Large-scale seroepidemiology identifies a nephro-vascular syndrome associated with autoimmune reactivity to tau

The microtubule-associated protein tau is involved in several neurodegenerative diseases and is currently being investigated as a plasma biomarker for the detection and monitoring of Alzheimer's disease and as an immunotherapeutical target in clinical trials. We assessed plasma anti-tau IgG reactivity in 40'098 unselected patients visiting a university hospital and healthy blood donors. We found that 4.97% patients and 1.58% healthy donors had natural anti-tau antibody titers >1.8 log10(EC50). In a multivariate model, female sex (P<0.001), age (P<0.001), cystitis (RR 1.59, 95%CI 1.14-2.16, P=0.004), other urinary disorders (RR 1.23, 95%CI 1.03-1.45, P=0.018), chronic kidney disease (RR 1.20, 95%CI 1.01-1.41, P=0.033), arterial embolism and thrombosis (RR 1.56, 95%CI 1.02-2.25, P=0.026) and atherosclerosis (RR 1.35, 95%CI 1.09-1.1.66, P=0.004) were independent predictors of anti-tau autoantibodies. We therefore conclude that anti-tau autoimmunity is associated with a systemic syndrome that includes vascular, kidney and urinary disorders. The expression of tau in these extraneural tissues suggests a potential role of autoimmunity in this syndrome.

Occult Autoimmune Background for Epilepsy—The Preliminary Study on Antibodies Against Neuronal Surface Antigens

Objective: The objective of the study was to determine the incidence of antibodies against neuronal surface antigens (NSA-ab) in patients with different types of epilepsy, in comparison with the subjects diagnosed with immune-mediated disorders.Methods: Forty patients with drug-resistant epilepsy (DRE) of unknown origin, 16 with post-stroke epilepsy, and 23 with systemic autoimmune disorders (SAD) with CNS involvement were included. NSA-ab were sought in serum using indirect immunofluorescence method. Relationships were analyzed between presence of NSA-ab and clinical presentation.Results: NSA-ab was detected in the sera from five patients: anti-DPPX in one patient, anti-AMPAR1/R2 in two, anti-LGI1 in one and, in one case, both anti-CASPR2 and DPPX IgG. Out of these five patients, three represented the SAD subgroup and two the DRE subgroup. None of the patients with post-stroke epilepsy was positive for NSA-ab.Significance: Autoimmune etiology is worth considering in patients with drug-resistant epilepsy of unknown origin. The presence of NSA-ab in patients with systemic autoimmune disorders may be caused by unspecifically enhanced autoimmune reactivity. NSA-ab seem not to be related to epilepsy resulting from ischemic brain injury.

Life and Heritage of Hakaru Hashimoto

In May 2021, the 140th anniversary of his birth is celebrated by Japanese doctor Hakaru Hashimoto. Did not receive recognition during his lifetime, this amazing scientist discovered a new disease of the thyroid gland, which later became the eponym. For a long time, his name was forgotten, but the main work of his life was decades ahead of the development of science. Without it, the study of autoimmune pathologies, the incidence of which currently continues to increase, would be impossible. It was on patients with Hashimoto’s thyroiditis that a study was conducted for the first time, demonstrating not only the uniqueness of the pathogenesis of thyroiditis, but also the existence of autoimmune reactivity of the body as a whole.

Paradoxical Sex-Specific Patterns of Autoantibodies Response to SARS-CoV-2 Infection

Background. Amidst the millions of individuals affected directly by the pandemic, pronounced sex differences in the susceptibility and response to SARS-CoV-2 infection remain poorly understood. Emerging evidence has highlighted the potential importance of autoimmune activation in modulating not only the acute response but also recovery trajectories following SARS-CoV-2 exposure. Given that immune-inflammatory activity can be sex-biased in the setting of severe COVID-19 illness, we deliberately examined sex-specific autoimmune reactivity to SARS-CoV-2 in the absence of extreme clinical disease. Methods. We used a bead-based array containing over 90 autoantigens previously linked to a range of classic autoimmune diseases to assess autoantibody (AAB) titers in 177 participants. All participants had confirmed evidence of prior SARS-CoV-2 infection based on presence of positive anti-nucleocapsid IgG serology results (Abbott Diagnostics, Abbott Park, Illinois). We used multivariate analysis to determine whether sex-bias was associated with increased rates of AABs reactivity and symptom burden after SARS-CoV2 infection. Results. 82.4% of AABs reactivity was associated with being male compared to 17.6% with female. We found a diversity of AABs responses that exhibited sex-specific patterns of frequency distribution as well as associations with symptomatology and symptom burden. Conclusion. Our results reveal a remarkable sex-specific prevalence and selectivity of AAB responses to SARS-CoV-2. Further understanding of the nature of triggered and persistent AAB activation among men and women exposed to SARS-CoV-2 will be essential for developing effective interventions against immune-mediated sequelae of COVID-19.

Lessons Learned from Targeting IGF-I Receptor in Thyroid-Associated Ophthalmopathy

Complex immunological mechanisms underlie the pathogenesis of thyroid-associated ophthalmopathy (TAO). Historical models of Graves’ disease and TAO have focused almost entirely on autoimmune reactivity directed against the thyrotropin receptor (TSHR). The insulin-like growth factor-I receptor (IGF-IR) has been proposed as a second participating antigen in TAO by virtue of its interactions with IGFs and anti-IGF-IR antibodies generated in Graves’ disease. Furthermore, the IGF-IR forms with TSHR a physical and functional complex which is involved in signaling downstream from both receptors. Inhibition of IGF-IR activity results in attenuation of signaling initiated at either receptor. Based on the aggregate of findings implicating IGF-IR in TAO, the receptor has become an attractive therapeutic target. Recently, teprotumumab, a human monoclonal antibody IGF-IR inhibitor was evaluated in two clinical trials of patients with moderate to severe, active TAO. Those studies revealed that teprotumumab was safe and highly effective in reducing disease activity and severity. Targeting IGF-IR with specific biologic agents may result in a paradigm shift in the therapy of TAO.

Autoimmunity in Acute Poststreptococcal GN: A Neglected Aspect of the Disease

Acute poststreptococcal GN (APSGN) is the prototype of immune complex GN and is associated with manifestations of autoimmune reactivity that have been neglected as epiphenomena. Recently, studies have demonstrated transient antifactor B autoantibodies that activate the alternative complement pathway, bringing self-immunity to a central position in the pathogenesis of APSGN. Therefore, examining other manifestations of autoimmunity that have been reported in association with poststreptococcal GN is of interest. This article reviews the renal and extrarenal manifestations of autoimmune reactivity in APSGN and considers their potential relevance in modifying the usually benign clinical course of the disease. It also discusses related aspects of the nephritogenic antigens, complement activation, and genetic elements associated with immune reactivity and their potential relevance to the familial incidence of the disease.

Broad Auto-Reactive IgM Responses Are Common In Critically Ill COVID-19 Patients.

The pathogenesis of severe COVID-19 remains poorly understood. While several studies suggest that immune dysregulation plays a central role, the key mediators of this process are yet to be defined. Here, we demonstrate that plasma from a high proportion (77%) of critically ill COVID-19 patients, but not healthy controls, contains broadly auto-reactive immunoglobulin M (IgM), and only infrequently auto-reactive IgG or IgA. Importantly, these auto-IgM preferentially recognize primary human lung cells in vitro, including pulmonary endothelial and epithelial cells. By using a combination of flow cytometry, LDH-release assays, and analytical proteome microarray technology, we identified high-affinity, complement-fixing, auto-reactive IgM directed against 263 candidate auto-antigens, including numerous molecules preferentially expressed on cellular membranes in pulmonary, vascular, gastrointestinal, and renal tissues. These findings suggest that broad IgM-mediated autoimmune reactivity may be involved in the pathogenesis of severe COVID-19, thereby identifying a potential target for novel therapeutic interventions.

Antigen Specificity Enhances Disease Control by Tregs in Vitiligo

Vitiligo is an autoimmune skin disease characterized by melanocyte destruction. Regulatory T cells (Tregs) are greatly reduced in vitiligo skin, and replenishing peripheral skin Tregs can provide protection against depigmentation. Ganglioside D3 (GD3) is overexpressed by perilesional epidermal cells, including melanocytes, which prompted us to generate GD3-reactive chimeric antigen receptor (CAR) Tregs to treat vitiligo. Mice received either untransduced Tregs or GD3-specific Tregs to test the hypothesis that antigen specificity contributes to reduced autoimmune reactivity in vitro and in vivo. CAR Tregs displayed increased IL-10 secretion in response to antigen, provided superior control of cytotoxicity towards melanocytes, and supported a significant delay in depigmentation compared to untransduced Tregs and vehicle control recipients in a TCR transgenic mouse model of spontaneous vitiligo. The latter findings were associated with a greater abundance of Tregs and melanocytes in treated mice versus both control groups. Our data support the concept that antigen-specific Tregs can be prepared, used, and stored for long-term control of progressive depigmentation.

Haemophagocytic lymphohistiocytosis after heart transplantation: a case report

Background Haemophagocytic lymphohistiocytosis (HLH) is an uncommon but serious systemic inflammatory response with high mortality rates. It can be triggered by malignancy or infectious agents, often in the context of immunosuppression. Literature covering HLH in heart transplantation (HTx) is scarce. Case summary A 25-year-old male with a history of celiac disease underwent HTx at Sahlgrenska Hospital in 2011 due to giant cell myocarditis and was treated with tacrolimus, mycophenolate mofetil (MMF), and prednisolone. He developed several episodes of acute cellular rejections (ACR) during the first 3 post-HTx years, which subsided after addition of everolimus. In May 2017, the patient was admitted to the hospital due to fever without focal symptoms. He had an extensive inflammatory reaction, but screening for infectious agents was negative. Haemophagocytic lymphohistiocytosis was discussed early, but first dismissed since two bone marrow biopsies revealed no signs of haemophagocytosis. Increasing levels of soluble IL-2 were considered confirmative of the diagnosis. Even with intense immunosuppressant treatment, the patient deteriorated and died in progressive multiorgan failure within 2 weeks of the symptom onset. Discussion A 25-year-old HTx recipient with an extensive inflammatory response, fulfilled criteria for HLH, but the diagnosis was delayed due to normal bone marrow biopsies. A background with autoimmune reactivity and immunosuppressive therapy may have contributed to HLH, but the actual trigger was not identified. Haemophagocytic lymphohistiocytosis can occur in HTx recipients in the absence of malignancy, identifiable infectious triggers and signs of haemophagocytosis. Early diagnosis and intervention are likely to be of importance for a favourable outcome.