Autoreactive Antibodies Research Articles

Efgartigimod, an FcRn antagonist, as a potential treatment for post COVID-19 syndrome

A significant proportion of patients who survive coronavirus disease of 2019 (COVID-19) develop a constellation of life-altering symptoms that persist long after the initial infection has resolved. This post-COVID-19 syndrome may result from the development of autoreactive IgG antibodies that cause inflammation and tissue injury. In this commentary, we suggest that efgartigimod, a drug approved for the treatment of generalized myasthenia gravis, be tested for use in patients with post-COVID-19. Efgartigimod is a humanized IgG Fc fragment containing five point mutations that significantly increase affinity for the Fc region of the neonatal crystallizable fragment receptor (FcRn). FcRn is involved in the pathogenesis of autoimmune diseases via the IgG recycling pathway because FcRN binds to autoreactive IgG antibodies and prevents the antibodies from being catabolized. Efgartigimod is a modified immunoglobulin that competitively displaces endogenous IgG from FcRn, thus increasing the level of unbound IgG, which is then catabolized and leads to decreased circulating levels of autoreactive as well as normal IgG. We suggest that efgartigimod be evaluated in a random, double-blind placebo-control trial in adults with post-COVID-19 for at least 2 months. If re-purposing this myasthenia gravis-approved drug for post - COVID-19 is successful, additional bioengineered FcRn antagonists should be tested for efficacy in patients with post-COVID-19.

B cell responses to SARS-CoV-2.

This chapter provides an overview of B cell responses in COVID-19, highlighting the structure of SARS-CoV-2 and its impact on B cell immunity. It explores the production and maturation of SARS-CoV-2-specific B cells, with a focus on the two distinct phases of the humoral immune response: the extrafollicular (EF) phase and the germinal center (GC) phase. Furthermore, the interplay between B cells, follicular T helper cells, CD4+ T cells, and plasma cells is discussed, emphasizing their collaborative role in mounting an effective humoral immune response against SARS-CoV-2. The concept of immunological memory is explored, highlighting the roles of plasma cells and B memory cells in providing long-term protection. The chapter delves into the antibody response during SARS-CoV-2 infection, categorizing the types of antibodies generated. This includes a detailed analysis of neutralizing antibodies, such as those directed against the receptor-binding domain (RBD) and the N-terminal domain (NTD), as well as non-neutralizing antibodies. The role of mucosal antibodies, cross-reactive antibodies, and auto-reactive antibodies is also discussed. Factors influencing the dynamics of anti-SARS-CoV-2 antibodies are examined, including the duration and strength of the humoral response. Additionally, the chapter highlights the impact of the Omicron variant on humoral immune responses and its implications for vaccine efficacy and antibody-mediated protection.

Epidemiological and mechanistic links between Epstein-Barr virus and multiple sclerosis

Epstein-Barr virus (EBV) is a ubiquitous human lymphotropic herpesvirus that causes several malignancies. EBV infects approximately 90% of individuals worldwide. Recent studies have provided robust evidence for a causal role of EBV in multiple sclerosis. Multiple sclerosis is the most prevalent chronic inflammatory and degenerative disease of the central nerve system (CNS) that progresses over time to progressive neurodegeneration and disability. Here, I review how a ubiquitous virus can elicit autoreactive antibodies through molecular mimicry between viral and host CNS antigens, triggering multiple sclerosis.

Guillain-Barré Syndrome Following Zika Virus Infection Is Associated With a Diverse Spectrum of Peripheral Nerve Reactive Antibodies.

Recent outbreaks of Zika virus (ZIKV) in South and Central America have highlighted significant neurologic side effects. Concurrence with the inflammatory neuropathy Guillain-Barré syndrome (GBS) is observed in 1:4,000 ZIKV cases. Whether the neurologic symptoms of ZIKV infection are immune mediated is unclear. We used rodent and human live cellular models to screen for anti-peripheral nerve reactive IgG and IgM autoantibodies in the sera of patients with ZIKV with and without GBS. In this study, 52 patients with ZIKV-GBS were compared with 134 ZIKV-infected patients without GBS and 91 non-ZIKV controls. Positive sera were taken forward for target identification by immunoprecipitation and mass spectrometry, and candidate antigens were validated by ELISA and cell-based assays. Autoantibody reactions against glycolipid antigens were also screened on an array. Overall, IgG antibody reactivities to rat Schwann cells (SCs) (6.5%) and myelinated cocultures (9.6%) were significantly higher, albeit infrequent, in the ZIKV-GBS group compared with all controls. IgM antibody immunoreactivity to dorsal root ganglia neurones (32.3%) and SCs (19.4%) was more frequently observed in the ZIKV-GBS group compared with other controls, whereas IgM reactivity to cocultures was as common in ZIKV and non-ZIKV sera. Strong axonal-binding ZIKV-GBS serum IgG antibodies from 1 patient were confirmed to react with neurofascin 155 and 186. Serum from a ZIKV-infected patient without GBS displayed strong myelin-binding and putative antilipid antigen reaction characteristics. There was, however, no significant association of ZIKV-GBS with any known antiglycolipid antibodies. Autoantibody responses in ZIKV-GBS target heterogeneous peripheral nerve antigens suggesting heterogeneity of the humoral immune response despite a common prodromal infection.

Abstract A035: Profiling of circulating autoreactive antibodies in some 1200 patients with pancreatic ductal adenocarcinoma and progressive precursor lesions

Abstract Tumor-associated autoreactive antibodies could represent a moderately sensitive but highly specific type of biomarker. While autoantibodies in the blood of patients with pancreatic cancer have been reported, the consensus among studies is low and data validation is lacking. We profiled the abundance of circulating autoantibodies in patients with pancreatic ductal adenocarcinoma (PDAC) in a multi-step approach. For this purpose, microarrays with in situ expressed proteins were produced that contained 3060 non-mutated human proteins; one emphasis was on cell surface proteins. The microarrays were utilized for autoantibody screening of sera collected from patients of PDAC stages I, IIA, IIB/III and IV. In addition, samples were studied that represented the different grades of the precursor lesion intraductal pupillary mucinous neoplasm (IPMN) – low-grade, high-grade dysplasia and IPMN with associated carcinoma. Third, sera from patients diseased with the PDAC risk factor chronic pancreatitis (CP) as well as healthy donors served as control groups. The analysis revealed a significant increase in the overall proportion of immunoreactive proteins in late grades of IPMN and stages of PDAC; within each group, some sera displayed higher reactivity than others. The screening phase led to the identification of about 100 proteins, which showed a relatively high immunoreactivity associated with PDAC in comparison to an age- and sex-matched healthy control group. The characteristics of PDAC-associated autoantibodies were confirmed for the 100 proteins by analyzing sera from a total of 1200 PDAC, IPMN and CP patients as well as healthy donors. The patient groups were age- and sex-matched among each other. This confirmation phase validated the PDAC-related immunoreactivity of 17 proteins, showing high specificity of samples from PDAC patients in comparison to the healthy control group but low sensitivity of less than 10%. The clinically defined PDAC stages displayed different autoantibody profiles. However, no stage-related autoantibodies could be identified. Further, these PDAC-related antigens were also immunoreactive in smaller proportions of CP and IPMN patients, demonstrating the biological relation between PDAC and its precursors CP and IPMN. The majority of the other antigens showed a high immunoreactivity without correlation of autoantibody abundance and PDAC diagnosis, highlighting the importance of validation in large cohorts. The presence of autoantibodies specific for the 17 identified PDAC-related proteins is currently technically cross-validated by Luminex multiplex serology. In conclusion, the study has identified novel PDAC-related autoantibodies towards non-modified human proteins. While the specificity of some detected autoantibodies was high, the low sensitivity and the immunoreactivity of related precursor lesions make the definition of a broad applicable biomarker panel unlikely or too complex. However, the antigens that are specific for PDAC indicate target molecules, which could offer new therapeutic options in a personalized approach. Citation Format: Henning Boekhoff, Laura Hendricks, Elena Cairo, Andrea Bauer, Mari Hambardzumyan, Markus W. Büchler, Silvia Calderazzo, Vivienn Weru, Anette Kopp-Schneider, Hermann Brenner, Thilo Hackert, Oliver Strobel, Tim Waterboer, Nathalia Giese, Joerg D. Hoheisel. Profiling of circulating autoreactive antibodies in some 1200 patients with pancreatic ductal adenocarcinoma and progressive precursor lesions [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr A035.

CD19-Targeted CAR-T Cells in Refractory Systemic Lupus Erythematosus: Safety, Efficacy, and Mechanistic Insights from the First Five Patients

Background: Systemic lupus erythematosus (SLE) is an auto-immune disease that is based on dysregulation of the adaptive immune system, autoantibody production and immune complex-mediated tissue damage. While treatment of SLE has substantially improved, a subset of patients experiences severe progressive disease despite T- and B-cell targeted therapy. Aim: For patients with refractory SLE, we aimed to achieve deep depletion of B cells using autologous CD19-CAR T cells with the goal of achieving an immunological reset and drug free remission. Methods: Five patients (4 women, 1 men) with SLE refractory to several immune-suppressive drugs including pulsed steroids, hydroxychloroquine, mycophenolate, cyclophosphamide, intravenous immunoglobulins, rituximab, and belimumab were treated with CD19 CAR T cells in a compassionate use program. Mean patient age was 21.8 ± 2.3 years, mean disease duration was 4.6 ± 3.0 years and mean SLE disease activity index (SLEDAI) was 11.8±3.8. Autologous T cells were transduced with a lentiviral anti-CD19 CAR vector composed of the FMC63 scFv, a CD8-derived hinge region, TNFRSF19-derived transmembrane domain, CD3ζ intracellular domain, and 4-1BB co-stimulatory domain and expanded within the local GMP facility utilizing the closed automated CliniMACS Prodigy® system (Miltenyi Biotec, Bergisch Gladbach, Germany). CAR T cells were re-infused at a dose of 1x106 CAR T cells/kg body weight after lymphodepletion with fludarabine/ cyclophosphamide. All SLE treatments with the exception of low dose prednisolone was stopped before CAR-T cell administration. After CAR-T cell treatment, no other immune-modulatory or immune-suppressive treatment was given. Tolerability was assessed following international guidelines. Results: Despite long-lasting high dose steroid treatment, sufficient numbers of CD19 CAR-T cells could be generated from 5/5 SLE patients. Lymphodepletion led to expected reduction of white blood cells. Following lymphodepletion, CAR T cells expanded in vivo with a peak on day 9 and a deep depletion of B cells was achieved in all patients. Bone marrow toxicity towards non-B cells was short and all patients recovered neutrophils (>500/nL) before day 14 post CAR T cells. Only mild CRS of °I occurred in all five patients. One patient received a single dose of tocilizumab due to persisting fever >24 hours. There were no ICANS, no CRS of any organ, and no infections. Remission of SLE according to DORIS criteria was achieved in all 5 patients after 3 months and the mean (±SD) SLEDAI score after 3 months was 0.4±0.9. Laboratory parameters normalized in all SLE patients after CAR-T transfer including seroconversion of anti-dsDNA antibodies and all patients were free of immune-suppressive drugs by month 3. One patient presented with proteinuria at month 4. Kidney biopsy as well as serum diagnostics showed no signs of SLE. After a steroid pulse, proteinuria went back to normal. Despite reconstitution of B cells no relapse of SLE was observed in the follow up of any of the patients which are now 17, 12, 8, 7, and 5 months after CAR T cell therapy. Reappearing B cells were naïve and showed non-class switched B cell receptors. While pre-existing vaccine-specific antibodies towards measles or VZV persisted, several auto-reactive antibodies were abrogated. Quality of life was poor at decision to treatment and improved substantially at month three. Improvement was mostly driven by abrogation of joint pain and of fatigue. Conclusions: Taken together, the preliminary data from this pilot study show that CD19 CAR T-cell therapy is very well tolerated in patients with a non-malignant B cell derived autoimmune disease and induce rapid remission of severe refractory SLE. Longer follow-up and higher patient numbers from controlled clinical trials are needed to confirm these promising results.

Rheumatoid factor IgM autoantibodies control IgG homeostasis.

Rheumatoid arthritis is an autoimmune disease characterized by joint inflammation due to autoantibodies targeting multiple self-proteins. Most patients with poor prognosis show elevated titers of IgM antibodies specifically binding to IgG. Such autoreactive antibodies are referred to as rheumatoid factor (RF). However, their biological function and contribution to disease progression remains elusive. We have recently shown that autoreactive antibodies are present in healthy individuals and play an important role in regulating physiological processes. This regulatory mechanism is determined by the class and affinity of the autoreactive antibody, as low-affinity autoreactive IgM neutralizes the recognized autoantigen while high-affinity IgM protects its autoantigen from degradation. Here, we show that RFs possessing a high affinity and mono-specificity to IgG have a stabilizing effect on IgG, whereas low-affinity polyreactive RFs neutralize IgG in vivo. These results suggest that autoreactive IgM antibodies recognizing IgG play a crucial role in regulating IgG homeostasis and that a disbalance between IgM-mediated IgG degradation and stabilization might affect the onset and progression of autoimmune diseases. Consequently, restoring this balance using low-affinity anti-IgG IgM might be a promising therapeutic approach for autoimmune diseases involving autoreactive IgG.

An Adjusted Process to Improve Efficiency and Efficacy of Adsorption Procedures to Resolve Warm Autoantibody Cases.

The presence of warm autoantibodies in patient plasma typically causes extended delays in patient care due to panreactive antibody identification tests. Adsorption is the primary method for resolution. A modified adsorption procedure was devised with the intent to minimize delays, and the aim of the study was to evaluate its efficacy. To evaluate the in-house developed (experimental) adsorption method, specimens were tested in parallel with the standard adsorption method described in the AABB Technical Manual, 20th edition. Specimens selected demonstrated panreactivity at the submitting facility and contained adequate volume for parallel adsorption studies. Ninety specimens were tested with both methods. Ninety specimens achieved complete adsorption with the experimental method and 88 specimens achieved complete adsorption with the standard method. Two underlying alloantibodies, which have been reported to cause hemolytic transfusion reactions and potential renal graft rejection, were detected using the experimental method that the standard method failed to detect. The experimental method demonstrated a significant reduction in rounds of adsorption required to resolve warm autoantibody reactivity, enhanced antibody detection ability with adsorbed plasma, and more cost-effective outcomes compared to the standard method. A follow-up study is planned to assess whether the incubation time can be decreased with the experimental method to further improve the efficiency of the method without sacrificing efficacy.

S3029 Hydralazine-Induced Liver Injury With Autoimmune Features: A Case Report and Literature Review

Introduction: Autoimmune drug induced liver injury (AI-DILI) is a syndrome characterized by liver injury accompanied by laboratory evidence of autoimmunity due to the ingestion of a drug or herbal product. DILI accounts for approximately 15% of the cases of acute liver failure. Many drugs have been associated with DILI such as Amoxicillin-clavulanate, Diclofenac, Azathioprine, Infliximab. However, very rare cases have been reported on hydralazine-induced DILI. A response to treatment with steroids supports the diagnosis. Case Description/Methods: We present a case of a 59 year old female with no reported past history of liver disease. Patient was admitted for workup of jaundice, fatigue, and abdominal dissension of one month duration. Labs were significant for liver enzymes elevation with a cholestatic pattern. ERCP and EUS were done and results came back unremarkable. An extensive infectious and autoimmune workup was also negative. On further clarification of medication history, patient appeared to have had started hydralazine roughly 3 months prior to presentation. A liver biopsy was done and showed cholestatic injury and granulomatous inflammation (Figures A&B). Hydralazine was presumed the cause of patient’s liver injury, it was immediately stopped and patient was started on oral prednisone with significant improvement in symptoms and liver function test. Discussion: Autoimmune features and autoantibody reactivity in such cases of DILI vary according to liver injury severity and disease progression. The presentation of AI-DILI is classically indistinguishable from idiopathic autoimmune hepatitis (I-AIH). The presence of autoimmune features of liver injury due to hydralazine is not associated with the typical HLA alleles found in I-AIH such as HLA-DRB1*03:01 and DRB1*04:01 alleles. Histologically, AI-DILI shows changes that cannot be definitively distinguished from I-AIH without clinical correlation. Features on liver biopsy favoring DILI with autoimmunity include portal inflammation, fibrosis, portal neutrophils and plasma cells, and intracellular cholestasis. Liver biopsy is not performed in many cases of DILI, but may be useful if the liver injury is prolonged and does not promptly resolve with discontinuation of the drug and to also decide on need for treatment with steroids. In the attached table we present a review of the body of research on hydralazine-induced DILI with autoimmune features.Figure 1.: A- H&E stained section of the liver demonstrates moderate cholestasis (arrows) with surrounding inflammation.​ B- H&E stained section of the liver demonstrating a portal triad with mixed inflammation composed of predominately lymphocytes with rare neutrophils and plasma cells and mild interface activity. Moderate bile duct injury is seen (arrow). Table 1. - Literature review for hydralazine-induced DILI with autoimmune features Author Number of cases Average age Signs/Symptoms Sex Type Average LFTs Markers Course Outcome Our case (2022) 1 59 Jaundice, ascites, abdominal distension F Cholestatic ALT 100sAST 200sBili 17 ANA-ASMA-AMA - Moderate Resolved de Boer (2016) 7 60 (42-76) Jaundice, itching, rash, fever, eosinophilia 5 F2 M Hepatocellular (3)Mixed (2)Cholestatic (2) ALT 500sAST 1000sALP 200sBili 2 - Mild (2)Moderate (3)Severe (2) Liver transplant (1)Death (0) deLemos et al. (2014) 1 42 Flu-like symptoms, jaundice, ascites M ALT 1000sAST 1000sALP 200sINR 2 ANA+ASMA-AMA- Very severe Liver transplant Donald Rice, MD (1983) 1 51 Nausea, vomiting, malaise, fever, dark urine F Granulomatous hepatitis AST 500sALP 200sBili 5 Lupus - mild Resolved Abbreviations: F:female, M:male, LFT: liver function test, ANA:anti-nuclear antibody, ASMA:anti-smooth muscle antibody, AMA:anti-mitochondrial antibody.

Autoantibodies elicited with SARS-CoV-2 infection are linked to alterations in double negative B cells.

Double negative (DN) B cells (CD27-IgD-) comprise a heterogenous population of DN1, DN2, and the recently described DN3 and DN4 subsets. In autoimmune disease, DN2 cells are reported to be precursors to autoreactive antibody secreting cells and expansion of DN2 cells is linked to elevated interferon levels. Severe SARS-CoV-2 infection is characterized by elevated systemic levels of pro-inflammatory cytokines and serum autoantibodies and expansion of the DN2 subset in severe SARS-CoV-2 infection has been reported. However, the activation status, functional capacity and contribution to virally-induced autoantibody production by DN subsets is not established. Here, we validate the finding that severe SARS-CoV-2 infection is associated with a reduction in the frequency of DN1 cells coinciding with an increase in the frequency of DN2 and DN3 cells. We further demonstrate that with severe viral infection DN subsets are at a heightened level of activation, display changes in immunoglobulin class isotype frequency and have functional BCR signaling. Increases in overall systemic inflammation (CRP), as well as specific pro-inflammatory cytokines (TNFα, IL-6, IFNγ, IL-1β), significantly correlate with the skewing of DN1, DN2 and DN3 subsets during severe SARS-CoV-2 infection. Importantly, the reduction in DN1 cell frequency and expansion of the DN3 population during severe infection significantly correlates with increased levels of serum autoantibodies. Thus, systemic inflammation during SARS-CoV-2 infection drives changes in Double Negative subset frequency, likely impacting their contribution to generation of autoreactive antibodies.

Dysregulated naive B cells and de novo autoreactivity in severe COVID-19

Severe SARS-CoV-2 infection1 has been associated with highly inflammatory immune activation since the earliest days of the COVID-19 pandemic2–5. More recently, these responses have been associated with the emergence of self-reactive antibodies with pathologic potential6–10, although their origins and resolution have remained unclear11. Previously, we and others have identified extrafollicular B cell activation, a pathway associated with the formation of new autoreactive antibodies in chronic autoimmunity12,13, as a dominant feature of severe and critical COVID-19 (refs. 14–18). Here, using single-cell B cell repertoire analysis of patients with mild and severe disease, we identify the expansion of a naive-derived, low-mutation IgG1 population of antibody-secreting cells (ASCs) reflecting features of low selective pressure. These features correlate with progressive, broad, clinically relevant autoreactivity, particularly directed against nuclear antigens and carbamylated proteins, emerging 10–15 days after the onset of symptoms. Detailed analysis of the low-selection compartment shows a high frequency of clonotypes specific for both SARS-CoV-2 and autoantigens, including pathogenic autoantibodies against the glomerular basement membrane. We further identify the contraction of this pathway on recovery, re-establishment of tolerance standards and concomitant loss of acute-derived ASCs irrespective of antigen specificity. However, serological autoreactivity persists in a subset of patients with postacute sequelae, raising important questions as to the contribution of emerging autoreactivity to continuing symptomology on recovery. In summary, this study demonstrates the origins, breadth and resolution of autoreactivity in severe COVID-19, with implications for early intervention and the treatment of patients with post-COVID sequelae.

Abnormal B cell glycosylation in autoimmunity: A new potential treatment strategy.

Systemic lupus erythematosus (SLE) and primary Sjögren’s syndrome (pSS) are two autoimmune diseases characterised by the production of pathogenic autoreactive antibodies. Their aetiology is poorly understood. Nevertheless, they have been shown to involve several factors, such as infections and epigenetic mechanisms. They also likely involve a physiological process known as glycosylation. Both SLE T cell markers and pSS-associated autoantibodies exhibit abnormal glycosylation. Such dysregulation suggests that defective glycosylation may also occur in B cells, thereby modifying their behaviour and reactivity. This study aimed to investigate B cell subset glycosylation in SLE, pSS and healthy donors and to extend the glycan profile to serum proteins and immunoglobulins. We used optimised lectin-based tests to demonstrate specific glycosylation profiles on B cell subsets that were specifically altered in both diseases. Compared to the healthy donor B cells, the SLE B cells exhibited hypofucosylation, whereas only the pSS B cells exhibited hyposialylation. Additionally, the SLE B lymphocytes had more galactose linked to N-acetylglucosamine or N-acetylgalactosamine (Gal-GlcNAc/Gal-GalNAc) residues on their cell surface markers. Interestingly, some similar alterations were observed in serum proteins, including immunoglobulins. These findings indicate that any perturbation of the natural glycosylation process in B cells could result in the development of pathogenic autoantibodies. The B cell glycoprofile can be established as a preferred biomarker for characterising pathologies and adapted therapeutics can be used for patients if there is a correlation between the extent of these alterations and the severity of the autoimmune diseases.

Unbiased discovery of autoantibodies associated with severe COVID-19 via genome-scale self-assembled DNA-barcoded protein libraries.

Pathogenic autoreactive antibodies that may be associated with life-threatening coronavirus disease 2019 (COVID-19) remain to be identified. Here, we show that self-assembled genome-scale libraries of full-length proteins covalently coupled to unique DNA barcodes for analysis by sequencing can be used for the unbiased identification of autoreactive antibodies in plasma samples. By screening 11,076 DNA-barcoded proteins expressed from a sequence-verified human ORFeome library, the method, which we named MIPSA (for Molecular Indexing of Proteins by Self-Assembly), allowed us to detect circulating neutralizing type-I and type-III interferon (IFN) autoantibodies in five plasma samples from 55 patients with life-threatening COVID-19. In addition to identifying neutralizing type-I IFN-α and IFN-ω autoantibodies and other previously known autoreactive antibodies in patient plasma, MIPSA enabled the detection of as yet unidentified neutralizing type-III anti-IFN-λ3 autoantibodies that were not seen in healthy plasma samples or in convalescent plasma from ten non-hospitalized individuals with COVID-19. The low cost and simple workflow of MIPSA will facilitate unbiased high-throughput analyses of protein-antibody, protein-protein and protein-small-molecule interactions.

Allelic polymorphism controls autoreactivity and vaccine elicitation of human broadly neutralizing antibodies against influenza virus

Human broadly neutralizing antibodies (bnAbs) targeting the hemagglutinin stalk of group 1 influenza A viruses (IAVs) are biased for IGHV1-69 alleles that use phenylalanine (F54) but not leucine (L54) within their CDRH2 loops. Despite this, we demonstrated that both alleles encode for human IAV bnAbs that employ structurally convergent modes of contact to the same epitope. To resolve differences in lineage expandability, we compared F54 versus L54 as substrate within humanized mice, where antibodies develop with human-like CDRH3 diversity but are restricted to single VH genes. While both alleles encoded for bnAb precursors, only F54 IGHV1-69 supported elicitation of heterosubtypic serum bnAbs following immunization with a stalk-only nanoparticle vaccine. L54 IGHV1-69 was unproductive, co-encoding for anergic B cells and autoreactive stalk antibodies that were cleared from B cell memory. Moreover, human stalk antibodies also demonstrated L54-dependent autoreactivity. Therefore, IGHV1-69 polymorphism, which is skewed ethnically, gates tolerance and vaccine expandability of influenza bnAbs.

Activation of Humoral Immunity during the Pathogenesis of Experimental Chronic Lung Allograft Dysfunction.

Alloreactive and autoreactive antibodies have been associated with the development of chronic lung allograft dysfunction (CLAD), but their pathogenic role is disputed. Orthotopic left lung transplantation was performed in the Fischer-344 to Lewis rat strain combination followed by the application of ciclosporine for 10 days. Four weeks after transplantation, lipopolysaccharide (LPS) was instilled into the trachea. Lungs were harvested before (postoperative day 28) and after LPS application (postoperative days 29, 33, 40, and 90) for histopathological, immunohistochemical, and Western blot analyses. Recipient serum was collected to investigate circulating antibodies. Lung allografts were more strongly infiltrated by B cells and deposits of immunoglobulin G and M were more prominent in allografts compared to right native lungs or isografts and increased in response to LPS instillation. LPS induced the secretion of autoreactive antibodies into the circulation of allograft and isograft recipients, while alloreactive antibodies were only rarely detected. Infiltration of B cells and accumulation of immunoglobulin, which is observed in allografts treated with LPS but not isografts or native lungs, might contribute to the pathogenesis of experimental CLAD. However, the LPS-induced appearance of circulating autoreactive antibodies does not seem to be related to CLAD, because it is observed in both, isograft and allograft recipients.

Use of Autoreactive Antibodies in Blood of Patients with Pancreatic Intraductal Papillary Mucinous Neoplasms (IPMN) for Grade Distinction and Detection of Malignancy.

Simple SummaryRisk stratification via biomarkers used with imaging could support predicting high-risk pancreatic intraductal papillary mucinous neoplasms (IPMN) with malignant potential. We explored the presence of autoreactive antibodies in the blood of patients with IPMN of different grades of dysplasia, including IPMN with associated invasive carcinoma and early-stage pancreatic ductal adenocarcinoma (PDAC), to identify signatures of early malignancy. Multivariate predictive models retained 14 proteins as potential biomarkers for discrimination between all disease classes. The integration of the autoreactive-antibody panel with clinical variables may aid in risk stratification of high-risk IPMN patients, which would subsequently improve clinical management.(1) Background: A reliable non-invasive distinction between low- and high-risk pancreatic intraductal papillary mucinous neoplasms (IPMN) is needed to effectively detect IPMN with malignant potential. This would improve preventative care and reduce the risk of developing pancreatic cancer and overtreatment. The present study aimed at exploring the presence of autoreactive antibodies in the blood of patients with IPMN of various grades of dysplasia. (2) Methods: A single-center cohort was studied composed of 378 serum samples from patients with low-grade IPMN (n = 91), high-grade IPMN (n = 66), IPMN with associated invasive cancer (n = 30), pancreatic ductal adenocarcinoma (PDAC) stages T1 (n = 24) and T2 (n = 113), and healthy controls (n = 54). A 249 full-length recombinant human protein microarray was used for profiling the serum samples. (3) Results: 14 proteins were identified as potential biomarkers for grade distinction in IPMN, yielding high specificity but mediocre sensitivity. (4) Conclusions: The identified autoantibodies are potential biomarkers that may assist in the detection of malignancy in IPMN patients.

Serum autoantibody reactivity in bullous pemphigoid is associated with neuropsychiatric disorders and the use of antidiabetics and antipsychotics: a large, prospective cohort study.

Bullous pemphigoid (BP), the by far most frequent autoimmune blistering skin disease (AIBD), is immunopathologically characterized by autoantibodies against the two hemidesmosomal proteins BP180 (collagen type XVII) and BP230 (BPAG1 or dystonin). Several comorbidities and potentially disease-inducing medication have been described in BP, yet a systematic analysis of these clinically relevant findings and autoantibody reactivities has not been performed. To determine associations of autoantibody reactivities with comorbidities and concomitant medication. In this prospective multicenter study, 499 patients diagnosed with BP in 16 European referral centers were included. The relation between anti-BP180 NC16A and anti-BP230 IgG ELISA values at the time of diagnosis as well as comorbidities and concomitant medication collected by a standardized form were analysed. An association between higher serum anti-BP180 reactivity and neuropsychiatric but not atopic and metabolic disorders was observed as well as with the use of insulin or antipsychotics but not with dipeptidyl peptidase-4 (DPP4) inhibitors, inhibitors of platelet aggregation and L-thyroxine. The use of DPP4 inhibitors was associated with less anti-BP180 and anti-BP230 reactivity compared with BP patients without these drugs. This finding was even more pronounced when compared with diabetic BP patients without DPP4 inhibitors. Associations between anti-BP180 and anti-BP230 reactivities were also found in patients using insulin and antipsychotics, respectively, compared with patients without this medication, but not for the use of inhibitors of platelet aggregation, and L-thyroxine. Taken together, these data imply a relation between autoantibody reactivities at the time of diagnosis and both neuropsychiatric comorbidities as well as distinct concomitant medication suggesting a link between the pathological immune mechanisms and clinical conditions that precede the clinically overt AIBD.

Relation Helicobacter pylori with Pathogenesis of Stomach and Immune Responses

Background: Helicobacter pylori, a member of Epsilonproteobacteria, is a Gram-negative microaerophilic bacterium that colonizes gastric mucosa of about 50% of the human population. Although most infections caused by H. pylori are asymptomatic, the microorganism is strongly associated with serious diseases of the upper gastrointestinal tract such as chronic gastritis, peptic ulcer, duodenal ulcer, and gastric cancer, and it is classified as a group I carcinogen. The prevalence of H. pylori infections varies worldwide. prevalence among middle-aged adults is over 80 percent in many developing countries, as compared with 20 to 50 percent in industrialized countries. The infection is acquired by oral ingestion of the bacterium and is mainly transmitted within families in early childhood, Humans can also become infected with Helicobacter heilmannii, a spiral bacterium found in dogs, cats, pigs, and nonhuman primates. 
 Conclusion: H. pylori infection stimulates the reaction of autoantibodies with gastric epithelial cells, and this leads to gastritis. These autoantibodies can be directly induced to epithelial cells by activating complement, inducing apoptosis or provoking an antibody-dependent cytotoxic reaction resulting in subsequent tissue destruction.

Auto-reactive antibodies as predictive markers for immune checkpoint–induced pneumonitis.

2554 Background: Certain immune-related adverse events (irAEs) that emerge with immune checkpoint blockade share clinical features of autoimmune conditions. Preexisting auto-reactive antibodies and their contribution to irAEs have not been well defined, and observations are limited. Methods: We longitudinally collected patient plasma samples from a clinical trial that combines immune checkpoint inhibitors, Ipilimumab, and Nivolumab (I+N) with subsequent radiation therapy (Lonestar, NCT03391869). Plasma samples were collected at baseline, after 12 weeks of I+N (induction), and at the time of Grade ≥ 2 pneumonitis (CTCAEv5.0). Auto reactive antibody profiles were analyzed using a fluorescence-based assay system that measures more than 130 antigens and is capable of assaying antibody reactivity for IgG and IgM fractions, including nuclear-cytosolic and tissue-specific antigens. Selected antibodies had a reportable result range, reference intervals, and reproducibility with quality controls. A paired t-test was used to compare the mean of longitudinally collected baseline and toxicity samples. An unpaired t-test was used to compare differences between groups. The False Discovery Rate was used to control the Type I error rate of multiple comparisons. Results: In the study cohort, G≥2 pneumonitis was observed in 11 patients out of 194 (5.6%). Serum was collected at baseline for all 11 patients, and 9 of the 11 patients had a serum sample collected at the time of pneumonitis event. Longitudinal serum samples (baseline and post-induction) collected from 32 patients without any irAEs were used as control. At baseline AChR3 and calmodulin antibodies were elevated in patients who developed pneumonitis, compared with baseline samples from controls (p≤0.05). At the time of pneumonitis IgM antibodies against AChR3, CXCL10, NSE, BAFF, CA242, Cytokeratin 19 were noted to be elevated in serum for pneumonitis cases compared with post induction samples from control (p≤0.005). Conclusions: We identified auto reactive antibodies associated with a higher risk of immunotherapy associated pneumonitis in patients treated with ipilimumab and nivolumab. These included auto reactive antibodies against proteins associated with lung injury (AChR3), lung inflammation (BAFF, CXCL10) and against alveolar epithelium (Cytokeratin 19). Future studies are warranted to determine if auto-reactive antibodies can be used as pre-treatment risk markers or to diagnose pneumonitis and may offer insights into to mechanisms that predispose toward pneumonitis.

Nutritional Management of Thyroiditis of Hashimoto.

Since the thyroid gland is one of the organs most affected by autoimmune processes, many patients with thyroiditis of Hashimoto (TH) seek medical advice on lifestyle variance and dietary modifications to improve and maintain their hyroid function. In this review, we aim to present and discuss some challenges associated with the nutritional management of TH, focusing on environmental and dietary deficits, inflammatory and toxic nutrients, cyanotoxins, etc. We discuss the relationships among different diets, chronic inflammation, and microbiota, and their impact on the development and exacerbation of TH in detail. We share some novel insights into the role of vitamin D and melatonin for preserving thyroid function during chronic inflammation in autoimmune predisposed subjects. A comprehensive overview is provided on anti-inflammatory nutrients and ecological diets, including foods for cleansing and detoxification, which represent strategies to prevent relapses and achieve overall improvement of life quality. In conclusion, data from biomedical and clinical studies provide evidence that an appropriate dietary and lighting regimen could significantly improve the function of the thyroid gland and reduce the reactivity of autoantibodies in TH. Compliance with nutritional guidelines may help TH patients to reduce the need for medicines.