers cell death via the disruption of mitochondrial homeostasis, which is modulated through the regulation of Mitochondrial ATP-sensitive Potassium Channel (MitoKATP). The addition of exogenous Potassium (K+) in the form of potassium chloride (KCl) attenuated mitochondrial apoptosis along with the inflammatory interferon response (IFN-β) triggered by SARS-ORF-3a. The addition of exogenous K+ strongly suggests that dysregulation of K+ ion channel function is the central mechanism underlying the mitochondrial dysfunction and stress response induced by SARS-CoV-2-ORF-3a. Our results designate that targeting the potassium channel or its interactions with ORF-3a may represent a promising therapeutic strategy to mitigate the damaging effects of infection with SARS-CoV-2.

COVID-19 skin manifestations are multifaceted, ranging from urticaria, morbilliform or papulovesicular rash, livedoid purpuric lesions, and to pseudochilblains (also called COVID toes). Recent insights into the mechanism of these manifestations have highlighted that morbilliform, papulovesicular, and livedoid/purpuric rashes are related to virus-induced endothelial cell damage and linked to moderate-to-severe disease, whereas pseudochilblains are related to an exaggerated IFN-1 production by plasmacytoid dendritic cells in protected individuals. In this paper, we will review the clinical and physiopathological features of cutaneous COVID-19 manifestations in relation to the direct viral cytopathic effects and dysregulated IFN-1 responses. We will also review the emerging insights into post-COVID conditions (also termed long COVID) and how they may be implicated in the persistence of COVID-19-associated skin diseases.

Many children suffer from lingering symptoms after COVID-19, known as long COVID syndrome (LCS), otherwise called Post COVID-19 Condition (PCC). Despite extensive research, the prevalence of symptoms, its impact on quality of life, and underlying mechanisms still need to be fully understood. As neutrophilic granulocytes play an essential role in COVID-19, and their prolonged disruption was found to cause immunological diseases, we hypothesized their ongoing disturbed functionality in LCS.

We studied 129 children with LCS, 32 convalescent children (CG+), and 8 uninfected children (CG-). Online questionnaires and in-person examinations assessed symptoms, quality of life, and functioning (QoL-F). Effector functions of neutrophilic granulocytes obtained from the venous blood of 29 LCS and 17 CG+ children were also investigated.

Persistent fatigue was the most common symptom in children with LCS, while both control groups complained about anxiety most frequently. LCS children experienced significantly more symptoms, impairing their QoL-F compared to CG+. Neutrophilic granulocyte dysfunction was found in LCS children, with decreased superoxide-producing activity and phagocytosis compared to CG+. The number of complaints of children with LCS correlated significantly with altered neutrophil effector functions.

Neutrophil dysfunction in children with LCS may be part of the disease pathogenesis or a predisposing factor.

Using online questionnaires validated during in-person medical examinations and including two different control groups, our study compellingly supports and adds to previous clinical observations in the field. Our study provides valuable insights into the prevalence and characteristics of pediatric LCS, highlighting the significant quality of life and functioning impairment compared to control groups. By detecting neutrophilic granulocyte dysfunction in children with LCS, we shed light on a previously overlooked pathophysiological component of the condition. We demonstrate a significant correlation between clinical symptoms and superoxide production, further enhancing our understanding of the underlying mechanisms of pediatric LCS.

Since the beginning of the coronavirus disease 2019 pandemic, the most common skin lesions observed due to infection with the severe acute respiratory syndrome coronavirus 2 are pseudochilblains (or coronavirus disease toes). However, this pathology remains infrequent and difficult to diagnose, as no specific test exists.

Two Caucasian women, 30 and 22 years old, presented to our General Medicine Unit with perniosis lesions on the feet during the first two waves of the coronavirus disease 2019 pandemic. They did not have respiratory or general symptoms of severe acute respiratory syndrome coronavirus 2 infection, the reverse transcription polymerase chain reaction on nasopharyngeal swabs was negative, and the serology was positive only in the first case. The clinical presentation differed for the two cases, as the second patient suffered from swelling and burning after cold application. The diagnosis was based on clinical presentation, temporality, exclusion of other differential diagnoses, and blood test results (positive serology in the first case and high level of CXCL13 and VEGF in the second), supported by current literature. Lesions resolved spontaneously in the first patient. The second case was hospitalized for pain management and received corticosteroid therapy with resolution of the symptoms.

These two cases with different clinical presentations illustrate the diagnostic approach to coronavirus disease 2019, a challenging disease with diverse manifestations, including, in some cases, coronavirus disease toes. We present a literature review that illustrates the progression of scientific research. Skin lesions associated with coronavirus disease 2019 infection could be the expression of an important interferon type 1 response and should be considered in the differential diagnosis in a primary care setting.

This case series describes the clinical course and reconstructive methods utilized for patients with diabetes and significant gangrene and necrosis following coronavirus disease 2019 (COVID-19) infection. COVID-19 produces mainly respiratory symptoms but has a variety of atypical presentations and sequelae. Serious complications are increased in patients with underlying medical conditions such as diabetes mellitus. By generating a prothrombotic milieu, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) increases the risk for arterial and venous thromboses. Inflammatory damage and micro-thromboses are thought to contribute to acro-ischemia, colloquially known as 'COVID toes,' which presents cutaneously as chilblain-like lesions. Necrosis can be severe and devastating, often resulting in major amputation. Two exemplary case reports are presented herein: first, a 57-year-old female presented for vascular evaluation with pedal gangrene to the midfoot one month after developing painful discoloration in her right toe. After angioplasty restored pedal blood flow, she received a transmetatarsal amputation (TMA) with a local tissue flap. Second, a 41-year-old female presented for vascular evaluation with extensive pedal gangrene three months after hospitalization for COVID-19. After arteriotomy improved pedal blood flow, she underwent a Lisfranc amputation followed by superficial circumflex iliac artery perforator (SCIP) flap reconstruction. Sufficient evidence suggests that COVID-19 impairs microcirculatory function and can be especially detrimental in diabetic patients. Reconstructive techniques in patients with severe gangrene with COVID toes help patients regain functionality.

In patients infected with severe acute respiratory syndrome coronavirus 2, vasculopathic changes of the skin are associated with a severe prognosis. However, the pathogenesis of this vasculopathy is not conclusively clarified. In this study, 25 prospectively collected skin samples from patients with COVID-19-related skin lesions were examined for vasculopathic changes and, in case of vasculitis, were further analyzed with electron microscopy and immunohistochemistry. Vasculopathy was observed in 76% of all COVID-19-related inflammatory skin lesions. Visual endothelial changes without manifest leukocytoclastic vasculitis were found in 60% of the COVID-19-related skin lesions, whereas leukocytoclastic vasculitis was diagnosed in 16%. In the cases of vasculitis, there were extensive spike protein depositions in microvascular endothelial cells that colocalized with the autophagosome proteins LC3B and LC3C. The autophagy protein complex LC3-associated endocytosis in microvascular endothelial cells seems to be an important pathogenic factor for severe acute respiratory syndrome coronavirus 2-related vasculitis in the skin. On ultrastructural morphology, the vasculitic process was dominated by intracellular vesicle formation and endothelial cell disruption. Direct presence of severe acute respiratory syndrome coronavirus 2 particles in the skin was not observed. Therefore, our results suggest that instead of direct viral infection, dermal vasculitic lesions in COVID-19 are caused by severe acute respiratory syndrome coronavirus 2 spike protein deposition followed by endothelial damage with activation of autophagy.

Severe SARS-CoV-2 elicits a hyper-inflammatory response that results in intravascular inflammation with endothelial injury, which contributes to increased mortality in COVID-19. To predict the outcome of severe SARS-CoV-2 infection, we analyzed the baseline level of different biomarkers of vascular disorders in COVID-19 subjects upon intensive care unit (ICU) admission and prior to any vaccination. A total of 70 severe COVID-19 patients (37 survivors and 33 non-survivors) were included with 16 age- and sex-matched controls. Vascular dysfunction was monitored via soluble VCAM-1, E-selectin, ACE2 and Lp-PLA2, while abnormal platelet activation was evaluated by soluble P-selectin and CD40L in parallel. These results were correlated with routine laboratory parameters and disease outcomes. Among these parameters, VCAM-1 and ACE2 showed significantly higher serum levels in COVID-19 patients with early death vs. convalescent subjects. VCAM-1 was significantly correlated with the Horowitz index (r = 0.3115) and IL-6 (r = 0.4599), while ACE2 was related to E-selectin (r = 0.4143) and CD40L (r = 0.2948). Lp-PLA2 was altered in none of these COVID-19 subcohorts and showed no relationship with the other parameters. Finally, the pre-treatment level of VCAM-1 (≥1420 ng/mL) and ACE2 activity (≥45.2 μU/mL) predicted a larger risk for mortality (Log-Rank p = 0.0031 and p = 0.0117, respectively). Vascular dysfunction with endothelial cell activation is linked to lethal COVID-19, and highly elevated soluble VCAM-1 and ACE2 at admission to ICU may predict unfavorable outcomes.

Multisystem inflammatory syndrome in children (MIS-C) is a complex syndrome characterized by multi-organ involvement that has emerged in the context of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak. The clinical presentation of MIS-C is similar to Kawasaki disease but predominantly presents with fever and gastrointestinal symptoms, and severe cases can involve toxic shock and cardiac dysfunction. Epidemiological findings indicate that the majority of MIS-C patients test positive for SARS-CoV-2 antibodies. The pathogenesis and pathophysiology of MIS-C remain unclear, though immune dysregulation following SARS-CoV-2 infection is considered a major contributing factor. Current treatment approaches for MIS-C primarily involve intravenous immunoglobulin therapy and symptomatic supportive care. This review article provides a comprehensive overview of the definition, epidemiology, pathogenesis, clinical presentation, diagnosis, treatment, and prognosis of MIS-C.

Despite the large number of articles published on skin lesions related to COVID-19, clinicopathological correlation has not been performed consistently and immunohistochemistry to demonstrate spike 3 protein expression has not been validated through RT-PCR.

We compiled 69 cases of patients with confirmed COVID-19, where skin lesions were clinically and histopathologically studied. Immunohistochemistry (IHC) and RT-PCR was performed in skin biopsies.

After a careful review of the cases, 15 were found to be dermatosis not related to COVID-19, while the rest of the lesions could be classified according to their clinical characteristics as vesicular (4), maculopapular eruptions (41), urticariform (9), livedo and necrosis (10) and pernio-like (5). Although histopathological features were similar to previously reported results, we found two previously unreported findings, maculopapular eruptions with squamous eccrine syringometaplasia and neutrophilic epitheliotropism. IHC showed in some cases endothelial and epidermal staining but RT-PCR was negative in all the tested cases. Thus, direct viral involvement could not be demonstrated.

Despite presenting the largest series of confirmed COVID-19 patients with histopathologically studied skin manifestations, direct viral involvement was difficult to establish. Vasculopathic and urticariform lesions seem to be those more clearly related to the viral infection, despite IHC or RT-PCR negative results failed to demonstrate viral presence. These findings, as in other dermatological areas, highlight the need of a clinico-pathological correlation to increase knowledge about viral involvement in COVID-19 skin-related lesions.

Despite the large number of articles published on skin lesions related to COVID-19, clinicopathological correlation has not been performed consistently and immunohistochemistry to demonstrate spike 3 protein expression has not been validated through RT-PCR.

We compiled 69 cases of patients with confirmed COVID-19, where skin lesions were clinically and histopathologically studied. Immunohistochemistry (IHC) and RT-PCR was performed in skin biopsies.

After a careful review of the cases, 15 were found to be dermatosis not related to COVID-19, while the rest of the lesions could be classified according to their clinical characteristics as vesicular (4), maculopapular eruptions (41), urticariform (9), livedo and necrosis (10) and pernio-like (5). Although histopathological features were similar to previously reported results, we found two previously unreported findings, maculopapular eruptions with squamous eccrine syringometaplasia and neutrophilic epitheliotropism. IHC showed in some cases endothelial and epidermal staining but RT-PCR was negative in all the tested cases. Thus, direct viral involvement could not be demonstrated.

Despite presenting the largest series of confirmed COVID-19 patients with histopathologically studied skin manifestations, direct viral involvement was difficult to establish. Vasculopathic and urticariform lesions seem to be those more clearly related to the viral infection, despite IHC or RT-PCR negative results failed to demonstrate viral presence. These findings, as in other dermatological areas, highlight the need of a clinico-pathological correlation to increase knowledge about viral involvement in COVID-19 skin-related lesions.

Eosinophils are known to be present in inflammatory skin diseases, but their diagnostic utility is not well established. Upon review of the published status of lesional eosinophils, several categories were identified. 1) Lesional eosinophils highly characteristic such that, in their absence, the pathologist may question the diagnosis. These include arthropod bite reactions and scabies, urticarial dermatitis, and other eosinophilic dermatoses. 2) Lesional eosinophils rare or absent, such that, in their presence, the pathologist may question the diagnosis. These include pityriasis lichenoides, graft versus host disease, and connective tissue disorders. 3) Lesional eosinophils variable and, while in some cases expected, are not required for diagnosis. These include drug reactions, atopic dermatitis and allergic contact dermatitis. 4) Lesional eosinophils variable and not expected but may be seen to a limited extent. These include lichen planus and psoriasis.

In this Personal View, we discuss current knowledge on SARS-CoV-2 RNA or antigen persistence in children infected with SARS-CoV-2. Based on the evidence that the virus can persist in adults, we have done a literature review and analysed studies that looked for SARS-CoV-2 RNA or antigens in children undergoing autopsy, biopsy, or surgery for either death from COVID-19 or multisystem inflammatory syndrome, or assessments for long COVID-19 or other conditions. Our analysis suggests that in children, independent from disease severity, SARS-CoV-2 can spread systemically and persist for weeks to months. We discuss what is known about the biological effects of viral persistence for other viral infections and highlight new scenarios for clinical, pharmacological, and basic research exploration. Such an approach will improve the understanding and management of post-viral syndromes.

Individuals with SARS-CoV-2 infection can develop symptoms that persist well beyond the acute phase of COVID-19 or emerge after the acute phase, lasting for weeks or months after the initial acute illness. The post-acute sequelae of COVID-19, which include physical, cognitive, and mental health impairments, are known collectively as long COVID or post-COVID-19 condition. The substantial burden of this multisystem condition is felt at individual, health-care system, and socioeconomic levels, on an unprecedented scale. Survivors of COVID-19-related critical illness are at risk of the well known sequelae of acute respiratory distress syndrome, sepsis, and chronic critical illness, and these multidimensional morbidities might be difficult to differentiate from the specific effects of SARS-CoV-2 and COVID-19. We provide an overview of the manifestations of post-COVID-19 condition after critical illness in adults. We explore the effects on various organ systems, describe potential pathophysiological mechanisms, and consider the challenges of providing clinical care and support for survivors of critical illness with multisystem manifestations. Research is needed to reduce the incidence of post-acute sequelae of COVID-19-related critical illness and to optimise therapeutic and rehabilitative care and support for patients.

To investigate the clinical features and treatment strategies of multisystemic inflammatory syndrome in children (MIS-C) after severe acute respiratory syndrome coronavirus 2 infection.

A retrospective analysis was performed on the medical data of four children with MIS-C who were admitted to the Department of Cardiology, Xuzhou Children's Hospital, Xuzhou Medical Universityfrom January to February 2023.

All four children had multiple organ involvements and elevated inflammatory markers, with a poor response to standard therapy for Kawasaki disease after admission. Two children were treated with intravenous immunoglobulin therapy pulse therapy twice, and all four children were treated with glucocorticoids. The children had a good prognosis after the treatment.

MIS-C often appears within 4-6 weeks or a longer time after severe acute respiratory syndrome coronavirus 2 infection, and anti-inflammatory therapy in addition to the standard treatment regimen for Kawasaki disease can help to achieve a favorable treatment outcome.

This review aimed to assess the impact of coronavirus disease 2019 (COVID-19) on skin health to establish a classification of the skin lesions that occur most frequently during the disease and whether a particular category of skin damage is more likely to occur both in the short term and in the long term.

We conducted a literature search of the PubMed database. Ultimately, 109 articles were included in this review. The exact phrases∕syntax and connectors used for the database search∕query were as follows: "Coronavirus and skin", "COVID-19 and skin", "SARS-CoV-2 and skin", "Coronavirus cutaneous manifestations", "COVID-19 cutaneous manifestations", "SARS-CoV-2 cutaneous manifestations", "Coronavirus dermatology", "SARS-CoV-2 and dermatology", "COVID-19 and dermatology", "COVID-19 and skin eruption", "Coronavirus and skin rash", "COVID-19 and hair", "Coronavirus and hair", "Coronavirus and nails", "SARS-CoV-2 and hair", and "SARS-CoV-2 and nails". Only articles with abstracts referring strictly to cutaneous manifestations of COVID-19 were chosen. Articles without abstracts were not considered.

We established six of the most frequently reported clinical patterns associated with COVID-19 and their probability of occurring during COVID-19 disease evolution based on the current literature reports. We did not identify the particular types of skin lesions that are most prone to long-term persistence; most such cases are rare, and no conclusion can be drawn based on them.

Apart from classified COVID-19-related skin disorders, this pandemic has been a challenge for dermatologists and a wide range of cutaneous side effects related to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) treatments have been reported. We are aware of other polymorphic clinical presentations, with novel data being reported periodically, but the pathophysiological mechanisms and evolution are largely unknown.

For over three years, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in children and adolescents has generated repercussions, especially a few weeks after infection, for symptomatic patients who tested positive, for asymptomatic ones, or even just the contacts of an infected person, and evolved from severe forms such as multisystem inflammatory syndrome in children (MIS-C) to multifarious clinical manifestations in long COVID (LC). Referred to under the umbrella term LC, the onset of persistent and highly heterogeneous symptoms such as fatigue, post-exertion malaise, cognitive dysfunction, and others have a major impact on the child's daily quality of life for months. The first aim of this review was to highlight the circumstances of the pathophysiological changes produced by COVID-19 in children and to better understand the hyperinflammation in COVID-19 and how MIS-C, as a life-threatening condition, could have been avoided in some patients. Another goal was to better identify the interplay between infection, dysbiosis, and inflammation at a molecular and cellular level, to better guide scientists, physicians, and pediatricians to advance new lines of medical action to avoid the post-acute sequelae of SARS-CoV-2 infection. The third objective was to identify symptoms and their connection to molecular pathways to recognize LC more easily. The fourth purpose was to connect the triggering factors of LC with related sequelae following acute SARS-CoV-2 injuries to systems and organs, the persistence of the virus, and some of its components in hidden reservoirs, including the gut and the central nervous system. The reactivation of other latent infectious agents in the host's immune environments, the interaction of this virus with the microbiome, immune hyperactivation, and autoimmunity generated by molecular mimicry between viral agents and host proteins, could initiate a targeted and individualized management. New high-tech solutions, molecules, probiotics, and others should be discovered to innovatively solve the interplay between RNA persistent viruses, microbiota, and our immune system.

Routine clinical assays, such as conventional immunohistochemistry, often fail to resolve the regional heterogeneity of complex inflammatory skin conditions. We introduce MANTIS (Multiplex Annotated Tissue Imaging System), a flexible analytic pipeline compatible with routine practice, specifically designed for spatially resolved immune phenotyping of the skin in experimental or clinical samples. On the basis of phenotype attribution matrices coupled to α-shape algorithms, MANTIS projects a representative digital immune landscape while enabling automated detection of major inflammatory clusters and concomitant single-cell data quantification of biomarkers. We observed that severe pathological lesions from systemic lupus erythematosus, Kawasaki syndrome, or COVID-19-associated skin manifestations share common quantitative immune features while displaying a nonrandom distribution of cells with the formation of disease-specific dermal immune structures. Given its accuracy and flexibility, MANTIS is designed to solve the spatial organization of complex immune environments to better apprehend the pathophysiology of skin manifestations.

COronaVIrus Disease 19 (COVID-19) is associated with a wide spectrum of skin manifestations, but SARS-CoV-2 RNA in lesional skin has been demonstrated only in few cases.

The objective of this study was to demonstrate SARS-CoV-2 presence in skin samples from patients with different COVID-19-related cutaneous phenotypes.

Demographic and clinical data from 52 patients with COVID-19-associated cutaneous manifestations were collected. Immunohistochemistry and digital PCR (dPCR) were performed in all skin samples. RNA in situ hybridization (ISH) was used to confirm the presence of SARS-CoV-2 RNA.

Twenty out of 52 (38%) patients presented SARS-CoV-2 positivity in the skin. Among these, 10/52 (19%) patients tested positive for spike protein on immunohistochemistry, five of whom had also positive testing on dPCR. Of the latter, one tested positive both for ISH and ACE-2 on immunohistochemistry while another one tested positive for nucleocapsid protein. Twelve patients showed positivity only for nucleocapsid protein on immunohistochemistry.

SARS-CoV-2 was detected only in 38% of patients, without any association with a specific cutaneous phenotype, suggesting that the pathophysiology of cutaneous lesions mostly depends on the activation of the immune system. The combination of spike and nucleocapsid immunohistochemistry has higher diagnostic yield than dPCR. Skin persistence of SARS-CoV-2 may depend on timing of skin lesions, viral load, and immune response.

Since the COVID-19 pandemic started, great interest has been given to this disease, especially to its possible clinical presentations. Besides classical respiratory symptoms, dermatological manifestations occur quite often among infected and non-infected patients, particularly in children. A prominent IFN-I response, that is generally higher in children compared to adults, may not only cause chilblain lesions, but it could also prevent infection and viral replication, thus justifying the negative swab results, as well as the absence of relevant systemic symptoms in positive cases. Indeed, reports have emerged describing chilblain-like acral lesions in children and adolescents with either proven or suspected infection.

Patients aged from 1 to 18 years old were enrolled in this study from 23 Italian dermatological units and were observed for an overall period of 6 months. Clinical pictures were collected along with data on the location and duration of skin lesions, their association with concomitant local and systemic symptoms, presence of nail and/or mucosal involvement, as well as histological, laboratory and imaging findings.

One hundred thirty-seven patients were included, of whom 56.9% were females. Mean age was 11.97±3.66 years. The most commonly affected sites were the feet (77 patients, 56.2%). Lesions (48.5%) featured cyanosis, chilblains, blisters, ecchymosis, bullae, erythema, edema, and papules. Concomitant skin manifestations included maculo-papular rashes (30%), unspecified rashes (25%), vesicular rashes (20%), erythema multiforme (10%), urticaria (10%) and erythema with desquamation (5%). Forty-one patients (29.9%) reported pruritus as the main symptom associated with chilblains, and 56 out of 137 patients also reported systemic symptoms such as respiratory symptoms (33.9%), fever (28%), intestinal (27%), headache (5.5%), asthenia (3.5%), and joint pain (2%). Associated comorbid conditions were observed in 9 patients presenting with skin lesions. Nasopharyngeal swabs turned out positive in 11 patients (8%), whereas the remainder were either negative (101, 73%) or unspecified (25, 18%).

COVID-19 has been credited as the etiology of the recent increase in acro-ischemic lesions. The present study provides a description of pediatric cutaneous manifestations deemed to be potentially associated with COVID-19, revealing a possible association between acral cyanosis and nasopharyngeal swab positivity in children and teenagers. The identification and characterization of newly recognized patterns of skin involvement may aid physicians in diagnosing cases of asymptomatic or pauci-symptomatic COVID patients.

COVID-19 usually presents with classic signs and symptoms, but it can involve multiple systems in atypical cases. SARS-CoV-2 has a complex interaction with the host immune system leading to atypical manifestations. In our case, a 32-year-old male patient presented with fatigue, sores on hands and feet, headache, productive cough with blood-tinged mucus, conjunctival hyperemia, purpuric rash on hands and feet, and splinter hemorrhages of fingernails for 2 weeks. The patient's SARS-CoV-2 antigen and PCR test were positive. Chest X-ray showed mixed density perihilar opacities in both lungs. Computed tomography of the chest showed extensive airspace opacities in both lungs, suggesting COVID-19 multifocal, multilobar pneumonitis. A renal biopsy indicated limited thrombotic microangiopathy and tubulointerstitial nephritis, for which he was started on steroids, and his renal functions gradually improved. He tested positive for C-ANCA during an immune workup. He was discharged with a steroid taper for nephritis. Once the taper reached less than 10 mg/day, he developed acute scleritis and a new pulmonary cavitary lesion of 6 cm. The biopsy via bronchoscopy revealed acute inflammatory cells with hemosiderin-laden macrophages. He was restarted on systemic steroids for scleritis after failing topical steroids, which incidentally also reduced the size of the cavitary lesion, indicating an immune component. Our case demonstrates the involvement of kidneys and vasculitis of the skin, sclera, and lungs by COVID-19. The patient's symptoms were not explained by any diseases other than COVID-19. Atypical cases of COVID-19 disease with multifocal systemic symptoms involving the skin, sclera, lungs, and kidneys should be high on differentials. Early recognition and intervention may decrease hospital stays and morbidity.

This study aimed to study the impact of the COVID-19 pandemic on patients living with systemic vasculitis in Kazakhstan. A single-centre retrospective study of the medical histories of 82 patients was carried out based on the regional clinical hospital of the city for all admissions with systemic vasculitis in the period from January 2019 to December 2021. The following qualitative (gender, disability, concomitant diseases) and quantitative (age, disease experience, laboratory data, etc.) variables were studied. To conduct the study, the criteria for the inclusion and exclusion of patients in the study were determined. According to the results of the study, there is a decrease in the number of hospitalized patients with vasculitis in the rheumatology department of the regional clinical hospital. Compared to 2019, in 2021, the number of hospitalized patients decreased by almost half (Table 1). Out of 82 cases, the most common was Takayasu disease (nonspecific aortoarteritis) (43.9%), IgA-vasculitis (Schenlein-Genoch disease) (31.71%), and they are typical mainly for females of rural origin, who were admitted to the hospital in a comorbid state (p < 0.001). 41.6% of patients have disabilities, and the majority of patients have a II disability group. The average body mass index is 24.2; 27 patients out of the total number of patients suffer from obesity. The most common clinical symptoms of patients with systemic vasculitis were injuries of the musculoskeletal system (75.6%). A negative average correlation was found between the indicators of the level of ESR and haemoglobin, the correlation coefficient is -0.535. The patients had concomitant diseases, such as diabetes mellitus, iron deficiency anaemia, coronary heart disease, hypertension, gastrointestinal tract diseases and hepatitis. Women of reproductive age from rural areas are often diagnosed with systemic vasculitis. A high rate of disability revealed among the patients can be explained by two main factors, the first is that the patients consulted the doctors untimely and the second is that the medical community are insufficiently informed about the management of autoimmune rheumatic diseases, in particular about systemic vasculitis, which hinders timely diagnosis and treatment, respectively. Patients, included in this survey, were mostly suffering from diseases of the musculoskeletal system, but depending on the type of vasculitis, other organs and systems may be affected. Table 1 Frequency of patients with systemic vasculitis over 3 years Year Frequency % p-value 2019 42 51.2 χ² = 12.463^a; p = 0.002 2020 23 28.0 2021 17 20.7 Total 82 100.0.

Vascular function assessment is useful for the evaluation of atherosclerosis severity, which may provide additional information for cardiovascular risk stratification. In addition, vascular function assessment is helpful for a better understanding of pathophysiological associations between vascular dysfunction and cardiometabolic disorders. In 2020 and 2021, although coronavirus disease 2019 (COVID-19) was still a worldwide challenge for health care systems, many excellent articles regarding vascular function were published in Hypertension Research and other major cardiovascular and hypertension journals. In this review, we summarize new findings on vascular function and discuss the association between vascular function and COVID-19, the importance of lifestyle modifications for the maintenance of vascular function, and the usefulness of vascular function tests for cardiovascular risk assessment. We hope this review will be helpful for the management of cardiovascular risk factors, including hypertension and cardiovascular diseases, in clinical practice.

The interactions between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and human host factors enable the virus to propagate infections that lead to Coronavirus Disease 2019 (COVID-19). The spike protein is the largest structural component of the virus and mediates interactions essential for infection, including with the primary angiotensin-converting enzyme 2 (ACE2) receptor. We performed two independent cell-based systematic screens to determine whether there are additional proteins by which the spike protein of SARS-CoV-2 can interact with human cells. We discovered that in addition to ACE2, expression of LRRC15 also causes spike protein binding. This interaction is distinct from other known spike attachment mechanisms such as heparan sulfates or lectin receptors. Measurements of orthologous coronavirus spike proteins implied the interaction was functionally restricted to SARS-CoV-2 by accessibility. We localized the interaction to the C-terminus of the S1 domain and showed that LRRC15 shares recognition of the ACE2 receptor binding domain. From analyzing proteomics and single-cell transcriptomics, we identify LRRC15 expression as being common in human lung vasculature cells and fibroblasts. Levels of LRRC15 were greatly elevated by inflammatory signals in the lungs of COVID-19 patients. Although infection assays demonstrated that LRRC15 alone is not sufficient to permit viral entry, we present evidence that it can modulate infection of human cells. This unexpected interaction merits further investigation to determine how SARS-CoV-2 exploits host LRRC15 and whether it could account for any of the distinctive features of COVID-19.

From the very first months of the pandemic, it became apparent that a variety of skin reactions could occur during COVID-19 disease, starting with 'erythema-pernio'-type lesions, similar to chilblains [...].

The novel coronavirus-19 (SARS-CoV-2), has infected numerous individuals worldwide, resulting in millions of fatalities. The pandemic spread with high mortality rates in multiple waves, leaving others with moderate to severe symptoms. Co-morbidity variables, including hypertension, diabetes, and immunosuppression, have exacerbated the severity of COVID-19. In addition, numerous efforts have been made to comprehend the pathogenic and host variables that contribute to COVID-19 susceptibility and pathogenesis. One of these endeavours is understanding the host genetic factors predisposing an individual to COVID-19. Genome-Wide Association Studies (GWAS) have demonstrated the host predisposition factors in different populations. These factors are involved in the appropriate immune response, their imbalance influences susceptibility or resistance to viral infection. This review investigated the host genetic components implicated at the various stages of viral pathogenesis, including viral entry, pathophysiological alterations, and immunological responses. In addition, the recent and most updated genetic variations associated with multiple host factors affecting COVID-19 pathogenesis are described in the study.

Adenoviral-based vaccines such as ChadoX1 CoV-19 (AstraZeneca) and Ad26.COV2.S (J&J) were developed to prevent infection and reduce hospitalization or death in Coronavirus Disease 2019 (COVID-19) patients. Although these vaccines passed safety and efficacy trials with excellent neutralizing capabilities against SARS-CoV-2, very rare reports of acute thrombotic thrombocytopenic events following administration emerged in certain populations, which triggered a series of clinical investigations that gave rise to a novel phenomenon called vaccine-induced immune thrombotic thrombocytopenia (VITT). Several converging pathways exist between VITT and other forms of thrombotic thrombocytopenic syndromes, specifically that of heparin-induced thrombocytopenia, which involves the formation of anti-PF4 antibodies and the activation of platelets leading to thrombocytopenia and thrombin-mediated clotting. Interestingly, certain differences in the presentation also exist in VITT, and guidelines have been published in recent months to assist clinicians in recognizing VITT to achieve desired outcomes. In this paper, we first discuss the clotting phenomenon in COVID-19 and delineate it from VITT, followed by a review of current knowledge on the clinical manifestations of VITT in lieu of other thrombotic thrombocytopenic syndromes. Likewise, emerging evidence on the role of adenoviral vectors and vaccine constituents is also discussed briefly.

Chilblains were first described over a hundred years ago as cutaneous inflammatory lesions, typically on the digits, occurring on cold exposure. Chilblains can be primary, or secondary to a number of conditions such as infections, including COVID-19, and immune-mediated inflammatory disorders (IMIDs) with SLE being the commonest. Chilblain lupus erythematosus (CHLE) was first described in 1888 as cold-induced erythematous lesions before the terms 'chilblains' or 'perniosis' were coined. Diagnostic criteria exist for both chilblains and CHLE. Histopathologically, CHLE lesions show interface dermatitis with perivascular lymphocytic infiltrate. Immunofluorescence demonstrates linear deposits of immunoglobulins and complement in the dermo-epidermal junction. This narrative review focuses on chilblains secondary to immune-mediated inflammatory disorders, primarily the epidemiology, pathogenesis and treatment of CHLE.

COVID-19 patients have a high incidence of thrombosis, and thromboembolic complications are associated with severe COVID-19 and high mortality. COVID-19 disease is associated with a hyper-inflammatory response (cytokine storm) mediated by the immune system. However, the role of the inflammatory response in thrombosis remains incompletely understood. In this review, we investigate the crosstalk between inflammation and thrombosis in the context of COVID-19, focusing on the contributions of inflammation to the pathogenesis of thrombosis, and propose combined use of anti-inflammatory and anticoagulant therapeutics. Under inflammatory conditions, the interactions between neutrophils and platelets, platelet activation, monocyte tissue factor expression, microparticle release, and phosphatidylserine (PS) externalization as well as complement activation are collectively involved in immune-thrombosis. Inflammation results in the activation and apoptosis of blood cells, leading to microparticle release and PS externalization on blood cells and microparticles, which significantly enhances the catalytic efficiency of the tenase and prothrombinase complexes, and promotes thrombin-mediated fibrin generation and local blood clot formation. Given the risk of thrombosis in the COVID-19, the importance of antithrombotic therapies has been generally recognized, but certain deficiencies and treatment gaps in remain. Antiplatelet drugs are not in combination with anticoagulant treatments, thus fail to dampen platelet procoagulant activity. Current treatments also do not propose an optimal time for anticoagulation. The efficacy of anticoagulant treatments depends on the time of therapy initiation. The best time for antithrombotic therapy is as early as possible after diagnosis, ideally in the early stage of the disease. We also elaborate on the possible mechanisms of long COVID thromboembolic complications, including persistent inflammation, endothelial injury and dysfunction, and coagulation abnormalities. The above-mentioned contents provide therapeutic strategies for COVID-19 patients and further improve patient outcomes.

We report a severe COVID-19 complicated with MIS-C in a girl treated by the author in China, and discuss the current research status and progress in the diagnosis and therapy of MIS-C in children. The patient was a 4-year-old child previously healthy who was referred to the hospital with a complaint of fever, finally, Multisystem inflammatory syndrome was diagnosed with COVID-19.

The COVID-19 pandemic resulted in substantial morbidity and mortality across the world. The prognosis was found to be poor in patients with co-morbidities such as diabetes, hypertension, interstitial lung disease, etc. Although biochemical studies were done in patient samples, no study has been reported from the Indian subcontinent about ultrastructural changes in the vital organs of COVID-19 patients. The present study was, therefore, conducted to understand the ultrastructural changes in the lung, liver, and brain of the deceased patients.

The present study was conducted on samples obtained from reverse transcription-polymerase chain reaction (RT-PCR)-positive patients who were admitted to a tertiary care hospital in Western India. Core needle biopsies were done in eight fatal cases of COVID-19. The samples were taken from the lungs, liver, and brain and subjected to light microscopy, immunohistochemistry (IHC), and transmission electron microscopy (TEM). Clinical details and biochemical findings were also collected.  Results: The study participants included seven males and one female. The presenting complaints included fever, breathlessness, and cough. Light microscopy revealed diffuse alveolar damage in the lungs. Further, a positive expression of SARS-CoV-2 nucleocapsid protein was observed in the pulmonary parenchyma of five patients. Also, the TEM microphotograph showed viral particles of size up to 80nm localized in alveolar epithelial cells. However, no viral particles were found in liver or brain samples. In the liver, macrovesicular steatosis and centrizonal congestion with loss of hepatocytes were observed in light microscopy.

 This is the first study in the Indian population showing the in-situ presence of viral particles in core biopsies from fatal cases of COVID-19. As evident from the results, histology and ultrastructural changes in the lung correlated with the presence of viral particles. The study revealed a positive correlation between the damage in the lungs and the presence of viral particles.

Although vaccination is widely accepted as an effective method of preventing and controlling the COVID-19 pandemic, many people are concerned about possible cutaneous side-effects, which can delay or prevent them from being vaccinated. The objectives of this systematic review were to assess the global prevalence and clinical manifestations of cutaneous adverse reactions following COVID-19 vaccination. PubMed and Scopus databases were searched for articles published from 1 January 2019 to 31 December 2021, and reference lists for each selected article were screened. Case reports, case series, observational studies and randomized controlled trials that provided information on cutaneous adverse reactions following COVID-19 vaccines were included. A total of 300 studies were included in a systematic review of which 32 studies with 946 366 participants were included in the meta-analysis. The pooled prevalence of cutaneous manifestations following COVID-19 vaccination was 3.8% (95% CI, 2.7%-5.3%). COVID-19 vaccines based on the mRNA platform had a higher prevalence than other platforms at 6.9% (95% CI, 3.8%-12.3%). Various cutaneous manifestations have been reported from injection site reactions, which were the most common (72.16%) to uncommon adverse reactions such as delayed inflammatory reactions to tissue filler (0.07%) and flares of pre-existing dermatoses (0.07%). Severe cutaneous reactions such as anaphylaxis have also been reported, but in rare cases (0.05%). In conclusion, cutaneous adverse reactions are common, especially in those receiving mRNA vaccines. Most reactions are mild and are not contraindications to subsequent vaccination except for anaphylaxis, which rarely occurs. COVID-19 vaccination may also be associated with flares of pre-existing dermatoses and delayed inflammatory reactions to tissue filler. Patients with a history of allergies, pre-existing skin conditions or scheduled for filler injections should receive additional precounselling and monitoring. A better understanding of potential side-effects may strengthen public confidence in those wary of new vaccine technologies.

Since early 2020, SARS-CoV-2-induced infection resulted in global pandemics with high morbidity, especially in the adult population. COVID-19 is a highly prothrombotic condition associated with subsequent multiorgan failure and lethal outcomes. The exact mechanism of the prothrombotic state is not well understood and might be multifactorial. Nevertheless, platelets are attributed to play a crucial role in COVID-19-associated thrombosis. To date, platelets' role was defined primarily in thrombosis and homeostasis. Currently, more focus has been set on their part in inflammation and immunity. Moreover, their ability to release various soluble factors under activation as well as internalize and degrade specific pathogens has been highly addressed in viral research. This review article will discuss platelet role in COVID-19-associated thrombosis and their role in the cholinergic anti-inflammatory pathway. Multiple studies confirmed that platelets display a hyperactivated phenotype in COVID-19 patients. Critically ill patients demonstrate increased platelet activation markers such as P-selectin, PF4, or serotonin. In addition, platelets contain acetylcholine and express α7 nicotinic acetylcholine receptors (α7nAchR). Thus, acetylcholine can be released under activation, and α7nAchR can be stimulated in an autocrine manner and support platelet function. α7 receptor is one of the most important mediators of the anti-inflammatory properties as it is associated with humoral and intrinsic immunity and was demonstrated to contribute to better outcomes in COVID-19 patients when under stimulation. Hematopoietic α7nAchR deficiency increases platelet activation and, in experimental studies, α7nAchR stimulation can diminish the pro-inflammatory state and modulate platelet reactiveness via increased levels of NO. NO has been described to inhibit platelet adhesion, activation, and aggregation. In addition, acetylcholine has been demonstrated to decrease platelet aggregation possibly by blocking the e p-38 pathway. SARS-CoV-2 proteins have been found to be similar to neurotoxins which can bind to nAChR and prevent the action of acetylcholine. Concluding, the platelet role in COVID-19 thrombotic events could be explained by their active function in the cholinergic anti-inflammatory pathway.