Autoantibodies of IgM and IgG classes show differences in recognition of multiple autoantigens in chronic obstructive pulmonary disease

Differential expression of sputum and serum autoantibodies in patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a complex and progressive respiratory disease. Autoimmune processes have been hypothesized to contribute to disease progression; however, the presence of autoantibodies in the serum has been variable. Given that COPD is a lung disease, we sought to investigate whether autoantibodies in sputum supernatant would better define pulmonary autoimmune processes. Matched sputum and serum samples were obtained from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study and at the Guangzhou Institute of Respiratory Health (GIRH). Samples were collected from patients with varying severity of COPD, asymptomatic smokers, and healthy control subjects. IgG and IgM autoantibodies were detected in sputum and serum of all subjects in both cohorts using a broad-spectrum autoantigen array. No differences were observed in sputum autoantibodies between COPD and asymptomatic smokers in either cohort. In contrast, 16% of detectable sputum IgG autoantibodies were decreased in subjects with COPD compared to healthy controls in the ADEPT cohort. Compared to asymptomatic smokers, approximately 13% of detectable serum IgG and 40% of detectable serum IgM autoantibodies were differentially expressed in GIRH COPD subjects. Of the differentially expressed specificities, anti-nuclear autoantibodies were predominately decreased. A weak correlation between increased serum IgM anti-tissue autoantibodies and a measure of airspace enlargement was observed. The differential expression of specificities varied between the cohorts. In closing, using a comprehensive autoantibody array, we demonstrate that autoantibodies are present in subjects with COPD, asymptomatic smokers, and healthy controls. Cohorts displayed high levels of heterogeneity, precluding the utilization of autoantibodies for diagnostic purposes.

Array-based measurements of aero-allergen-specific IgE correlate with skin-prick test reactivity in asthma regardless of specific IgG4 or total IgE measurements

Skin prick testing (SPT) and measurement of serum allergen-specific IgE (sIgE) are used to investigate asthma and other allergic conditions. Measurement of serum total IgE (tIgE) and allergen-specific IgG4 (sIgG4) may also be useful. The aim was to ascertain the correlation between these serological parameters and SPT. Sera from 60 suspected asthmatic patients and 18 healthy controls were assayed for sIgE and sIgG4 reactivity against a panel of 70 SPT allergen preparations, and for tIgE. The patients were also assessed by skin prick tests for reactivity to cat, dog, house dust mite and grass allergens. Over 50% of the patients had tIgE levels above the 75th percentile of the controls. 58% of patients and 39% of controls showed sIgE reactivity to ≥1 allergen. The mean number of allergens detected by sIgE was 3.1 in suspected asthma patients and 0.9 in controls. 58% of patients and 50% of controls showed sIgG4 reactivity to ≥1 allergen. The mean number of allergens detected by sIgG4 was 2.5 in patients and 1.7 in controls. For the patients, a strong correlation was observed between clinical SPT reactivity and serum sIgE levels to cat, dog, house dust mite (HDM) and grass allergens. SPT correlations using sIgE/sIgG4 or sIgE/tIgE ratios were not markedly higher. The measurement of serum sIgE by microarray using SPT allergen preparations showed good correlation with clinical SPT reactivity to cat, dog, HDM and grass allergens. This concordance was not improved by measuring tIgE or sIgG4.

The role of oxidised self-lipids and alveolar macrophage CD1b expression in COPD

In chronic obstructive pulmonary disease (COPD) apoptotic bronchial epithelial cells are increased, and their phagocytosis by alveolar macrophages (AM) is decreased alongside bacterial phagocytosis. Epithelial cellular lipids, including those exposed on uncleared apoptotic bodies, can become oxidized, and may be recognized and presented as non-self by antigen presenting cells. CD1b is a lipid-presenting protein, previously only described in dendritic cells. We investigated whether CD1b is upregulated in COPD AM, and whether lipid oxidation products are found in the airways of cigarette smoke (CS) exposed mice. We also characterise CD1b for the first time in a range of macrophages and assess CD1b expression and phagocytic function in response to oxidised lipid. Bronchoalveolar lavage and exhaled breath condensate were collected from never-smoker, current-smoker, and COPD patients and AM CD1b expression and airway 8-isoprostane levels assessed. Malondialdehyde was measured in CS-exposed mouse airways by confocal/immunofluorescence. Oxidation of lipids produced from CS-exposed 16HBE14o- (HBE) bronchial epithelial cells was assessed by spectrophotometry and changes in lipid classes assessed by mass spectrometry. 16HBE cell toxicity was measured by flow cytometry as was phagocytosis, CD1b expression, HLA class I/II, and mannose receptor (MR) in monocyte derived macrophages (MDM). AM CD1b was significantly increased in COPD smokers (4.5 fold), COPD ex-smokers (4.3 fold), and smokers (3.9 fold), and AM CD1b significantly correlated with disease severity (FEV₁) and smoking pack years. Airway 8-isoprostane also increased in smokers and COPD smokers and ex-smokers. Malondialdehyde was significantly increased in the bronchial epithelium of CS-exposed mice (MFI of 18.18 vs 23.50 for control). Oxidised lipid was produced from CS-exposed bronchial epithelial cells (9.8-fold of control) and showed a different overall lipid makeup to that of control total cellular lipid. This oxidised epithelial lipid significantly upregulated MDM CD1b, caused bronchial epithelial cell toxicity, and reduced MDM phagocytic capacity and MR in a dose dependent manner. Increased levels of oxidised lipids in the airways of COPD patients may be responsible for reduced phagocytosis and may become a self-antigen to be presented by CD1b on macrophages to perpetuate disease progression despite smoking cessation.

Immune modulation via T regulatory cell enhancement: Disease-modifying therapies for autoimmunity and their potential for chronic allergic and inflammatory diseases-An EAACI position paper of the Task Force on Immunopharmacology (TIPCO)

Therapeutic advances using targeted biologicals and small-molecule drugs have achieved significant success in the treatment of chronic allergic, autoimmune, and inflammatory diseases particularly for some patients with severe, treatment-resistant forms. This has been aided by improved identification of disease phenotypes. Despite these achievements, not all severe forms of chronic inflammatory and autoimmune diseases are successfully targeted, and current treatment options, besides allergen immunotherapy for selected allergic diseases, fail to change the disease course. T cell-based therapies aim to cure diseases through the selective induction of appropriate immune responses following the delivery of engineered, specific cytotoxic, or regulatory T cells (Tregs). Adoptive cell therapies (ACT) with genetically engineered T cells have revolutionized the oncology field, bringing curative treatment for leukemia and lymphoma, while therapies exploiting the suppressive functions of Tregs have been developed in nononcological settings, such as in transplantation and autoimmune diseases. ACT with Tregs are also being considered in nononcological settings such as cardiovascular disease, obesity, and chronic inflammatory disorders. After describing the general features of T cell-based approaches and current applications in autoimmune diseases, this position paper reviews the experimental models testing or supporting T cell-based approaches, especially Treg-based approaches, in severe IgE-mediated responses and chronic respiratory airway diseases, such as severe asthma and COPD. Along with an assessment of challenges and unmet needs facing the application of ACT in these settings, this article underscores the potential of ACT to offer curative options for patients with severe or treatment-resistant forms of these immune-driven disorders.

Cigarette smoking differentially affects immunoglobulin class levels in serum and saliva: An investigation and review

The aim of the present study was to compare concentrations of IgG, IgA, IgM and IgD in both serum and saliva samples from smoking and non-smoking individuals using a protein microarray assay. The findings were also compared to previous studies. Serum and saliva were collected from 48 smoking male individuals and 48 age-matched never-smoker male individuals. The protein microarray assays for detection of human IgG, IgM, IgA and IgD were established and optimized using Ig class-specific affinity-purified goat anti-human Ig-Fc capture antibodies and horseradish peroxidase (HRP)-conjugated goat anti-human Ig-Fc detection antibodies. The Ig class specificity of the microarray assays was verified, and the optimal dilutions of serum and saliva samples were determined for quantification of Ig levels against standard curves. We found that smoking is associated with reduced IgG concentrations and enhanced IgA concentrations in both serum and saliva. By contrast, smoking differentially affected IgM concentrations-causing increased concentrations in serum, but decreased concentrations in saliva. Smoking was associated with decreased IgD concentrations in serum and did not have a significant effect on the very low IgD concentrations in saliva. Thus, cigarette smoking differentially affects the levels of Ig classes systemically and in the oral mucosa. Although there is variation between the results of different published studies, there is a consensus that smokers have significantly reduced levels of IgG in both serum and saliva. A functional antibody deficiency associated with smoking may compromise the body's response to infection and result in a predisposition to the development of autoimmunity.

Tobacco smoke and nicotine suppress expression of activating signaling molecules in human dendritic cells

Cigarette smoke has significant toxic effects on the immune system, and increases the risk of developing autoimmune diseases; one immunosuppressive effect of cigarette smoke is that it inhibits the T cell-stimulating, immunogenic properties of myeloid dendritic cells (DCs). As the functions of DCs are regulated by intra-cellular signaling pathways, we investigated the effects of cigarette smoke extract (CSE) and nicotine on multiple signaling molecules and other regulatory proteins in human DCs to elucidate the molecular basis of the inhibition of DC maturation and function by CSE and nicotine. Maturation of monocyte-derived DCs was induced with the TLR3-agonist poly I:C or with the TLR4-agonist lipopolysaccharide, in the absence or presence of CSE or nicotine. Reverse-phase protein microarray was used to quantify multiple signaling molecules and other proteins in cell lysates. Particularly in poly I:C-matured DCs, cigarette smoke constituents and nicotine suppressed the expression of signaling molecules associated with DC maturation and T cell stimulation, cell survival and cell migration. In conclusion, constituents of tobacco smoke suppress the immunogenic potential of DCs at the signaling pathway level.