Kita, H

AbstractAsthma is independently associated with HLA‐DR3 and increased risks of pneumococcal diseases. We aimed to determine whether HLA‐DR polymorphism (HLA‐DRB1*03), sensitization to house dust mite (HDM), or their interaction affects humoral immune responses to pneumococcal polysaccharide and protein antigens of intact pneumococci. Induction of serum titers of anti‐pneumococcal polysaccharide and anti‐surface protein IgM and IgG in response to immunization with intact pneumococci (Pn) serotype 14 was determined using humanized HLA‐DR3 and DR2 transgenic mice. Transgenic mice were sensitized by injecting HDM and challenged with intranasal HDM. Mice were subsequently immunized with heat‐killed Pn14 at day 24. Serum titers of anti‐phosphorylcholine (PC) IgM and IgG, anti‐pneumococcal polysaccharide, capsular type 14 (PPS14) IgM and IgG, and anti‐pneumococcal surface protein A (PspA) IgG were measured. We included a total of 44 mice (22 DR3 and 22 DR2 mice) and half of mice in each group were sensitized with HDM (i.e. 22 HDM‐sensitized and 22 control mice). HDM‐sensitized mice, irrespective of HLA‐DR polymorphism, had significantly lower humoral immune responses. HLA‐DR3 mice, irrespective of HDM sensitization, elicited a significantly lower anti‐PC IgG response. In contrast, the anti‐PspA IgG response was higher in DR3 relative to DR2 mice. The effect of HDM sensitization on lowering humoral immune responses to Pn14 was observed in DR3 mice regardless of the nature of the antigen, whereas such decreases were observed only for the anti‐PPS14 IgG and anti‐PC IgM responses in DR2 mice. HDM sensitization lowered humoral immune responses to intact pneumococcus and this effect was significantly modified by the HLA‐DR polymorphism.

Abstract Innate lymphoid cells (ILCs) are a new family of immune cells that play important roles in innate immunity in mucosal tissues, and in the maintenance of tissue and metabolic homeostasis. Recently, group 2 ILCs (ILC2s) were found to promote the development and effector functions of Th2-type CD4+ T cells by interacting directly with T cells or by activating dendritic cells, suggesting a role for ILC2s in regulating adaptive immunity. However, our current knowledge on the role of ILCs in humoral immunity is limited. In this study, we found that ILC2s isolated from the lungs of naive BALB/c mice enhanced the proliferation of B1- as well as B2-type B cells and promoted the production of IgM, IgG1, IgA, and IgE by these cells in vitro. Soluble factors secreted by ILC2s were sufficient to enhance B cell Ig production. By using blocking Abs and ILC2s isolated from IL-5–deficient mice, we found that ILC2-derived IL-5 is critically involved in the enhanced production of IgM. Furthermore, when adoptively transferred to Il7r−/− mice, which lack ILC2s and mature T cells, lung ILC2s promoted the production of IgM Abs to a polysaccharide Ag, 4-hydroxy-3-nitrophenylacetyl Ficoll, within 7 d of airway exposure in vivo. These findings add to the growing body of literature regarding the regulatory functions of ILCs in adaptive immunity, and suggest that lung ILC2s promote B cell production of early Abs to a respiratory Ag even in the absence of T cells.

AbstractBackgroundExposure to aeroallergens induces eosinophilic airway inflammation in patients with asthma and allergic airway diseases. The circulating number of eosinophils in peripheral blood is relatively small, leading us to hypothesize that bone marrow needs to be engaged quickly to meet the demands of the tissues.MethodsTo investigate the communication between the lungs and bone marrow, we used acute allergen exposure and airway inflammation models in mice. Gene‐deficient mice and cytokine reporter mice as well as in vitro cell culture models were used to dissect the mechanisms.ResultsNaïve BALB/c mice produced increased numbers of eosinophil precursors and mature eosinophils in the bone marrow when their airways were exposed to a common fungal allergen, Alternaria alternata. Expression of IL‐5 and IL‐33 increased rapidly in the lungs, but not in the bone marrow. Sera from allergen‐exposed mice promoted eosinophilopoiesis in bone marrow cells from naïve mice, which was blocked by anti‐IL‐5 antibody. Mice deficient in the IL‐33 receptor ST2 (i.e., Il1rl1−/− mice) were unable to increase their serum levels of IL‐5 and allergen‐induced eosinophilopoiesis in the bone marrow after allergen exposure. Finally, group 2 innate lymphoid cells (ILC2s) in the lungs showed robust expression of IL‐5 after Alternaria exposure.ConclusionsThese finding suggests that lung IL‐33, through innate activation of ILC2s and their production of IL‐5, plays a key role in promoting acute reactive eosinophilopoiesis in the bone marrow when naïve animals are exposed to airborne allergens. Therefore, bone marrow eosinophilopoiesis may be affected by atmospheric environmental conditions.

Abstract Rationale Most immunocompetent patients diagnosed with latent tuberculosis infection (LTBI) will not progress to tuberculosis (TB) reactivation. However, current diagnostic tools cannot reliably distinguish nonprogressing from progressing patients a priori, and thus LTBI therapy must be prescribed with suboptimal patient specificity. We hypothesized that LTBI diagnostics could be improved by generating immunomarker profiles capable of categorizing distinct patient subsets by a combinatorial immunoassay approach. Objectives A combinatorial immunoassay analysis was applied to identify potential immunomarker combinations that distinguish among unexposed subjects, untreated patients with LTBI, and treated patients with LTBI and to differentiate risk of reactivation. Methods IFN-γ release assay (IGRA) was combined with a flow cytometric assay that detects induction of CD25+CD134+ coexpression on TB antigen–stimulated T cells from peripheral blood. The combinatorial immunoassay analysis was based on receiver operating characteristic curves, technical cut-offs, 95% bivariate normal density ellipse prediction, and statistical analysis. Risk of reactivation was estimated with a prediction formula. Measurements and Main Results Sixty-five out of 150 subjects were included. The combinatorial immunoassay approach identified at least four different T-cell subsets. The representation of these immune phenotypes was more heterogeneous in untreated patients with LTBI than in treated patients with LTBI or unexposed groups. Patients with IGRA(+) CD4+CD25+CD134+ T-cell phenotypes had the highest estimated reactivation risk (4.11 ± 2.11%). Conclusions These findings suggest that immune phenotypes defined by combinatorial assays may potentially have a role in identifying those at risk of developing TB; this potential role is supported by risk of reactivation modeling. Prospective studies will be needed to test this novel approach.

Calcilytics reduce airway hyperresponsiveness and inflammation and may represent effective asthma therapeutics.

CD38 is a cell-surface protein involved in calcium signaling and contractility of airway smooth muscle. It has a role in normal airway responsiveness and in airway hyperresponsiveness (AHR) developed following airway exposure to IL-13 and TNF-α but appears not to be critical to airway inflammation in response to the cytokines. CD38 is also involved in T cell-mediated immune response to protein antigens. In this study, we assessed the contribution of CD38 to AHR and inflammation to two distinct allergens, ovalbumin and the epidemiologically relevant environmental fungus Alternaria. We also generated bone marrow chimeras to assess whether Cd38+/+inflammatory cells would restore AHR in the CD38-deficient ( Cd38−/−) hosts following ovalbumin challenge. Results show that wild-type (WT) mice develop greater AHR to inhaled methacholine than Cd38−/−mice following challenge with either allergen, with comparable airway inflammation. Reciprocal bone marrow transfers did not change the native airway phenotypic differences between WT and Cd38−/−mice, indicating that the lower airway reactivity of Cd38−/−mice stems from Cd38−/−lung parenchymal cells. Following bone marrow transfer from either source and ovalbumin challenge, the phenotype of Cd38−/−hosts was partially reversed, whereas the airway phenotype of the WT hosts was preserved. Airway inflammation was similar in Cd38−/−and WT chimeras. These results indicate that loss of CD38 on hematopoietic cells is not sufficient to prevent AHR and that the magnitude of airway inflammation is not the predominant underlying determinant of AHR in mice.

SummaryBackgroundThe mechanisms and immune pathways associated with chronic rhinosinusitis (CRS) are not fully understood. Immunological changes during acute exacerbation of CRS may provide valuable clues to the pathogenesis and perpetuation of the disease.ObjectiveTo characterize local and systemic immune responses associated with acute worsening of sinonasal symptoms during exacerbation in CRS with nasal polyps (CRSwNP) compared to controls.MethodsThis was a non‐interventional prospective study of individuals with CRSwNP and normal controls. Subjects underwent a baseline visit with collection of nasal secretions, nasal washes, and serum specimens. Within 3 days of acute worsening of sinonasal symptoms, subjects underwent a study visit, followed by a post‐visit 2 weeks later. The sinonasal outcome test‐22 (SNOT‐22) scores and immunological parameters in the specimens were analysed using a novel, unsupervised learning method and by conventional univariate analysis.ResultsBoth CRSwNP patients and control subjects showed a significant increase in SNOT‐22 scores during acute exacerbation. Increased nasal levels of IL‐6, IL‐5, and eosinophil major basic protein were observed in CRSwNP patients. A network analysis of serum specimens revealed changes in a set of immunological parameters, which are distinctly associated with CRSwNP but not with controls. In particular, systemic increases in VEGF and GM‐CSF levels were notable and were validated by a conventional analysis.ConclusionsCRSwNP patients demonstrate distinct immunological changes locally and systemically during acute exacerbation. Growth factors VEGF and GM‐CSF may be involved in the immunopathogenesis of subjects with CRS and nasal polyps experiencing exacerbation.

BackgroundA histologic hallmark of chronic rhinosinusitis (CRS) is an eosinophilic inflammation, present with and without nasal polyposis and independent of atopy. Eosinophils migrate through nasal tissue including the epithelium into the nasal airway mucus, where they form clusters and degranulate, releasing granule proteins including the toxic major basic protein (MBP). Specific biomarkers for CRS, which could be used as a diagnostic test for CRS with a high sensitivity and specificity, are presently lacking. Recently, an enzyme‐linked immunosorbent assay (ELISA)‐based test for MBP in nasal airway mucus received regulatory approval.MethodsA new assay was specifically developed to detect released MBP in airway mucus. MBP levels in nasal mucus of 85 randomly selected CRS patients diagnosed by endoscopy, computed tomography (CT) scans and symptoms were compared to 13 healthy controls and 5 disease controls (allergic rhinitis).ResultsOverall, 92% (78/85) of CRS patients’ mucus were positive for MBP (mean 7722 ng/mL) vs none of 13 healthy controls and none of 5 allergic rhinitis patients (<7.8 ng/mL; p < 0.000000000002). In this study, the MBP ELISA had a 92% sensitivity and 100% specificity for CRS.ConclusionFree MBP in nasal mucus can be used as a biomarker to diagnose CRS. The MBP ELISA represents the first immunologically‐based test to potentially distinguish CRS from the eosinophilic inflammation in allergic rhinitis.

Abstract Humans are frequently exposed to various airborne allergens in the atmospheric environment. These allergens may trigger a complex network of immune responses in the airways, resulting in asthma and other chronic airway diseases. In this study, we investigated the immunological mechanisms involved in the pathological changes induced by chronic exposure to multiple airborne allergens. Naive mice were exposed intranasally to a combination of common airborne allergens, including the house dust mite, Alternaria, and Aspergillus, for up to 8 wk. These allergens acted synergistically and induced robust eosinophilic airway inflammation, specific IgE Ab production, type 2 cytokine response, and airway hyperresponsiveness in 4 wk, followed by airway remodeling in 8 wk. Increased lung infiltration of T cells, B cells, and type 2 innate lymphoid cells was observed. CD4+ T cells and type 2 innate lymphoid cells contributed to the sources of IL-5 and IL-13, suggesting involvement of both innate and adaptive immunity in this model. The lung levels of IL-33 increased quickly within several hours after allergen exposure and continued to rise throughout the chronic phase of inflammation. Mice deficient in IL-33R (Il1rl1−/−) and thymic stromal lymphopoietin receptor (Tslpr−/−) showed significant reduction in airway inflammation, IgE Ab levels, and airway hyperresponsiveness. In contrast, mice deficient in IL-25R or IL-1R showed minimal differences as compared with wild-type animals. Thus, chronic exposure to natural airborne allergens triggers a network of innate and adaptive type 2 immune responses and airway pathology, and IL-33 and thymic stromal lymphopoietin most likely play key roles in this process.