SARS-CoV-2, the autoimmune virus

The intersection of microbiome and autoimmunity in long COVID-19: Current insights and future directions

Long COVID-19 affects a significant percentage of patients and is characterized by a wide range of symptoms, including weariness and mental fog as well as emotional symptoms like worry and sadness. COVID-19 is closely linked to the autoimmune disorders that are becoming more prevalent worldwide and are linked to immune system hyperactivation, neutrophil extracellular trap (NET) development, and molecular mimicry pathways. Long-term COVID-related autoimmune responses include a watchful immune system referring to the ability of immune system to constantly monitor the body for signs of infection, disease, or abnormal cells; altered innate and adaptive immune cells, autoantigens secreted by living or dead neutrophils, and high concentrations of autoantibodies directed against different proteins. The microbiome, which consists of billions of bacteria living in the human body, is essential for controlling immune responses and supporting overall health. The microbiome can affect the course of long COVID-associated autoimmunity, including the degree of illness, the rate of recovery, and the onset of autoimmune reactions. Although the precise role of the microbiome in long COVID autoimmunity is still being investigated, new studies indicate that probiotics, prebiotics, and dietary changes-interventions that target the microbiome-may be able to reduce autoimmune reactions and enhance long-term outcomes for COVID-19 survivors. More research is required to precisely understand how the microbiome affects COVID-19-related autoimmunity and to create tailored treatment plans.

The Onset of Antinuclear Antibodies (ANAs) as a Potential Risk Factor for Mortality and Morbidity in COVID-19 Patients: A Single-Center Retrospective Study

The immune system's amplified response to SARS-CoV-2 may lead to the production of autoantibodies, but their specific impact on disease severity and outcome remains unclear. This study aims to assess if hospitalized COVID-19 patients face a worse prognosis based on ANA presence, even without autoimmune diseases. We performed a retrospective, single-center, observational cohort study, enrolling 638 COVID-19 patients hospitalized from April 2020 to March 2021 at Hospital "Policlinico Riuniti" of Foggia (Italy). COVID-19 patients with a positive ANA test exhibited a significantly lower 30-day survival rate (64.4% vs. 83.0%) and a higher likelihood of severe respiratory complications during hospitalization than those with negative ANA screening (35.4% vs. 17.0%) (p < 0.001). The association between poor prognosis and ANA status was identified by calculating the HALP score (Hemoglobin-Albumin-Lymphocyte-Platelet), which was lower in COVID-19 patients with a positive ANA test compared to ANA-negative patients (108.1 ± 7.4 vs. 218.6 ± 11.2 AU; p < 0.011). In detail, COVID-19 patients with a low HALP showed a lower 30-day survival rate (99.1% vs. 83.6% vs. 55.2% for high, medium, and low HALP, respectively; p < 0.001) and a higher incidence of adverse respiratory events compared to those with high and medium HALP (13.1% vs. 35.2% vs. 64.6% for high, medium, and low HALP, respectively; p < 0.001). In summary, ANA positivity in COVID-19 patients appears to be linked to a more aggressive disease phenotype with a reduced survival rate. Furthermore, we propose that the HALP score could serve as a valuable parameter to assess prognosis for COVID-19 patients.

Association Between Lifetime Interpersonal Violence and Post-COVID-19 Condition Among Women in Kentucky, 2020-2022

OBJECTIVE

The COVID-19 pandemic increased the risk of interpersonal violence. We investigated the association between lifetime interpersonal violence experience and risk of post-COVID-19 condition (the persistence of symptoms of COVID-19 and severity of health problems associated with COVID-19 that last a few weeks, months, or years) among women with lifetime interpersonal violence experience.

METHODS

Women participants aged ≥18 years in Kentucky's Wellness, Health & You-COVID-19 study completed online quantitative surveys about the impacts of the pandemic, developing COVID-19, and symptoms of post-COVID-19 condition. We conducted cross-sectional analyses estimating rate ratios of developing COVID-19 and symptoms of post-COVID-19 condition during the pandemic (October 13, 2020-February 28, 2022).

RESULTS

Of the analytic sample (N = 938), 342 (36.5%) disclosed a history of lifetime interpersonal violence. Compared with women with no lifetime interpersonal violence experience, women with lifetime interpersonal violence experience had significantly more distress because of the pandemic, defined as family financial challenges (P = .001), symptoms of mental health challenges (P < .001), and negative coping behaviors (P < .001). While experiencing lifetime interpersonal violence was not significantly associated with either receiving COVID-19 vaccinations (adjusted rate ratio [aRR] = 1.10; 95% CI, 0.75-1.61) or developing COVID-19 (aRR = 1.15; 95% CI, 0.92-1.44), experiencing lifetime interpersonal violence was associated with an increased rate of developing symptoms of post-COVID-19 condition (aRR = 2.09; 95% CI, 1.19-3.65).

CONCLUSION

Symptoms of post-COVID-19 condition may be linked to lifetime interpersonal violence experience, possibly through stress or violence-associated trauma. Future research is needed to assess the negative effects of the pandemic, prioritizing people with lifetime interpersonal violence experience.

Precision nutrition to reset virus-induced human metabolic reprogramming and dysregulation (HMRD) in long-COVID

SARS-CoV-2, the etiological agent of COVID-19, is devoid of any metabolic capacity; therefore, it is critical for the viral pathogen to hijack host cellular metabolic machinery for its replication and propagation. This single-stranded RNA virus with a 29.9 kb genome encodes 14 open reading frames (ORFs) and initiates a plethora of virus-host protein-protein interactions in the human body. These extensive viral protein interactions with host-specific cellular targets could trigger severe human metabolic reprogramming/dysregulation (HMRD), a rewiring of sugar-, amino acid-, lipid-, and nucleotide-metabolism(s), as well as altered or impaired bioenergetics, immune dysfunction, and redox imbalance in the body. In the infectious process, the viral pathogen hijacks two major human receptors, angiotensin-converting enzyme (ACE)-2 and/or neuropilin (NRP)-1, for initial adhesion to cell surface; then utilizes two major host proteases, TMPRSS2 and/or furin, to gain cellular entry; and finally employs an endosomal enzyme, cathepsin L (CTSL) for fusogenic release of its viral genome. The virus-induced HMRD results in 5 possible infectious outcomes: asymptomatic, mild, moderate, severe to fatal episodes; while the symptomatic acute COVID-19 condition could manifest into 3 clinical phases: (i) hypoxia and hypoxemia (Warburg effect), (ii) hyperferritinemia ('cytokine storm'), and (iii) thrombocytosis (coagulopathy). The mean incubation period for COVID-19 onset was estimated to be 5.1 days, and most cases develop symptoms after 14 days. The mean viral clearance times were 24, 30, and 39 days for acute, severe, and ICU-admitted COVID-19 patients, respectively. However, about 25-70% of virus-free COVID-19 survivors continue to sustain virus-induced HMRD and exhibit a wide range of symptoms that are persistent, exacerbated, or new 'onset' clinical incidents, collectively termed as post-acute sequelae of COVID-19 (PASC) or long COVID. PASC patients experience several debilitating clinical condition(s) with >200 different and overlapping symptoms that may last for weeks to months. Chronic PASC is a cumulative outcome of at least 10 different HMRD-related pathophysiological mechanisms involving both virus-derived virulence factors and a multitude of innate host responses. Based on HMRD and virus-free clinical impairments of different human organs/systems, PASC patients can be categorized into 4 different clusters or sub-phenotypes: sub-phenotype-1 (33.8%) with cardiac and renal manifestations; sub-phenotype-2 (32.8%) with respiratory, sleep and anxiety disorders; sub-phenotype-3 (23.4%) with skeleto-muscular and nervous disorders; and sub-phenotype-4 (10.1%) with digestive and pulmonary dysfunctions. This narrative review elucidates the effects of viral hijack on host cellular machinery during SARS-CoV-2 infection, ensuing detrimental effect(s) of virus-induced HMRD on human metabolism, consequential symptomatic clinical implications, and damage to multiple organ systems; as well as chronic pathophysiological sequelae in virus-free PASC patients. We have also provided a few evidence-based, human randomized controlled trial (RCT)-tested, precision nutrients to reset HMRD for health recovery of PASC patients.

Vaccination and the risk of systemic lupus erythematosus: a meta-analysis of observational studies

OBJECTIVE

This meta-analysis aims to explore the potential link between vaccines and systemic lupus erythematosus (SLE).

METHODS

We systematically searched PubMed, Cochrane Library, and Embase for observational studies from inception to September 3, 2023, using medical subject headings (MeSH) and keywords. Study quality was assessed using the NOS scale. Statistical analyses were conducted using STATA software (version 14.0). Publication bias was evaluated using funnel plots and Egger's regression.

RESULTS

The meta-analysis incorporated 17 studies, encompassing 45,067,349 individuals with follow-up periods ranging from 0.5 to 2 years. The pooled analysis revealed no significant association between vaccinations and an increased risk of SLE [OR = 1.14, 95% CI (0.86-1.52), I2 = 78.1%, P = 0.348]. Subgroup analyses indicated that HBV vaccination was significantly associated with an elevated risk of SLE [OR =2.11, 95% CI (1.11-4.00), I2 = 63.3%, P = 0.02], HPV vaccination was slightly associated with an increased risk of SLE [OR = 1.43, 95% CI (0.88-2.31), I2 = 72.4%, P = 0.148], influenza vaccination showed no association with an increased risk of SLE [OR = 0.96, 95% CI (0.82-1.12), I2 = 0.0%, P = 0.559], and COVID-19 vaccine was marginally associated with a decreased risk of SLE [OR = 0.44, 95% CI (0.18-1.21), I2 = 91.3%, P = 0.118].

CONCLUSIONS

This study suggests that vaccinations are not linked to an increased risk of SLE. Our meta-analysis results provide valuable insights, alleviating concerns about SLE risk post-vaccination and supporting further vaccine development efforts.

Autoimmune response after SARS-CoV-2 infection and SARS-CoV-2 vaccines

The complicated relationships between autoimmunity, COVID-19, and COVID-19 vaccinations are described, giving insight into their intricacies. Antinuclear antibodies (ANA), anti-Ro/SSA, rheumatoid factor, lupus anticoagulant, and antibodies against interferon (IFN)-I have all been consistently found in COVID-19 patients, indicating a high prevalence of autoimmune reactions following viral exposure. Furthermore, the discovery of human proteins with structural similarities to SARS-CoV-2 peptides as possible autoantigens highlights the complex interplay between the virus and the immune system in initiating autoimmunity. An updated summary of the current status of COVID-19 vaccines is presented. We present probable pathways underpinning the genesis of COVID-19 autoimmunity, such as bystander activation caused by hyperinflammatory conditions, viral persistence, and the creation of neutrophil extracellular traps. These pathways provide important insights into the development of autoimmune-related symptoms ranging from organ-specific to systemic autoimmune and inflammatory illnesses, demonstrating the wide influence of COVID-19 on the immune system.

The impact of the COVID-19 pandemic on SLE

Little is known about the association between coronavirus disease 2019 (COVID-19) and autoimmune diseases, especially in the case of systemic lupus erythematosus (SLE). SLE patients met with many questions during the pandemic in COVID-19, such as how to minimize risk of infection, the complex pathological features and cytokine profiles, diagnosis and treatment, rational choice of drugs and vaccine, good nursing, psychological supervision, and so on. In this study, we review and discuss the multifaceted effects of the COVID-19 pandemic on patients living with SLE using the available literature. Cross-talk in implicated inflammatory pathways/mechanisms exists between SLE and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and SARS-CoV-2 displays similar clinical characteristics and immuno-inflammatory responses to SLE. Current epidemiological data inadequately assess the risk and severity of COVID-19 infection in patients with SLE. More evidence has shown that hydroxychloroquine and chloroquine cannot prevent COVID-19. During the pandemic, patients with SLE had a higher rate of hospitalization. Vaccination helps to reduce the risk of infection. Several therapies for patients with SLE infected with COVID-19 are discussed. The cases in the study can provide meaningful information for clinical diagnosis and management. Our main aim is to help preventing infection and highlight treatment options for patients with SLE infected with COVID-19.

Impact of IL-6 rs1800795 and IL-17A rs2275913 gene polymorphisms on the COVID-19 prognosis and susceptibility in a sample of Iranian patients

BACKGROUND

From asymptomatic to acute and life-threatening pulmonary infection, the clinical manifestations of COVID-19 are highly variable. Interleukin (IL)-6 and IL-17A are key drivers of hyper inflammation status in COVID-19, and their elevated levels are hallmarks of the infection progression. To explore whether prognosis and susceptibility to COVID-19 are linked to IL-6 rs1800795 and IL-17A rs2275913, these single-nucleotide polymorphisms (SNPs) were assessed in a sample of Iranian COVID-19 patients.

METHODS

This study enrolled two hundred and eighty COVID-19 patients (140 non-severe and 140 severe). Genotyping for IL-6 rs1800795 and IL-17A rs2275913 was performed using tetra primer-amplification refractory mutation system-polymerase chain reaction (tetra-ARMS-PCR). IL-6 and IL-17A circulating levels were measured using enzyme-linked immunosorbent assay (ELISA). Also, mortality predictors of COVID-19 were investigated.

RESULTS

The rs1800795 GG genotype (78/140 (55.7 %)) and G allele (205/280 (73.2 %)) were significantly associated with a positive risk of COVID-19 severe infection (OR = 2.19, 95 %CI: 1.35-3.54, P =.006 and OR = 1.79, 95 %CI: 1.25-2.56, P <.001, respectively). Also, rs1800795 GG genotype was significantly linked to disease mortality (OR = 1.95, 95 %CI: 1.06-3.61, P =.04). The rs2275913 GA genotype was protective against severe COVID-19 (OR = 0.5, 95 %CI: 0.31--0.80, P =.012). However, the present study did not reveal any significant link between rs2275913 genotypes with disease mortality. INR ≥ 1.2 (OR = 2.19, 95 %CI: 1.61-3.78, P =.007), D-dimer ≥ 565.5 ng/mL (OR = 3.12, 95 %CI: 1.27-5.68, P =.019), respiratory rate ≥ 29 (OR = 1.19, 95 %CI: 1.12-1.28, P =.001), IL-6 serum concentration ≥ 28.5 pg/mL (OR = 1.97, 95 %CI: 1.942-2.06, P =.013), and IL-6 rs1800795 GG genotype (OR = 1.95, 95 %CI: 1.06-3.61, P =.04) were predictive of COVID-19 mortality.

CONCLUSION

The rs1800795 GG genotype and G allele were associated with disease severity, and INR, D-dimer, respiratory rate, IL-6 serum concentration, and IL-6 rs1800795 GG genotype were predictive of COVID-19 mortality.

[SARS-CoV-2 infection and autoimmunity]

Even in the early phase of the corona pandemic in 2020, severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) was referred to as an "autoimmune virus". Since then, there have been numerous reports on the increased incidence of autoantibodies and autoimmune phenomena after SARS-CoV‑2 infections. On the one hand, autoantibodies can influence the course of the disease and on the other hand, they can lead to the first manifestation of new autoimmune diseases. In addition, a role of autoantibodies in the pathogenesis of post-coronavirus disease (post-COVID) is discussed. In the present review article, important aspects and studies are listed and the possible therapeutic consequences resulting from the findings are presented.

The association between autoimmune encephalitis mediated by N-methyl-ᴅ-aspartate receptor autoantibodies and COVID-19: a systematic review

Neurological complications related to coronavirus disease 2019 (COVID-19) infection have been increasingly reported. One of the most serious neurological complications is encephalitis, which could be due either to direct viral invasion or an immune-mediated inflammatory reaction. In this study, we conducted a systematic review of reported cases of autoimmune encephalitis mediated by N-methyl-ᴅ-aspartate receptor antibodies in conjunction with or after diagnosis of COVID-19 infection.

COVID-19 and SLE: Infection and autoimmunity at its best

If one had any doubts before the pandemic regarding the correlation between infections and autoimmunity, COVID-19 left us fascinated on the strong bond between the two entities. The immune and autoimmune reactions seen in patients infected with SARS-CoV-2 have served as a base for this assumption. Later on, the use of immunosuppressants such as systemic glucocorticoids, among other biological agents, turned this assumption to a fact. This was no different when it comes to the vaccines against COVID-19. Through several postulated mechanisms these vaccines, although generally considered safe, are thought to have the potential to result in autoimmune reactions making them not more innocent than the infection itself. When systemic lupus erythematous (SLE) is viewed as a classical autoimmune multisystemic disorder, the connection with SARS-CoV-2 infection and COVID-19 vaccination is of extreme importance. This is because early reports during the pandemic have shown increased rates of SARS-CoV-2 infection among patients known previously to have SLE and much more interestingly, cases of new-onset SLE after COVID-19 have been documented in the literature. Subsequently vaccines against COVID-19, those mRNA-based and adenovirus-vector based, were reported to induce new SLE cases, trigger immune thrombocytopenia or lupus nephritis, two common presentations of SLE, or exacerbate flares. In our paper, we concluded various aspects of available and recent data regarding SLE and COVID-19 as both an infection and vaccination.

Humoral immunity to an endemic coronavirus is associated with postacute sequelae of COVID-19 in individuals with rheumatic diseases

Beyond the acute illness caused by severe acute respiratory coronavirus 2 (SARS-CoV-2) infection, about one-fifth of infections result in long-term persistence of symptoms despite the apparent clearance of infection. Insights into the mechanisms that underlie postacute sequelae of COVID-19 (PASC) will be critical for the prevention and clinical management of long-term complications of COVID-19. Several hypotheses have been proposed that may account for the development of PASC, including persistence of virus and dysregulation of immune responses. Among the immunological changes noted in PASC, alterations in humoral immunity have been observed in some patient subsets. To begin to determine whether SARS-CoV-2- or other pathogen-specific humoral immune responses evolve uniquely in PASC, we performed comprehensive antibody profiling against SARS-CoV-2, a panel of endemic pathogens, and a panel of routine vaccine antigens using systems serology in two cohorts of patients with preexisting systemic autoimmune rheumatic disease (SARD) who either developed or did not develop PASC. A distinct qualitative shift observed in Fcγ receptor (FcγR) binding was observed in individuals with PASC. Specifically, individuals with PASC harbored weaker FcγR-binding anti-SARS-CoV-2 antibodies and stronger FcγR-binding antibody responses against the endemic coronavirus OC43. Individuals with PASC developed an OC43 S2-specific antibody response with stronger FcγR binding, linked to cross-reactivity across SARS-CoV-2 and common coronaviruses. These findings identify previous coronavirus imprinting as a potential marker for the development of PASC in individuals with SARDs.

Featured immune characteristics of COVID-19 and systemic lupus erythematosus revealed by multidimensional integrated analyses

BACKGROUND

Coronavirus disease 2019 (COVID-19) shares similar immune characteristics with autoimmune diseases like systemic lupus erythematosus (SLE). However, such associations have not yet been investigated at the single-cell level.

METHODS

We integrated and analyzed RNA sequencing results from different patients and normal controls from the GEO database and identified subsets of immune cells that might involve in the pathogenesis of SLE and COVID- 19. We also disentangled the characteristic alterations in cell and molecular subset proportions as well as gene expression patterns in SLE patients compared with COVID-19 patients.

RESULTS

Key immune characteristic genes (such as CXCL10 and RACK1) and multiple immune-related pathways (such as the coronavirus disease-COVID-19, T-cell receptor signaling, and MIF-related signaling pathways) were identified. We also highlighted the differences in peripheral blood mononuclear cells (PBMCs) between SLE and COVID-19 patients. Moreover, we provided an opportunity to comprehensively probe underlying B-cell‒cell communication with multiple ligand-receptor pairs (MIF-CD74+CXCR4, MIF-CD74+CD44) and the differentiation trajectory of B-cell clusters that is deemed to promote cell state transitions in COVID-19 and SLE.

CONCLUSIONS

Our results demonstrate the immune response differences and immune characteristic similarities, such as the cytokine storm, between COVID-19 and SLE, which might pivotally function in the pathogenesis of the two diseases and provide potential intervention targets for both diseases.

Risk of autoimmune diseases following COVID-19 and the potential protective effect from vaccination: a population-based cohort study

Background

Case reports suggest that SARS-CoV-2 infection could lead to immune dysregulation and trigger autoimmunity while COVID-19 vaccination is effective against severe COVID-19 outcomes. We aim to examine the association between COVID-19 and development of autoimmune diseases (ADs), and the potential protective effect of COVID-19 vaccination on such an association.

Methods

A retrospective cohort study was conducted in Hong Kong between 1 April 2020 and 15 November 2022. COVID-19 was confirmed by positive polymerase chain reaction or rapid antigen test. Cox proportional hazard regression with inverse probability of treatment weighting was applied to estimate the risk of incident ADs following COVID-19. COVID-19 vaccinated population was compared against COVID-19 unvaccinated population to examine the protective effect of COVID-19 vaccination on new ADs.

Findings

The study included 1,028,721 COVID-19 and 3,168,467 non-COVID individuals. Compared with non-COVID controls, patients with COVID-19 presented an increased risk of developing pernicious anaemia [adjusted Hazard Ratio (aHR): 1.72; 95% Confidence Interval (CI): 1.12-2.64]; spondyloarthritis [aHR: 1.32 (95% CI: 1.03-1.69)]; rheumatoid arthritis [aHR: 1.29 (95% CI: 1.09-1.54)]; other autoimmune arthritis [aHR: 1.43 (95% CI: 1.33-1.54)]; psoriasis [aHR: 1.42 (95% CI: 1.13-1.78)]; pemphigoid [aHR: 2.39 (95% CI: 1.83-3.11)]; Graves' disease [aHR: 1.30 (95% CI: 1.10-1.54)]; anti-phospholipid antibody syndrome [aHR: 2.12 (95% CI: 1.47-3.05)]; immune mediated thrombocytopenia [aHR: 2.1 (95% CI: 1.82-2.43)]; multiple sclerosis [aHR: 2.66 (95% CI: 1.17-6.05)]; vasculitis [aHR: 1.46 (95% CI: 1.04-2.04)]. Among COVID-19 patients, completion of two doses of COVID-19 vaccine shows a decreased risk of pemphigoid, Graves' disease, anti-phospholipid antibody syndrome, immune-mediated thrombocytopenia, systemic lupus erythematosus and other autoimmune arthritis.

Interpretation

Our findings suggested that COVID-19 is associated with an increased risk of developing various ADs and the risk could be attenuated by COVID-19 vaccination. Future studies investigating pathology and mechanisms would be valuable to interpreting our findings.

Funding

Supported by RGC Collaborative Research Fund (C7154-20GF).

"Multisystem Inflammatory Syndrome in Children" (MIS-C) after COVID-19 Infection in the Metropolitan Area of Nuremberg-Erlangen, Germany-Expectations and Results of a Two-Year Period

BACKGROUND

Multisystemic Inflammatory Syndrome in children (MIS-C) is a rare autoimmune disorder occurring after a latency period following acute SARS-CoV-2 infection. The therapeutic regime of MIS-C is adapted to the therapy of the Kawasaki disease, as clinical symptoms are similar. Since the Kawasaki disease can potentially result in severe symptoms, which may even affect long-term health, it is essential to gain further knowledge about MIS-C. Thus, we aimed to investigate the incidence, symptoms, therapeutical procedure and outcome of MIS-C patients in the metropolitan area of Nuremberg-Erlangen during the SARS-CoV2 pandemic.

MATERIAL AND METHODS

Retrospective analysis of clinical charts of MIS-C patients was carried out at three children's hospitals covering the medical care of the metropolitan area of Nuremberg-Erlangen in Germany. Demographic characteristics and symptoms at first visit, their clinical course, therapeutic regime and outcome were recorded within the time period January 2021-December 2022.

RESULTS

Analysis of 10 patients (5 male, 5 female) with MIS-C resulting in an incidence of 2.14/100.000 children. The median time between COVID-19 infection and admission to hospital was 5 weeks. The median age was 7 years. Symptoms comprised fever (100%), rash (70%), bilateral non-purulent conjunctivitis (70%) and urticaria (20%). At the time of presentation, diagnosis-defining inflammation parameters were increased and the range for C-reactive protein was 4.13 mg/dL to 28 mg/dL, with a median of 24.7 mg/dL. Procalcitonin was initially determined in six patients (1.92 ng/mL to 21.5 ng/mL) with a median value of 5.5 pg/mL. Two patients displayed leukocytosis and two displayed leukopenia. None of the patients presented coronary pathologies. Nine of the ten patients received intravenous immunoglobulin (IVIG) therapy. In addition, patients received intravenous steroids (80%) and acetylsalicylic acid (80%).

CONCLUSION

SARS-CoV virus may rarely exert multiorgan manifestations due to hyperinflammatory immunological processes. Within two years of the COVID-19 pandemic, we identified ten patients with COVID-induced MIS-C in the metropolitan area Nuremberg-Erlangen. In the description of the patient collective, we can confirm that MIS-C is distinguished from the Kawasaki disease by the lack of coronary manifestations. Interestingly, although having monitored all pediatric facilities in the investigated area, we find lower incidences of MIS-C compared to findings in the literature. In conclusion, an overestimation of incidences in the upcoming MIS-C during the pandemic needs to be considered.

Are Measles-Mumps-Rubella (MMR) Antibodies Friends or Foes for Covid-19 Disease?

Many factors have been implicated in the pathogenesis and severity of COVID-19 pandemic. A wide variation in the susceptibility for SARS-CoV-2 infection among different population, gender and age has been observed. Multiple studies investigated the relationship between the antibody's titre of previously vaccinated individuals and the susceptibility of coronavirus infection, to find a rapid effective therapy for this pandemic. This study focused on the association between measles-mumps-rubella (MMR) antibodies titre and the severity of COVID-19 infection. We aimed to investigate the correlation between the antibody's titre of MMR and the SARS-CoV-2 infection susceptibility and disease severity, in a cohort of COVID-19 Egyptian patients, compared to a control group. MMR antibody titre was measured using enzyme Linked Immune Sorbent Assay; (ELISA) for 136 COVID-19 patients and 44 healthy individuals, as control group. There were high levels of measles and mumps antibodies titer in the deteriorating cases, which could not protect from SARS-CoV-2 infection. However, the rubella antibodies might protect from SARS-CoV-2 infection, but once the infection occurs, it may aggravate the risk of case deterioration. MMR antibodies could be used as a guideline for COVID-19 symptom-severity and, in turn, may be considered as an economic prognostic marker used for early protection from multiple autoimmune organ failure.

Mycobacterium tuberculosis disease associates with higher HIV-1-specific antibody responses

Mycobacterium tuberculosis (Mtb) is the most common infection among people with HIV (PWH). Mtb disease-associated inflammation could affect HIV-directed immune responses in PWH. We show that HIV antibodies are broader and more potent in PWH in the presence as compared to the absence of Mtb disease. With co-existing Mtb disease, the virus in PWH also encounters unique antibody selection pressure. The Mtb-linked HIV antibody enhancement associates with specific mediators important for B cell and antibody development. This Mtb humoral augmentation does not occur due to cross-reactivity, a generalized increase in all antibodies, or differences in duration or amount of antigen exposure. We speculate that the co-localization of Mtb and HIV in lymphatic tissues leads to the emergence of potent HIV antibodies. PWH's Mtb disease status has implications for the future use of HIV broadly neutralizing antibodies as prophylaxis or treatment and the induction of better humoral immunity.

Cytokine Response Following SARS-CoV-2 Antigen Stimulation in Patients with Predominantly Antibody Deficiencies

Predominantly antibody deficiencies (PADs) are inborn disorders characterized by immune dysregulation and increased susceptibility to infections. Response to vaccination, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), may be impaired in these patients, and studies on responsiveness correlates, including cytokine signatures to antigen stimulation, are sparse. In this study, we aimed to describe the spike-specific cytokine response following whole-blood stimulation with SARS-CoV-2 spike peptides in patients with PAD (n = 16 with common variable immunodeficiency and n = 15 with selective IgA deficiency) and its relationship with the occurrence of coronavirus disease 2019 (COVID-19) during up to 10-month follow-up period. Spike-induced antibody and cytokine production was measured using ELISA (anti-spike IgG, IFN-γ) and xMAP technology (interleukin-1β (IL-1β), IL-4, IL-6, IL-10, IL-15, IL-17A, IL-21, TNF-α, TGF-β1). No difference was found in the production of cytokines between patients with PAD and controls. Anti-spike IgG and cytokine levels did not predict contraction of COVID-19. The only cytokine that distinguished between vaccinated and naturally infected unvaccinated PAD patients was IFN-γ (median 0.64 (IQR = 1.08) in vaccinated vs. 0.10 (IQR = 0.28) in unvaccinated). This study describes the spike-specific cytokine response to SARS-CoV-2 antigens, which is not predictive of contracting COVID-19 during the follow-up.

Acute arthritis following SARS-CoV-2 infection: About two cases

Joint involvement in COVID-19 may occur at different stages of the disease and maybe represented by non-specific arthralgia or by acute arthritis. We report two cases of COVID-19 infection that were complicated by postviral reactive arthritis. Case 1: A 47-year-old male was presented 20 days after a COVID-19 infection with acute right knee arthritis. On biologic data, erythrocyte sedimentation rate and C-reactive protein were normal, and immunologic data were negative. A joint puncture was performed showing a turbid fluid. Testing for microcrystals was negative, as well as the synovial fluid culture. An infectious investigation was conducted, which was negative. The patient's complaints improved significantly, with analgesics and non-steroidal anti-inflammatory drugs (NSAID). Case 2: A 33-year-old female presented with acute left knee arthritis evolving for 48 h, free of fever, after a COVID-19 infection treated 15 days ago. On examination, besides knee arthritis, the osteoarticular examination was normal. A biological inflammatory syndrome was noted in laboratory tests. A yellow fluid with multiple PNN was detected in the joint fluid aspiration, with a negative culture. The patient was treated by analgesics and NSAID. The follow-up was highlighted by the arthritis resolution. Conclusion: Both of our cases are consistent with what has already been reported in the literature confirming the development of PostCOVID arthritis and strengthen the impending necessity of wider studies to identify rheumatologic manifestations in the short- and long-terms after surviving COVID-19.

Is COVID-19 All That Glitters?

Over the last three years, the Coronavirus-19 disease has been a global health emergency, playing a primary role in the international scientific community. Clinical activity and scientific research have concentrated their efforts on facing the pandemic, allowing the description of novel pathologies correlated to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), such as the Multisystemic Inflammatory Syndrome in Children and Adults (MIS-C, MIS-A). Conversely, this shift of attention to COVID-19 disease and its complications could, in some cases, have delayed and underestimated the diagnosis of diseases not associated with SARS-CoV-2, including rare diseases. Here we describe the diagnostic process that led to the definition of a rare vasculitis in a young woman with a recent clinical history of SARS-CoV-2.

Autoimmune liver diseases and SARS-CoV-2

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing coronavirus disease 2019 (COVID-19), can trigger autoimmunity in genetically predisposed individuals through hyperstimulation of immune response and molecular mimicry. Here we summarise the current knowledge about auto-immune liver diseases (AILDs) and SARS-CoV-2, focusing on: (1) The risk of SARS-CoV-2 infection and the course of COVID-19 in patients affected by AILDs; (2) the role of SARS-CoV-2 in inducing liver damage and triggering AILDs; and (3) the ability of vaccines against SARS-CoV-2 to induce autoimmune responses in the liver. Data derived from the literature suggest that patients with AILDs do not carry an increased risk of SARS-Cov-2 infection but may develop a more severe course of COVID-19 if on treatment with steroids or thiopurine. Although SARS-CoV-2 infection can lead to the development of several autoimmune diseases, few reports correlate it to the appearance of de novo manifestation of immune-mediated liver diseases such as autoimmune hepatitis (AIH), primary biliary cholangitis (PBC) or AIH/PBC overlap syndrome. Different case series of an AIH-like syndrome with a good prognosis after SARS-CoV-2 vaccination have been described. Although the causal link between SARS-CoV-2 vaccines and AIH cannot be definitively established, these reports suggest that this association could be more than coincidental.

COVID-19 morbidity in lower versus higher income populations underscores the need to restore lost biodiversity of eukaryotic symbionts

The avoidance of infectious disease by widespread use of 'systems hygiene', defined by hygiene-enhancing technology such as sewage systems, water treatment facilities, and secure food storage containers, has led to a dramatic decrease in symbiotic helminths and protists in high-income human populations. Over a half-century of research has revealed that this 'biota alteration' leads to altered immune function and a propensity for chronic inflammatory diseases, including allergic, autoimmune and neuropsychiatric disorders. A recent Ethiopian study (EClinicalMedicine 39: 101054), validating predictions made by several laboratories, found that symbiotic helminths and protists were associated with a reduced risk of severe COVID-19 (adjusted odds ratio = 0.35; p<0.0001). Thus, it is now apparent that 'biome reconstitution', defined as the artificial re-introduction of benign, symbiotic helminths or protists into the ecosystem of the human body, is important not only for alleviation of chronic immune disease, but likely also for pandemic preparedness.

Autoantibodies targeting G protein-coupled receptors: An evolving history in autoimmunity. Report of the 4th international symposium

G protein-coupled receptors (GPCR) are involved in various physiological and pathophysiological processes. Functional autoantibodies targeting GPCRs have been associated with multiple disease manifestations in this context. Here we summarize and discuss the relevant findings and concepts presented in the biennial International Meeting on autoantibodies targeting GPCRs (the 4th Symposium), held in Lübeck, Germany, 15-16 September 2022. The symposium focused on the current knowledge of these autoantibodies' role in various diseases, such as cardiovascular, renal, infectious (COVID-19), and autoimmune diseases (e.g., systemic sclerosis and systemic lupus erythematosus). Beyond their association with disease phenotypes, intense research related to the mechanistic action of these autoantibodies on immune regulation and pathogenesis has been developed, underscoring the role of autoantibodies targeting GPCRs on disease outcomes and etiopathogenesis. The observation repeatedly highlighted that autoantibodies targeting GPCRs could also be present in healthy individuals, suggesting that anti-GPCR autoantibodies play a physiologic role in modeling the course of diseases. Since numerous therapies targeting GPCRs have been developed, including small molecules and monoclonal antibodies designed for treating cancer, infections, metabolic disorders, or inflammatory conditions, anti-GPCR autoantibodies themselves can serve as therapeutic targets to reduce patients' morbidity and mortality, representing a new area for the development of novel therapeutic interventions.

Dysregulated Levels of Circulating Autoantibodies against Neuronal and Nervous System Autoantigens in COVID-19 Patients

BACKGROUND

COVID-19 is a heterogenous disease resulting in long-term sequela in predisposed individuals. It is not uncommon that recovering patients endure non-respiratory ill-defined manifestations, including anosmia, and neurological and cognitive deficit persisting beyond recovery-a constellation of conditions that are grouped under the umbrella of long-term COVID-19 syndrome. Association between COVID-19 and autoimmune responses in predisposed individuals was shown in several studies.

AIM AND METHODS

To investigate autoimmune responses against neuronal and CNS autoantigens in SARS-CoV-2-infected patients, we performed a cross-sectional study with 246 participants, including 169 COVID-19 patients and 77 controls. Levels of antibodies against the acetylcholine receptor, glutamate receptor, amyloid β peptide, alpha-synucleins, dopamine 1 receptor, dopamine 2 receptor, tau protein, GAD-65, N-methyl D-aspartate (NMDA) receptor, BDNF, cerebellar, ganglioside, myelin basic protein, myelin oligodendrocyte glycoprotein, S100-B, glial fibrillary acidic protein, and enteric nerve were measured using an Enzyme-Linked Immunosorbent Assay (ELISA). Circulating levels of autoantibodies were compared between healthy controls and COVID-19 patients and then classified by disease severity (mild [n = 74], severe [n = 65], and requiring supplemental oxygen [n = 32]).

RESULTS

COVID-19 patients were found to have dysregulated autoantibody levels correlating with the disease severity, e.g., IgG to dopamine 1 receptor, NMDA receptors, brain-derived neurotrophic factor, and myelin oligodendrocyte glycoprotein. Elevated levels of IgA autoantibodies against amyloid β peptide, acetylcholine receptor, dopamine 2 receptor, myelin basic protein, and α-synuclein were detected in COVID-19 patients compared with healthy controls. Lower IgA autoantibody levels against NMDA receptors, and IgG autoantibodies against glutamic acid decarboxylase 65, amyloid β peptide, tau protein, enteric nerve, and S100-B were detected in COVID-19 patients versus healthy controls. Some of these antibodies have known clinical correlations with symptoms commonly reported in the long COVID-19 syndrome.

CONCLUSIONS

Overall, our study shows a widespread dysregulation in the titer of various autoantibodies against neuronal and CNS-related autoantigens in convalescent COVID-19 patients. Further research is needed to provide insight into the association between these neuronal autoantibodies and the enigmatic neurological and psychological symptoms reported in COVID-19 patients.

The Prevalence of Hearing Impairments in Women with Silicone Breast Implants

Many women with silicone breast implants (SBIs) report non-specific complaints, including hearing impairments. Hearing impairment appears to be associated with a number of autoimmune conditions. The current study aimed to evaluate the prevalence and severity of hearing impairments among women with SBIs and to explore potential improvements in their hearing capability following implant removal. Symptomatic women with SBIs (n = 160) underwent an initial anamnestic interview, and women who reported hearing impairments were selected for the study. These women completed self-report telephone questionnaires regarding their hearing difficulties. Some of these women underwent subjective and objective hearing tests. Out of 159 (50.3%) symptomatic women with SBIs, 80 reported hearing impairments, including hearing loss (44/80; 55%) and tinnitus (45/80; 56.2%). Five out of seven (71.4%) women who underwent an audiologic evaluation exhibited hearing loss. Of women who underwent silicone implant removal, 27 out of 47 (57.4%) reported the improvement or resolution of their hearing complaints. In conclusion, hearing impairment is a frequent complaint among symptomatic women with SBIs, and tinnitus was found to be the most common complaint. A significant reduction in hearing difficulties was observed following silicone implant removal. Further studies using larger populations are needed to verify the occurrence of hearing impairments in these women.

Cross-sectional analysis reveals autoantibody signatures associated with COVID-19 severity

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased levels of autoantibodies targeting immunological proteins such as cytokines and chemokines. Reports further indicate that COVID-19 patients may develop a broad spectrum of autoimmune diseases due to reasons not fully understood. Even so, the landscape of autoantibodies induced by SARS-CoV-2 infection remains uncharted territory. To gain more insight, we carried out a comprehensive assessment of autoantibodies known to be linked to diverse autoimmune diseases observed in COVID-19 patients in a cohort of 231 individuals, of which 161 were COVID-19 patients (72 with mild, 61 moderate, and 28 with severe disease) and 70 were healthy controls. Dysregulated IgG and IgA autoantibody signatures, characterized mainly by elevated concentrations, occurred predominantly in patients with moderate or severe COVID-19 infection. Autoantibody levels often accompanied anti-SARS-CoV-2 antibody concentrations while stratifying COVID-19 severity as indicated by random forest and principal component analyses. Furthermore, while young versus elderly COVID-19 patients showed only slight differences in autoantibody levels, elderly patients with severe disease presented higher IgG autoantibody concentrations than young individuals with severe COVID-19. This work maps the intersection of COVID-19 and autoimmunity by demonstrating the dysregulation of multiple autoantibodies triggered during SARS-CoV-2 infection. Thus, this cross-sectional study suggests that SARS-CoV-2 infection induces autoantibody signatures associated with COVID-19 severity and several autoantibodies that can be used as biomarkers of COVID-19 severity, indicating autoantibodies as potential therapeutical targets for these patients.

Autoimmune complications of COVID-19 and potential consequences for long-lasting disease syndromes

The latest WHO report determined the increasing diversity within the CoV-2 omicron and its descendent lineages. Some heavily mutated offshoots of BA.5 and BA.2, such as BA.4.6, BF.7, BQ.1.1, and BA.2.75, are responsible for about 20% of infections and are spreading rapidly in multiple countries. It is a sign that Omicron subvariants are now developing a capacity to be more immune escaping and may contribute to a new wave of COVID-19. Covid-19 infections often induce many alterations in human physiological defense and the natural control systems, with exacerbated activation of the inflammatory and homeostatic response, as for any infectious diseases. Severe activation of the early phase of hemostatic components, often occurs, leading to thrombotic complications and often contributing to a lethal outcome selectively in certain populations. Development of autoimmune complications increases the disease burden and lowers its prognosis. While the true mechanism still remains unclear, it is believed to mainly be related to the host autoimmune responses as demonstrated, only in some patients suffering from the presence of autoantibodies that worsens the disease evolution. In fact in some studies the development of autoantibodies to angiotensin converting enzyme 2 (ACE2) was identified, and in other studies autoantibodies, thought to be targeting interferon or binding to annexin A1, or autoantibodies to phospholipids were seen. Moreover, the occurrence of autoimmune heparin induced thrombocytopenia has also been described in infected patients treated with heparin for controlling thrombogenicity. This commentary focuses on the presence of various autoantibodies reported so far in Covid-19 diseases, exploring their association with the disease course and the durability of some related symptoms. Attempts are also made to further analyze the potential mechanism of actions and link the presence of antibodies with pathological complications.

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.

Persistent SARS-CoV-2 Infection, EBV, HHV-6 and Other Factors May Contribute to Inflammation and Autoimmunity in Long COVID

A novel syndrome called long-haul COVID or long COVID is increasingly recognized in a significant percentage of individuals within a few months after infection with SARS-CoV-2. This disorder is characterized by a wide range of persisting, returning or even new but related symptoms that involve different tissues and organs, including respiratory, cardiac, vascular, gastrointestinal, musculo-skeletal, neurological, endocrine and systemic. Some overlapping symptomatologies exist between long COVID and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Very much like with long ME/CFS, infections with herpes family viruses, immune dysregulation, and the persistence of inflammation have been reported as the most common pattern for the development of long COVID. This review describes several factors and determinants of long COVID that have been proposed, elaborating mainly on viral persistence, reactivation of latent viruses such as Epstein-Barr virus and human herpesvirus 6 which are also associated with the pathology of ME/CFS, viral superantigen activation of the immune system, disturbance in the gut microbiome, and multiple tissue damage and autoimmunity. Based on these factors, we propose diagnostic strategies such as the measurement of IgG and IgM antibodies against SARS-CoV-2, EBV, HHV-6, viral superantigens, gut microbiota, and biomarkers of autoimmunity to better understand and manage this multi-factorial disorder that continues to affect millions of people in the world.

Is COVID-19 severity unrelated to antinuclear antibodies?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces an overreaction of the immune system, resulting in the production of auto-antibodies. Several studies have reported that autoantibodies are prevalent in COVID-19 patients. In our study, antinuclear antibodies were evaluated in patients with COVID-19. We examined 131 sera from patients (>17-year-old) with confirmed COVID-19. Samples were collected prior to receiving any medication and antinuclear antibodies (ANA) levels were measured by the indirect immunofluorescence (IIF) method. Furthermore, the immunoblotting test was used to determine the presence of anti-nuclear antigen antibodies. The IIF-ANA test was positive in 36.4% (48/131) of patients. Overall, non-ICU patients had higher IIF-ANA titers than ICU patients. In particular, ICU patients had fewer nuclear, cytoplasmic, and mitotic IIF-ANA antibodies than non-ICU patients. In conclusion, COVID-19 patients frequently have ANA possibly reflecting the immune dysregulation due to several damaged cells by SARS-CoV-2 virus.

Adaptive Immunity to Viruses: What Did We Learn from SARS-CoV-2 Infection?

The SARS-CoV-2 virus causes various conditions, from asymptomatic infection to the fatal coronavirus disease 2019 (COVID-19). An intact immune system can overcome SARS-CoV-2 and other viral infections. Defective natural, mainly interferon I- and III-dependent, responses may lead to the spread of the virus to multiple organs. Adaptive B- and T-cell responses, including memory, highly influence the severity and outcome of COVID-19. With respect to B-cell immunity, germinal centre formation is delayed or even absent in the most severe cases. Extrafollicular low-affinity anti-SARS-CoV-2 antibody production will occur instead of specific, high-affinity antibodies. Helper and CD8+ cytotoxic T-cells become hyperactivated and then exhausted, leading to ineffective viral clearance from the body. The dysregulation of neutrophils and monocytes/macrophages, as well as lymphocyte hyperreactivity, might lead to the robust production of inflammatory mediators, also known as cytokine storm. Eventually, the disruption of this complex network of immune cells and mediators leads to severe, sometimes fatal COVID-19 or another viral disease.

Shared 6mer Peptides of Human and Omicron (21K and 21L) at SARS-CoV-2 Mutation Sites

We investigated the short sequences involving Omicron 21K and Omicron 21L variants to reveal any possible molecular mimicry-associated autoimmunity risks and changes in those. We first identified common 6mers of the viral and human protein sequences present for both the mutant (Omicron) and nonmutant (SARS-CoV-2) versions of the same viral sequence and then predicted the binding affinities of those sequences to the HLA supertype representatives. We evaluated change in the potential autoimmunity risk, through comparative assessment of the nonmutant and mutant viral sequences and their similar human peptides with common 6mers and affinities to the same HLA allele. This change is the lost and the new, or de novo, autoimmunity risk, associated with the mutations in the Omicron 21K and Omicron 21L variants. Accordingly, e.g., the affinity of virus-similar sequences of the Ig heavy chain junction regions shifted from the HLA-B*15:01 to the HLA-A*01:01 allele at the mutant sequences. Additionally, peptides of different human proteins sharing 6mers with SARS-CoV-2 proteins at the mutation sites of interest and with affinities to the HLA-B*07:02 allele, such as the respective SARS-CoV-2 sequences, were lost. Among all, any possible molecular mimicry-associated novel risk appeared to be prominent in HLA-A*24:02 and HLA-B*27:05 serotypes upon infection with Omicron 21L. Associated disease, pathway, and tissue expression data supported possible new risks for the HLA-B*27:05 and HLA-A*01:01 serotypes, while the risks for the HLA-B*07:02 serotypes could have been lost or diminished, and those for the HLA-A*03:01 serotypes could have been retained, for the individuals infected with Omicron variants under study. These are likely to affect the complications related to cross-reactions influencing the relevant HLA serotypes upon infection with Omicron 21K and Omicron 21L.

Impact of COVID-19 Infection, Vaccination, and Serological Response in Immune Thrombocytopenic Purpura Patients: A Single-Center Global Analysis

Both SARS-CoV-2 infection and vaccination have raised concern in immune-mediated diseases, including immune thrombocytopenic purpura (ITP) considering risk of de novo ITP development and ITP recurrence. Here, we report on data from a single-center retrospective-prospective collection aiming to evaluate platelet (plt) dynamics in patients (pts) with chronic ITP after COVID-19 infection (before and after vaccination) and after the first, second and third vaccine doses. Furthermore, we analyzed the serological response after the first two doses of COVID-19 vaccination. A total of 64 pts currently followed for chronic ITP who experienced COVD-19 infection and/or vaccination with an available plt count before and after such events were included in the analysis. A low incidence of ITP exacerbation following vaccine sessions (6-16%) was observed in comparison with a high frequency of exacerbation and rescue treatment necessity after COVID-19 infection in unvaccinated pts (83%). Moreover, the lower ITP exacerbation rate observed in infected pts previously vaccinated (18%) suggests further protective effects in this population. Finally, a high seroconversion rate was observed, confirming data reported in previously published studies on immune cytopenia and rheumatological diseases, but more evidence is awaited to establish the clinical impact of serological response.

Complement Regulation in Immortalized Fibroblast-like Synoviocytes and Primary Human Endothelial Cells in Response to SARS-CoV-2 Nucleocapsid Protein and Pro-Inflammatory Cytokine TNFα

Background: Case reports are available showing that patients develop symptoms of acute arthritis during or after recovery from SARS-CoV-2 infection. Since the interrelation is still unknown, our aim was to study the impact of the SARS-CoV-2 nucleocapsid protein (NP) on human fibroblast-like synoviocytes and human endothelial cells (hEC) in terms of complement and cytokine regulation. Methods: Non-arthritic (K4IM) synoviocyte, arthritic (HSE) synoviocyte cell lines and primary hEC were stimulated with recombinant NP and/or TNFα. Analyses of cell viability, proliferation, gene and protein expression of cytokines and complement factors were performed. Results: NP suppressed significantly the vitality of hEC and proliferation of HSE. NP alone did not induce any significant changes in the examined gene expressions. However, NP combined with TNFα induced significantly higher TNFα in HSE and K4IM as well as higher IL-6 and CD55 gene expression in HSE and suppressed C3aR1 gene expression in hEC. HSE proliferated twice as fast as K4IM, but showed significantly lesser gene expressions of CD46, CD55, CD59 and TNFα with significantly higher IL-6 gene expression. CD35 gene expression was undetectable in K4IM, HSE and hEC. Conclusions: NP might contribute in combination with other inflammatory factors to complement regulation in arthritis.

Impact of cross-coronavirus immunity in post-acute sequelae of COVID-19

Beyond the unpredictable acute illness caused by SARS-CoV-2, one-fifth of infections unpredictably result in long-term persistence of symptoms despite the apparent clearance of infection. Insights into the mechanisms that underlie post-acute sequelae of COVID-19 (PASC) will be critical for the prevention and clinical management of long-term complications of COVID-19. Several hypotheses have been proposed that may account for the development of PASC, including persistence of virus or the dysregulation of immunity. Among the immunological changes noted in PASC, alterations in humoral immunity have been observed in some patient subsets. To begin to determine whether SARS-CoV-2 or other pathogen specific humoral immune responses evolve uniquely in PASC, we performed comprehensive antibody profiling against SARS-CoV-2 and a panel of endemic pathogens or routine vaccine antigens using Systems Serology in a cohort of patients with pre-existing rheumatic disease who either developed or did not develop PASC. A distinct humoral immune response was observed in individuals with PASC. Specifically, individuals with PASC harbored less inflamed and weaker Fcγ receptor binding anti-SARS-CoV-2 antibodies and a significantly expanded and more inflamed antibody response against endemic Coronavirus OC43. Individuals with PASC, further, generated more avid IgM responses and developed an expanded inflammatory OC43 S2-specific Fc-receptor binding response, linked to cross reactivity across SARS-CoV-2 and common coronaviruses. These findings implicate previous common Coronavirus imprinting as a marker for the development of PASC.

Diplopia, COVID-19 and Vaccination: Results from a Cross-Sectional Study in Croatia

The aim of this study was to explore diplopia as a symptom of undetected COVID-19 infection or as a possible side effect of COVID-19 vaccination. We examined 380 patients with diplopia admitted to the Department of Ophthalmology of the University Hospital Centre Sestre milosrdnice in Zagreb, Croatia, from July 2020 to June 2022. After excluding patients with confirmed organic underlying diplopia causes or monocular diplopia, we linked the patient information with the national COVID-19 and vaccination registries. Among the 91 patients included in this study, previously undetected COVID-19 infection as the possible cause of diplopia was confirmed in five of them (5.5%). An additional nine patients (9.9%) were vaccinated within one month from the onset of their symptoms, while the remaining 77 had neither and were therefore considered as controls. The breakdown according to the mechanism of diplopia showed no substantial difference between the vaccinated patients and the controls. We detected marginally insignificant excess abducens nerve affection in the COVID-positive group compared with that in the controls (p = 0.051). Post-vaccination diplopia was equally common in patients who received vector-based or RNA-based vaccines (21.4 vs. 16.7%; p = 0.694). COVID-19 testing should be performed for all cases of otherwise unexplained diplopia. The risk of post-vaccination diplopia was similar in both types of vaccines administered, suggesting a lack of evidence linking specific vaccine types to diplopia.

Coronavirus Infection 2019 (COVID-19) and Autoimmunity

The pandemic of coronavirus disease 2019, etiologically associated with the SARS-CoV-2 virus, has drawn the attention of the medical community to new clinical and fundamental problems in the immunopathology of human diseases. During a detailed analysis of the clinical manifestations and immunopathological disorders in COVID-19, it became apparent that SARS-CoV-2 infection is accompanied by the development of a wide range of extrapulmonary clinical and laboratory disorders, some of which are characteristic of immunoinflammatory rheumatic diseases and other human autoimmune and autoinflammatory diseases. All this taken together served as a theoretical justification for the repositioning of anti-inflammatory drugs in COVID-19, previously specifically designed for the treatment of immunoinflammatory rheumatic diseases. The prospects for studying the autoimmune mechanisms of COVID-19 and the possibility of anti-inflammatory therapy are discussed.

COVID-19 and inflammatory bowel disease crosstalk: From emerging association to clinical proposal

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can cause coronavirus disease 2019 (COVID-19), an acute respiratory inflammation that has emerged worldwide since December 2019, and it quickly became a global epidemic. Inflammatory bowel disease (IBD) is a group of chronic nonspecific intestinal inflammatory diseases whose etiology has not been elucidated. The two have many overlapping symptoms in clinical presentation, such as abdominal pain, diarrhea, pneumonia, etc. Imbalance of the autoimmune system in IBD patients and long-term use of immunosuppressive drugs may increase the risk of infection; and systemic symptoms caused by COVID-19 may also induce or exacerbate intestinal inflammation. It has been found that the SARS-CoV-2 receptor angiotensin converting enzyme 2, which is highly expressed in the lung and intestine, is an inflammatory protective factor, and is downregulated and upregulated in COVID-19 and IBD, respectively, suggesting that there may be a coregulatory pathway. In addition, the immune activation pattern of COVID-19 and the cytokine storm in the inflammatory response have similar roles in IBD, indicating that the two diseases may influence each other. Therefore, this review aimed to address the following research questions: whether SARS-CoV-2 infection leads to the progression of IBD; whether IBD increases the risk of COVID-19 infection and poor prognosis; possible common mechanisms and genetic cross-linking between the two diseases; new treatment and care strategies for IBD patients, and the feasibility and risk of vaccination in the context of the COVID-19 epidemic.

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

SARS-CoV-2 infection can produce a variety of clinical manifestations, which are either directly related to viral tissue damage or indirectly induced by the antiviral immune response. Molecular mimicry enables this virus to undermine self-tolerance in a host's immune system also immune system's attempts to eliminate SARS-COV-2 may trigger autoimmunity by hyper-activating the innate and adaptive immune systems. Auto immune diseases include Systemic lupus erythematosus, autoimmune thyroid diseases, Guillain‐Barre syndrome, Immune thrombocytopenic purpura, and the detection of autoantibodies are the cues to the discovery of the potential of COVID‐19 in inducing autoimmunity. As COVID-19 and autoimmune diseases share a common pathogenesis, autoimmune drugs may be an effective treatment option. Susceptible patients must be monitored for autoimmune symptoms after contracting CVID-19. In light of the SARS-COV-2 virus' ability to induce autoimmunity in susceptible patients, will the various COVID-19 vaccines that are the only way to end the pandemic induce autoimmunity?

COVID-19 disease and autoimmune disorders: A mutual pathway

Coronavirus disease 2019 (COVID-19) is a real challenge for humanity with high morbidity and mortality. Despite being primarily a respiratory illness, COVID-19 can affect nearly every human body tissue, causing many diseases. After viral infection, the immune system can recognize the viral antigens presented by the immune cells. This immune response is usually controlled and terminated once the infection is aborted. Nevertheless, in some patients, the immune reaction becomes out of control with the development of autoimmune diseases. Several human tissue antigens showed a strong response with antibodies directed against many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) proteins, such as SARS-CoV-2 S, N, and autoimmune target proteins. The immunogenic effects of SARS-CoV-2 are due to the sizeable viral RNA molecules with interrupted transcription increasing the pool of epitopes with increased chances of molecular mimicry and interaction with the host immune system, the overlap between some viral and human peptides, the viral induced-tissue damage, and the robust and complex binding between sACE-2 and SARS-CoV-2 S protein. Consequently, COVID-19 and its vaccine may trigger the development of many autoimmune diseases in a predisposed patient. This review discusses the mutual relation between COVID-19 and autoimmune diseases, their interactive effects on each other, the role of the COVID-19 vaccine in triggering autoimmune diseases, the factors affecting the severity of COVID-19 in patients suffering from autoimmune diseases, and the different ways to minimize the risk of COVID-19 in patients with autoimmune diseases.

A structural homology approach to identify potential cross-reactive antibody responses following SARS-CoV-2 infection

The emergence of the novel SARS-CoV-2 virus is the most important public-health issue of our time. Understanding the diverse clinical presentations of the ensuing disease, COVID-19, remains a critical unmet need. Here we present a comprehensive listing of the diverse clinical indications associated with COVID-19. We explore the theory that anti-SARS-CoV-2 antibodies could cross-react with endogenous human proteins driving some of the pathologies associated with COVID-19. We describe a novel computational approach to estimate structural homology between SARS-CoV-2 proteins and human proteins. Antibodies are more likely to interrogate 3D-structural epitopes than continuous linear epitopes. This computational workflow identified 346 human proteins containing a domain with high structural homology to a SARS-CoV-2 Wuhan strain protein. Of these, 102 proteins exhibit functions that could contribute to COVID-19 clinical pathologies. We present a testable hypothesis to delineate unexplained clinical observations vis-à-vis COVID-19 and a tool to evaluate the safety-risk profile of potential COVID-19 therapies.

SARS-CoV-2 the ASIA virus (autoimmune/autoinflammatory syndrome induced by adjuvants), the risk of infertility and vaccine hesitancy

INTRODUCTION

COVID-19 has had a calamitous impact on the global community. The current death toll far exceeds 6 million and large numbers of patients are experiencing long-term medical and psychiatric morbidity from the infection. The immunopathology of severe COVID-19 is now better understood. In severely affected patients, there is a chaotic, destructive immune response triggered by SARS-CoV-2, where autoimmunity features prominently.

AREAS COVERED

COVID-19 vaccines ensure a coordinated, balanced immune response to future SARS-CoV-2 infection. The rapid global deployment of effective COVID-19 vaccines has been hindered by financial, logistical and political barriers. Of concern is increasing vaccine hesitancy caused by unfounded conspiracy theories of vaccine adverse effects, often fueled by misinformation and disinformation on social media.

EXPERT OPINION

This perspective discusses the potential impact of the so-called autoimmune/autoinflammatory syndrome caused by adjuvants (ASIA) on COVID-19 vaccine uptake. Proponents of the ASIA syndrome have inappropriately linked infertility to HPV vaccines and have recently suggested antigenic cross-reactivity between SARS-CoV-2 and ovarian follicles. COVID-19 vaccines have also been linked to ASIA and unfounded fear of infertility is a leading cause of vaccine hesitancy. Vaccine hesitancy caused by spurious disorders such as ASIA are likely to harm individuals and delay global vaccination efforts leading to emergence of vaccine and monoclonal antibody resistant mutants, thereby prolonging the COVID-19 pandemic.

Mono/polyclonal free light chains as challenging biomarkers for immunological abnormalities

Free light chain (FLC) kappa (k) and lambda (λ) consist of low molecular weight proteins produced in excess during immunoglobulin synthesis and secreted into the circulation. In patients with normal renal function, over 99% of FLCs are filtered and reabsorbed. Thus, the presence of FLCs in the serum is directly related to plasma cell activity and the balance between production and renal clearance. FLCs are bioactive molecules that may exist as monoclonal (m) and polyclonal (p) FLCs. These have been detected in several body fluids and may be key indicators of ongoing damage and/or illness. International guidelines now recommend mFLC for screening, diagnosis and monitoring multiple myeloma and other plasma cell dyscrasias. In current clinical practice, FLCs in urine indicate cast nephropathy and other renal injury, whereas their presence in cerebrospinal fluid is important for identifying central nervous system inflammatory diseases such as multiple sclerosis. Increased pFLCs have also been detected in various conditions characterized by B cell activation, i.e., chronic inflammation, autoimmune disease and HCV infection. Monitoring the coronavirus (COVID-19) pandemic by analysis of salivary FLCs presents a significant opportunity in clinical immunology worthy of scientific pursuit.

The Role of Exposomes in the Pathophysiology of Autoimmune Diseases II: Pathogens

In our continuing examination of the role of exposomes in autoimmune disease, we use this review to focus on pathogens. Infections are major contributors to the pathophysiology of autoimmune diseases through various mechanisms, foremost being molecular mimicry, when the structural similarity between the pathogen and a human tissue antigen leads to autoimmune reactivity and even autoimmune disease. The three best examples of this are oral pathogens, SARS-CoV-2, and the herpesviruses. Oral pathogens reach the gut, disturb the microbiota, increase gut permeability, cause local inflammation, and generate autoantigens, leading to systemic inflammation, multiple autoimmune reactivities, and systemic autoimmunity. The COVID-19 pandemic put the spotlight on SARS-CoV-2, which has been called “the autoimmune virus.” We explore in detail the evidence supporting this. We also describe how viruses, in particular herpesviruses, have a role in the induction of many different autoimmune diseases, detailing the various mechanisms involved. Lastly, we discuss the microbiome and the beneficial microbiota that populate it. We look at the role of the gut microbiome in autoimmune disorders, because of its role in regulating the immune system. Dysbiosis of the microbiota in the gut microbiome can lead to multiple autoimmune disorders. We conclude that understanding the precise roles and relationships shared by all these factors that comprise the exposome and identifying early events and root causes of these disorders can help us to develop more targeted therapeutic protocols for the management of this worldwide epidemic of autoimmunity.

Post-Corona-Fatigue – das bekannte Bild in neuem Gewand?

Hintergrund

Die myalgische Enzephalitis oder das „chronic fatigue syndrome“ (ME/CFS) ist als Folge von COVID(Corona Virus Disease)-19 erneut in den Fokus gerückt. Grundsätzlich problematisch ist die Tatsache, dass ME/CFS als eigenständige Entität gilt, aber extreme Fatigue auch ein häufiges Symptom einer zugrunde liegenden Erkrankung ist. Ziel des Beitrags ist es, die Akzeptanz für ME/CFS und extreme Fatigue bei nicht vollumfänglich verstandener Symptomatologie zu erhöhen und den Bedarf an Forschung, Orientierung für niedergelassene Ärzte sowie an Beratungsangeboten für Patienten hervorzuheben

Material und Methoden

Orientierende Recherchen in Form einer fokussierten Informationsbeschaffung.

Ergebnisse

In verschiedenen Forschungsprojekten konnte die Hypothese von postinfektiöser ME/CFS als Autoimmunerkrankung bestätigt werden. Generell erschweren sowohl die Heterogenität der diagnostischen Kriterien als auch die Vielfalt von Formulierungen zur Beschreibung der Symptomatik sowie verschiedene Codierungsmöglichkeiten eine klare Zuordnung der Symptome zu einem Krankheitsbild. Belastungsintoleranz wurde als schwerwiegendes Symptom einer Post-COVID-19-Erkrankung identifiziert. Aus diesem Grund werden aktuell die Empfehlungen in internationalen Leitlinien insbesondere hinsichtlich von Pacing überarbeitet. Die Auswirkungen auf Empfehlungen bei tumorbedingter Fatigue oder bei MS sind unklar.

Schlussfolgerung

Vor dem Hintergrund eines abnehmenden „burden of disease“ durch steigende Impfraten sollte die Forschung zu Fatigue nicht nur viral bedingte Erkrankungen umfassen.

Autoantibodies targeting GPCRs and RAS-related molecules associate with COVID-19 severity

COVID-19 shares the feature of autoantibody production with systemic autoimmune diseases. In order to understand the role of these immune globulins in the pathogenesis of the disease, it is important to explore the autoantibody spectra. Here we show, by a cross-sectional study of 246 individuals, that autoantibodies targeting G protein-coupled receptors (GPCR) and RAS-related molecules associate with the clinical severity of COVID-19. Patients with moderate and severe disease are characterized by higher autoantibody levels than healthy controls and those with mild COVID-19 disease. Among the anti-GPCR autoantibodies, machine learning classification identifies the chemokine receptor CXCR3 and the RAS-related molecule AGTR1 as targets for antibodies with the strongest association to disease severity. Besides antibody levels, autoantibody network signatures are also changing in patients with intermediate or high disease severity. Although our current and previous studies identify anti-GPCR antibodies as natural components of human biology, their production is deregulated in COVID-19 and their level and pattern alterations might predict COVID-19 disease severity.

Coronaviruses and their relationship with multiple sclerosis: is the prevalence of multiple sclerosis going to increase after the Covid-19 pandemia?

The purpose of this review is to examine whether there is a possible (etiological/triggering) relationship between infection with various Coronaviruses, including Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), the virus responsible for the Coronavirus disease-19 (Covid-19) pandemia, and Multiple Sclerosis (MS), and whether an increase of the prevalence of MS after the current Covid-19 pandemia should be expected, examining new and preexisting data. Although the exact pathogenesis of MS remains unknown, environmental agents seem to greatly influence the onset of the disease, with viruses being the most popular candidate. Existing data support this possible etiological relationship between viruses and MS, and experimental studies show that Coronaviruses can actually induce an MS-like demyelinating disease in animal models. Findings in MS patients could also be compatible with this coronaviral MS hypothesis. More importantly, current data from the Covid-19 pandemia show that SARS-CoV-2 can trigger autoimmunity and possibly induce autoimmune diseases, in the Central Nervous System as well, strengthening the viral hypothesis of MS. If we accept that Coronaviruses can induce MS, it is reasonable to expect an increase in the prevalence of MS after the Covid-19 pandemia. This knowledge is of great importance in order to protect the aging groups that are more vulnerable against autoimmune diseases and MS specifically, and to establish proper vaccination and health policies.

Autoantibodies and SARS-CoV2 infection: The spectrum from association to clinical implication: Report of the 15th Dresden Symposium on Autoantibodies

The relation between infections and autoimmune diseases has been extensively investigated. Multiple studies suggest a causal relation between these two entities with molecular mimicry, hyperstimulation and dysregulation of the immune system as plausible mechanisms. The recent pandemic with a new virus, i.e., SARS-CoV-2, has resulted in numerous studies addressing the potential of this virus to induce autoimmunity and, eventually, autoimmune disease. In addition, it has also revealed that pre-existing auto-immunity (auto-Abs neutralizing type I IFNs) could cause life-threatening disease. Therefore, the topic of the 15th Dresden Symposium on Autoantibodies was focused on autoimmunity in the SARS-CoV-2 era. This report is a collection and distillation of the topics presented at this meeting.