Isotype and IgG subclass distribution of autoantibody response to alpha-enolase protein in adult patients with severe asthma

A microarray-based IgE-molecular mimicry index (IgE-MMI): A biomarker for disease severity, clinical phenotypes, and therapeutic response in atopic dermatitis?

BACKGROUND

The role of autoimmune IgE responses in atopic dermatitis (AD) is highly debated. While IgE targeting self-proteins has been extensively studied, IgE responses induced by human-homologous exogenous molecular allergens (HEMAs) remains less understood.

AIM

To investigate whether IgE antibody responses to HEMAs are associated with AD, its severity, and response to dupilumab.

METHODS

We enrolled 3325 participants with a history of allergic diseases, including 577 (17.3%) diagnosed with AD. Serum IgE antibodies against 183 exogenous allergenic molecules were measured using the IgE microarray (Allergy Explorer-ALEX-2®, MADX, Vienna). Based on international classification criteria, participants were stratified by AD severity and clinical phenotypes. For each patient, we developed an 'IgE molecular-mimicry index' (IgE-MMI), calculated from IgE reactivity to a panel of five HEMA protein families: arginine kinase, enolase (ENO), cyclophilin (CYP), lipocalin, and MnSOD. Logistic regression was employed to assess the association between IgE to HEMAs or IgE-MMI and AD, its severity, and response to dupilumab.

RESULTS

IgE sensitization to most HEMAs (32/48, 67%), but only to a small fraction of non-HEMAs (3/135, 2.2%), was significantly more common in patients with severe AD compared to other patient groups. The IgE-MMI was positive in 295/2748 (10.7%) of allergic patients without AD, and in 58/283 (20%), 52/134 (39%), and 86/160 (54%) of patients with remitting, moderate, or severe AD, respectively. It was strongly associated with specific phenotypes, such as flexural dermatitis (OR 8.4, 95% CI: 6.3-11.2), head and neck dermatitis (OR: 16.5, 95% CI: 7.4-37.2), and generalized eczema (OR: 8.6, 95% CI: 4.9-15.6). Poor response to dupilumab was associated with IgE antibodies to ENO (OR: 22.7, 95% CI: 1.7-302.9), but inversely associated with IgE antibodies to MnSOD (OR: 0.1, 95% CI: 0.02-0.8) and NPC-2 from dust mites (OR: 0.1, 95% CI: 0.01-0.9).

CONCLUSION

IgE microarrays are useful for broadly assessing IgE to HEMAs in allergic patients. IgE reactivity to HEMAs and a positive IgE-MMI may serve as valuable biomarkers for severe AD, its clinical phenotypes, and the response to dupilumab.

Determination of the Predictive Roles and Potentially Pathogenic Antigen Epitopes of α-Enolase Related to the Development of Miscarriage in Females with Autoimmune Thyroiditis

Autoimmune thyroiditis (AIT) is a common endocrine disease which causes a significantly increased risk of miscarriage. Our recent study has shown that the increased ENO1 autoantibody (ENO1Ab) expression in an experimental AIT mouse model was induced by thyroglobulin (Tg) immunization only. In this study, we explored the potential roles of ENO1Ab in miscarriage occurrence among AIT women, and the specific epitopes of ENO1 targeted by ENO1Ab. A total of 432 euthyroid pregnant participants were selected from the project of Subclinical Hypothyroid during Early Pregnancy, including 48 women with AIT and miscarriage, 96 with miscarriage but no AIT, 96 with AIT but no miscarriage, and 192 without either AIT or miscarriage. The enzyme-linked immunosorbent assay was used to determine the serum levels of total IgG against ENO1 and 18 predicted antigen epitopes of ENO1. The results showed that women with AIT and miscarriage had the highest serum levels of ENO1Ab compared to the other groups. Logistic regression analysis showed that the serum ENO1Ab was an independent risk factor for miscarriage, especially among AIT females. The serum level of total IgG against the predicted epitope peptide 6 (i.e., P6 and aa168-183) of ENO1 was significantly increased in women with AIT and miscarriage when compared with those of both the AIT non-miscarriage group and non-AIT miscarriage group. This pilot study suggests that serum ENO1Ab may have a fair predictive value for AIT-related miscarriage, and the autoantibody specific to P6 epitope may especially be more specifically related to this disorder.

Airway autoimmunity, asthma exacerbations, and response to biologics

Biologic therapies in asthma are indicated in severe disease, and they are directed against specific inflammatory modulators that contribute to pathogenesis and severity. Currently approved biologics target T2 cytokines (IgE, IL-5, IL-4/IL-13, and TLSP) and have demonstrated efficacy in clinical outcomes such as exacerbation rate and oral corticosteroid dose reductions, blood and airway eosinophil depletion, and lung function improvement. However, a proportion of these patients may show inadequate responses to biologics, with either initial lack of improvement or clinical and functional worsening after an optimal initial response. Exacerbations while on a biologic may be due to several reasons, including imprecise identification of the dominant effector pathway contributing to severity, additional inflammatory pathways that are not targeted by the biologic, inaccuracies of the biomarker used to guide therapy, inadequate dosing schedules, intercurrent airway infections, anti-drug neutralizing antibodies, and a novel phenomenon of autoimmune responses in the airways interfering with the effectiveness of the monoclonal antibodies. This review, illustrated using case scenarios, describes the underpinnings of airway autoimmune responses in driving exacerbations while patients are being treated with biologics, device a strategy to evaluate such exacerbations, an algorithm to switch between biologics, and perhaps to consider two biologics concurrently.

Autoimmune Responses in Severe Asthma

Asthma and autoimmune diseases both result from a dysregulated immune system, and have been conventionally considered to have mutually exclusive pathogenesis. Autoimmunity is believed to be an exaggerated Th1 response, while asthma with a Th2 underpinning is congruent with the well-accepted Th1/Th2 paradigm. The hypothesis of autoimmune involvement in asthma has received much recent interest, particularly in the adult late-onset non-atopic patients (the “intrinsic asthma”). Over the past decades, circulating autoantibodies against diverse self-targets (beta-2-adrenergic receptors, epithelial antigens, nuclear antigens, etc.) have been reported and subsequently dismissed to be epiphenomena resulting from a chronic inflammatory condition, primarily due to lack of evidence of causality/pathomechanism. Recent evidence of ‘granulomas’ in the lung biopsies of severe asthmatics, detection of pathogenic sputum autoantibodies against autologous eosinophil proteins (e.g., eosinophil peroxidase) and inadequate response to monoclonal antibody therapies (e.g., subcutaneous mepolizumab) in patients with evidence of airway autoantibodies suggest that the role of autoimmune mechanisms be revisited. In this review, we have gathered available reports of autoimmune responses in the lungs, reviewed the evidence in the context of immunogenic tissue-response and danger-associated molecular patterns, and constructed the possibility of an autoimmune-associated pathomechanism that may contribute to the severity of asthma.

Bickerstaff's brainstem encephalitis, Miller Fisher syndrome and Guillain-Barré syndrome overlap in an asthma patient with negative anti-ganglioside antibodies

Background

Bickerstaff’s brainstem encephalitis (BBE), together with Miller Fisher syndrome (MFS) and Guillain-Barré syndrome (GBS) were considered to form a continuous clinical spectrum. An anti-GQ1b antibody syndrome has been proposed to underlie the common pathophysiology for the three disorders; however, other studies have found a positive anti-GM1 instead of anti-GQ1b antibody.

Case presentation

Here we report a 20-year-old male patient with overlapping BBE, MFS and GBS. The patient had a positive family history of bronchial asthma and had suffered from the condition for over 15 years. He developed BBE symptoms nine days after an asthma exacerbation. During the course of illness, he had significantly elevated IgE levels in both serum and cerebrospinal fluid. Serologic analysis of antibodies against ganglioside complexes (anti-GDIa, anti-GDIb, anti-GM1, anti-GM2, anti-GM3, anti-GQIb and anti-GTIb antibodies) showed negative results.

Conclusions

Since asthma has recently been related to autoimmune disease, our case supports an autoimmune mechanism underlying the clinical spectrum composed of BBE, MFS and GBS. However, contrary to a proposed anti-GQ1b antibody syndrome, we would suggest that pathogenesis of this clinical spectrum is not limited to anti-ganglioside antibodies.

Immune responses to self-antigens in asthma patients: clinical and immunopathological implications

Asthma leads to chronic airway inflammation that shares pathological features of chronic rejection after lung transplantation. Due to the significant role of autoimmunity in chronic rejection, we hypothesized that immunity to self-antigens may also be present in asthma. The goal was to define immune responses to self-antigens in patients with asthma. Blood and clinical data were collected from 99 asthmatics and 60 controls. Serum was analyzed for antibodies (Abs) to collagen V (ColV) by enzyme-linked immunosorbent assay and correlated with disease severity. Asthmatics' sera were tested in a human protein array to determine immune responses to other self-antigens. Asthmatics had higher concentrations of Abs to ColV (predominantly immunoglobulin G isotype) compared with controls (p < 0.01). These Abs correlated with severe asthma (p < 0.01) and corticosteroid use (p = 0.032). Additionally, Abs to novel self-antigens epidermal group factor receptor (EGFr), activin A type 1 receptor, and α-catenin were detected in asthmatics. We conclude that Abs to self-antigens (ColV, EGFr, activin A type 1 receptor, and α-catenin) are present in the sera of asthmatics, correlating with clinical disease. Epithelial damage from airway inflammation during asthma may result in the exposure of cryptic self-antigens or their determinants, resulting in immune response to self-antigens, which may contribute to the pathogenesis of asthma.

Development of a multiplexed tumor-associated autoantibody-based blood test for the detection of non-small cell lung cancer

PURPOSE

Non-small cell lung cancer (NSCLC) has an overall 5-year survival of <15%; however, the 5-year survival for stage I disease is over 50%. Unfortunately, 75% of NSCLC is diagnosed at an advanced stage not amenable to surgery. A convenient serum assay capable of unambiguously identifying patients with NSCLC may provide an ideal diagnostic measure to complement computed tomography-based screening protocols.

EXPERIMENTAL DESIGN

Standard immunoproteomic method was used to assess differences in circulating autoantibodies among lung adenocarcinoma patients relative to cancer-free controls. Candidate autoantibodies identified by these discovery phase studies were translated into Luminex-based "direct-capture" immunobead assays along with 10 autoantigens with previously reported diagnostic value. These assays were then used to evaluate a second patient cohort composed of four discrete populations, including: 117 NSCLC (81 T(1-2)N(0)M(0) and 36 T(1-2)N(1-2)M(0)), 30 chronic obstructive pulmonary disorder (COPD)/asthma, 13 nonmalignant lung nodule, and 31 "normal" controls. Multivariate statistical methods were then used to identify the optimal combination of biomarkers for classifying patient disease status and develop a convenient algorithm for this purpose.

RESULTS

Our immunoproteomic-based biomarker discovery efforts yielded 16 autoantibodies differentially expressed in NSCLC versus control serum. Thirteen of the 25 analytes tested showed statistical significance (Mann-Whitney P < 0.05 and a receiver operator characteristic "area under the curve" over 0.65) when evaluated against a second patient cohort. Multivariate statistical analyses identified a six-biomarker panel with only a 7% misclassification rate.

CONCLUSIONS

We developed a six-autoantibody algorithm for detecting cases of NSCLC among several high-risk populations. Population-based validation studies are now required to assign the true value of this tool for identifying early-stage NSCLC.

Identifications of inhibitors of IgE production by human lymphocytes isolated from 'Cha Chuukanbohon Nou 6' tea leaves

BACKGROUND

Tea (Camellia sinensis L.) is consumed all over the world and in especially large quantities in Japan and China, where it has been used not only as a daily beverage but also for medicinal purposes for thousands of years. Tea has been found to exhibit various bioregulatory activities, including antiallergic, anticarcinogenic, antimetastatic, antioxidative, antihypertensive, antihypercholesterolemic, anti-dental caries and antibacterial effects, and to influence intestinal flora.

RESULTS

Cha Chuukanbohon Nou 6 is a tea cultivar improved by the National Institute of Vegetable and Tea Science (NIVTS) in Japan. On comparing chemical constituents of 11 varieties of tea leaves by high-performance liquid chromatography, we found two new major compounds in Cha Chuukanbohon Nou 6. Nuclear magnetic resonance spectroscopy revealed these compounds to be theogallin and 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-beta-D-glucopyranose. The two were similar in chemical structure to strictinin, an inhibitor of immunoglobulin (Ig) production. Thus their effects on the production of Igs by peripheral blood lymphocytes were tested. Both compounds, like strictinin, inhibited IgE production.

CONCLUSION

The results suggest Cha Chuukanbohon Nou 6 to be the basis of an antiallergic beverage.

SLA/LP/tRNP((Ser)Sec) antigen in autoimmune hepatitis: identification of the native protein in human hepatic cell extract

A diagnostic subgroup of AIH type 1 is characterized by specific serum antibodies against soluble liver protein. The respective autoantigen was named SLA/LP/tRNP((Ser)Sec), after three homologous recombinant polypeptides were isolated from expression gene libraries. We analyzed human cultured liver cells for the human homologue of recombinant SLA/LP/tRNP((Ser)Sec) by antigen purification. In addition, a monoclonal antibody was generated against recombinant SLA-p35, a truncated recombinant SLA-reactive polypeptide. With a positive patient serum, immune affinity chromatography was performed on the 52 kD-SLA main antigenic determinant pre-enriched by ion exchange chromatography. By mass spectrometry, the 52 kD-SLA/LP/tRNP ((Ser)Sec) autoantigen was unambiguously identified in the purification product. The identity of the recombinant SLA-p35 and its human homologue was further confirmed by a specific signal of the anti SLA-p35 monoclonal antibody with purified human SLA/LP/tRNP((Ser)Sec). The 48 kD-SLA species frequently comigrating in SLA-immunoblotting however was not identified by either approach. We conclude that the native counterpart of recombinant tRNP((Ser)(Sec)) indeed is detectable with a molecular weight of 52 kD in soluble liver extract of human cells as the major antigenic component of SLA/LP/tRNP((Ser)Sec).