Immunoglobulin G4 in eosinophilic esophagitis: Immune complex formation and correlation with disease activity.

BACKGROUND: Recent studies have shown deposition of immunoglobulin G4 (IgG4) and food proteins in the esophageal mucosa of eosinophilic esophagitis (EoE) patients. Our aims were to assess whether co-localization of IgG4 and major cow's milk proteins (CMPs) was associated with EoE disease activity and to investigate the proteins enriched in proximity to IgG4 deposits. METHODS: This study included adult subjects with EoE (n = 13) and non-EoE controls (n = 5). Esophageal biopsies were immunofluorescence stained for IgG4 and CMPs. Co-localization in paired samples from active disease and remission was assessed and compared to controls. The proteome surrounding IgG4 deposits was evaluated by the novel technique, AutoSTOMP. IgG4-food protein interactions were confirmed with co-immunoprecipitation and mass spectrometry. RESULTS: IgG4-CMP co-localization was higher in the active EoE group compared to paired remission samples (Bos d 4, p = .02; Bos d 5, p = .002; Bos d 8, p = .002). Co-localization was also significantly higher in the active EoE group compared to non-EoE controls (Bos d 4, p = .0013; Bos d 5, p = .0007; Bos d 8, p = .0013). AutoSTOMP identified eosinophil-derived proteins (PRG 2 and 3, EPX, RNASE3) and calpain-14 in IgG4-enriched areas. Co-immunoprecipitation and mass spectrometry confirmed IgG4 binding to multiple food allergens. CONCLUSION: These findings further contribute to the understanding of the interaction of IgG4 with food antigens as it relates to EoE disease activity. These data strongly suggest the immune complex formation of IgG4 and major cow's milk proteins. These immune complexes may have a potential role in the pathophysiology of EoE by contributing to eosinophil activation and disease progression.

Impaired Response to Polysaccharide Vaccine in Selective IgE Deficiency.

PURPOSE: Immunoglobulin E deficiency (IgED) (defined as IgE < 2 IU/mL) is enriched in patients with primary antibody deficiency (PAD). We hypothesized that selective IgED (sIgED) is a more sensitive predictor of the development of PAD than declining IgG, as IgE production typically requires two class switch recombination (CSR) events in contrast to IgG. Thus, the inability of patients with sIgED to mount an appropriate antibody response to a T-cell independent antigen or evidence of aberrant induction of ɛ germ line (ɛGL) or IgE heavy chain (IgEHC) transcripts in vitro would support the concept that sIgED is a biomarker for emerging PAD. METHODS: We compared pre- and post-polysaccharide vaccination titers in healthy patients with sIgED without a history of recurrent infections or autoimmunity (n = 20) and in healthy controls (HCs) (n = 17). Subsequently, we assessed in vitro induction of εGL and IgEHC transcripts in patients with sIgED and HC (n = 6) in response to IL-4 + CD40L stimulation. RESULTS: Thirty percent of patients with sIgED did not have a robust vaccine response compared to 0% of HCs (p = 0.017). Individuals with sIgED with an abnormal vaccine response demonstrated persistent germline mRNA expression in their B-cells at day 5, with lower levels of IgEHC, compared to both HCs and sIgED participants with a normal vaccine response. CONCLUSION: Patients with sIgED are more likely to have abnormal antibody responses to a T cell-independent antigen and may have dysregulated CSR machinery. Following individuals with sIgED longitudinally may be beneficial in the early identification of PAD.

The Impact of CFTR Modulator Triple Therapy on Type 2 Inflammatory Response in Patients with Cystic Fibrosis.

Background Treatment of cystic fibrosis (CF) has been revolutionized by the use of cystic fibrosis transmembrane conductance regulator (CFTR) protein modulators such as elexacaftor/tezacaftor/ivacaftor (ETI) triple therapy. Prior studies support a role for type 2 (T2) inflammation in many people with CF (PwCF) and CF-asthma overlap syndrome (CFAOS) is considered a separate clinical entity. It is unknown whether initiation of ETI therapy impacts T2 inflammation in PwCF. We hypothesized that ETI initiation decreases T2 inflammation in PwCF. Methods A single center retrospective chart review was conducted for adult PwCF. As markers of T2 inflammation, absolute eosinophil count (AEC) and total immunoglobulin E (IgE) data were collected longitudinally 12 months prior to ETI therapy initiation and 12 months following therapy initiation. Multivariable analyses adjusted for the age, gender, CFTR mutation, disease severity, inhaled steroid use, and microbiological colonization. Results There was a statistically significant reduction (20.10%, p < 0.001) in 12-month mean IgE following ETI initiation; this change remained statistically significant in the multivariate model. The longitudinal analysis demonstrated no change in AEC following therapy initiation. Conclusion This study shows reduction in IgE but no change in AEC after ETI therapy initiation. We think that the lack of influence on AEC argues against an impact on previously established T2 inflammation and that the reduction in IgE is likely related to antigen load reduction post ETI. Further studies are warranted to determine the underlying mechanism of ETI impact on T2 inflammation and possible role for asthma immunomodulator therapy post ETI initiation in CFAOS.

Dupilumab Efficacy in Patients with Uncontrolled Moderate-to-Severe Type 2 Asthma Regardless of Perennial Aeroallergen Sensitization.

Purpose: Dupilumab, a fully human monoclonal antibody, blocks the shared receptor component for interleukins-4/-13, key and central drivers of type 2 (T2) inflammation in multiple diseases. In phase 3 QUEST (NCT02414854), dupilumab vs placebo significantly reduced asthma exacerbation rates (AER) and improved pre-bronchodilator forced expiratory volume in 1 second (FEV1) in patients with uncontrolled, moderate-to-severe asthma, with greater effects in patients with elevated T2 biomarkers (≥150 eosinophils/µL or fractional exhaled nitric oxide [FeNO] ≥25 parts per billion). Overall safety was consistent with the known dupilumab safety profile. This post hoc analysis assessed dupilumab efficacy in QUEST patients with T2 asthma with evidence of an allergic phenotype (baseline serum IgE ≥30 IU/mL and aeroallergen-specific IgE ≥0.35 IU/mL) by number of aeroallergen sensitizations: 1, 2, 3, or ≥4. Non-sensitized patients (serum total IgE <30 IU/mL without evidence of allergic phenotype) were also assessed. Patients and Methods: Endpoints were annualized AER, change from baseline in pre-bronchodilator FEV1 and asthma control (5-item Asthma Control Questionnaire [ACQ-5]), and FeNO and serum total IgE levels over the 52-week treatment period. Results: In all subgroups by number of allergens sensitized, dupilumab vs placebo reduced AER by 35-67% and improved both pre-bronchodilator FEV1 at Week 12 (least squares mean differences: 0.10-0.26 L across subgroups) and ACQ-5 score at Week 52 (-0.26 to -0.43). Dupilumab significantly reduced FeNO and total IgE levels at Week 52 compared with placebo. Similar results were observed in non-sensitized patients. Conclusion: Dupilumab improved clinical outcomes and reduced biomarker levels in patients with uncontrolled, moderate-to-severe T2 asthma irrespective of allergen sensitization status or number. Clinical Trial Registration: ClinicalTrials.gov Identifier: NCT02414854.

Further evidence of a type 2 inflammatory signature in chronic obstructive pulmonary disease or emphysema.

BACKGROUND: There is increasing recognition of a type 2 (T2) inflammatory pattern in a subset of patients with chronic obstructive pulmonary disease (COPD) or emphysema, characterized by blood and airway eosinophilia. The mechanism underlying this is not well established. The recognition that CD125 (interleukin [IL]-5 receptor alpha) is expressed on some lung neutrophils and eosinophils in patients with asthma led us to speculate that CD125 may also be expressed on lung neutrophils in patients with COPD or emphysema. OBJECTIVE: To interrogate the expression of CD125 on lung neutrophils (and, when present, eosinophils) in patients with COPD/emphysema and identify a meaningful biomarker to predict neutrophil CD125 expression, including other markers of T2 inflammation. METHODS: We obtained blood and bronchoalveolar lavage (BAL) samples from patients with physician-diagnosed COPD/emphysema undergoing a clinically indicated bronchoscopy. RESULTS: We found that a highly variable percentage of BAL neutrophils indeed expressed surface CD125 (0%-78.7%), with obvious clustering of CD125high and CD125low patterns. No correlation was found with clinical characteristics, blood or BAL eosinophil or neutrophil counts, BAL cytokines, or BAL eosinophil CD125 expression. CONCLUSION: We conclude that, similar to asthma, lung neutrophils from patients with COPD display interleukin-5 receptor alpha (CD125) on their surface. This along with the frequent presence of IL-4 and IL-5 in airway fluid further suggests a possible role of the T2 pathway in contributing to COPD severity. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03984799.

Association between Cystic Fibrosis exacerbations, lung function, T2 inflammation and microbiological colonization.

BACKGROUND: The Cystic Fibrosis Foundation Patient Registry (CFFPR) reports a high prevalence of asthma (34.6%) in people with Cystic Fibrosis (PwCF). While our current understanding of this relationship is limited, a type 2 inflammatory (T2) phenotype has often been identified in CF patients. RESEARCH QUESTION: This study aimed to evaluate the relationship between the eosinophilic CF T2 inflammatory phenotype and CF-related pulmonary outcomes and microbiological data. STUDY DESIGN AND METHODS: We conducted a retrospective chart review of adult patients with CF (18 and older; n = 93) receiving their care at University of Virginia Medical Center adult program from January, 2013 through December, 2018. Data collected included demographic data, CFTR (CF transmembrane conductance regulator) mutation, CF comorbidities, medications, Absolute Eosinophil Counts (AEC) in cells/µL and Immunoglobulin E (IgE) levels in IU/mL. RESULTS: Of 93 patients screened for study eligibility, 74 were included in the final analysis; 19 patients were excluded due to lack of longitudinal data across the study timeline. Lung function decline correlated with increased AEC (p < 0.001) and IgE (p < 0.001) even when adjusting for covariates: age, gender, presence of Pseudomonas spp., MRSA, other bacterial spp., Aspergillus spp., and other fungi (p < 0.001). Univariate analysis demonstrated that people with CF who experienced more than 2 exacerbations requiring hospitalizations and/or intravenous antibiotics a year were more likely to have high AEC (p = 0.018). Logistic regression showed that as AEC increases, the probability that the measurement was taken during a CF exacerbation increases (p = 0.0039). A linear mixed model showed that each additional annual exacerbation event increased on average the log IgE by 0.04. (p = 0.015). This finding remained stable in a multivariate model (p = 0.0145). When adjusted for atopy, log IgE increases as the number of exacerbation events increases (p = 0.022). There was no association between AEC and IgE and microbiological colonization. INTERPRETATION: This study has shown that in CF patients, T2 inflammation based on serum AEC and IgE correlated with pulmonary exacerbations requiring hospitalizations and/or intravenous antibiotics, independent of bacterial airway colonization. In addition, lung function decline correlated with increased IgE and AEC. Further studies are needed to explore these correlations and potential impact on treatment.

Fever, Rash, and Cough in a 7-Year-Old Boy.

A 7-year-old boy presented to the emergency department with fever, cough, congestion, abdominal pain, myalgias, and morbilliform rash. Several aspects of the patient's history, including recent travel, living on a farm, exposure to sick contacts, and new medications, resulted in a wide differential diagnosis. Initial laboratory testing revealed leukocytosis with neutrophilia and elevated atypical lymphocytes, but did not reveal any infectious causes of illness. He was discharged from the hospital, but then represented to the emergency department a day later with worsening rash, continued fever, abdominal pain, and poor intake. He was then admitted. A more comprehensive laboratory evaluation was initiated. During this hospital course, the patient's physical examination changed when he developed head and neck edema, and certain laboratory trends became clearer. With the assistance of several specialists, the team was able to reach a more definitive diagnosis and initiate treatment to appropriately manage his condition.

Over-expression of CRTH2 indicates eosinophilic inflammation and poor prognosis in recurrent nasal polyps.

Background: Chronic rhinosinusitis with nasal polyps (CRSwNP) is often characterized by recurrent nasal polyp (NP) growth following surgical removal, but the mechanisms are still not clear. This study aimed to investigate the expression of chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2) receptor on NP and the role it plays in eosinophil inflammation and polyp recurrence. Methods: Forty-one CRSwNPs patients and seventeen controls were enrolled in this study. mRNA was extracted from nasal tissues and evaluated for expression of CRTH2. Immunofluorescence staining was performed to confirm the distribution and expression of CRTH2 protein. CRTH2 expression on peripheral blood eosinophils was quantified by flow cytometry. The eosinophil count and clinical implications were also evaluated and their correlations with CRTH2 expression were analyzed. Results: Nasal polyps displayed increased expression of CRTH2 in mRNA level compared with control samples, with the highest expression observed in recurrent NP. Immunofluorescence confirmed over-expression of CRTH2 in recurrent NP and this was independent of the concurrent presence of asthma. CRTH2 expression was positively correlated with tissue eosinophil number (Spearman's ρ=0.69, P<0.001) and the postoperative sino-nasal outcome test-22 (SNOT-22) score (Spearman's ρ=0.67, P<0.001). Receiver operating characteristic (ROC) curves revealed CRTH2 was more predictive for NP recurrence compared to either eosinophil number and concomitant asthma, with an area under the ROC curve of 0.9107. Conclusion: The over-expression of CRTH2 in recurrent nasal polyps correlates with greater eosinophilic inflammation and poor prognosis which is independent of concomitant asthma.

Respiratory mucosal immunity against SARS-CoV-2 after mRNA vaccination.

SARS-CoV-2 mRNA vaccination induces robust humoral and cellular immunity in the circulation; however, it is currently unknown whether it elicits effective immune responses in the respiratory tract, particularly against variants of concern (VOCs), including Omicron. We compared the SARS-CoV-2 S-specific total and neutralizing antibody responses, and B and T cell immunity, in the bronchoalveolar lavage fluid (BAL) and blood of COVID-19-vaccinated individuals and hospitalized patients. Vaccinated individuals had significantly lower levels of neutralizing antibody against D614G, Delta (B.1.617.2), and Omicron BA.1.1 in the BAL compared with COVID-19 convalescents despite robust S-specific antibody responses in the blood. Furthermore, mRNA vaccination induced circulating S-specific B and T cell immunity, but in contrast to COVID-19 convalescents, these responses were absent in the BAL of vaccinated individuals. Using a mouse immunization model, we demonstrated that systemic mRNA vaccination alone induced weak respiratory mucosal neutralizing antibody responses, especially against SARS-CoV-2 Omicron BA.1.1 in mice; however, a combination of systemic mRNA vaccination plus mucosal adenovirus-S immunization induced strong neutralizing antibody responses not only against the ancestral virus but also the Omicron BA.1.1 variant. Together, our study supports the contention that the current COVID-19 vaccines are highly effective against severe disease development, likely through recruiting circulating B and T cell responses during reinfection, but offer limited protection against breakthrough infection, especially by the Omicron sublineage. Hence, mucosal booster vaccination is needed to establish robust sterilizing immunity in the respiratory tract against SARS-CoV-2, including infection by the Omicron sublineage and future VOCs.

Improvement of Subjective Olfactory Dysfunction in Chronic Rhinosinusitis With Nasal Polyps After Endoscopic Sinus Surgery.

Objective: Olfactory impairment is a common complaint in patients with chronic rhinosinusitis with nasal polyps (CRSwNP), but the influence of endoscopic sinus surgery (ESS) on olfaction and the factors predicting olfactory impairment are not fully understood. This study aimed to assess the effect of ESS on improving olfactory dysfunction in patients with CRSwNP and to identify factors that predict prognosis. Methods: A total of 56 patients with CRSwNP reported their self-evaluated olfactory dysfunction score preoperatively and 1 month, 3 months, and 12 months after ESS. Preoperative clinical characteristics, computed tomography (CT) scan, and sinonasal endoscopy examination results were collected before surgery. Additionally, factors that predicted olfactory loss and affected the improvement of olfaction after ESS were evaluated. Results: Olfactory improvement can be observed 1 month after ESS. A total of 73.2% (41/56) subjects experienced sustained recovery of subjective olfaction with the self-evaluated olfactory dysfunction score improving from 2.04 to 0.64 (P < 0.001) after 12 months. The Lund-Mackay scores (r = 0.593, P < 0.001) and Lund-Kennedy scores (r = 0.265, P < 0.05) correlated with the preoperative olfactory dysfunction score. Multivariate logistic regression analysis revealed that longer duration of olfactory dysfunction, blood eosinophilia, lower Lund-Mackay scores, and peripheral distribution of CT opacification were risk factors that adversely affected the recovery of olfactory function (P < 0.05). Conclusion: ESS improved self-evaluated olfactory function in patients with CRSwNP. Lund-Mackay scores and Lund-Kennedy scores were correlated with olfactory function prior to surgery, while a longer course of the disease, higher blood eosinophilia, lower Lund-Mackay scores, and peripheral distribution of CT opacification were risk factors for poor olfactory prognosis.