Development Of Autoimmune Diseases Research Articles

Characteristics and predictors of Long Covid in children: a 3-year prospective cohort study

Children can develop Long Covid, however long term outcomes and their predictors are poorly described in these patients. The primary aim is to describe characteristics and predictors of Long Covid in children assessed in-clinics up to 36 months post-SARS-CoV-2 infection, as well as investigate the role of vaccines in preventing Long Covid, risk of reinfections and development of autoimmune diseases. Children aged 0-18 years old with confirmed SARS-CoV-2 infection were invited for a prospective follow-up assessment at a peadiatric post-covid clinic in Rome, Italy, at serial intervals (3-, 6-, 12-, 18-, 24- and 36-months post-infection onset, between 01/02/2020 and 28/02/2024). Long Covid was defined as persistence of otherwise unexplained symptoms for at least three months after initial infection. 1319 patients were initially included, 1296 reached the 3 months follow-up or more. Of the patients who underwent multiple follow-ups, 23.2% (301), 169 (13.2%), 89 (7.9%), 67 (6.1%), 47 (7.1%) were diagnosed with Long Covid at 3-6-12-18-24 months, respectively For the primary outcome of Long Covid at three months, age >12 years (P<0.001, OR 11.33, 95% CI 4.2; 15.15), comorbidities (P=0.008, OR 1.83, 95% CI 1.06; 2.44), being infected with original variants (P<0.001, OR 4.77, 95% CI 2.46; 14.47), female sex (P<0.001, OR 1.62, 95% CI 1.02; 1.89) were statistically significant risk factors. Age >12 years (P=0.002, OR 9.37, 95% CI 1.58; 8.64), and infection with original (P=0.012, OR 3.52, 95% CI 1.32; 8.64) and alfa (P<0.001, OR 4.09, 95% CI 2.01; 8.3) SARS-CoV-2 variants remained statistically significant risk factors for Long Covid duration for at least 18 months. Vaccination was associated with a lower risk of long covid at 3, 6 and 12 months for older children and a lower risk of reinfections. Being infected with the original SARS-CoV-2 variant was associated with a higher risk of new-onset autoimmune diseases ((P=0.035, 95% CI 1.12; 2.4). One patient was diagnosed with Long Covid after a re-infection. This is the longest follow-up study of children with SARS-CoV-2 infection, showing a significant and long-lasting burden of Long Covid in the pediatric population. Our findings highlight the urgent need of investing in pediatric Long Covid in order to find effective diagnostic and therapeutic approaches, as well can inform preventive strategies in case of future pandemics. This study has been funde by Pfizer non-competitive grant, granted to DB (#65925795).

Evaluation of Progression From Preclinical to Systemic Autoimmune Rheumatic Disease: Novel Use of the European Alliance of Associations for Rheumatology/American College of Rheumatology Systemic Lupus Erythematosus Classification Criteria as an Outcome Measure.

Our objective was to evaluate the development of a systemic autoimmune rheumatic disease (SARD) in undifferentiated and asymptomatic individuals with antinuclear antibodies (ANAs). We comparatively evaluated those who did and did not develop a SARD and fulfillment of classification criteria. We conducted a cohort study of undifferentiated and asymptomatic patients with ANAs who were assessed for the development of a SARD. The primary outcome was a diagnosis of a SARD over a two-year period. We assessed fulfillment of classification criteria. Risk ratios (RRs) were used to evaluate differences among those who did and did not progress to a SARD. We evaluated 207 asymptomatic ANA-positive or undifferentiated patients, of whom 23 (11%) progressed to a SARD, whereas 187 (89%) did not progress. Progressors developed systemic lupus erythematosus (SLE) (n = 11 [48%]), Sjögren disease (n = 5 [22%]), systemic sclerosis (n = 3 [13%]), rheumatoid arthritis (n = 1 [4%]), and from ANA-positive to undifferentiated connective tissue disease (n = 3 [13%]). Fever (RR 0.89, 95% confidence interval [CI] 0.8-0.93) and antiphospholipid antibodies (RR 0.89, 95% CI 0.87-0.93) occurred less frequently, whereas arthritis (RR 1.74, 95% CI 1.20-2.55) occurred more frequently in progressors. Progressors to SLE had arthritis (91%), whereas none developed delirium, psychosis, or nephritis. Among patients with SLE, 100% fulfilled the EULAR/American College of Rheumatology (ACR) SLE criteria (sensitivity 91.7%, specificity 100%), whereas 73% fulfilled the 1997 ACR SLE criteria (sensitivity 81.8%, specificity 98.9%). Most undifferentiated/asymptomatic individuals with ANA do not progress to a SARD over a two-year period. SLE progressors appear to have mild disease in the short term. The EULAR/ACR SLE criteria have improved ability to identify those who develop SLE.

Structure and Physiological Significance of IL-17: A Review Article

IL-17 is a pleiotropic cytokine key in lead to the proinflammatory nature within the immune system and thus it has a pronounced effect of inflammation and therefore disease pathogenesis which is particularly relevant in the case of osteoarthritis as well as other immune-mediated inflammatory diseases. While enormous strides have been made regarding its functions, additional studies are required to fill the gaps left over from previous studies and develop novel ways of treating or managing chronic inflammatory conditions on the basis of our advanced understanding of IL-17. IL-17 immune responses are still a mysterious package in acting in defense mechanisms of hosts and at the same trace back to autoimmune disease development due to its biphasic nature— this therefore justifies why an interest for exploring mechanisms by which production is achieved plus effects produced scientifically can be directed towards therapeutic opportunities yet to be fully realized. Such studies will unquestionably provide insights into immune regulation with an optimism for the development of alternative treatment strategies.

Distinct characteristics of various autoimmune liver diseases: A 22‐year hospital‐based study in Taiwan

AbstractBackground and AimThe characteristics of autoimmune liver diseases (AILDs), including primary biliary cholangitis (PBC), autoimmune hepatitis (AIH), and PBC‐AIH overlap syndrome (OS), have rarely been investigated and compared in Asia.MethodsAt the Taiwan tertiary referral center, 330 PBC patients (87% treated with ursodeoxycholic acid [UDCA]), 143 AIH patients (94.4% treated with immunosuppressive therapy [IST]) and 21 PBC‐AIH OS patients (85.7% treated with UDCA and IST) were enrolled.ResultsCompared with AIH patients, PBC patients were older at baseline and had greater female‐to‐male sex ratios, alkaline phosphatase (ALP) and γ‐glutamyl transferase (γ‐GT) levels, and liver cirrhosis (LC), dyslipidemia, and hepatic and cardiometabolic complication rates. PBC patients had the lowest transaminase levels, whereas AIH patients had the highest transaminase levels. PBC patients had greater 22‐year all‐cause mortality and liver transplantation (ACMaLT) (43.5 vs 25.4%, P = 0.004), LC (75 vs 58.5%, P &lt; 0.01), dyslipidemia (54.4 vs 45.9%, P = 0.001), and cerebrovascular accident (11.3 vs 0.8%, P = 0.019) cumulative incidences (CIs) than did AIH patients; PBC‐AIH OS patients had greater systemic lupus erythematosus (28.9 vs 8.9%, P = 0.009) CI than did PBC patients. Baseline ALP (hazard ratio: 1.001), albumin (0.514), platelet count (0.997), and LC (3.438) were associated with ACMaLT; age (1.110), albumin (0.350), cirrhosis (46.219), and hepatitis C virus antibody positivity (5.068) were associated with hepatocellular carcinoma (HCC); and female sex (2.183) and body mass index (1.054) were associated with autoimmune diseases.ConclusionsCompared with AIH patients, PBC patients had greater cardiometabolic CI, and ACMaLT CI, which was associated with cholestasis, liver functional reserve and LC. Older AILD patients with LC and females with obesity demand special caution for the development of HCC and extrahepatic autoimmune diseases, respectively.

Cellular and Immunological Analysis of 2D2/Th Hybrid Mice Prone to Experimental Autoimmune Encephalomyelitis in Comparison with 2D2 and Th Lines.

Previously, we described the mechanisms of development of autoimmune encephalomyelitis (EAE) in 3-month-old C57BL/6, Th, and 2D2 mice. The faster and more profound spontaneous development of EAE with the achievement of deeper pathology occurs in hybrid 2D2/Th mice. Here, the cellular and immunological analysis of EAE development in 2D2/Th mice was carried out. In Th, 2D2, and 2D2/Th mice, the development of EAE is associated with a change in the differentiation profile of hemopoietic bone marrow stem cells, which, in 2D2/Th, differs significantly from 2D2 and Th mice. Hybrid 2D2/Th mice demonstrate a significant difference in these changes in all strains of mice, leading to the production of antibodies with catalytic activities, known as abzymes, against self-antigens: myelin oligodendrocyte glycoprotein (MOG), DNA, myelin basic protein (MBP), and five histones (H1-H4) hydrolyze these antigens. There is also the proliferation of B and T lymphocytes in different organs (blood, bone marrow, thymus, spleen, lymph nodes). The patterns of changes in the concentration of antibodies and the relative activity of abzymes during the spontaneous development of EAE in the hydrolysis of these immunogens are significantly or radically different for the three lines of mice: Th, 2D2, and 2D2/Th. Several factors may play an essential role in the acceleration of EAE in 2D2/Th mice. The treatment of mice with MOG accelerates the development of EAE pathology. In the initial period of EAE development, the concentration of anti-MOG antibodies in 2D2/Th is significantly higher than in Th (29.1-fold) and 2D2 (11.7-fold). As shown earlier, antibodies with DNase activity penetrate cellular and nuclear membranes and activate cell apoptosis, stimulating autoimmune processes. In the initial period of EAE development, the concentration of anti-DNA antibodies in 2D2/Th hybrids is higher than in Th (4.6-fold) and 2D2 (25.7-fold); only 2D2/Th mice exhibited a very strong 10.6-fold increase in the DNase activity of IgGs during the development of EAE. Free histones in the blood are cytotoxic and stimulate the development of autoimmune diseases. Only in 2D2/Th mice, during different periods of EAE development, was a sharp increase in the anti-antibody activity in the hydrolysis of some histones observed.

Thyroid autoimmunity is associated with dietary fat consumption.

Dietary factors are crucial in the onset and development of autoimmune thyroid disease (AITD), but the relationship between specific fatty acids and AITD remains unexplored. We analyzed the US National Health and Nutrition Examination Survey (NHANES) 2007-2012 data on 3949 men and 3964 women aged 20 years and over with valid data on TPOAb, TgAb and details of fat intake, using multivariable regression models to examine the relationship of fat intake and specific fatty acid intake with thyroid autoimmunity. Of the 7913 participants, 7.5% had TgAb seropositivity and 11.9% had TPOAb seropositivity. The seropositivity of TgAb and TPOAb was more common in low-fat intake participants. In the overall population and men, fats were associated with thyroid autoimmunity before and after full adjustment for age, ethnicity, body mass index, smoking status and urine iodine concentration (total fat: OR=0.64, 95% CI 0.49 to 0.83; SFA: OR=0.65, 95% CI 0.51 to 0.84; MUFA: OR=0.65, 95% CI 0.50 to 0.85; PUFA: OR=0.76, 95% CI 0.57 to 0.995, after full adjustment in men). Some specific fatty acids followed a similar pattern. The association between fats and TgAb seropositivity was significant in the overall population and men. The association between fats and TPOAb seropositivity was only found in the overall population. We found a strong association between fat consumption and thyroid autoimmunity in the overall population and men from the nationally representative population-based survey. Fat and fatty acid consumption may be of benefit to individuals with thyroid autoimmunity.

Alemtuzumab-induced thyroid disease: A Danish cohort study

ObjectivesAlemtuzumab, a monoclonal antibody against the cluster of differentiation 52 (CD52) molecule, is used in the treatment of multiple sclerosis (MS). A side effect of the treatment is development of secondary autoimmune thyroid disease. The aim of this study was to evaluate the rate, type and course of thyroid disease in Danish patients with multiple sclerosis (MS) treated with alemtuzumab. MethodsWe conducted a retrospective cohort study of patients treated with a first series of alemtuzumab for MS in the Capital and Zealand regions of Denmark (population: 2.6 million) between 2014 and 2018 (n = 60 ResultsThe duration of follow-up was median 81 months (range 54–105). Thyroid disease occurred in 47 % of the patients with the following distribution: Graves’ disease (GD), thyrotropin (TSH) receptor antibody (TRAb) positive hyper- or hypothyroidism 35 %; multinodular goitre 5 %; silent thyroiditis, gestational transient thyrotoxicosis or unclassified hyperthyroidism 7 %. Of patients with GD, 14 % had an additional silent or postpartum thyroiditis before onset or after remission of GD. Unusual courses of GD occurred in 67 %, most commonly fluctuation from hypo- to hyperthyroidism or vice versa, mainly treated with antithyroid drug alone or thyroxine substitution regime but switched to concomitant block and replace treatment in 25 % and/or subsequent total thyroidectomy in less than 25 %. ConclusionData from the largest Danish MS center supports previous observations of unusual, long-lasting and unpredictable courses of alemtuzumab-induced GD. Thus, follow-up of these patients may require long lasting and more frequent biochemical measurements compared to other patients with GD. Also, concomitant block and replace treatment or definitive treatment, such as thyroidectomy, should be considered in a subgroup of patients.

Structure and function of N-acetylglucosaminyltransferase V (GnT-V)

BackgroundThe β1,6-GlcNAc branch in N-glycans, produced by a glycosyltransferase N-acetylglucosaminyltransferase V (GnT-V or MGAT5), is associated with cancer and autoimmune diseases. ScopeHere, we summarize the structure and activity regulation of GnT-V. We also describe the roles of the β1,6-GlcNAc branch on glycoproteins in cells and the phenotypes of Mgat5-deficient mice, focusing on cancer and the immune system. Major conclusionsGnT-V has a unique structure for substrate recognition, and its activity and function are regulated by shedding. The glycans produced by GnT-V play pivotal roles in the differentiation of neural cells, cancer malignancy and immunotherapy, and the development of autoimmune diseases by regulating the functions and cell surface residency of glycoproteins. General significanceControlling the expression or activity of GnT-V could be a therapeutic option against cancer and autoimmune diseases. Future work should clarify how GnT-V selectively modifies the specific glycoproteins or N-glycosylation sites in vivo.

SARS-CoV-2 spike aggravates lupus nephritis and lung fibrosis in systemic lupus erythematosus

ObjectiveCOVID-19 induces the development of autoimmune diseases, including SLE, which are characterised by inflammation, autoantibodies and thrombosis. However, the effects of COVID-19 on SLE remain unclear.MethodsWe investigated the effects of...

Endothelial Cell-Derived Soluble CD200 Determines the Ability of Immune Cells to Cross the Blood-Brain Barrier.

The infiltration of immune cells into the central nervous system mediates the development of autoimmune neuroinflammatory diseases. We previously showed that the loss of either Fabp5 or calnexin causes resistance to the induction of experimental autoimmune encephalomyelitis (EAE) in mice, an animal model of multiple sclerosis (MS). Here we show that brain endothelial cells lacking either Fabp5 or calnexin have an increased abundance of cell surface CD200 and soluble CD200 (sCD200) as well as decreased T-cell adhesion. In a tissue culture model of the blood-brain barrier, antagonizing the interaction of CD200 and sCD200 with T-cell CD200 receptor (CD200R1) via anti-CD200 blocking antibodies or the RNAi-mediated inhibition of CD200 production by endothelial cells increased T-cell adhesion and transmigration across monolayers of endothelial cells. Our findings demonstrate that sCD200 produced by brain endothelial cells regulates immune cell trafficking through the blood-brain barrier and is primarily responsible for preventing activated T-cells from entering the brain.

Total tanshinones ameliorates cGAS-STING-mediated inflammatory and autoimmune diseases by affecting STING-IRF3 binding

BackgroundAn important signaling pathway connecting illness and natural immunity is the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway, but aberrant activation of this pathway is associated with the development of autoimmune and inflammatory diseases. Hence, targeted inhibition of the activation of the cGAS-STING pathway is potentially valuable in the treatment of disease. The primary active component of Salvia miltiorrhiza is total tanshinone (TTN). Research has indicated that TTN possesses noteworthy anti-inflammatory properties. However, the protective mechanism of TTN against acute liver injury (ALI) and autoimmune diseases is unknown.MethodsA model of aberrant activation of the cGAS-STING pathway was established in various cells and treated with TTN, and the expression of cGAS-STING pathway-related proteins, type I interferon, interferon stimulated genes and inflammatory factors was assessed by western blotting, real-time qPCR. Immunofluorescence analysis of the effect of TTN on the entry of associated proteins into the nucleus following aberrant activation of the cGAS-STING pathway. The effect of TTN on STING oligomerisation was investigated using 2'-3'-cyclic GMP-AMP (2',3'-cGAMP) to induce STING oligomerisation. Western blotting was used to examine the impact of TTN on the interactions of STING, tank-binding kinase 1 (TBK1), and interferon regulatory factor 3 (IRF3) after HA or Flag-labelled plasmids were transfected into HEK-293 T cells. A dimethylxanthenone-4-acetic acid (DMXAA) -induced activation model of the cGAS-STING pathway in mice was established to study the effect of TTN on aberrant activation of the cGAS-STING pathway in vivo. On the other hand, an animal model of lipopolysaccharide/D-galactosamine (LPS/D-GaIN)-induced ALI and an autoimmune disease model induced by trex1 knockout were established to study the effects of TTN on inflammatory and autoimmune diseases mediated by the cGAS-STING pathway in vivo.ResultsIn several models of aberrant activation of the cGAS-STING pathway, TTN significantly inhibited the phosphorylation of STING and IRF3, thereby suppressing the expression of type I interferon, interferon-stimulated genes and inflammatory factors. Additionally, TTN prevented P65 and IRF3 from entering the nucleus after the cGAS-STING signalling pathway was abnormally activated. Subsequent research indicated that TTN was not involved in the oligomerization of STING or the integration of STING-TBK1 and TBK1-IRF3. However, TTN was found to have a substantial effect on the binding process between STING and IRF3. On the other hand, DMXAA-induced STING activation and activation of downstream signalling in vivo are inhibited by TTN. Furthermore, TTN exhibits positive treatment effects on autoimmune diseases caused by deficiency of trex1 and LPS/D-GaIN-induced ALI.ConclusionOur research indicates that TTN effectively treats ALI and autoimmune illnesses mediated by the cGAS-STING pathway by inhibiting the abnormal activation of this pathway.Graphical

Traditional approaches and recent tools for studying inflammasome activity

Inflammasomes play a major role in the immune response to infection, development of autoimmune disease, and control of cancer. Western blots were originally used in the early 2000s to characterize inflammasome activation. Since then, a panoply of techniques has been developed to characterize and visualize inflammasome activation in cells, tissues, and animals. This review article describes the most common techniques used by researchers in the inflammasome field and proposes that cell-specific characterization of inflammasome activation in tissues or animals may soon be commonly reported.

Identification of key genes with abnormal RNA methylation modification and selected m6A regulators in ankylosing spondylitis.

N6-methyladenosine (m6A) has been identified as the most abundant modification of RNA molecules and the aberrant m6A modifications have been associated with the development of autoimmune diseases. However, the role of m6A modification in ankylosing spondylitis (AS) has not been adequately investigated. Therefore, we aimed to explore the significance of m6A regulator-mediated RNA methylation in AS. The methylated RNA immunoprecipitation sequencing (meRIP-seq) and digital RNA sequencing (Digital RNA-seq) were conducted using the peripheral blood mononuclear cells from three AS cases and three healthy controls, to identify genes affected by abnormal RNA methylation. The genes associated with different peaks were cross-referenced with AS-related genes obtained from the GeneCards Suite. Subsequently, the expression levels of shared differentially expressed genes (DEGs) and key m6A regulators in AS were evaluated using data from 68 AS cases and 36 healthy controls from two data sets (GSE25101 and GSE73754). In addition, the results were validated through quantitative polymerase chain reaction (qPCR). The meRIP-seq and Digital RNA-seq analyses identified 28 genes with upregulated m6A peaks but with downregulated expression, and 52 genes with downregulated m6A peaks but with upregulated expression. By intersecting the genes associated with different peaks with 2184 AS-related genes from the GeneCards Suite, we identified a total of five shared DEGs: BCL11B, KAT6B, IL1R1, TRIB1, and ALDH2. Through analysis of the data sets and qPCR, we found that BCL11B and IL1R1 were differentially expressed in AS. Moreover, two key m6A regulators, WTAP and heterogeneous nuclear ribonucleoprotein C, were identified. In conclusion, the current study revealed that m6A modification plays a crucial role in AS and might hence provide a new treatment strategy for AS disease.

Development of Autoimmune Diseases Among Children With Pediatric Acute-Onset Neuropsychiatric Syndrome

Epidemiologic studies indicate a high rate of autoimmune conditions among patients with obsessive-complusive disorder and other psychiatric conditions. Furthering the understanding of the inflammatory diatheses of psychiatric conditions may open doors to new treatment paradigms for psychiatric disorders. To evaluate whether pediatric acute-onset neuropsychiatric syndrome (PANS) is associated with an inflammatory diathesis by assessing signs of immune activation and vasculopathy during a psychiatric symptom exacerbation (flare), estimating the risk of developing arthritis and other autoimmune diseases, and characterizing subtypes of arthritis. This retrospective cohort study used longitudinal clinical data on 193 consecutive patients with PANS followed up within the Stanford Immune Behavioral Health Clinic from September 1, 2012, to December 31, 2021. Medical records were reviewed, and a predefined set of immune markers that were measured during a flare and the features and imaging findings of arthritis and other autoimmune diseases were collected. Immune activation markers included (1) autoimmunity signs (antinuclear antibody, antihistone antibody, antithyroglobulin antibody, C1q binding assay, and complement levels [C3 and C4]); (2) immune dysregulation or inflammation signs (leukopenia, thrombocytosis, C-reactive protein, and erythrocyte sedimentation rate); and (3) vasculopathy signs (livedo reticularis, periungual redness and swelling, abnormally prominent onychodermal band, palatal petechiae, high von Willebrand factor antigen, and high d-dimer). Last, the cumulative risk of developing arthritis and autoimmune diseases was estimated using product limit (Kaplan-Meier) survival probability. The study included data from 193 children (112 boys [58.0%]) who had PANS at a mean (SD) age of 7.5 (3.5) years. They were followed up for a mean (SD) of 4.0 (2.1) years. Among those tested for immune activation markers, 54.2% (97 of 179) had nonspecific markers of autoimmunity, 12.0% (22 of 184) had nonspecific signs of immune dysregulation or inflammation, and 35.8% (69 of 193) had signs of vasculopathy. By 14 years of age, the estimated cumulative incidence of arthritis was 28.3% (95% CI, 20.8%-36.3%), and the estimated cumulative incidence of another autoimmune disease was 7.5% (95% CI, 4.0%-12.4%). Novel findings in the subgroup with arthritis include joint capsule thickening (55.0% [22 of 40]), distal interphalangeal joint tenderness (81.8% [45 of 55]), and spinous process tenderness (80.0% [44 of 55]). Among the 55 patients with arthritis, the most common subtypes of arthritis included enthesitis-related arthritis (37 [67.3%]), spondyloarthritis (27 [49.1%]), and psoriatic arthritis (10 [18.2%]). This study found that patients with PANS show signs of immune activation and vasculopathy during psychiatric symptom flares and have an increased risk of developing arthritis and other autoimmune diseases compared with the general pediatric population. The most common arthritis subtype was enthesitis-related arthritis. These findings suggest that PANS may be part of a multisystem inflammatory condition rather than an isolated psychiatric or neuroinflammatory disorder.

Long-term risk of autoimmune diseases after mRNA-based SARS-CoV2 vaccination in a Korean, nationwide, population-based cohort study

The long-term association between mRNA-based coronavirus disease 2019 (COVID-19) vaccination and the development of autoimmune connective tissue diseases (AI-CTDs) remains unclear. In this nationwide, population-based cohort study involving 9,258,803 individuals, we aim to determine whether the incidence of AI-CTDs is associated with mRNA vaccination. The study spans over 1 year of observation and further analyses the risk of AI-CTDs by stratifying demographics and vaccination profiles and treating booster vaccination as time-varying covariate. We report that the risk of developing most AI-CTDs did not increase following mRNA vaccination, except for systemic lupus erythematosus with a 1.16-fold risk in vaccinated individuals relative to controls. Comparable results were reported in the stratified analyses for age, sex, mRNA vaccine type, and prior history of non-mRNA vaccination. However, a booster vaccination was associated with an increased risk of some AI-CTDs including alopecia areata, psoriasis, and rheumatoid arthritis. Overall, we conclude that mRNA-based vaccinations are not associated with an increased risk of most AI-CTDs, although further research is needed regarding its potential association with certain conditions.

Tridecylcyclohexane in incomplete Freund's adjuvant is a critical component in inducing experimental autoimmune diseases.

Incomplete Freund's adjuvant (IFA) has been used for many years to induce autoimmune diseases in animal models, including experimental autoimmune encephalitis and collagen-induced arthritis. However, it remains unclear why it is necessary to emulsify autoantigen and heat-killed Mycobacterium tuberculosis (HKMtb) with IFA to induce experimental autoimmune diseases. Here, we found that immunization with self-antigen and HKMtb was insufficient to induce autoimmune diseases in mice. Furthermore, IFA or one of its components, mineral oil, but not mannide monooleate, was required for the development of experimental autoimmune disease. Immunization with autoantigen and HKMtb emulsified in mineral oil facilitated innate immune activation and promoted the differentiation of pathogenic CD4+ T cells, followed by their accumulation in neuronal tissues. Several water-soluble hydrocarbon compounds were identified in mineral oil. Of these, immunization with HKMtb and autoantigen emulsified with the same amount of hexadecane or tridecylcyclohexane as mineral oil induced the development of experimental autoimmune encephalitis. In contrast, immunization with HKMtb and autoantigen emulsified with tridecylcyclohexane, but not hexadecane, at doses equivalent to those found in mineral oil, resulted in neuronal dysfunction. These data indicate that tridecylcyclohexane in mineral oil is a critical component in the induction of experimental autoimmune disease.

RNF213 promotes Treg cell differentiation by facilitating K63-linked ubiquitination and nuclear translocation of FOXO1

Autoreactive CD4+ T helper cells are critical players that orchestrate the immune response both in multiple sclerosis (MS) and in other neuroinflammatory autoimmune diseases. Ubiquitination is a posttranslational protein modification involved in regulating a variety of cellular processes, including CD4+ T cell differentiation and function. However, only a limited number of E3 ubiquitin ligases have been characterized in terms of their biological functions, particularly in CD4+ T cell differentiation and function. In this study, we found that the RING finger protein 213 (RNF213) specifically promoted regulatory T (Treg) cell differentiation in CD4+ T cells and attenuated autoimmune disease development in an FOXO1-dependent manner. Mechanistically, RNF213 interacts with Forkhead Box Protein O1 (FOXO1) and promotes nuclear translocation of FOXO1 by K63-linked ubiquitination. Notably, RNF213 expression in CD4+ T cells was induced by IFN-β and exerts a crucial role in the therapeutic efficacy of IFN-β for MS. Together, our study findings collectively emphasize the pivotal role of RNF213 in modulating adaptive immune responses. RNF213 holds potential as a promising therapeutic target for addressing disorders associated with Treg cells.

PTBP1 protects Y RNA from cleavage leading to its apoptosis-specific degradation

Some RNAs such as 28S rRNA, U1 small nuclear RNA (snRNA), and Y RNAs are known to be cleaved during apoptosis. The underlying mechanism, functions, and biological significance of RNA degradation in apoptosis remain elusive. Y RNAs are non-coding RNAs widely conserved from bacteria to mammals, and are major components of Ro ribonucleoprotein (RNP) complexes which contain the 60 kDa Ro protein (SS-A) and the 50 kDa La protein (SS-B). The autoantigenic Ro and La proteins were identified by autoantibodies present in the sera from patients with Systemic lupus erythematosus (SLE) and Sjögren’s syndrome (SjS). We previously identified novel, functional small RNAs named AGO-taxis small RNAs (ASRs) that are specifically bound to Argonaute protein 1 (AGO1), which are processed from Y RNAs. Cell-free analysis combined with fractionation methods revealed that the apoptosis-specific biogenesis of ASRs or cleavage of Y RNA was induced by truncation of polypyrimidine tract-binding protein 1 (PTBP1), which is an endoribonuclease inhibitor of Y RNAs by caspase 3. Caspase 3-resistant PTBP1 mutant protected cleavage of Y RNAs in apoptosis induced by staurosporine. Furthermore, caspase 3-resistant PTBP1 mutant knock-in mice showed elevated cytokines, dysregulation of the germinal center formation compared to the wild-type mice at LPS stimulation, and high positivity of antinuclear antibody. Those results suggest that cleavage of Y RNAs or biogenesis of ASR during apoptosis has critical biological functions and their deregulation result in immune dysregulation and the formation of autoantibody, possibly leading to the development of autoimmune diseases.

PD-1 regulation of pathogenic IL-17-secreting γδ T cells in experimental autoimmune encephalomyelitis.

The PD-1-PD-L1 immune checkpoint helps to maintain self-tolerance and prevent the development of autoimmune diseases. Immune checkpoint inhibitors are successful immunotherapeutics for several cancers, but responding patients can develop immune-mediated adverse events. It is well established that PD-1 regulates CD4 and CD8 T-cell responses, but its role in controlling the activation of pathogenic γδ T cells is less clear. Here we examined the role of PD-1 in regulating γδ T cells in experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. We found that PD-1 was highly expressed on CD27- Vγ4 γδ T cells in the lymph node (LN) and CNS of mice with EAE. Treatment of mice with anti-PD-1 significantly augmented IL-17A-producing CD27- Vγ4 γδ T cells in the LN and CNS and enhanced the severity of EAE. The exacerbating effect of anti-PD-1 on EAE was lost in Tcrd-/- mice. Conversely, ligation of PD-1 suppressed Il17a and Rorc gene expression and IL-17A production by purified Vγ4 γδ T cells stimulated via the TCR, but not with IL-1β and IL-23. Our study demonstrates that PD-1 regulates TCR-activated CD27- Vγ4 γδ T cells, but that cytokine-activated IL-17A producing γδ T cells escape the regulatory effects of the PD-1-PD-L1 pathway.

Autoimmune manifestations following COVID-19 infection in two individuals with primary immunodeficiency

Background: Due to widespread vaccination efforts worldwide, the mortality rates linked to COVID-19 have been decreasing. Nevertheless, there persists a notable level of morbidity, marked by increased occurrences of post-COVID-19 conditions. This includes the development of new autoimmune and inflammatory diseases in individuals who have recovered from COVID-19. A more severe progression of COVID-19 has been correlated with an increased probability of newly diagnosed autoimmune disease, and among individuals with pre-existing autoimmune conditions, COVID-19 increased the risk of developing another autoimmune disease. Methods: Our patients’ medical records were analyzed retrospectively, including their medical history. Results: We present two cases of primary immunodeficiency patients. One of them experienced the onset of new autoimmune symptoms, while the other had a worsening of her autoimmune condition following COVID-19 infection. Conclusion: Recognizing the potential connection between COVID-19 and autoimmune conditions is crucial for identifying symptoms promptly in primary immunodeficiency patients and ensuring timely treatment. Further research is required to comprehensively grasp the relationship between COVID-19 and the development of autoimmunity in this particular patient group. Statement of novelty: In this paper, we present a novel exploration into the emergence of autoimmune manifestations in primary immunodeficiency patients subsequent to COVID-19 infection, through an analysis of two distinct case reports.