Development Of Autoantibodies Research Articles

Genetic basis of defects in immune tolerance underlying the development of autoimmunity.

Genetic variants associated with susceptibility to autoimmune disease have provided important insight into the mechanisms responsible for the loss of immune tolerance and the subsequent development of autoantibodies, tissue damage, and onset of clinical disease. Here, we review how genetic variants shared across multiple autoimmune diseases have contributed to our understanding of global tolerance failure, focusing on variants in the human leukocyte antigen region, PTPN2 and PTPN22, and their role in antigen presentation and T and B cell homeostasis. Variants unique to a specific autoimmune disease such as those in PADI2 and PADI4 that are associated with rheumatoid arthritis are also discussed, addressing their role in disease-specific immunopathology. Current research continues to focus on determining the functional consequences of autoimmune disease-associated variants but has recently expanded to variants in the non-coding regions of the genome using novel approaches to investigate the impact of these variants on mechanisms regulating gene expression. Lastly, studying genetic risk variants in the setting of autoimmunity has clinical implications, helping predict who will develop autoimmune disease and also identifying potential therapeutic targets.

A gut microbial peptide and molecular mimicry in the pathogenesis of type 1 diabetes

Type 1 diabetes (T1D) is an autoimmune disease characterized by the destruction of pancreatic β-cells. One of the earliest aspects of this process is the development of autoantibodies and T cells directed at an epitope in the B-chain of insulin (insB:9-23). Analysis of microbial protein sequences with homology to the insB:9-23 sequence revealed 17 peptides showing >50% identity to insB:9-23. Of these 17 peptides, the hprt4-18 peptide, found in the normal human gut commensal Parabacteroides distasonis, activated both human T cell clones from T1D patients and T cell hybridomas from nonobese diabetic (NOD) mice specific to insB:9-23. Immunization of NOD mice with P. distasonis insB:9-23 peptide mimic or insB:9-23 peptide verified immune cross-reactivity. Colonization of female NOD mice with P. distasonis accelerated the development of T1D, increasing macrophages, dendritic cells, and destructive CD8+ T cells, while decreasing FoxP3+ regulatory T cells. Western blot analysis identified P. distasonis-reacting antibodies in sera of NOD mice colonized with P. distasonis and human T1D patients. Furthermore, adoptive transfer of splenocytes from P. distasonis-treated mice to NOD/SCID mice enhanced disease phenotype in the recipients. Finally, analysis of human children gut microbiome data from a longitudinal DIABIMMUNE study revealed that seroconversion rates (i.e., the proportion of individuals developing two or more autoantibodies) were consistently higher in children whose microbiome harbored sequences capable of producing the hprt4-18 peptide compared to individuals who did not harbor it. Taken together, these data demonstrate the potential role of a gut microbiota-derived insB:9-23-mimic peptide as a molecular trigger of T1D pathogenesis.

Environmental Triggering of Type 1 Diabetes Autoimmunity.

Type 1 diabetes (T1D) is a chronic autoimmune disease in which pancreatic islet β cells are destroyed by immune cells, ultimately leading to overt diabetes. The progressive increase in T1D incidence over the years points to the role of environmental factors in triggering or accelerating the disease process which develops on a highly multigenic susceptibility background. Evidence that environmental factors induce T1D has mostly been obtained in animal models. In the human, associations between viruses, dietary habits or changes in the microbiota and the development of islet cell autoantibodies or overt diabetes have been reported. So far, prediction of T1D development is mostly based on autoantibody detection. Future work should focus on identifying a causality between the different environmental risk factors and T1D development to improve prediction scores. This should allow developing preventive strategies to limit the T1D burden in the future.

Medullary thyroid cancer in combination with autoimmune thyroiditis after covid-19

Background. Coronavirus disease 2019 (COVID-19) is a pandemic of the new millennium. COVID-19 can cause both pulmonary and systemic infammation, and can rapidly progress to multiple organ failure. Data on the relationship between COVID-19 and the thyroid gland have been available since March 2020. The thyroid gland and viral infection as well as associated infammatory-immune reactions participate in a complex interaction. The most common autoimmune disease is chronic autoimmune thyroiditis (chronic lymphocytic thyroiditis, Hashimoto thyroiditis). The majority of medullary thyroid cancers present as a thyroid nodule. Cervical lymph nodes and distant metastases are often detected at the time of diagnosis. The development of autoantibodies may be part of a more complex protective antitumor mechanism, the purpose of which is to eliminate the precursors of future tumor cells. The purpose of the study was to describe a clinical case of diagnosing medullary thyroid cancer in the patient who had COVID-19. Case description. We present the case of a 43-year-old woman who had coronavirus pneumonia (COVID-19), which was accompanied by an increase in serum procalcitonin (PC) level, which required additional examination. Since 2020, she had been observed for autoimmune thyroiditis, which was manifested by a thyroid nodular of a small size. After discharge from the COVID hospital, an ultrasound examination of the thyroid gland revealed an increase in the left lobe thyroid nodule up to 15 mm. The level of calcitonin was 681 pg/ml. Fine needle aspiration (FNA) biopsy of the thyroid gland showed suspicion for medullary thyroid cancer. Thyroidectomy with central lymph node dissection (level VI) was performed. A planned histological examination of the surgical specimen confrmed medullary thyroid cancer. Conclusion. In the present clinical case, medullary thyroid cancer was detected in the patient who had COVID-19 with elevated PC level, which was the basis for a diagnostic search.

Epstein-Barr Virus et lupus systémique : quels liens ?

Systemic lupus erythematosus (SLE) is a complex multifactorial autoimmune disease depending on both intrinsic and environmental factors. Among the latter, the Epstein-Barr Virus (EBV) has long been suggested as one of the responsible factors for the onset and activity of lupus disease. It is a herpes virus with a very specific tropism for B lymphocytes and therefore closely linked to the immune system. EBV infection almost always precedes the onset of lupus disease and in vitro data and animal models suggest that anti-EBV response may favor the development of autoantibodies and lupus disease in some subjects. Also, there are abnormalities in humoral and cellular responses to EBV and lupus patients have impaired control of EBV, with higher blood viral loads. Interstingly, this virus seems to be able to promote disease activity, by promoting the survival of autoreactive B lymphocytes and the production of interferon-α, which are two pivotal mechanisms in the pathophysiology of lupus disease.

A Roadmap for Investigating Preclinical Autoimmunity Using Patient-Oriented and Epidemiologic Study Designs: Example of Rheumatoid Arthritis.

Background & AimsRheumatoid arthritis (RA) is a prototypic autoimmune disease causing inflammatory polyarthritis that affects nearly 1% of the population. RA can lead to joint destruction and disability along with increased morbidity and mortality. Similar to other autoimmune diseases, RA has distinct preclinical phases corresponding to genetic risk, lifestyle risk factors, autoantibody development, and non-specific symptoms prior to clinical diagnosis. This narrative review will detail observational studies for RA risk and clinical trials for RA prevention as a roadmap to investigating preclinical autoimmunity that could be applied to other diseases.MethodsIn this narrative review, we summarized previous and ongoing research studies investigating RA risk and prevention, categorizing them related to their design and preclinical phases.ResultsWe detailed the following types of studies investigating RA risk and prevention: retrospective population-based and administrative datasets; prospective studies (case-control and cohort; some enrolling based on genetics, first-degree relative status, elevated biomarkers, or early symptoms/arthritis); and randomized clinical trials. These correspond to all preclinical RA phases (genetic, lifestyle, autoimmunity, early signs/symptoms). Previous and ongoing randomized controlled trials have enrolled individuals at very elevated risk for RA based on biomarkers, symptoms, imaging abnormalities, or early signs/symptoms.ConclusionWe detailed the rich variety of study designs that is necessary to investigate distinct preclinical phases of an autoimmune disease such as RA. However, further progress is needed to fully elucidate the pathogenesis of RA that may ultimately lead to prevention or delay of disease onset.

Autoantibodies against ATP4A are a feature of the abundant autoimmunity that develops in first-degree relatives of patients with type 1 diabetes.

Type 1 diabetes is associated with autoantibodies to different organs that include the gut. The objective of the study was to determine the risk of developing gastric parietal cell autoimmunity in relation to other autoimmunity in individuals with a family history of type 1 diabetes. Autoantibodies to the parietal cell autoantigen, H+ /K+ ATPase subunit A (ATP4A) was measured in 2218 first-degree relatives of patients with type 1 diabetes, who were prospectively followed from birth for a median of 14.5 years. All were also tested regularly for the development of islet autoantibodies, transglutaminase autoantibodies, and thyroid peroxidase autoantibodies. The cumulative risk to develop ATP4A autoantibodies was 8.1% (95% CI, 6.6-9.6) by age 20 years with a maximum incidence observed at age 2 years. Risk was increased in females (HR, 1.9; 95% CI, 1.3-2.8; p=0.0004), relatives with the HLA DR4-DQ8/DR4-DQ8 genotype (HR, 3.4; 95% CI, 1.9-5.9; p < 0.0001) and in participants who also had thyroid peroxidase autoantibodies (HR, 3.7; 95% CI, 2.5-5.5; p < 0.0001). Risk for at least one of ATP4A-, islet-, transglutaminase-, or thyroid peroxidase-autoantibodies was 24.7% (95% CI, 22.6-26.7) by age 20 years and was 47.3% (95% CI, 41.3-53.3) in relatives who had an HLA DR3/DR4-DQ8, DR4-DQ8/DR4-DQ8, or DR3/DR3 genotype (p < 0.0001 vs. other genotypes). Relatives of patients with type 1 diabetes who have risk genotypes are at very high risk for the development of autoimmunity against gastric and other organs.

Manifestations of the central nervous system after COVID-19

Zahlreiche Erkrankungen des Zentralnervensystems sind insbesondere in der Postakutphase nach einer Infektion mit SARS-CoV‑2 („severe acute respiratory syndrome coronavirus 2“) beschrieben. Diese umfassen neuroimmunologisch vermittelte Erkrankungen wie Enzephalopathien, Enzephalitiden, Myelitiden, ADEM (akute disseminierte Enzephalomyelitis), ANHLE (akute nekrotisierende hämorrhagische Leukoenzephalitis) und NMOSD (Neuromyelitis-optica-Spektrum-Erkrankungen), aber auch andere wie PRES (posteriores reversibles Enzephalopathiesyndrom), OMAS (Opsoklonus-Myoklonus-Ataxie-Syndrom) sowie zerebrovaskuläre Erkrankungen. Ein para- oder postinfektiöser Zusammenhang wird diskutiert, jedoch sind pathophysiologische Mechanismen bislang unbekannt. Ursächlich könnte eine virusgetriggerte Überaktivierung des Immunsystems mit Hyperinflammation und Zytokinsturm, aber möglicherweise auch die Bildung spezifischer Autoantikörper gegen Gewebe des Zentralnervensystems sein. Eine direkte Schädigung durch die Invasion von SARS-CoV‑2 in das Gehirn oder das Rückenmark scheint keine relevante Rolle zu spielen. Eine exakte klinische Phänotypisierung und Einleitung von Zusatzdiagnostik, auch zum Ausschluss anderer Ursachen, ist empfohlen. Bislang existieren noch keine medikamentösen Therapieoptionen zur Behandlung von ZNS-Manifestationen beim Long-COVID(„coronavirus disease“)-Syndrom. Erste Befunde zu Inflammation und Autoimmunität sind jedoch vielversprechend und könnten zu neuen Therapieansätzen führen.

Utilization of emicizumab in acquired hemophilia A: A case report

BackgroundAcquired Hemophilia A (AHA) is a rare autoimmune disorder associated with the development of autoantibodies against factor VIII (FVIII). Although obtaining hemostatic control through the use of recombinant factor VIIa, activated prothrombin complex concentrate and recombinant porcine FVIII are cornerstones in the clinical management of AHA, these therapies have several disadvantages, including a higher risk for the development of thromboembolic events, unpredictable efficacy and short half-lives. While emicizumab has been FDA licensed for use in bleeding prophylaxis for patients with Congenital Hemophilia A (CHA) with and without inhibitors, it has not been approved for use in AHA, with only a few reports describing its use in this context. Case reportWe report our experience with the use of emicizumab in an 83-year old male with AHA, complicated by the onset of atrial fibrillation following admission, drug-induced thrombocytopenia, infectious complications, and the identification of a low-grade lymphoproliferative disorder, in which emicizumab prophylaxis was used for bleeding prophylaxis in the context of persistently elevated inhibitor titers without evidence of thrombotic events or thrombotic microangiopathy.

Myosin 18A is a novel checkpoint regulator in B cell differentiation and antibody-mediated immunity

Abstract The B cell antibody response is tightly regulated to facilitate pathogen-specific immunity and prevent self-reactivity, with actin cytoskeleton dynamics playing an important role in regulating B cell activation. The newly discovered unconventional myosin family protein Myosin 18A (Myo18A) is most closely related to Myo2A, and regulates important cellular processes in non-lymphoid cells. Myo18A is expressed in both precursor and mature B cells, and interacts with ezrin, Myo2A and tyrosine phosphorylated proteins suggesting that it may regulate physiological functions of B cells. We investigated the function of Myo18A in antibody-mediated immunity by generating B cell-conditional Myo18A-deficient mice. Basally, Myo18A deficiency led to expansion of both bone marrow progenitor B cells, and mature B cells in secondary lymphoid organs. Myo18A-deficient mice displayed serum IgM hyperglobulinemia with greater levels of splenic IgM secreting cells, with older mice switching to IgG1 hyperglobulinemia and autoantibody development. Immunization of Myo18A-deficient mice with inactivated influenza virus led to development of more potent neutralizing antibodies against the major antigen hemagglutinin, associated with early expansion and persistent accumulation of antigen-specific germinal center B cells. In vitro stimulation with TLR7 and BCR ligands revealed a greater ability of Myo18A-deficient B cells to differentiate into antibody secreting cells, and induce Blimp-1 expression. Overall, our study demonstrates that Myo18A is a novel negative regulator of B cell homeostasis, differentiation, self-tolerance and humoral immunity. Supported by an NIH grant (R21 AI117350) to Neetu Gupta

Serum autoantibodyome reveals that healthy individuals share common autoantibodies

SUMMARYAutoantibodies are a hallmark of both autoimmune disease and cancer, but they also occur in healthy individuals. Here, we perform a meta-analysis of nine datasets and focus on the common autoantibodies shared by healthy individuals. We report 77 common autoantibodies based on the protein microarray data obtained from probing 182 healthy individual sera on 7,653 human proteins and an additional 90 healthy individual sera on 1,666 human proteins. There is no gender bias; however, the number of autoantibodies increase with age, plateauing around adolescence. We use a bioinformatics pipeline to determine possible molecular-mimicry peptides that can contribute to the elicitation of these common autoantibodies. There is enrichment of intrinsic properties of proteins like hydrophilicity, basicity, aromaticity, and flexibility for common autoantigens. Subcellular localization and tissue-expression analysis reveal that several common autoantigens are sequestered from the circulating autoantibodies.

Patients with severe COVID-19 do not have elevated autoantibodies against common diagnostic autoantigens.

Infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative pathogen of coronavirus disease 2019 (COVID-19) presents occasionally with an aberrant autoinflammatory response, including the presence of elevated circulating autoantibodies in some individuals. Whether the development of autoantibodies against self-antigens affects COVID-19 outcomes remains unclear. To better understand the prognostic role of autoantibodies in COVID-19, we quantified autoantibodies against 23 markers that are used for diagnosis of autoimmune disease. To this end, we used serum samples from patients with severe [intensive care unit (ICU)] and moderate (ward) COVID-19, across two to six consecutive time points, and compared autoantibody levels to uninfected healthy and ICU controls. Acute and post-acute serum (from 1 to 26 ICU days) was collected from 18 ICU COVID-19-positive patients at three to six time points; 18 ICU COVID-19-negative patients (sampled on ICU day 1 and 3); 21 ward COVID-19-positive patients (sampled on hospital day 1 and 3); and from 59 healthy uninfected controls deriving from two cohorts. Levels of IgG autoantibodies against 23 autoantigens, commonly used for autoimmune disease diagnosis, were measured in serum samples using MSD® U-PLEX electrochemiluminescence technology (MSD division Meso Scale Discovery®), and results were compared between groups. There were no significant elevations of autoantibodies for any of the markers tested in patients with severe COVID-19. Sample collections at longer time points should be considered in future studies, for assessing the possible development of autoantibody responses following infection with SARS-CoV-2.

Anti-CD45RC antibody immunotherapy prevents and treats experimental autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome.

Targeted monoclonal antibody (mAb) therapies show great promise for the treatment of transplant rejection and autoimmune diseases by inducing more specific immunomodulatory effects than broadly immunosuppressive drugs routinely used. We recently described the therapeutic advantage of targeting CD45RC, expressed at high levels by conventional T (Tconv) cells (CD45RChi), their precursors, and terminally differentiated T (TEMRA) cells, but not by regulatory T cells (Tregs; CD45RClo/–). We demonstrated efficacy of anti-CD45RC mAb treatment in transplantation, but its potential has not been examined in autoimmune diseases. Autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED) is a rare genetic syndrome caused by loss-of-function mutations of autoimmune regulator (AIRE), a key central tolerance mediator, leading to abnormal autoreactive T cell responses and autoantibody production. Herein, we show that, in a rat model of APECED syndrome, anti-CD45RC mAb was effective for both prevention and treatment of autoimmune manifestations and inhibited autoantibody development. Anti-CD45RC mAb intervention depleted CD45RChi T cells, inhibited CD45RChi B cells, and restored the Treg/Tconv cell ratio and the altered Treg transcriptomic profile. In APECED patients, CD45RC was significantly increased in peripheral blood T cells, and lesioned organs from APECED patients were infiltrated by CD45RChi cells. Our observations highlight the potential role for CD45RChi cells in the pathogenesis of experimental and human APECED syndrome and the potential of anti-CD45RC antibody treatment.

IL-1 receptor antagonist, MIS-C, and the peculiar autoimmunity of SARS-CoV-2

IL-1 receptor antagonist, MIS-C, and the peculiar autoimmunity of SARS-CoV-2

Laboratory coagulation tests and recombinant porcine factor VIII: A United Kingdom Haemophilia Centre Doctors' Organisation guideline.

Acquired haemophilia A (AHA) is a rare bleeding disorder caused by development of auto-antibodies to endogenous coagulation factor VIII (FVIII). Recombinant porcine factor VIII (rpFVIII) is currently licensed only for the management of bleeding in patients with AHA. Regular monitoring of rpFVIII is recommended to assess treatment effectiveness. This guideline from the United Kingdom Haemophilia Centre Doctors' Organisation (UKHCDO) examines the current publications in the area and aims to offer advice for the laboratory monitoring of rpFVIII in patients with AHA. A review of the current literature was undertaken followed by critical review by the authors. A validated one-stage clotting FVIII assay is recommended for the measurement and regular monitoring of rpFVIII. Assessment of cross-reacting rpFVIII inhibitors by one-stage porcine Bethesda assay should be performed as part of the initial diagnosis of AHA or prior to treatment with rpFVIII. Available data show that chromogenic FVIII assays underestimate rpFVIII and this should be considered if measurement of rpFVIII is required in patients receiving Emicizumab.

Critical role of WASp in germinal center tolerance through regulation of B cell apoptosis and diversification

A main feature of Wiskott-Aldrich syndrome (WAS) is increased susceptibility to autoimmunity. A key contribution of B cells to development of these complications has been demonstrated through studies of samples from affected individuals and mouse models of the disease, but the role of the WAS protein (WASp) in controlling peripheral tolerance has not been specifically explored. Here we show that B cell responses remain Tcell dependent in constitutive WASp-deficient mice, whereas selective WASp deletion in germinal center B cells (GCBs) is sufficient to induce broad development of self-reactive antibodies and kidney pathology, pointing to loss of germinal center tolerance as a primary cause leading to autoimmunity. Mechanistically, we show that WASp is upregulated in GCBs and regulates apoptosis and plasma cell differentiation in the germinal center and that the somatic hypermutation-derived diversification is the basis of autoantibody development.

Inhibition of spleen tyrosine kinase decreases donor specific antibody levels in a rat model of sensitization

Antibody mediated rejection is a major cause of renal allograft loss. Circulating preformed donor specific antibodies (DSA) can result as a consequence of blood transfusion, pregnancy or prior transplantation. Current treatment strategies are limited due to partial or transient efficacy, adverse side-effects or patient unsuitability. Previous in vivo studies exploring autoimmune diseases have shown that spleen tyrosine kinase (SYK) signalling is involved in the development of pathogenic autoantibody. The role of SYK in allogenic antibody production is unknown, and we investigated this in a rodent model of sensitization, established by the transfusion of F344 whole blood into LEW rats. Two-week treatment of sensitized rats with selective SYK inhibitor fostamatinib strongly blocked circulating DSA production without affecting overall total immunoglobulin levels, and inhibition was sustained up to 5 weeks post-completion of the treatment regimen. Fostamatinib treatment did not affect mature B cell subset or plasma cell levels, which remained similar between non-treated controls, vehicle treated and fostamatinib treated animals. Our data indicate fostamatinib may provide an alternative therapeutic option for patients who are at risk of sensitization following blood transfusion while awaiting renal transplant.

Growth in Children with HLA-Conferred Susceptibility to Type 1 Diabetes.

The incidence of type 1 diabetes (T1D) is increasing throughout the world. This trend may be explained by the accelerator hypothesis. Our study investigated growth, its biochemical markers, and their associations with the development of diabetes-associated autoantibodies (DAAB) in 219 children with genetic risk for T1D. Subjects were divided into risk groups based on their human leukocyte antigen genotype. Children in the moderate- to high-risk group were significantly taller when corrected to mid-parental height and had a lower insulin-like growth factor 1 (IGF-1)/IGF-1 binding protein (IGFBP-3) molar ratio than those in the low-risk group (corrected height standard deviation score 0.22±0.93 vs. −0.04±0.84, P<0.05; molar ratio 0.199±0.035 vs. 0.211+0.039, P<0.05). Children with DAAB tended to be taller and to have a higher body mass index than those with no DAAB. Our results suggest that the accelerator hypothesis explaining the increasing incidence of T1D may not solely be dependent on environmental factors, but could be partially genetically determined.

Homologous and Heterologous Anti-COVID-19 Vaccination Does Not Induce New-Onset Formation of Autoantibodies Typically Accompanying Lupus Erythematodes, Rheumatoid Arthritis, Celiac Disease and Antiphospholipid Syndrome.

The COVID-19 pandemics has caused the death of almost six million people worldwide. In order to establish collective immunity, the first vaccines that were approved in Germany were the vector virus-based vaccine Vaxzevria and the mRNA vaccines Comirnaty and Spikevax, respectively. As it was reported that SARS-CoV-2 can trigger autoimmunity, it is of significant interest to investigate whether COVID-19 vaccines evoke the formation of autoantibodies and subsequent autoimmunity. Here, we analyzed immune responses after different vaccination regimens (mRNA/mRNA, Vector/Vector or Vector/mRNA) with respect to anti-SARS-CoV-2-specific immunity and the development of autoantibodies well known for their appearance in distinct autoimmune diseases. We found that anti-SARS-CoV-2 antibody levels were 90% lower after Vector/Vector vaccination compared to the other vaccinations and that Vector/mRNA vaccination was more effective than mRNA/mRNA vaccination in terms of IgM and IgA responses. However, until 4 months after booster vaccination we only detected increases in autoantibodies in participants with already pre-existing autoantibodies whereas vaccinees showing no autoantibody formation before vaccination did not respond with sustained autoantibody production. Taken together, our study suggests that all used COVID-19 vaccines do not significantly foster the appearance of autoantibodies commonly associated with lupus erythematodes, rheumatoid arthritis, Celiac disease and antiphospholipid-syndrome but provide immunity to SARS-CoV-2.

Plasma proteomics associated with autoimmune coagulation factor deficiencies reveals the link between inflammation and autoantibody development.

Autoimmune coagulation factor deficiency (AiCFD) is characterized by sudden excessive bleeding due to autoantibodies against coagulation factors. This occurs primarily in elderly patients with no family history or previous clotting issues. However, the detailed mechanisms underlying autoantibody development are not well understood. Here, we evaluated the plasma proteome in patients with AiCFD and compared it with that of 22 healthy controls and 17 patients with non-autoimmune acquired factor XIII deficiency (acF13D). We identified eighteen proteins whose plasma levels were higher in AiCFD than in either healthy controls or patients with acF13D. Most of these proteins were found to be acute-phase reactants or immunoglobulins. Patients with acF13D had lower levels of nine of these proteins and higher levels of the remaining nine compared to healthy controls. However, in all cases, these protein levels were much higher in patients with AiCFD than in those with acF13D. These results suggest that an inflammatory response independent of the acute inflammation caused by bleeding can occur, which may lead to the development of AiCFD. Therefore, we believe that severe and/or chronic inflammation, probably due to an underlying disease or aging, is the most important factor in autoantibody development.