Molecular Mimicry, Hyperactive Immune System, And SARS-COV-2 Are Three Prerequisites of the Autoimmune Disease Triangle Following COVID-19 Infection

NETosis: A key player in autoimmunity, COVID-19, and long COVID

NETosis, the process through which neutrophils release neutrophil extracellular traps (NETs), has emerged as a crucial mechanism in host defense and the pathogenesis of autoimmune responses. During the SARS-CoV-2 pandemic, this process received significant attention due to the central role of neutrophil recruitment and activation in infection control. However, elevated neutrophil levels and dysregulated NET formation have been linked to coagulopathy and endothelial damage, correlating with disease severity and poor prognosis in COVID-19. Moreover, it is known that SARS-CoV-2 can induce persistent low-grade systemic inflammation, known as long COVID, although the underlying causes remain unclear. It has been increasingly acknowledged that excessive NETosis and NET generation contribute to further pathophysiological abnormalities following SARS-CoV-2 infection. This review provides an updated overview of the role of NETosis in autoimmune diseases, but also the relationship between COVID-19 and long COVID with autoimmunity (e.g., latent and overt autoimmunity, molecular mimicry, epitope spreading) and NETosis (e.g., immune responses, NET markers). Finally, we discuss potential therapeutic strategies targeting dysregulated NETosis to mitigate the severe complications of COVID-19 and long COVID.

Identifying potential co-expressed genes and molecular mechanisms linking post-COVID-19 and Guillain-Barre syndrome through neutrophil extracellular trap-related genes

Introduction

Neutrophil extracellular traps (NETs) play a pivotal role in immunity and autoinflammatory disease, leading us to hypothesize that NETs are crucial in Guillain-Barre Syndrome (GBS) after SARS-CoV-2 infection.

Methods

By collecting six Gene Expression Omnibus (GEO) datasets from the GEO database and dividing them into discovery and validation sets, we screened differentially expressed genes (DEGs) within the discovery set, with further analyses using functional enrichment analysis. Using single-sample gene set enrichment analysis (ssGSEA), we assessed immune cell infiltration in both coronavirus disease 2019 (COVID-19) and GBS datasets. NETs-related genes (NETRGs) were identified through a protein-protein interaction (PPI) network and NETs gene datasets. Finally, candidate drugs were screened using Connectivity Map.

Results

In this study, a total of 3254 DEGs were identified from the COVID-19 dataset, and 692 DEGs were obtained from the GBS dataset. Among these, 145 co-expressed DEGs were obtained. Bioinformatics functional analysis indicated that co-expressed DEGs were predominantly gathered in immune-related and inflammatory response pathways. Employing various algorithms, we identified MMP9, CAMP, and CASP1 as NETRGs, demonstrating good discriminatory capacity in COVID-19 and GBS. Notably, neutrophils and macrophages were identified as co-upregulated differential immune infiltrating cells significantly associated with both COVID-19 and GBS. Moreover, we identified 10 candidate drugs for patients with post-COVID-19 GBS.

Conclusion

In conclusion, MMP9, CASP1, and CAMP were identified as promising biomarkers and potential targets for therapy of post-COVID-19 GBS.

Role of toll-like receptors in post-COVID-19 associated neurodegenerative disorders?

In the intricate realm of interactions between hosts and pathogens, Toll-like receptors (TLRs), which play a crucial role in the innate immune response, possess the ability to identify specific molecular signatures. This includes components originating from pathogens such as SARS-CoV-2, as well as the resulting damage-associated molecular patterns (DAMPs), the endogenous molecules released after cellular damage. A developing perspective suggests that TLRs play a central role in neuroinflammation, a fundamental factor in neurodegenerative conditions like Alzheimer's and Parkinson's disease (PD). This comprehensive review consolidates current research investigating the potential interplay between TLRs, their signaling mechanisms, and the processes of neurodegeneration following SARS-CoV-2 infection with an aim to elucidate the involvement of TLRs in the long-term neurological complications of COVID-19 and explore the potential of targeting TLRs as a means of implementing intervention strategies for the prevention or treatment of COVID-19-associated long-term brain outcomes.

Increasing prevalence of thyroid autoimmunity in childhood type 1 diabetes in the pre-COVID but not during the COVID era

Introduction

Studies assessing longitudinal changes in the prevalence of autoimmune thyroiditis (AIT) among the pediatric population are limited. During the COVID-19 era, several papers proposed a rise in AIT cases. Our study aimed to analyze the prevalence of thyroid autoimmunity (TA) over a 10-year period spanning pre-pandemic and pandemic years in a population who are regularly screened for thyroid disturbances.

Materials and methods

This single-center retrospective cohort study analyzed data from 1,361 children and young adults with type 1 diabetes (T1D) treated between 2013 and 2022 in Hungary's largest pediatric endocrinology center. Results of anti-thyroid autoantibodies (anti-thyroid peroxidase/ATPO/and antithyroglobulin/ATG/), thyroid function tests (TFTs) and thyroid ultrasound examinations were obtained. Annual prevalence rates of TA and ultrasound-proven thyroiditis were calculated. Mean (± SD) follow-up period was 4.7 (± 2.8) years.

Results

The overall prevalence of TA among our T1D children was 22.8% ([20.3;25.5], 310 cases) with significantly more girls affected (p<0.001). From 2013 to 2022, TA prevalence rose from 15.9% to 20.6% (p=0.041). The increase was detected during the pre-pandemic years but not in the COVID-19 era. Ultrasound-confirmed thyroiditis was present in 80.0% of examined TA cases. Ultrasound positivity rate was stable during the study period. Among our children with TA, 28.5% exhibited clinically relevant thyroid-stimulating hormone (TSH) abnormalities (most commonly subclinical hypothyroidism) and/or were prescribed thyroid medication. Children with AIT had a significantly elevated risk of thyroid dysfunction compared to those with only thyroid autoantibody positivity (p<0.001).

Conclusion

Our results show a rise in the prevalence of thyroid autoimmunity among T1D children over the past decade, but our data do not support the assumed role of SARS-CoV-2 in the development of the disease.

Clinical Activity of Behcet's Disease Associated with SARS-CoV-2 and Herpes Simplex Virus: Insights from Three Case Reports

Introduction

The Behçet's Disease Current Activity Form (BDCAF) is crucial for monitoring the progression and treatment efficacy of Behçet's Disease (BD), an autoimmune disorder that can be triggered or exacerbated by viral infections. Herpes simplex virus type 1 (HSV-1) has long been recognized as a potential trigger for BD, as it can induce systemic inflammation and exacerbate symptoms. In contrast, Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has recently emerged and may also initiate or worsen BD symptoms. This report examines three BD cases with oral manifestations specifically triggered by HSV-1 and SARS-CoV-2, comparing their clinical activity and treatment responses.

Case

Three female patients, aged 29, 24, and 41 years, presented to the Oral Medicine Department with complaints of canker sores, along with genital and skin lesions and red eyes. Intraoral examination showed ulcerative, erosive, and white plaque lesions throughout the oral mucosa. The first patient was confirmed to have COVID-19 by the SARS-CoV-2 RNA test. The second and third patients had a two-year history of recurrent oral ulcerations with reactive IgG anti-HSV-1 tests. All patients were diagnosed with BD according to the International Criteria for Behcet's Disease. The BDCAF measurements were conducted, showing a BD activity index score of 4 for the COVID-19-positive patient, while scores of 6 and 7 were recorded for the other two patients with seropositive HSV-1.

Case Management

Medications provided include corticosteroid, antimetabolite, analgesic, antiviral, antifungal, antiseptic mouthwash, and multivitamin. All patients showed good clinical improvement after treatment.

Conclusion

The BD activity index scores of a BD patient with COVID-19 were lower than those with HSV-1 infection. This difference may be due to the recent SARS-CoV-2 infection in the patient, whereas reactivation of chronic latent HSV-1 in the other patients likely contributed to a longer history of clinical manifestations, resulting in increased disease activity.

Increased Risk of Myositis-Specific and Myositis-Associated Autoantibodies After COVID-19 Pandemic and Vaccination: A Spanish Multicenter Collaborative Study

Background: Emerging evidence suggests that SARS-CoV-2 infection and vaccines may trigger autoimmune responses in predisposed individuals. Idiopathic inflammatory myopathies (IIMs) are diseases with diverse clinical manifestations, often associated with myositis autoantibodies (MAs). Diagnosing IIM is challenging due to limitations in classification criteria and diagnostic assays. This study aimed to describe the incidence of IIM following SARS-CoV-2 infection or vaccination and compare rates between exposures. Methods: A multicenter observational study was conducted with 788 patients from 11 Spanish referral centers. A total of 1209 autoantibodies including myositis-specific autoantibodies (MSAs) and myositis-associated autoantibodies (MAAs), were analyzed using line blot immunoassay (LIA). Results: The study identified distinct patterns in aminoacyl-tRNA synthetase (ARS) antibody frequencies compared to pre-pandemic periods. Anti-PL-7 was the most prevalent ARS antibody (14.85%), while anti-Jo-1 was less frequent (7.23%). Anti-MDA5, commonly linked to SARS-CoV-2 infection, was detected in 11.68%. ANA positivity was observed in 60.66%, suggesting an autoimmune background. The most frequent diagnoses were anti-synthetase syndrome (ASSD) or IIM-non-ASSD (21.31%), followed by other systemic autoimmune diseases (SAIDs) (13.57%). Among the cohort, 91.13% received at least one dose of a messenger RNA (mRNA) COVID-19 vaccine, with a median of three doses per patient. Patients with prior SARS-CoV-2 infection or heterologous vaccination showed a higher frequency of multiple autoantibody positivity (p < 0.05), reflecting distinct immune signatures. Conclusions: This study provides valuable insights into the autoimmune risks and phenotypes associated with SARS-CoV-2 infection and vaccination, establishing a basis for further research on IIM and its link to MSAs and MAAs.

Effect of SARS-CoV2 infection on disease flares in patients with systemic lupus erythematosus: a case-control study

OBJECTIVES

To study the effect of SARS-CoV2 infection on flares of systemic lupus erythematosus (SLE).

METHODS

Patients who fulfilled the ACR/SLICC criteria for SLE and had documented COVID-19 between February and November 2022 were identified retrospectively from our hospital COVID-19 registry. SLE controls who did not have SARS-CoV2 infection were randomly matched for age, sex and the time of infection in a 2:1 ratio with those infected. The primary outcome of interest was clinical flare of SLE within 90 days of COVID-19. The rate of SLE flares (mild/moderate or severe) was compared between SARS-CoV2-infected SLE patients and controls.

RESULTS

Ninety-one SLE patients with COVID-19 (age 48.6 (14.0) years; 95.6% women) and 182 SLE controls (age 48.7 (13.8) years; 95.6% women) were studied. Eleven of 91 (12.1%) SARS-CoV2-infected patients had serious manifestations. One (1.1%) patient died and 7 (7.7%) developed severe complications. Within 90 days of SARS-CoV2 infection, 14 (15.4%) patients developed mild/moderate clinical SLE flares and two (2.2%) patients had severe SLE flares. The incidence of SLE flares in SARS-CoV2-infected patients was significantly higher than in those without the infection (17.6% vs 5.5%; odds ratio 3.67 [95% CI: 1.59, 8.46]; P = 0.001). The changes in anti-dsDNA and complement levels, however, were not significantly different between the two groups. Among SARS-CoV2-infected SLE patients, those with clinical SLE flares had significantly lower C3 values (P = 0.004) before the infection than those without.

CONCLUSION

Clinical flares within 90 days were significantly more common in SLE patients infected with SARS-CoV2 than matched non-infected SLE controls.

The relationship between SARS-CoV-2 infection and type 1 diabetes mellitus

Environmental factors, in particular viral infections, are thought to have an important role in the pathogenesis of type 1 diabetes mellitus (T1DM). The COVID-19 pandemic reinforced this hypothesis as many observational studies and meta-analyses reported a notable increase in the incidence of T1DM following infection with SARS-CoV-2 as well as an association between SARS-CoV-2 infection and the risk of new-onset T1DM. Experimental evidence suggests that human β-cells express SARS-CoV-2 receptors and that SARS-CoV-2 can infect and replicate in β-cells, resulting in structural or functional alterations of these cells. These alterations include reduced numbers of insulin-secreting granules, impaired pro-insulin (or insulin) secretion, and β-cell transdifferentiation or dedifferentiation. The inflammatory environment induced by local or systemic SARS-CoV-2 infection might result in a set of signals (such as pro-inflammatory cytokines) that lead to β-cell alteration or apoptosis or to a bystander activation of T cells and disruption of peripheral tolerance that triggers autoimmunity. Other mechanisms, such as viral persistence, molecular mimicry and activation of endogenous human retroviruses, are also likely to be involved in the pathogenesis of T1DM following SARS-CoV-2 infection. This Review addresses the issue of the involvement of SARS-CoV-2 infection in the development of T1DM using evidence from epidemiological, clinical and experimental studies.

Infections Combined With Myelin Oligodendrocyte Glycoprotein Antibody-Associated Disease: A Case Report and Systematic Review of the Literature

Myelinating oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is an immune-mediated inflammatory demyelinating disease of the central nervous system. Its specific etiology and pathogenesis remain unclear. In recent years, there have been increasing reports of MOGAD occurring after infections. Even cases of concurrent infection and MOGAD have been documented. We report a clinical case of a 14-year-old male patient admitted to the hospital with a fever and loss of consciousness. He underwent thorough medical examinations. The results of second-generation sequencing of the metagenome of the cerebrospinal fluid revealed that he was infected with Haemophilus parainfluenzae, and serum testing showed positive MOG antibodies. He was discharged after improving with intravenous immunoglobulin and other treatments.

Prevalence and factors associated with thyroid autoimmunity among children newly diagnosed with type 1 diabetes before and during the COVID-19 pandemic: Evidence from Kuwait

AIMS

This study reports the prevalence and characteristics related to the development of thyroid autoimmunity among children newly diagnosed with type I diabetes (T1D) during the COVID-19 pandemic in Kuwait.

MATERIALS AND METHODS

This is a prospective observational study of all children under age 14 years newly diagnosed with T1D in Kuwait. We define the duration of the COVID-19 pandemic from the official declaration of the first identified positive COVID-19 case on 24 February 2020 until 31 December 2022. For comparison, we use the time period directly before the COVID-19 pandemic, 1 January 2017 to 23 February 2020.

RESULTS

One thousand twenty-four (1024) children newly diagnosed with T1D in Kuwait during the study period were included. Among newly diagnosed children, 20.3% tested positive for thyroid antibodies during the COVID-19 pandemic, compared with 14.5% during the pre-pandemic period (p = 0.015). Children with positive COVID-19 status were more likely to present with thyroid antibodies (p = 0.035). After adjusting for other characteristics, patients diagnosed with T1D during the COVID-19 pandemic had double the odds of testing positive for thyroid antibodies (Adjusted odds ratio = 2.173, 95%CI: 1.108, 4.261, p = 0.024).

CONCLUSIONS

Incident cases of T1D during the COVID-19 pandemic may be different in aetiology or contextual factors leading to a higher risk of thyroid autoimmunity. Longitudinal studies are needed to understand the role of COVID-19 in the onset and progression of T1D and on thyroid autoimmunity and disease.

Guillain-Barre syndrome and link with COVID-19 infection and vaccination: a review of literature

Background

Guillain-Barré syndrome (GBS) is an autoimmune disease associated with significant morbidity. A wide variety of infectious and non-infectious triggers have been identified to be associated with GBS. COVID-19 has gained attention in recent years for its role in GBS pathogenesis. Our study aims to review the literature on GBS and its epidemiological and pathophysiological association with COVID-19.

Description

Recent literature on GBS associated with COVID-19 infections, such as case reports, case series, systematic reviews, and large-scale epidemiological studies, were reviewed. We also reviewed studies that included vaccines against COVID-19 in association with GBS. Studies that focused on understanding the pathobiology of GBS and its association with infectious agents including COVID-19 were reviewed.

Conclusion

Despite a lack of consensus, GBS is strongly associated with COVID-19 infection. The exact pathophysiological mechanism regarding COVID-19 as a causative agent of GBS is unknown. Mechanisms, such as the proinflammatory state, triggering of autoimmunity, and direct viral invasion, are postulated and remain to be investigated. Adenovirus vector vaccines are most likely associated with GBS, and the consensual reports clearly suggest mRNA vaccines are associated with low risk and may be protective against GBS by reducing the risk of COVID-19 infection.

Immunoglobulins in COVID-19 pneumonia: from the acute phase to the recovery phase

BACKGROUND

COVID-19 pneumonia causes hyperinflammatory response that culminates in acute respiratory syndrome (ARDS) related to increased multiorgan dysfunction and mortality risk. Antiviral-neutralizing immunoglobulins production reflect the host humoral status and illness severity, and thus, immunoglobulin (Ig) circulating levels could be evidence of COVID-19 prognosis.

METHODS

The relationship among circulating immunoglobulins (IgA, IgG, IgM) and COVID-19 pneumonia was evaluated using clinical information and blood samples in a COVID-19 cohort composed by 320 individuals recruited during the acute phase and followed up to 4 to 8 weeks (n = 252) from the Spanish first to fourth waves.

RESULTS

COVID-19 pneumonia development depended on baseline Ig concentrations. Circulating IgA levels together with clinical features at acute phase was highly associated with COVID-19 pneumonia development. IgM was positively correlated with obesity (ρb = 0.156, P = 0.020), dyslipemia (ρb = 0.140, P = 0.029), COPD (ρb = 0.133, P = 0.037), cancer (ρb = 0.173, P = 0.007) and hypertension (ρb = 0.148, P = 0.020). Ig concentrations at recovery phase were related to COVID-19 treatments.

CONCLUSIONS

Our results provide valuable information on the dynamics of immunoglobulins upon SARS-CoV-2 infection or other similar viruses.

Characteristics and outcomes of COVID-19 in Chinese immune thrombocytopenia patients: A prospective cohort study

The coronavirus disease 2019 (COVID-19) pandemic has a significant impact on the immune system. This is the first and largest study on pre-existing immune thrombocytopenia (ITP) patients infected with COVID-19 in China. We prospectively collected ITP patients infected with COVID-19 enrolled in the National Longitudinal Cohort of Hematological Diseases (NICHE, NCT04645199) and followed up for at least 1 month after infection. One thousand and one hundred forty-eight pre-existing ITP patients were included. Two hundred and twelve (18.5%) patients showed a decrease in the platelet (PLT) count after infection. Forty-seven (4.1%) patients were diagnosed with pneumonia. Risk factors for a decrease in the PLT count included baseline PLT count <50 × 109/L (OR, 1.76; 95% CI, 1.25-2.46; p = 0.001), maintenance therapy including thrombopoietin receptor agonists (TPO-RAs) (OR, 2.27; 95% CI, 1.60-3.21; p < 0.001) and previous splenectomy (OR, 1.98; 95% CI, 1.09-3.61; p = 0.03). Risk factors for pneumonia included age ≥40 years (OR, 2.45; 95% CI, 1.12-5.33; p = 0.02), ≥2 comorbidities (OR, 3.47; 95% CI, 1.63-7.64; p = 0.001), maintenance therapy including TPO-RAs (OR, 2.14; 95% CI, 1.17-3.91; p = 0.01) and immunosuppressants (OR, 3.05; 95% CI, 1.17-7.91; p = 0.02). In this cohort study, we described the characteristics of pre-existing ITP patients infected with COVID-19 and identified several factors associated with poor outcomes.

Interferon lambda in respiratory viral infection: immunomodulatory functions and antiviral effects in epithelium

Type III interferon (IFN-λ), a new member of the IFN family, was initially considered to possess antiviral functions similar to those of type I interferon, both of which are induced via the JAK/STAT pathway. Nevertheless, recent findings demonstrated that IFN-λ exerts a nonredundant antiviral function at the mucosal surface, preferentially produced in epithelial cells in contrast to type I interferon, and its function cannot be replaced by type I interferon. This review summarizes recent studies showing that IFN-λ inhibits the spread of viruses from the cell surface to the body. Further studies have found that the role of IFN-λ is not only limited to the abovementioned functions, but it can also can exert direct and/or indirect effects on immune cells in virus-induced inflammation. This review focuses on the antiviral activity of IFN-λ in the mucosal epithelial cells and its action on immune cells and summarizes the pathways by which IFN-λ exerts its action and differentiates it from other interferons in terms of mechanism. Finally, we conclude that IFN-λ is a potent epidermal antiviral factor that enhances the respiratory mucosal immune response and has excellent therapeutic potential in combating respiratory viral infections.

Psoriatic arthritis and COVID-19: a new challenge for rheumatologists and dermatologists

COVID-19 has changed the global health system and has great impact on different types of medical specialties including, dermatology and rheumatology. This point is important because although these two specialties are distinct subfields of medicine, there is some overlap between them. The overlap can be described by a number of rheumatic diseases that have cutaneous manifestations and vice versa. A good example of this is psoriatic arthritis because, in up to 42% of people, cutaneous lesions and arthritis coexist. Interestingly, emerging reports have described the possible occurrence of psoriasis and psoriatic arthritis in COVID-19 patients. Although the exact mechanism is unclear, some common pathophysiological mechanisms may contribute to disease pathogenesis. Therefore, elucidation of shared pathological pathways that connect these diseases will be valuable for better diagnosis and the complete treatment of COVID-19 patients with cutaneous and rheumatologic diseases.

SARS-CoV-2 infection associated with antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN): a systematic review and two case reports

BACKGROUND

It has been observed that SARS-CoV-2 infections are associated with the development of various de-novo autoimmune diseases; little is known on new-onset antineutrophil cytoplasmic antibody (ANCA)-associated glomerulonephritis (ANCA-GN) after SARS-CoV-2 infections.

METHODS

We conducted a systematic review of previously reported cases with a presumed association of new-onset antineutrophil cytoplasmic antibody-associated glomerulonephritis (ANCA-GN). No language restrictions were applied during the search. The eligible articles included reports of biopsy-proven pauci-immune glomerulonephritis that occurred following SARS-CoV-2 infection. The review was registered in PROSPERO database (CRD42023407786). Two further cases are reported.

RESULTS

The mean age of SARS-CoV-2 infection-associated ANCA-GN was 48 ± 19 years. Fifty-six percent of patients showed positivity for myeloperoxidase (MPO)-ANCA. Among tested patients, 36% had concomitantly positive antinuclear antibodies, and 100% had positive rheumatoid factor. Eleven out of the 21 cases (55%) were diagnosed with ANCA-GN during hospitalization due to SARS-CoV-2 infection. The remaining cases were diagnosed after a median of 2.1 months following COVID-19. Seventy-one percent of patients showed improvement in kidney function following different treatments.

CASE REPORTS

one patient had positive p-ANCA and cryoglobulin. Another case had positive MPO-ANCA, c-ANCA, cryoglobulinemia, and rheumatoid factor.

CONCLUSION

SARS-CoV-2 infection-associated ANCA-GN patients are younger than primary ANCA-GN patients. The presence of atypical ANCA along with co-positivity with other autoantibodies can raise suspicion for SARS-CoV-2 infection-associated ANCA-GN.

Gut Microbiota and Mitochondria: Health and Pathophysiological Aspects of Long COVID

The current understanding of long COVID (LC) is still limited. This review highlights key findings regarding the role of gut microbiota, mitochondria, and the main pathophysiological aspects of LC revealed by clinical studies, related to the complex interplay between infection, intestinal dysbiosis, dysfunctional mitochondria, and systemic inflammation generated in a vicious circle, reflecting the molecular and cellular processes from the "leaky gut" to the "leaky electron transport chain (ETC)" into a quantum leap. The heterogeneity of LC has hindered progress in deciphering all the pathophysiological mechanisms, and therefore, the approach must be multidisciplinary, with a special focus not only on symptomatic management but also on addressing the underlying health problems of the patients. It is imperative to further assess and validate the effects of COVID-19 and LC on the gut microbiome and their relationship to infections with other viral agents or pathogens. Further studies are needed to better understand LC and expand the interdisciplinary points of view that are required to accurately diagnose and effectively treat this heterogeneous condition. Given the ability of SARS-CoV-2 to induce autoimmunity in susceptible patients, they should be monitored for symptoms of autoimmune disease after contracting the viral infection. One question remains open, namely, whether the various vaccines developed to end the pandemic will also induce autoimmunity. Recent data highlighted in this review have revealed that the persistence of SARS-CoV-2 and dysfunctional mitochondria in organs such as the heart and, to a lesser extent, the kidneys, liver, and lymph nodes, long after the organism has been able to clear the virus from the lungs, could be an explanation for LC.

Effects of SARS-CoV-2 infection on hypothyroidism and subclinical hypothyroidism: a meta-analysis

Background

In recent years, the outbreak of COVID-19 caused by SARS-CoV-2 has been witnessed globally. However, the impact of SARS-CoV-2 infection on thyroid dysfunction and subclinical thyroid dysfunction remains unclear. Therefore, this meta-analysis aimed to assess the effects of SARS-CoV-2 infection on thyroid dysfunction and its relationship with the severity of COVID-19.

Methods

We systematically searched databases including PubMed, Willey Library, Embase, Web of Science, CNKI, Wanfang, and VIP. We focused on randomized controlled trials, case-control studies, and cohort studies published between December 2019 and August 2023, examining the association between SARS-CoV-2 infection and hypothyroidism, with a specific emphasis on the severity of the infection. The quality of the research was assessed using the Newcastle-Ottawa Scale (NOS), while statistical analysis was conducted using the meta and metafor packages in R 4.2.1 software.

Results

For the meta-analysis, a total of eight articles were identified based on strict inclusion and exclusion criteria. For the association between SARS-CoV-2 infection and hypothyroidism, three studies (266 samples) comparing TSH levels of COVID-19 and control groups showed no difference in TSH levels [SMD=-0.04,95%CI(-1.22,1.15),P=0.95]. Additionally, two studies examining TT3 (a sample of 176 cases) and two studies examining TT4 (a sample of 176 cases) also showed no difference in TT3 and TT4 between the COVID-19 group and the control group, respectively. However, when evaluating the severity of COVID-19, six studies (565 samples) showed that TSH in the severe group was significantly lower than in the mild group [SMD = -0.55, 95% CI (-0.96, -0.14)], while FT3 was also lower in the severe group [SMD = -0.96, 95% CI (-1.24, -0.67)]. No noticeable differences were observed between the severe and mild groups in their TT3, FT4, and TT4 levels.

Conclusion

SARS-CoV-2 infection may have detrimental effects on thyroid function in individuals with severe symptoms. More research is needed to confirm and explore this relationship.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023486042.

Brain MRI findings in neurologically symptomatic COVID-19 patients: a systematic review and meta-analysis

BACKGROUND

Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological manifestations. Utilizing a systematic review, this study aims to summarize brain MRI findings in COVID-19 patients presenting with neurological symptoms.

METHODS

Systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched for literature addressing brain MRI findings in COVID-19 patients with neurological symptoms.

RESULTS

25 publications containing a total number of 3118 COVID-19 patients with neurological symptoms who underwent MRI were included. The most common MRI findings and the respective pooled incidences in decreasing order were acute/subacute infarct (22%), olfactory bulb abnormalities (22%), white matter abnormalities (20%), cerebral microbleeds (17%), grey matter abnormalities (12%), leptomeningeal enhancement (10%), ADEM (Acute Disseminated Encephalomyelitis) or ADEM-like lesions (10%), non-traumatic ICH (10%), cranial neuropathy (8%), cortical gray matter signal changes compatible with encephalitis (8%), basal ganglia abnormalities (5%), PRES (Posterior Reversible Encephalopathy Syndrome) (3%), hypoxic-ischemic lesions (4%), venous thrombosis (2%), and cytotoxic lesions of the corpus callosum (2%).

CONCLUSION

The present study revealed that a considerable proportion of patients with COVID-19 might harbor neurological abnormalities detectable by MRI. Among various findings, the most common MRI alterations are acute/subacute infarction, olfactory bulb abnormalities, white matter abnormalities, and cerebral microbleeds.

Navigating the Post-COVID-19 Immunological Era: Understanding Long COVID-19 and Immune Response

The COVID-19 pandemic has affected the world unprecedentedly, with both positive and negative impacts. COVID-19 significantly impacted the immune system, and understanding the immunological consequences of COVID-19 is essential for developing effective treatment strategies. The purpose of this review is to comprehensively explore and provide insights into the immunological aspects of long COVID-19, a phenomenon where individuals continue to experience a range of symptoms and complications, even after the acute phase of COVID-19 infection has subsided. The immune system responds to the initial infection by producing various immune cells and molecules, including antibodies, T cells, and cytokines. However, in some patients, this immune response becomes dysregulated, leading to chronic inflammation and persistent symptoms. Long COVID-19 encompasses diverse persistent symptoms affecting multiple organ systems, including the respiratory, cardiovascular, neurological, and gastrointestinal systems. In the post-COVID-19 immunological era, long COVID-19 and its impact on immune response have become a significant concern. Post-COVID-19 immune pathology, including autoimmunity and immune-mediated disorders, has also been reported in some patients. This review provides an overview of the current understanding of long COVID-19, its relationship to immunological responses, and the impact of post-COVID-19 immune pathology on patient outcomes. Additionally, the review addresses the current and potential treatments for long COVID-19, including immunomodulatory therapies, rehabilitation programs, and mental health support, all of which aim to improve the quality of life for individuals with long COVID-19. Understanding the complex interplay between the immune system and long COVID-19 is crucial for developing targeted therapeutic strategies and providing optimal care in the post-COVID-19 era.

Immune-related adverse events and disease outcomes after the third dose of SARS-CoV-2 mRNA-BNT162b2 vaccine in cancer patients receiving immune checkpoint inhibitors

BACKGROUND

The clinical implications of the third dose of coronavirus disease 2019 (COVID-19) vaccines in patients receiving immune checkpoint inhibitors are currently unknown. We performed a prospective analysis of the Vax-On-Third study to investigate the effects of antibody response on immune-related adverse events (irAEs) and disease outcomes.

METHODS

Recipients of the booster dose of SARS-CoV-2 mRNA-BNT162b2 vaccine who had received at least one course of an anti-PD-1/PD-L1 treatment before vaccination for an advanced solid malignancy were eligible.

RESULTS

The current analysis included 56 patients with metastatic disease (median age: 66 years; male: 71%), most of whom had a lung cancer diagnosis and were being treated with pembrolizumab- or nivolumab-based regimens. The optimal cut-point antibody titer of 486 BAU/mL allowed a dichotomization of recipients into low-responders (Low-R, < 486 BAU/mL) or high-responders (High-R, ≥ 486 BAU/mL). After a median follow-up time of 226 days, 21.4% of patients experienced moderate to severe irAEs without any recrudescence of immune toxicities preceding the booster dose. The frequencies of irAE before and after the third dose did not differ, but an increase in the cumulative incidence of immuno-related thyroiditis was observed within the High-R subgroup. On multivariate analysis, an enhanced humoral response correlated with a better outcome in terms of durable clinical benefit, which resulted in a significant reduction in the risk of disease control loss but not mortality.

CONCLUSIONS

Our findings would strengthen the recommendation not to change anti-PD-1/PD-L1 treatment plans based on current or future immunization schedules, implying that all these patients should be closely monitored.

SARS-CoV-2 and Its Bacterial Co- or Super-Infections Synergize to Trigger COVID-19 Autoimmune Cardiopathies

Autoimmune cardiopathies (AC) following COVID-19 and vaccination against SARS-CoV-2 occur at significant rates but are of unknown etiology. This study investigated the possible roles of viral and bacterial mimicry, as well as viral-bacterial co-infections, as possible inducers of COVID-19 AC using proteomic methods and enzyme-linked immunoadsorption assays. BLAST and LALIGN results of this study demonstrate that SARS-CoV-2 shares a significantly greater number of high quality similarities to some cardiac protein compared with other viruses; that bacteria such as Streptococci, Staphylococci and Enterococci also display very significant similarities to cardiac proteins but to a different set than SARS-CoV-2; that the importance of these similarities is largely validated by ELISA experiments demonstrating that polyclonal antibodies against SARS-CoV-2 and COVID-19-associated bacteria recognize cardiac proteins with high affinity; that to account for the range of cardiac proteins targeted by autoantibodies in COVID-19-associated autoimmune myocarditis, both viral and bacterial triggers are probably required; that the targets of the viral and bacterial antibodies are often molecularly complementary antigens such as actin and myosin, laminin and collagen, or creatine kinase and pyruvate kinase, that are known to bind to each other; and that the corresponding viral and bacterial antibodies recognizing these complementary antigens also bind to each other with high affinity as if they have an idiotype-anti-idiotype relationship. These results suggest that AC results from SARS-CoV-2 infections or vaccination complicated by bacterial infections. Vaccination against some of these bacterial infections, such as Streptococci and Haemophilus, may therefore decrease AC risk, as may the appropriate and timely use of antibiotics among COVID-19 patients and careful screening of vaccinees for signs of infection such as fever, diarrhea, infected wounds, gum disease, etc.

Clinical improvement of Long-COVID is associated with reduction in autoantibodies, lipids, and inflammation following therapeutic apheresis

In the aftermath of the COVID-19 pandemic, we are witnessing an unprecedented wave of post-infectious complications. Most prominently, millions of patients with Long-Covid complain about chronic fatigue and severe post-exertional malaise. Therapeutic apheresis has been suggested as an efficient treatment option for alleviating and mitigating symptoms in this desperate group of patients. However, little is known about the mechanisms and biomarkers correlating with treatment outcomes. Here, we have analyzed in different cohorts of Long-Covid patients specific biomarkers before and after therapeutic apheresis. In patients that reported a significant improvement following two cycles of therapeutic apheresis, there was a significant reduction in neurotransmitter autoantibodies, lipids, and inflammatory markers. Furthermore, we observed a 70% reduction in fibrinogen, and following apheresis, erythrocyte rouleaux formation and fibrin fibers largely disappeared as demonstrated by dark field microscopy. This is the first study demonstrating a pattern of specific biomarkers with clinical symptoms in this patient group. It may therefore form the basis for a more objective monitoring and a clinical score for the treatment of Long-Covid and other postinfectious syndromes.

Infection, Dysbiosis and Inflammation Interplay in the COVID Era in Children

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.

The pathophysiology of postacute sequelae of COVID-19 (PASC): Possible role for persistent inflammation

As the SARS-CoV-2-induced pandemic wanes, a substantial number of patients with acute Corona Virus-induced disease (COVID-19 continue to have symptoms for a prolonged time after initial infection. These patients are said to have postacute sequelae of COVID (PASC) or "long COVID". The underlying pathophysiology of this syndrome is poorly understood and likely quite heterogeneous. The role of persistent, possibly deviant inflammation as a major factor in comorbidity is suspected.

Objective

To review data that address the relative importance of inflammation in the pathophysiology spectrum of PASC and to address how this would impact diagnosis and approach to therapy in patients identified as having such inflammatory abnormalities.

Methods

A review of public databases, including PubMed, MeSH, NLM catalog, and clinical trial databases such as clinicaltrials.gov.

Results

The literature supports a prominent role for various forms and types of inflammation in the pathophysiologic spectrum of PASC. Such inflammation can be persistent ant CoV-2-specific responses, new onset autoimmune responses, or a loss of normal immunoregulation resulting in widespread, sustained inflammatory pathologies that can affect both broad constitutional symptoms (such as fatigue, neurocognitive dysfunction, and anxiety/depression) and organ-specific dysfunction and/or failure.

Conclusions

PASC is a significant clinical entity with similarities to and differences from other postviral syndromes. Significant research efforts are ongoing to better understand specific aberrant inflammatory pathways present in individual patients for the purpose of developing and implementing effective therapies and ultimately prophylaxis strategies to prevent the progression of COVID-19 as well as likely future viral illnesses and pandemics.

De novo lupus nephritis after SARS-CoV-2 infection

The relationship between viral infection and onset of autoimmune diseases such as systemic lupus erythematosus remains uncertain. During the COVID-19 pandemic, organ-specific and multisystemic autoimmune phenomena temporally related to the viral infection have been described. Immune dysregulation triggered by the SARS-CoV-2 virus leading to hyperactivation of both the innate and adaptive immune systems contributes to the excessive production of pro-inflammatory cytokines, autoantibodies, and subsequent autoimmune manifestations. We report two patients without known autoimmune diseases who developed lupus nephritis shortly after a documented mild SARS-CoV-2 infection. Together with other similar cases in the literature, the observation supports a viral trigger of the development of systemic lupus erythematosus in susceptible individuals.

Incorporating the Molecular Mimicry of Environmental Antigens into the Causality of Autoimmune Hepatitis

Molecular mimicry between foreign and self-antigens has been implicated as a cause of autoimmune hepatitis in experimental models and cross-reacting antibodies in patients. This review describes the experimental and clinical evidence for molecular mimicry as a cause of autoimmune hepatitis, indicates the limitations and uncertainties of this premise, and encourages investigations that assess diverse environmental antigens as sources of disease-relevant molecular mimics. Pertinent articles were identified in PubMed using multiple search phrases. Several pathogens have linear or conformational epitopes that mimic the self-antigens of autoimmune hepatitis. The occurrence of an acute immune-mediated hepatitis after vaccination for severe acute respiratory syndrome (SARS)-associated coronavirus 2 (SARS-CoV-2) has suggested that vaccine-induced peptides may mimic disease-relevant tissue antigens. The intestinal microbiome is an under-evaluated source of gut-derived antigens that could also engage in molecular mimicry. Chaperone molecules may enhance the pathogenicity of molecular mimics, and they warrant investigation. Molecular mimics of immune dominant epitopes within cytochrome P450 IID6, the autoantigen most closely associated with autoimmune hepatitis, should be sought in diverse environmental antigens and assessed for pathogenicity. Avoidance strategies, dietary adjustments, vaccine improvement, and targeted manipulation of the intestinal microbiota may emerge as therapeutic possibilities. In conclusion, molecular mimicry may be a missing causality of autoimmune hepatitis. Molecular mimics of key immune dominant epitopes of disease-specific antigens must be sought in diverse environmental antigens. The ubiquity of molecular mimicry compels rigorous assessments of peptide mimics for immunogenicity and pathogenicity in experimental models. Molecular mimicry may complement epigenetic modifications as causative mechanisms of autoimmune hepatitis.

COVID-19 as a trigger of Guillain-Barré syndrome: A review of the molecular mechanism

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused a pandemic with serious complications. After coronavirus disease 2019 (COVID-19), several post-acute COVID-19 syndromes (PACSs) and long-COVID sequels were reported. PACSs involve many organs, including the nervous, gustatory, and immune systems. One of the PACSs after SARS-CoV-2 infection and vaccination is Guillain-Barré syndrome (GBS). The incidence rate of GBS after SARS-CoV-2 infection or vaccination is low. However, the high prevalence of COVID-19 and severe complications of GBS, for example, autonomic dysfunction and respiratory failure, highlight the importance of post-COVID-19 GBS. It is while patients with simultaneous COVID-19 and GBS seem to have higher admission rates to the intensive care unit, and demyelination is more aggressive in post-COVID-19 GBS patients. SARS-CoV-2 can trigger GBS via several pathways like direct neurotropism and neurovirulence, microvascular dysfunction and oxidative stress, immune system disruption, molecular mimicry, and autoantibody production. Although there are few molecular studies on the molecular and cellular mechanisms of GBS occurrence after SARS-CoV-2 infection and vaccination, we aimed to discuss the possible pathomechanism of post-COVID-19 GBS by gathering the most recent molecular evidence.

SARS-CoV-2-Induced TSLP Is Associated with Duration of Hospital Stay in COVID-19 Patients

Thymic stromal lymphopoietin (TSLP) is an epithelium-derived pro-inflammatory cytokine involved in lung inflammatory responses. Previous studies show conflicting observations in blood TSLP in COVID-19, while none report SARS-CoV-2 inducing TSLP expression in bronchial epithelial cells. Our objective in this study was to determine whether TSLP levels increase in COVID-19 patients and if SARS-CoV-2 induces TSLP expression in bronchial epithelial cells. Plasma cytokine levels were measured in patients hospitalized with confirmed COVID-19 and age- and sex-matched healthy controls. Demographic and clinical information from COVID-19 patients was collected. We determined associations between plasma TSLP and clinical parameters using Poisson regression. Cultured human nasal (HNEpC) and bronchial epithelial cells (NHBEs), Caco-2 cells, and patient-derived bronchial epithelial cells (HBECs) obtained from elective bronchoscopy were infected in vitro with SARS-CoV-2, and secretion as well as intracellular expression of TSLP was detected by immunofluorescence. Increased TSLP levels were detected in the plasma of hospitalized COVID-19 patients (603.4 ± 75.4 vs 997.6 ± 241.4 fg/mL, mean ± SEM), the levels of which correlated with duration of stay in hospital (β: 0.11; 95% confidence interval (CI): 0.01-0.21). In cultured NHBE and HBECs but not HNEpCs or Caco-2 cells, TSLP levels were significantly elevated after 24 h post-infection with SARS-CoV-2 (p < 0.001) in a dose-dependent manner. Plasma TSLP in COVID-19 patients significantly correlated with duration of hospitalization, while SARS-CoV-2 induced TSLP secretion from bronchial epithelial cells in vitro. Based on our findings, TSLP may be considered an important therapeutic target for COVID-19 treatment.

Maternal brain reactive antibodies profile in autism spectrum disorder: an update

Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder with multifactorial etiologies involving both genetic and environmental factors. In the past two decades it has become clear that in utero exposure to toxins, inflammation, microbiome, and antibodies (Abs), may play a role in the etiology of ASD. Maternal brain-reactive Abs, present in 10-20% of mothers of a child with ASD, pose a potential risk to the developing brain because they can gain access to the brain during gestation, altering brain development during a critical period. Different maternal anti-brain Abs have been associated with ASD and have been suggested to bind extracellular or intracellular neuronal antigens. Clinical data from various cohorts support the increase in prevalence of such maternal brain-reactive Abs in mothers of a child with ASD compared to mothers of a typically developing child. Animal models of both non-human primates and rodents have provided compelling evidence supporting a pathogenic role of these Abs. In this review we summarize the data from clinical and animal models addressing the role of pathogenic maternal Abs in ASD. We propose that maternal brain-reactive Abs are an overlooked and promising field of research, representing a modifiable risk factor that may account for up to 20% of cases of ASD. More studies are needed to better characterize the Abs that contribute to the risk of having a child with ASD, to understand whether we can we predict such cases of ASD, and to better pinpoint the antigenic specificity of these Abs and their mechanisms of pathogenicity.

Post-COVID Endocrine Disorders: Putative Role of Molecular Mimicry and Some Pathomorphological Correlates

In order to identify corresponding amino acid sequences (pentapeptides) between the SPs, MPs and NPs of human coronaviruses and human autoantigens targeted in autoimmune endocrinopathies, and for a comparative analysis of the various coronaviruses proteome and the proteome of human, the original computer program was used. Quantitatively, SP, MP and NP of the human coronaviruses were found to share totally 117 minimal immune pentapeptide epitopes: 79 in SP, 14 in MP and 24 in NP, - with 18 autoantigens expressed by human endocrinocytes. The shared pentapeptides belong to the proteins of human endocrine cells. Samples of the pituitary, adrenal and thyroid from patients who died from coronavirus infection (COVID-19) were studied morphologically using histochemical methods. A high incidence of SARS-CoV-2 infection of endocrine cells was showed. The high affinity of SARS-CoV-2 the cells of the adenohypophysis was revealed, but there was no expression of viral proteins by the cells of the neurohypophysis. The foci of lesions in endocrine organs contained abundant lymphocytic infiltrates which may indicate the impact of autoimmune processes. Autoimmune disorders have a multi-faceted etiology and depend on polygenic predispose and additive action of many epigenetic and environmental factors causing hyperstimulation of imperfectly functioning immune system. It means that the phenomenon of molecular mimicry cannot be blamed as their single prerequisite, but it is just a tile in mosaic of autoimmunity. The facts revealed emphasize the need of endocrinological diagnostic alertness of a physician while observing patients with post-vaccination and post-COVID-19 health disorders.

Molecular Mimicry between Respiratory Syncytial Virus F Antigen and the Human Proteome

This study examined respiratory syncytial virus (RSV) F glycoprotein (gp) antigen for molecular mimicry with the human proteome. It was found that the viral antigen presents an impressive number of pentapeptides (namely, 525 out of 570) in common with the human proteome, with viral sequences widely and repeatedly distributed among 3,762 human proteins implicated in crucial fundamental cellular functions. The data can have implications for anti-RSV vaccines. Indeed, the high level of molecular mimicry can lead to cross-reactivity and autoimmunity, and invites to follow safer vaccinal protocols based on pentapeptide sequences uniquely present in the viral antigen.

Increased prevalence of autoimmune thyroid disease after COVID-19: A single-center, prospective study

INTRODUCTION

Thyroid dysfunctions associated with SARS-CoV-2 acute infection have been extensively described since the beginning of COVID-19 pandemics. Conversely, few data are available on the occurrence of thyroid autoimmunity after COVID-19 resolution. We assessed the prevalence of autoimmune thyroid disease (ATD) and thyroid dysfunctions in COVID-19 survivors three months after hospital admission.

DESIGN AND METHODS

Single-center, prospective, observational, cohort study performed at ASST Papa Giovanni XXIII Hospital, Bergamo, Italy. 599 COVID-19 survivors were prospectively evaluated for thyroid function and autoimmunity thyroperoxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb). When a positive antibody concentration was detected, thyroid ultrasound was performed. Multiple logistic regression model was used to estimate the association between autoimmunity and demographic characteristics, respiratory support, and comorbidities. Autoimmunity results were compared to a cohort of 498 controls referred to our Institution for non-thyroid diseases before the pandemic onset. A sensitivity analysis comparing 330 COVID-19 patients with 330 age and sex-matched controls was performed.

RESULTS

Univariate and multivariate analysis found that female sex was positively associated (OR 2.01, SE 0.48, p = 0.003), and type 2 diabetes (T2DM) was negatively associated (OR 0.36, SE 0.16, p = 0.025) with thyroid autoimmunity; hospitalization, ICU admission, respiratory support, or COVID-19 treatment were not associated with thyroid autoimmunity (p > 0.05). TPOAb prevalence was greater in COVID-19 survivors than in controls: 15.7% vs 7.7%, p = 0.002. Ultrasonographic features of thyroiditis were present in 94.9% of the evaluated patients with positive antibodies. TSH was within the normal range in 95% of patients.

CONCLUSIONS

Autoimmune thyroid disease prevalence in COVID-19 survivors was doubled as compared to age and sex-matched controls, suggesting a role of SARS-CoV-2 in eliciting thyroid autoimmunity.

Autoimmunity and Immunodeficiency in Severe SARS-CoV-2 Infection and Prolonged COVID-19

SARS-CoV-2 causes the complex and heterogeneous illness known as COVID-19. The disease primarily affects the respiratory system but can quickly become systemic, harming multiple organs and leading to long-lasting sequelae in some patients. Most infected individuals are asymptomatic or present mild symptoms. Antibodies, complement, and immune cells can efficiently eliminate the virus. However, 20% of individuals develop severe respiratory illness and multiple organ failure. Virus replication has been described in several organs in patients who died from COVID-19, suggesting a compromised immune response. Immunodeficiency and autoimmunity are responsible for this impairment and facilitate viral escape. Mutations in IFN signal transduction and T cell activation are responsible for the inadequate response in young individuals. Autoantibodies are accountable for secondary immunodeficiency in patients with severe infection or prolonged COVID-19. Antibodies against cytokines (interferons α, γ and ω, IL1β, IL6, IL10, IL-17, IL21), chemokines, complement, nuclear proteins and DNA, anticardiolipin, and several extracellular proteins have been reported. The type and titer of autoantibodies depend on age and gender. Organ-specific autoantibodies have been described in prolonged COVID-19. Their role in the disease is under study. Autoimmunity and immunodeficiency should be screened as risk factors for severe or prolonged COVID-19.

Autoimmune Diseases Affecting Hemostasis: A Narrative Review

Hemostasis reflects a homeostatic mechanism that aims to balance out pro-coagulant and anti-coagulant forces to maintain blood flow within the circulation. Simplistically, a relative excess of procoagulant forces can lead to thrombosis, and a relative excess of anticoagulant forces can lead to bleeding. There are a wide variety of congenital disorders associated with bleeding or thrombosis. In addition, there exist a vast array of autoimmune diseases that can also lead to either bleeding or thrombosis. For example, autoantibodies generated against clotting factors can lead to bleeding, of which acquired hemophilia A is the most common. As another example, autoimmune-mediated antibodies against phospholipids can generate a prothrombotic milieu in a condition known as antiphospholipid (antibody) syndrome (APS). Moreover, there exist various autoimmunity promoting environments that can lead to a variety of antibodies that affect hemostasis. Coronavirus disease 2019 (COVID-19) represents perhaps the contemporary example of such a state, with potential development of a kaleidoscope of such antibodies that primarily drive thrombosis, but may also lead to bleeding on rarer occasions. We provide here a narrative review to discuss the interaction between various autoimmune diseases and hemostasis.