Dynamics of SARS-CoV-2 IgG antibodies and neutralising antibodies in rheumatic and musculoskeletal diseases patients with COVID-19.

OBJECTIVES: Rheumatic and musculoskeletal diseases (RMD) may exhibit different immune responses to novel coronavirus (COVID-19) infection compared to healthy individuals. While previous studies have primarily investigated changes in COVID-19-related antibodies post-vaccination for RMD patients, this study sought to explore the dynamics of SARS-CoV-2 IgG antibodies and neutralising antibodies (NAb) in RMD patients after COVID-19 infection. METHODS: In this longitudinal study, we monitored the SARS-CoV-2 IgG antibodies and NAb levels in RMD patients and healthy controls (HC) at 60 and 90 days post-COVID-19 infection. Chemiluminescent immunoassay was used to detect the levels of novel coronavirus-specific IgG (anti-S1/S2 IgG) antibodies and NAb. RESULTS: A total of 292 RMD patients and 104 HC were enrolled in the study. At both the 60-day and 90-day post-COVID-19 infection, RMD patients exhibited significantly lower levels of anti-S1/S2 IgG and NAb than those in the HC group (p<0.001). The anti-S1/S2 IgG antibody levels remained relatively stable, while the NAb levels in RMD patients could vary greatly between the 60th and 90th days. A logistic regression analysis revealed that the prior administration of glucocorticoids (GC), immunosuppressants, and b/tsDMARDs stood out as independent risk factors associated with reduced anti-S1/S2 IgG and NAb levels, irrespective of the specific RMD subtypes. CONCLUSIONS: GC and anti-rheumatic medications can potentially alter the production of specific antibodies, especially NAb, in RMD patients post-COVID-19 infection. These findings emphasise the importance of continuous monitoring for NAb fluctuations in RMD patients following a COVID-19 infection.

Therapeutic Potential of Human Fetal Mesenchymal Stem Cells in Musculoskeletal Disorders: A Narrative Review.

Mesenchymal stem cells (MSCs) have emerged as a promising therapeutic approach for diverse diseases and injuries. The biological and clinical advantages of human fetal MSCs (hfMSCs) have recently been reported. In terms of promising therapeutic approaches for diverse diseases and injuries, hfMSCs have gained prominence as healing tools for clinical therapies. Therefore, this review assesses not the only biological advantages of hfMSCs for healing human diseases and regeneration, but also the research evidence for the engraftment and immunomodulation of hfMSCs based on their sources and biological components. Of particular clinical relevance, the present review also suggests the potential therapeutic feasibilities of hfMSCs for musculoskeletal disorders, including osteoporosis, osteoarthritis, and osteogenesis imperfecta.

Disease Flare and Reactogenicity in Patients With Rheumatic and Musculoskeletal Diseases Following Two-Dose SARS-CoV-2 Messenger RNA Vaccination.

OBJECTIVE: To evaluate disease flare and postvaccination reactions (reactogenicity) in patients with rheumatic and musculoskeletal diseases (RMDs) following 2-dose SARS-CoV-2 messenger RNA (mRNA) vaccination. METHODS: RMD patients (n = 1,377) who received 2-dose SARS-CoV-2 mRNA vaccination between December 16, 2020 and April 15, 2021 completed questionnaires detailing local and systemic reactions experienced within 7 days of each vaccine dose (dose 1 and dose 2), and 1 month after dose 2, detailing any flares of RMD. Associations between demographic/clinical characteristics and flares requiring treatment were evaluated using modified Poisson regression. RESULTS: Among the patients, 11% reported flares requiring treatment; there were no reports of severe flares. Flares were associated with prior SARS-CoV-2 infection (incidence rate ratio [IRR] 2.09, P = 0.02), flares in the 6 months preceding vaccination (IRR 2.36, P < 0.001), and the use of combination immunomodulatory therapy (IRR 1.95, P < 0.001). The most frequently reported local and systemic reactions included injection site pain (87% after dose 1, 86% after dose 2) and fatigue (60% after dose 1, 80% after dose 2). Reactogenicity increased after dose 2, particularly for systemic reactions. No allergic reactions or SARS-CoV-2 diagnoses were reported. CONCLUSION: Flares of underlying RMD following SARS-CoV-2 vaccination were uncommon. There were no reports of severe flares. Local and systemic reactions typically did not interfere with daily activity. These early safety data can help address vaccine hesitancy in RMD patients.

The Role of Mesenchymal Stem Cells (MSCs) in Veterinary Medicine and Their Use in Musculoskeletal Disorders.

Regenerative medicine is a dynamically developing field of human and veterinary medicine. The animal model was most commonly used for mesenchymal stem cells (MSCs) treatment in experimental and preclinical studies with a satisfactory therapeutic effect. Year by year, the need for alternative treatments in veterinary medicine is increasing, and other applications for promising MSCs and their biological derivatives are constantly being sought. There is also an increase in demand for other methods of treating disease states, of which the classical treatment methods did not bring the desired results. Cell therapy can be a realistic option for treating human and animal diseases in the near future and therefore additional research is needed to optimize cell origins, numbers, or application methods in order to standardize the treatment process and assess its effects. The aim of the following work was to summarize available knowledge about stem cells in veterinary medicine and their possible application in the treatment of chosen musculoskeletal disorders in dogs and horses.

Autoinflammation and autoimmunity across rheumatic and musculoskeletal diseases.

Most rheumatic and musculoskeletal diseases (RMDs) can be placed along a spectrum of disorders, with autoinflammatory diseases (including monogenic systemic autoinflammatory diseases) and autoimmune diseases (such as systemic lupus erythematosus and antiphospholipid syndrome) representing the two ends of this spectrum. However, although most autoinflammatory diseases are characterized by the activation of innate immunity and inflammasomes and classical autoimmunity typically involves adaptive immune responses, there is some overlap in the features of autoimmunity and autoinflammation in RMDs. Indeed, some 'mixed-pattern' diseases such as spondyloarthritis and some forms of rheumatoid arthritis can also be delineated. A better understanding of the pathogenic pathways of autoinflammation and autoimmunity in RMDs, as well as the preferential cytokine patterns observed in these diseases, could help us to design targeted treatment strategies.

American College of Rheumatology Guidance for COVID-19 Vaccination in Patients With Rheumatic and Musculoskeletal Diseases: Version 2.

OBJECTIVE: To provide guidance to rheumatology providers on the use of coronavirus disease 2019 (COVID-19) vaccines for patients with rheumatic and musculoskeletal diseases (RMDs). METHODS: A task force was assembled that included 9 rheumatologists/immunologists, 2 infectious disease specialists, and 2 public health physicians. After agreeing on scoping questions, an evidence report was created that summarized the published literature and publicly available data regarding COVID-19 vaccine efficacy and safety, as well as literature for other vaccines in RMD patients. Task force members rated their agreement with draft consensus statements on a 9-point numerical scoring system, using a modified Delphi process and the RAND/University of California Los Angeles Appropriateness Method, with refinement and iteration over 2 sessions. Consensus was determined based on the distribution of ratings. RESULTS: Despite a paucity of direct evidence, 74 draft guidance statements were developed by the task force and agreed upon with consensus to provide guidance for use of the COVID-19 vaccines in RMD patients and to offer recommendations regarding the use and timing of immunomodulatory therapies around the time of vaccination. CONCLUSION: These guidance statements, made in the context of limited clinical data, are intended to provide direction to rheumatology health care providers on how to best use COVID-19 vaccines and to facilitate implementation of vaccination strategies for RMD patients.

Adipokine role in physiopathology of inflammatory and degenerative musculoskeletal diseases.

We performed a systematic literature review to summarize the underlying pathogenic mechanisms by which adipokines influence rheumatological diseases and the resulting clinical manifestations. Increasing evidence display that numerous adipokines may significantly influence the development or clinical course of various rheumatological diseases. Despite the normal anti- or pro-inflammatory role of the cytokines, the serum level varies enormously in various rheumatological diseases. The expression of high levels of pro-inflammatory cytokines such as leptin or visfatin, respectively in systemic lupus erythematosus and in rheumatoid arthritis, represents a negative prognostic factor; other adipokines such as adiponectin, broadly known for their anti-inflammatory effects, showed a correlation with disease activity in rheumatoid arthritis. In the near future pro-inflammatory cytokines may represent a potential therapeutic target to restrain the severity of rheumatological diseases. Further studies on adipokines may provide important information on the pathogenesis of these diseases, which are not yet fully understood. The mechanisms by which adipokines induce, worsen, or suppress inflammatory and degenerative musculoskeletal pathologies and their clinical significance will be discussed in this review.

The mechanistic basis of protection by non-neutralizing anti-alphavirus antibodies.

Although neutralizing monoclonal antibodies (mAbs) against epitopes within the alphavirus E2 protein can protect against infection, the functional significance of non-neutralizing mAbs is poorly understood. Here, we evaluate the activity of 13 non-neutralizing mAbs against Mayaro virus (MAYV), an emerging arthritogenic alphavirus. These mAbs bind to the MAYV virion and surface of infected cells but fail to neutralize infection in cell culture. Mapping studies identify six mAb binding groups that localize to discrete epitopes within or adjacent to the A domain of the E2 glycoprotein. Remarkably, passive transfer of non-neutralizing mAbs protects against MAYV infection and disease in mice, and their efficacy requires Fc effector functions. Monocytes mediate the protection of non-neutralizing mAbs in vivo, as Fcγ-receptor-expressing myeloid cells facilitate the binding, uptake, and clearance of MAYV without antibody-dependent enhancement of infection. Humoral protection against alphaviruses likely reflects contributions from non-neutralizing antibodies through Fc-dependent mechanisms that accelerate viral clearance.

Bitter Taste Receptor as a Therapeutic Target in Orthopaedic Disorders.

Non-gustatory, extraoral bitter taste receptors (T2Rs) are G-protein coupled receptors that are expressed throughout the body and have various functional responses when stimulated by bitter agonists. Presently, T2Rs have been found to be expressed in osteoclasts and osteocytes where osteoclasts were capable of detecting bacterial quorum-sensing molecules through the T2R38 isoform. In the innate immune system, stimulating T2Rs induces anti-inflammatory and anti-pathogenic effects through the phospholipase C/inositol triphosphate pathway, which leads to intracellular calcium release from the endoplasmic reticulum. The immune cells with functional responses to T2R activation also play a role in bone inflammation and orthopaedic disorders. Furthermore, increasing intracellular calcium levels in bone cells through T2R activation can potentially influence bone formation and resorption. With recent studies finding T2R expression in bone cells, we examine the potential of targeting this receptor to treat bone inflammation and to promote bone anabolism.

A cross-reactive antibody protects against Ross River virus musculoskeletal disease despite rapid neutralization escape in mice.

Arthritogenic alphaviruses cause debilitating musculoskeletal disease and historically have circulated in distinct regions. With the global spread of chikungunya virus (CHIKV), there now is more geographic overlap, which could result in heterologous immunity affecting natural infection or vaccination. Here, we evaluated the capacity of a cross-reactive anti-CHIKV monoclonal antibody (CHK-265) to protect against disease caused by the distantly related alphavirus, Ross River virus (RRV). Although CHK-265 only moderately neutralizes RRV infection in cell culture, it limited clinical disease in mice independently of Fc effector function activity. Despite this protective phenotype, RRV escaped from CHK-265 neutralization in vivo, with resistant variants retaining pathogenic potential. Near the inoculation site, CHK-265 reduced viral burden in a type I interferon signaling-dependent manner and limited immune cell infiltration into musculoskeletal tissue. In a parallel set of experiments, purified human CHIKV immune IgG also weakly neutralized RRV, yet when transferred to mice, resulted in improved clinical outcome during RRV infection despite the emergence of resistant viruses. Overall, this study suggests that weakly cross-neutralizing antibodies can protect against heterologous alphavirus disease, even if neutralization escape occurs, through an early viral control program that tempers inflammation.

Autoimmune and rheumatic musculoskeletal diseases as a consequence of SARS-CoV-2 infection and its treatment.

The coronavirus disease-2019 (COVID-19) pandemic is likely to pose new challenges to the rheumatology community in the near and distant future. Some of the challenges, like the severity of COVID-19 among patients on immunosuppressive agents, are predictable and are being evaluated with great care and effort across the globe. A few others, such as atypical manifestations of COVID-19 mimicking rheumatic musculoskeletal diseases (RMDs) are being reported. Like in many other viral infections, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can potentially lead to an array of rheumatological and autoimmune manifestations by molecular mimicry (cross-reacting epitope between the virus and the host), bystander killing (virus-specific CD8 + T cells migrating to the target tissues and exerting cytotoxicity), epitope spreading, viral persistence (polyclonal activation due to the constant presence of viral antigens driving immune-mediated injury) and formation of neutrophil extracellular traps. In addition, the myriad of antiviral drugs presently being tried in the treatment of COVID-19 can result in several rheumatic musculoskeletal adverse effects. In this review, we have addressed the possible spectrum and mechanisms of various autoimmune and rheumatic musculoskeletal manifestations that can be precipitated by COVID-19 infection, its therapy, and the preventive strategies to contain the infection.

Risk factors for immune-related adverse events associated with anti-PD-1 pembrolizumab.

We investigated risk factors for immune-related adverse events (irAEs) in patients treated with anti-programmed cell death protein1 antibody pembrolizumab. A retrospective medical record review was performed to identify all patients who received at least one dose of pembrolizumab at Samsung Medical Center, Seoul, Korea between June 2015 and December 2017. Three hundred and ninety-one patients were included in the study. Data were collected on baseline characteristics, treatment details, and adverse events. Univariate and multivariate logistic regression models were used to identify risk factors for irAEs. Sixty-seven (17.1%) patients experienced clinically significant irAEs; most commonly dermatologic disorders, followed by pneumonitis, musculoskeletal disorders, and endocrine disorders. Fourteen patients (3.6%) experienced serious irAEs (grade ≥ 3). Most common serious irAEs were pneumonitis (2.3%). Four deaths were associated with irAEs, all of which were due to pneumonitis. In multivariate regression analysis, a higher body mass index (BMI) and multiple cycles of pembrolizumab were associated with higher risk of irAEs (BMI: odds ratio [OR] 1.08, 95% confidence interval [CI] 1.01-1.16; pembrolizumab cycle: OR 1.15, 95% CI 1.08-1.22). A derived neutrophil-lymphocyte ratio (dNLR) greater than 3 at baseline was correlated with low risk of irAEs (OR 0.37, 95% CI 0.17-0.81). Our study demonstrated that an elevated BMI and higher number of cycles of pembrolizumab were associated with an increased risk of irAEs in patients treated with pembrolizumab. Additionally, increased dNLR at baseline was negatively correlated with the risk of developing irAEs.

Immune-related adverse events following administration of anti-cytotoxic T-lymphocyte-associated protein-4 drugs: a comprehensive systematic review and meta-analysis.

Objective: Administration of drugs targeting anti-cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) is often associated with serious immune-related adverse events (irAEs). Here, we performed a comprehensive analysis of organ-specific irAEs and treatment-related hematologic abnormalities and musculoskeletal disorders resulting from anti-CTLA-4 treatment. Materials and methods: PubMed, the Cochrane library, Web of Science, and ClinicalTrials.gov were searched for studies between January 1990 and March 2018 reporting AEs associated with anti-CTLA-4 therapies. Results: A total of 11 clinical trials with 7,088 patients were included; of these, data were accessible for 10 on ClinicalTrials.gov. Compared with control therapies (placebo, chemotherapy, radiation therapy, or vaccine), anti-CTLA-4 therapies (ipilimumab and tremelimumab) were associated with an increased risk of serious irAEs, predominantly dermatologic (rash: odds ratio [OR] 3.39, P<0.01), gastrointestinal (diarrhea and colitis: OR 6.57 and 14.01, respectively; both P<0.001), endocrine (hypophysitis, hypothyroidism, adrenal insufficiency, and hypopituitarism: OR 4.22, 3.72, 3.77, and 4.73, respectively; all P<0.05), and hepatic (hepatitis, elevated alanine aminotransferase, and elevated aspartate aminotransferase: OR 4.44, 3.28, and 3.12, respectively; all P<0.05). The most common serious organ-specific irAEs were gastrointestinal (diarrhea 9.8% and colitis 5.3%). Although the incidence of selected events was higher in anti-CTLA-4-treated patients, no significant differences were found between anti-CTLA-4 and the control therapies in treatment-related hematologic abnormalities or severe musculoskeletal disorders. Conclusion: Anti-CTLA-4 therapies are associated with an increased risk of serious organ-specific irAEs, most frequently involving the gastrointestinal system; however, no increased risk of hematologic abnormalities or severe musculoskeletal disorders was detected compared with other therapies. These results underscore the need for clinical awareness and prompt and effective management of multi-organ irAEs related to anti-CTLA-4 drugs.

The Impact of Vitamin D on the Immunopathophysiology, Disease Activity, and Extra-Musculoskeletal Manifestations of Systemic Lupus Erythematosus.

Over the past two decades it has been increasingly recognized that vitamin D, aside from its crucial involvement in calcium and phosphate homeostasis and the dynamics of the musculoskeletal system, exerts its influential impact on the immune system. The mechanistic roles that vitamin D plays regarding immune activation for combating infection, as well as pathologically and mediating autoimmune conditions, have been progressively unraveled. In vitro and in vivo models have demonstrated that the action of vitamin D on various immunocytes is not unidirectional. Rather, how vitamin D affects immunocyte functions depends on the context of the immune response, in the way that its suppressive or stimulatory action offers physiologically appropriate and immunologically advantageous outcomes. In this review, the relationship between various aspects of vitamin D, starting from its adequacy in circulation to its immunological functions, as well as its autoimmune conditions, in particular systemic lupus erythematosus (SLE), a prototype autoimmune condition characterized by immune-complex mediated inflammation, will be discussed. Concurring with other groups of investigators, our group found that vitamin D deficiency is highly prevalent in patients with SLE. Furthermore, the circulating vitamin D levels appear to be correlated with a higher disease activity of SLE as well as extra-musculoskeletal complications of SLE such as fatigue, cardiovascular risk, and cognitive impairment.

[Research consortium Neuroimmunology and pain in the research network musculoskeletal diseases]. / Forschungsverbund Neuroimmunologie und Schmerz (Neuroimpa) im Forschungsnetz Muskuloskelettale Erkrankungen.

BACKGROUND: The research consortium Neuroimmunology and Pain (Neuroimpa) explores the importance of the relationships between the immune system and the nervous system in musculoskeletal diseases for the generation of pain and for the course of fracture healing and arthritis. MATERIAL AND METHODS: The spectrum of methods includes analyses at the single cell level, in vivo models of arthritis and fracture healing, imaging studies on brain function in animals and humans and analysis of data from patients. RESULTS: Proinflammatory cytokines significantly contribute to the generation of joint pain through neuronal cytokine receptors. Immune cells release opioid peptides which activate opioid receptors at peripheral nociceptors and thereby evoke hypoalgesia. The formation of new bone after fractures is significantly supported by the nervous system. The sympathetic nervous system promotes the development of immune-mediated arthritis. The studies show a significant analgesic potential of the neutralization of proinflammatory cytokines and of opioids which selectively inhibit peripheral neurons. Furthermore, they show that the modulation of neuronal mechanisms can beneficially influence the course of musculoskeletal diseases. DISCUSSION: Interventions in the interactions between the immune system and the nervous system hold a great therapeutic potential for the treatment of musculoskeletal diseases and pain.

Rheumatic paraneoplastic syndromes - A clinical link between malignancy and autoimmunity.

Paraneoplastic syndromes are rare but can have enormous clinical impact on diagnosis and outcome of neoplastic diseases. The rheumatologist should be familiar with a few typical musculoskeletal manifestations of malignancies to be able to diagnose them early for a timely initiation of anti-tumour therapies. This review describes the characteristic features of various paraneoplastic arthritides and vasculitides, cancer-associated myositis, hypertrophic osteoarthropathy, and tumour-induced osteomalacia. In addition, the current knowledge about underlying pathomechanisms of these syndromes is discussed.

Dendrimers: Breaking the paradigm of current musculoskeletal autoimmune therapies.

The advances achieved by cell-based therapies to treat autoimmune diseases such as rheumatoid arthritis (RA) and multiple sclerosis (MS), despite promising, are still insufficient for the current demands. RA and MS therapeutic approaches follow world guidelines to use disease modifying drugs and biological agents that, regardless of some good results in clinical outcomes, are well known for several systemic secondary side effects. Dendrimers are custom-made nanoparticles with proved clinical potential, displaying proper size, chemistries, immunomodulatory, and anti-inflammatory properties. This has directed their potential use as drug delivery systems for cancer therapy, for instance. This review manuscript discloses the hidden potential behind dendrimers as alternative viable solutions to treat RA and MS, by focusing in the most recent reports describing the use of dendrimers for suppressing inflammation and possibly preventing disease progression. The advantages of their use as compared with current applied therapies is also discussed herein.

Early molecular correlates of adverse events following yellow fever vaccination.

The innate immune response shapes the development of adaptive immunity following infections and vaccination. However, it can also induce symptoms such as fever and myalgia, leading to the possibility that the molecular basis of immunogenicity and reactogenicity of vaccination are inseparably linked. To test this possibility, we used the yellow fever live-attenuated vaccine (YFLAV) as a model to study the molecular correlates of reactogenicity or adverse events (AEs). We analyzed the outcome of 68 adults who completed a YFLAV clinical trial, of which 43 (63.2%) reported systemic AEs. Through whole-genome profiling of blood collected before and after YFLAV dosing, we observed that activation of innate immune genes at day 1, but not day 3 after vaccination, was directly correlated with AEs. These findings contrast with the gene expression profile at day 3 that we and others have previously shown to be correlated with immunogenicity. We conclude that although the innate immune response is a double-edged sword, its expression that induces AEs is temporally distinct from that which engenders robust immunity. The use of genomic profiling thus provides molecular insights into the biology of AEs that potentially forms a basis for the development of safer vaccines.