New insights into the taxonomy of autoimmune diseases based on polyautoimmunity

Ocular cicatricial pemphigoid: is there an association with autoimmune diseases?

PURPOSE

To assess the prevalence of autoimmune diseases (ADs) associated with ocular cicatricial pemphigoid (OCP) and analyze clinical, laboratory, and treatment associations between these entities.

METHODS

A multicentre cross-sectional study of patients with an OCP diagnosis. The population was divided into two groups according to their association with other ADs or not. Clinical, laboratory and treatment variables were described and compared between groups. A multivariable logistic regression analysis was performed to identify variables that could suggest the association between OCP and ADs.

RESULTS

Eighty-eight patients were recruited, with a mean age at diagnosis of 64.3 years (SD 11.9). Biopsy was performed in 86.8% of the patients. There was a median delay of 2 years from the onset of symptoms to diagnosis. Extraocular involvement was evidenced in 11.5%. The group associated with ADs included 24 patients (27.3%). The most prevalent diagnosis was Sjögren´s syndrome. Hypergammaglobulinemia was associated with ADs and OCP, adjusted for age, sex, smoking, skin and mucosal involvement, and erythrocyte sedimentation rate (OR 8.7; 95%CI 1.6-46.8; p = 0.012).

CONCLUSIONS

Due to OCP's autoimmune nature, it could coexist with other ADs. This study observed that more than a quarter of the population presented with this association, and hypergammaglobulinemia could suggest it.

[Autoimmunity in rheumatology: A review]

Autoimmunity and autoinflammation, co-potentiating pathological processes, are considered within the "immune-inflammatory" continuum (continuity with a variety of elements), reflecting the close relationship between the innate and acquired immune responses. Autoimmunity is the leading pathogenetic mechanism for a specific type of human chronic inflammatory disorders - autoimmune diseases, affecting more than 10% of people in the general population. Advances in molecular biology, pharmacogenetics, and bioinformatics provided the background for individualizing therapy for systemic autoimmune rheumatic diseases within personalized medicine. Studying the immunopathogenesis mechanisms, improving diagnostics, interpreting the molecular taxonomy, and developing approaches to the prevention and personalized therapy of systemic autoimmune rheumatic diseases are the priority issues of modern medicine.

Polygenic autoimmune disease risk alleles impacting B cell tolerance act in concert across shared molecular networks in mouse and in humans

Most B cells produced in the bone marrow have some level of autoreactivity. Despite efforts of central tolerance to eliminate these cells, many escape to periphery, where in healthy individuals, they are rendered functionally non-responsive to restimulation through their antigen receptor via a process termed anergy. Broad repertoire autoreactivity may reflect the chances of generating autoreactivity by stochastic use of germline immunoglobulin gene segments or active mechanisms may select autoreactive cells during egress to the naïve peripheral B cell pool. Likewise, it is unclear why in some individuals autoreactive B cell clones become activated and drive pathophysiologic changes in autoimmune diseases. Both of these remain central questions in the study of the immune system(s). In most individuals, autoimmune diseases arise from complex interplay of genetic risk factors and environmental influences. Advances in genome sequencing and increased statistical power from large autoimmune disease cohorts has led to identification of more than 200 autoimmune disease risk loci. It has been observed that autoantibodies are detectable in the serum years to decades prior to the diagnosis of autoimmune disease. Thus, current models hold that genetic defects in the pathways that control autoreactive B cell tolerance set genetic liability thresholds across multiple autoimmune diseases. Despite the fact these seminal concepts were developed in animal (especially murine) models of autoimmune disease, some perceive a disconnect between human risk alleles and those identified in murine models of autoimmune disease. Here, we synthesize the current state of the art in our understanding of human risk alleles in two prototypical autoimmune diseases – systemic lupus erythematosus (SLE) and type 1 diabetes (T1D) along with spontaneous murine disease models. We compare these risk networks to those reported in murine models of these diseases, focusing on pathways relevant to anergy and central tolerance. We highlight some differences between murine and human environmental and genetic factors that may impact autoimmune disease development and expression and may, in turn, explain some of this discrepancy. Finally, we show that there is substantial overlap between the molecular networks that define these disease states across species. Our synthesis and analysis of the current state of the field are consistent with the idea that the same molecular networks are perturbed in murine and human autoimmune disease. Based on these analyses, we anticipate that murine autoimmune disease models will continue to yield novel insights into how best to diagnose, prognose, prevent and treat human autoimmune diseases.

Regulatory B Cells in Systemic Sclerosis Isolated or Concomitant With Hashimoto Thyroiditis

Systemic sclerosis (SSc) is a systemic autoimmune disease in which gastrointestinal disorders represent a complication in up to 90% of patients. SSc may associate with thyroid autoimmune disorders, with Hashimoto’s thyroiditis (HT) being the more prevalent worldwide. Previous studies have examined the behavior of Th17 lymphocytes and Breg cells in patients with HT and concomitant autoimmune organ-specific disorders. These immune phenotypes seem to play a significant role in the pathogenesis of both these autoimmune processes, but their behavior when these two disorders coexist has not been described. We analyzed Th17 and Breg (CD24hiCD38hi) cell subsets in 50 subjects (45F/5M; median age = 49 years): 18 were healthy donors (HD), 20 had isolated HT, and 12 had SSc, seven of whom had both HT and SSc. Breg cells’ function was also evaluated by measuring their IL-10 production when stimulated by specific activators. An increased percentage of Th17 lymphocytes characterized HT patients as compared to both HD and the whole group of SSc patients (p = 0.0018). On the contrary, the percentage of unstimulated Breg cells in SSc patients was higher (p = 0.0260), either associated or not with HT, as compared to both HT patients and HD, which, instead, showed a similar percentage of Breg cells. Following a specific stimulation with CpG, the percentages of Breg cells were increased in the whole sample of SSc patients (p < 0.001) as well as in isolated SSc and in SSc+HT ones as compared to isolated HT. However, qualitative analysis, obtained through the detection of the IL-10-producing phenotype, revealed that the percentage of CpG-stimulated CD24hiCD38hi-IL10+cells was significantly decreased in SSc patients (p < 0.0001) with no difference between isolated SSc and SSc+HT patients. The IL-10-producing phenotype was instead slightly increased in HT patients as compared to HD (4.1% vs. 2.8%). The presence of SSc seems to be characterized by an enrichment of total Breg cells but by a reduced Breg IL-10-producing phenotype, representing functional Bregs. This last finding was entirely due to the presence of SSc independently from the association with HT. This behavior is different from the ones described about the association of HT with organ-specific autoimmune disorders.

The NOD Mouse Beyond Autoimmune Diabetes

Autoimmune diabetes arises spontaneously in Non-Obese Diabetic (NOD) mice, and the pathophysiology of this disease shares many similarities with human type 1 diabetes. Since its generation in 1980, the NOD mouse, derived from the Cataract Shinogi strain, has represented the gold standard of spontaneous disease models, allowing to investigate autoimmune diabetes disease progression and susceptibility traits, as well as to test a wide array of potential treatments and therapies. Beyond autoimmune diabetes, NOD mice also exhibit polyautoimmunity, presenting with a low incidence of autoimmune thyroiditis and Sjögren’s syndrome. Genetic manipulation of the NOD strain has led to the generation of new mouse models facilitating the study of these and other autoimmune pathologies. For instance, following deletion of specific genes or via insertion of resistance alleles at genetic loci, NOD mice can become fully resistant to autoimmune diabetes; yet the newly generated diabetes-resistant NOD strains often show a high incidence of other autoimmune diseases. This suggests that the NOD genetic background is highly autoimmune-prone and that genetic manipulations can shift the autoimmune response from the pancreas to other organs. Overall, multiple NOD variant strains have become invaluable tools for understanding the pathophysiology of and for dissecting the genetic susceptibility of organ-specific autoimmune diseases. An interesting commonality to all autoimmune diseases developing in variant strains of the NOD mice is the presence of autoantibodies. This review will present the NOD mouse as a model for studying autoimmune diseases beyond autoimmune diabetes.

Association of anti-SARS-COV-2 vaccine with increased incidence of myositis-related anti-RNA-synthetases auto-antibodies

Introduction

SARS-CoV-2 is a RNA virus that associates with heterogeneous clinical manifestations and complications. Auto-antibodies are identified in approximately 50% of hospitalized COVID-19 patients.

Objectives

To determine the global incidence of myositis-related auto-antibodies (non Jo1-RNA synthetases: anti-PL7, anti-PL12, anti-EJ, anti-OJ and RNA-sensor: anti-MDA5) in our laboratory during COVID-19 pandemics, and to describe the clinical and laboratory features of these patients.

Study design

A retrospective study was performed from 2015 to 2021 in a cohort of 444 patients with suspected inflammatory myopathy. The incidence of positive results for the MSA was expressed as absolute value per year for the reference population. Immunoblot analysis, indirect immunofluorescence and HLA typing of 36 patients with positivity for MSAs were collected and analyzed.

Results

We observed MSA positive in 28 patients in 2020 and 36 patients in 2021, representing a mean increase of 6-fold respect to previous years since 2015 (range, 0 to 19). In 2020, the most common antibody detected was anti-MDA5 (68%). In contrast, in 2021 the most common antibodies were anti-PL7 and/or anti-PL12 (69%). All patients in 2021 with positive anti-synthetases were fully vaccinated, 4 had previous documented infection, with median time from vaccine to MSA positivity of 5 months. Eight out of 36 patients (22%) reported clinical onset after SARS-CoV-2 vaccination and 6 out of 36 (17%) presented clinical and/or radiological worsening after SARS-CoV-2 vaccination. All patients presented with a known human leukocyte antigen (HLA)-DRB1* allele associated with ASS. The most prevalent alleles identified were DRB1*03:01, DRB1*04, DRB1*11:01, corresponding to 70% (16/23) of our cohort.

Conclusions

Our preliminary data show an increased incidence of anti-synthetase antibodies during COVID-19 pandemic and SARS-CoV-2 vaccination associated to HLA DRB1* risk allele. Differential profiles of MSA specificities were observed: mainly against RNA-sensors in 2020 and against RNA-synthetases in 2021. Further studies are needed to support the association between SARS-CoV-2 infection and/or vaccination and the occurrence of this autoimmune syndrome.