Molecular Mimicry and HLA Polymorphisms May Drive Autoimmunity in Recipients of the BNT-162b2 mRNA Vaccine: A Computational Analysis

The effects of SARS-CoV-2 vaccines on antinuclear autoantibody formation in individuals without prior COVID-19 infection

BACKGROUND

Viral particles in SARS-CoV-2 vaccines have molecular motifs resembling self-antigens, potentially triggering autoantibody production. This study aimed to investigate the effects of mRNA vaccines (BioNTech), which contain a single viral particle, and inactivated whole viral particles (Sinovac) on antinuclear autoantibody (ANA) formation in individuals without prior COVID-19 infection.

MATERIAL AND METHODS

The study was retrospective and included individuals who had not contracted SARS-CoV-2 (tested negative for antigen or antibody). The effects of the inactivated vaccine were assessed in individuals with samples before and after both doses (n = 36); the mRNA vaccine was evaluated in individuals unvaccinated and after two doses (n = 17); and the effects of both vaccines were assessed in individuals who received only the inactivated vaccine (n = 15), only the mRNA vaccine (n = 15), or both (n = 15). ANAs were determined using validated anti-dsDNA, anti-ENA, and anti-Hep-2 nucleus tests.

RESULTS

The inactivated vaccines cumulatively increased (p < 0.05) positivity for anti-dsDNA (from 13.9 to 36.1%) and anti-Hep-2 nuclear antibody (from 13.9 to 38.9%) but not anti-ENA antibodies (from 11.1 to 22.2%). The mRNA vaccine did not affect ANA formation compared to unvaccinated stages (p > 0.05). On the other hand, combination of both vaccine types increased the rate of positivity for the anti-dsDNA antibody (from 20.0 to 53.3%, p < 0.05).

CONCLUSIONS

Small, yet valuable, sample size suggest that whole molecule vaccines may increase likelihood of ANA formation, probably due to exposure to increased number of assorted viral epitopes. Moreover, combination of both vaccines appears to increase anti-dsDNA antibodies and this deserves further investigation.

Post-COVID-19 Small Fiber Neuropathy as a New Emerging Quality of Life-Threatening Disease: A Systematic Review

Post-acute sequelae of COVID-19 (PASC) syndrome is considered an emergent and diffuse multidisciplinary problem. Compelling evidence suggests that COVID-19 increases symptoms of pre-existent small fiber neuropathy (SFN) and might trigger de novo onset of SFN. In this systematic review, for the first time, we provide a comprehensive overview of the clinical and diagnostic features of PASC-SFN, including the accompanying disorders, disease evolution, and possible treatments, described in the recent literature. Following infection, many patients reported a wide range of symptoms and complications, not self-limiting and independent from previous infection severity. SFN begins more frequently with distal limb burning pain and numbness, which accompany other dysautonomia, cognitive, visual, and osteoarticular disorders involving multiple organ systems. In an initial diagnostic suspicion, some tests might be useful as complementary examinations, such as nerve quantitative sensory testing, electromyography, and optic nerve tomography. Otherwise, definite diagnosis is reached with skin biopsy as the gold standard, along with corneal in vivo microscopy when ocular discomfort is present. Being a long-term condition, multiple and dissimilar symptomatic and disease-modifying drugs were employed for the treatment of this condition with the achievement of partial results, including steroids, pregabalin, gabapentin, duloxetine, vitamins, homotaurine and phosphatidylserine, alpha lipoic acid, immunosuppressants, and intravenous immunoglobulin therapy. PASC-SFN is a complex emerging disease and extremely challenging for physicians. At present, the only feasible management of PASC-SFN is represented by a multidisciplinary tailored approach, with future definitive protocols for diagnosis and treatment deemed essential.

Autoantibodies Targeting G-Protein-Coupled Receptors and RAS-Related Molecules in Post-Acute COVID Vaccination Syndrome: A Retrospective Case Series Study

Background/Objectives: While post-acute COVID-19 syndrome is well known and extensively studied, the post-acute COVID vaccination syndrome (PACVS) is a more recent nosological entity that is poorly defined at the immunopathological level, although it shares many symptoms with the sequelae of viral infections. Methods: This single-center retrospective study reports a case series of 17 subjects vaccinated with mRNA or adenoviral vector vaccines who were healthy before vaccination and had never been infected with SARS-CoV-2 but who presented with symptoms similar to PACVS for a median time of 20 months (min 4, max 32). The medical records of all patients referred to our outpatient clinic over a one-year period were retrospectively analyzed. Results: In this group, serological tests showed that, in addition to positivity for anti-spike protein antibodies, a high percentage of subjects were positive for antibodies against G protein-coupled receptors and molecules involved in the response to SARS-CoV-2. In a panel of 16 autoantibodies tested, a few were positively associated with some of the symptoms reported by patients: anti-ATR1 with lymphadenopathy and/or tonsillitis; anti-ACE2 with skin symptoms such as ecchymosis, skin oedema, and rash; anti-MAS1 with widespread burning sensation; and anti-STAB1 with skin oedema and rash. Anti-ADRA2A were negatively associated with memory loss and/or mental fog. ACE2 correlated with the serum levels of anti-S antibodies, supporting the hypothesis of an anti-idiotype mechanism in the immunopathogenesis of PACVS. Conclusions: This exploratory analysis suggests that the levels of autoantibodies directed against ACE2, and probably also MAS1 and STAB1, may serve as biomarkers for PACVS.

Evidence for Molecular Mimicry between SARS-CoV-2 and Human Antigens: Implications for Autoimmunity in COVID-19

As for other viral diseases, the mechanisms behind the apparent relationship between COVID-19 and autoimmunity are yet to be clearly defined. Molecular mimicry, the existence of sequence and/or conformational homology between viral and human antigens, could be an important contributing factor. Here, we review the accumulated evidence supporting the occurrence of mimicry between SARS-CoV-2 and human proteins. Both bioinformatic approaches and antibody cross-reactions have yielded a significant magnitude of mimicry events, far more common than expected to happen by chance. The clinical implication of this phenomenon is ample since many of the identified antigens may participate in COVID-19 pathophysiology or are targets of autoimmune diseases. Thus, autoimmunity related to COVID-19 may be partially explained by molecular mimicry and further research designed specifically to address this possibility is needed.

A Comprehensive Review on the Intricate Interplay between COVID-19 Immunization and the New Onset of Pemphigus Foliaceus

Autoimmune bullous diseases (AIBDs) are characterized by the formation of vesicles, bullous lesions, and mucosal erosions. The autoantibodies target the cellular anchoring structures from the surface of epidermal keratinocyte named desmosomes, leading to a loss of cellular cohesion named acantholysis. AIBDs are classified into intraepidermal or subepidermal types based on clinical features, histological characteristics, and immunofluorescence patterns. Pemphigus foliaceus (PF) is an acquired, rare, autoimmune skin condition associated with autoantibodies that specifically target desmoglein-1, leading to a clinical presentation characterized by delicate cutaneous blisters, typically sparing the mucous membranes. Several factors, including genetic predisposition, environmental triggers, malignancies, medication use, and vaccination (for influenza, hepatitis B, rabies, tetanus, and more recently, severe acute respiratory syndrome Coronavirus 2 known as SARS-CoV-2), can potentially trigger the onset of pemphigus. With the advent of vaccines playing a pivotal role in combatting the 2019 coronavirus disease (COVID-19), extensive research has been conducted globally to ascertain their efficacy and potential cutaneous adverse effects. While reports of AIBDs post-COVID-19 vaccination exist in the medical literature, instances of PF following vaccination have been less commonly reported worldwide. The disease's pathophysiology is likely attributed to the resemblance between the ribonucleic acid (RNA) antigen present in these vaccines and cellular nuclear matter. The protein produced by the BNT-162b2 messenger ribonucleic acid (mRNA) vaccine includes immunogenic epitopes that could potentially trigger autoimmune phenomena in predisposed individuals through several mechanisms, including molecular mimicry, the activation of pattern recognition receptors, the polyclonal stimulation of B cells, type I interferon production, and autoinflammation. In this review, we present a comprehensive examination of the existing literature regarding the relationship between COVID-19 and PF, delving into their intricate interactions. This exploration improves the understanding of both pemphigus and mRNA vaccine mechanisms, highlighting the importance of close monitoring for PF post-immunization.

Small Fiber Neuropathy Associated with Post-COVID-19 and Post-COVID-19 Vaccination Arthritis: A Rare Post-Infective Syndrome or a New-Onset Disease?

Post-COVID-19 (PC) and post-COVID-19 vaccination (PCV) syndromes are considered emergent multidisciplinary disorders. PC/PCV small fiber neuropathy (SFN) was rarely described and its association with undifferentiated arthritis (UA) was never defined. We aimed to evaluate PC/PCV-UA associated with the recent onset of severe lower limb paresthesia, compare SFN positive (+) to negative (-) patients, and evaluate changes in biomarkers in SFN+ during treatments. Nineteen PC/PCV-UA-patients with possible SFN underwent skin biopsy at the Usl Tuscany Center (Florence) early arthritis outpatient clinic from September 2021 to March 2024. Eight selected SFN+ were compared to ten SFN- patients. In SFN+ patients, baseline joint ultrasound (US), electromyography (EMG), optical coherence tomography (OCT), and skin biopsy were repeated at six months. Moreover, SFN+ patients were clinically assessed by a 0-10 numeric rating scale for neurological symptoms and DAS28/ESR up to 12 months follow-up. SFN+ patients showed a lower intraepidermal nerve fiber density at histopathological examination of skin biopsies and a higher frequency of OCT and EMG abnormalities in comparison to SFN- patients. In SFN+ patients, US and DAS28/ESR significantly improved, while intraepidermal nerve fiber density did not significantly change at the six-month follow-up. Fatigue, motor impairment, burning pain, brain fog, and sensitivity disorders decreased at long-term follow-up (12 months).

New-onset Immune-mediated Necrotizing Myopathy and Trigeminal Neuropathy after SARS-CoV-2 mRNA Vaccination in a Patient with Rheumatoid Arthritis and Sjögren's Syndrome

We present the case of a 42-year-old woman with rheumatoid arthritis and Sjögren's syndrome treated with adalimumab who developed immune-mediated necrotizing myopathy (IMNM) and trigeminal neuropathy after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccination. Trigeminal neuralgia and elevated serum creatine kinase levels emerged 12 days post-vaccination, followed by myalgia in the femoral muscles. IMNM was histologically diagnosed. The pathogenesis may involve molecular mimicry between the SARS-CoV-2 spike glycoprotein and autologous tissues triggered by vaccination. This case emphasizes the association between SARS-CoV-2 vaccination, tumor necrosis factor inhibitor, IMNM, and trigeminal neuropathy, as well as the importance of monitoring immune-mediated adverse events following SARS-CoV-2 vaccination in patients with autoimmune disease.

Post-COVID-19 and Post-COVID-19 Vaccine Arthritis, Polymyalgia Rheumatica and Horton's Arteritis: A Single-Center Assessment of Clinical, Serological, Genetic, and Ultrasonographic Biomarkers

The potential role of the COVID-19 vaccine and infection to induce autoimmunity is currently underestimated despite the literature emphasizing arthralgia as a common adverse event. We aimed to study the impact of rheumatological complications post-COVID-19 (PC) and post-COVID-19 vaccine (PCV), comparing undifferentiated arthritis (UA) to Polymyalgia Rheumatica, Horton's Arteritis (PMR-HA) and isolated arthritis to UA with "connective-like" accompanying symptoms. We retrospectively included 109 patients with at least 6 months of follow-up, analyzing serum biomarkers, joint ultrasound (US), lung HRCT, DLCO, and HLA haplotypes. There were 87 UA patients showing increased gastrointestinal and lung involvement (p = 0.021 and p = 0.012), higher anti-spike protein IgG levels (p = 0.003), and anti-SARS-CoV-2 IgG positivity (p = 0.003). Among them, 66 cases progressed to ACR-EULAR 2010 early arthritis after 3 months, whereas PMR-HA patients were more commonly PCV (81.8%, p = 0.008), demonstrating higher CRP (p = 0.007) and ESR (p = 0.006) levels, a lower rate of ANA positivity (p = 0.005), and a higher remission rate after six months (p = 0.050). In UA patients, the prevalent HLA was DRB1*11 and C*07 (36.8% and 42.1%). Serum calprotectin, interleukin-6, and C*07 (p = 0.021, 0.041, 0.018) seemed more specific for isolated UA. Conversely, "connective-like" arthritis showed poorer DLCO (p = 0.041) and more frequent US synovitis (p = 0.041). In conclusion, UA is a frequent common PC and PCV complication and may persist over time when compared to PMR-HA.

Vogt-Koyanagi-Harada Disease and COVID

Vogt-Koyanagi-Harada (VKH) is a rare multisystem inflammatory disease affecting the eyes, ears, brain, skin, and hair. The Coronavirus Disease 2019 (COVID-19) is a new contagious infection that might trigger the onset of VKH disease, as previously proposed for other viruses. Moreover, after the mass vaccination against SARS-CoV-2 worldwide, cases of VKH disease associated with COVID-19 vaccination have been reported. We present an overview of VKH and a comprehensive literature revision of all the VKH cases described after COVID-19 infection and vaccination, adding our experience. No differences have been found considering epidemiology and clinical findings of the disease compared to those reported in the no-COVID era. All of the patients promptly responded to systemic and local corticosteroid therapy with a good final visual prognosis. Different possible pathogenetic mechanisms underlying the onset of VKH after COVID-19 vaccination are discussed, while the presence of the HLA DR4 antigen as a genetic predisposition for the onset of the disease after COVID-19 infection and vaccination is proposed. VKH disease is one of the most frequently reported uveitic entities after COVID-19 vaccination, but a good response to therapy should not discourage vaccination. Nevertheless, ophthalmologists should be alerted to the possibility of VKH occurrence or relapse after COVID-19 vaccination, especially in genetically predisposed subjects.