Moderate-High Blood Eosinophilia Is Associated with Increased Hospitalization and Other Asthma Comorbidities.

(1) Background: Eosinophilia has traditionally been linked to eosinophilic asthma, for which it is the gold-standard prognostic biomarker. However, the association between eosinophilia and the presence of other diseases and comorbidities is yet unclear. (2) Methods: For this retrospective study, we reviewed the electronic medical records of 49,909 subjects with blood eosinophilia to gather data on the presence of asthma, COPD, sleep apnea, tuberculosis, dyslipidemia, hypertension, and other cardiovascular diseases and severe CRSwNP among these subjects. Demographic features including age, sex, and smoking habits were collected, as well as the number of hospitalizations and emergency department visits. T-tests, ANOVA, Fisher test, and logistic regression models were used. (3) Results: For all age groups studied, eosinophilia was significantly more prevalent among asthmatic subjects than nonasthmatics, especially in patients also presenting CRSwNP, hypertension, and dyslipidemia. The likelihood of developing asthma, COPD, and CRSwNP, and hospitalization, was increased when BEC was above 600 eosinophils/µL. The association between asthma, CRSwNP, and BEC was corroborated by multiple logistic regressions models. (4) Conclusions: We demonstrated the association of having over 600 blood eosinophils/µL with a higher number of hospitalizations and comorbidities (CRSwNP and COPD), which proves that BEC is a highly useful parameter to consider in subjects who present blood eosinophilia.

How reliably can algorithms identify eosinophilic asthma phenotypes using non-invasive biomarkers?

Background and Aims: Asthma is a heterogeneous respiratory disease that encompasses different inflammatory and functional endophenotypes. Many non-invasive biomarkers has been investigated to its pathobiology. Heany et al proposed a clinical algorithm that classifies severe asthmatic patients into likely-eosinophilic phenotypes, based on accessible biomarkers: PBE, current treatment, FeNO, presence of nasal polyps (NP) and age of onset. Materials and Methods: We assessed the concordance between the algorithm proposed by Heany et al. with sputum examination, the gold standard, in 145 asthmatic patients of the MEGA cohort with varying grades of severity. Results: No correlation was found between both classifications 0.025 (CI = 0.013-0.037). Moreover, no relationship was found between sputum eosinophilia and peripheral blood eosinophilia count in the total studied population. Discussion and Conclusion: In conclusion, our results suggest that grouping the biomarkers proposed by Heany et al. are insufficient to diagnose eosinophilic phenotypes in asthmatic patients. Sputum analysis remains the gold standard to assess airway inflammation.

Isolation and Functional Aspects of Eosinophil-Derived Exosomes.

Eosinophils are granulocytes involved in inflammatory processes related to type 2 immune responses as allergy and parasitic infestation. Eosinophils are scarce in homeostatic situations, comprising 3-6% of total granulocytes. In peripheral blood, they have a life span of 18-25 h. These cells are characterized by the presence of several types of granules that are very important because of their functions. Recently, we have described that these immune cells are able to release exosomes, which are nanovesicles involved in intercellular communication and implicated in development of several diseases such as cancer, cardiovascular diseases, and asthma. Here, we describe a technique for isolation of eosinophil-derived exosomes from human peripheral blood and for their utilization in cell functional assays.

Bronchiolitis and recurrent wheezing are distinguished by type 2 innate lymphoid cells and immune response.

BACKGROUND: Recurrent wheezing (RW) is frequently developed in infants that have suffered bronchiolitis (BCH) during first months of life, but the immune mechanism underlying is not clear. The goal was to analyze the innate immune response that characterizes BCH and RW. METHODS: Ninety-eight and seventy hospitalized infants with BCH or RW diagnosis, respectively, were included. Nasopharyngeal aspirate (NPA) was processed. Cellular pellet was employed to evaluate type 2 innate lymphoid cells (ILC2) by flow cytometry and mRNA expression assays by semi-quantitative real-time PCR (qRT-PCR). In supernatant, twenty-seven pro-inflammatory and immunomodulatory factors, as well as lipid mediators and nitrites, were evaluated by ELISA and Luminex. RESULTS: Bronchiolitis patients showed higher ILC2 percentage compared with RW (P < .05). Also, ST2+ /ILC2 percentage was higher in the BCH group than in the RW group (P < .01). TLR3, IL33, IFNG, IL10, and FLG mRNA levels were significantly increased in BCH vs RW (P < .05). In supernatant, no significant differences were reached, observing similar levels of parameters linked to vascular damage, monocyte activation, and fibroblast growth. Prostaglandin E2 and cysteinyl leukotrienes C4 were evaluated; a significant difference was only found in their ratio. CONCLUSION: Bronchiolitis is associated with elevated nasal percentage of ILC2. This cellular population could be the key element in the differential immune response between BCH and RW which share some mechanisms such us monocyte activation, vascular damage, and fibroblast repair. Lipid mediators could play a role in the evolution of the disease later in life through innate lymphoid cells.

Immune recovery following bronchiolitis is linked to a drop in cytokine and LTC4 levels.

BACKGROUND: Bronchiolitis is the main cause of hospitalization of children younger than 1 year; however, the immune mechanism of bronchiolitis is not completely understood. The aim of this study was to analyze the recovery of immune response after a bronchiolitis episode. METHODS: Forty-nine infants hospitalized with bronchiolitis diagnosis were enrolled. Nasopharyngeal aspirates (NPAs) were processed. Twenty-seven pro-inflammatory biomarkers linked to innate immunity, inflammation, and epithelial damage, as well as nitrites and lipid mediators, were evaluated in the NPA supernatant by ELISA (enzyme-linked immunosorbent assay) and Luminex. Also, 11 genes were analyzed in NPA cells by quantitative PCR. RESULTS: A widespread statistically significant decline of multiple pro-inflammatory parameters and cytokines were detected in the recovery period after respiratory infection: interferon-α2 (IFNα2), IFNγ, interleukin-10 (IL-10), IL-1ß, IL-8, IFN-γ-inducible protein-10, vascular endothelial growth factor, monocyte chemoattractant protein-1, macrophage inflammatory protein-1α (MIP-1α), and MIP-1ß. Supporting these results, a decreased nuclear factor-κB gene expression was observed (P = 0.0116). A significant diminution of cysteinyl leukotriene C4 (LTC4) soluble levels (P = 0.0319) and cyclooxygenase-2 (COX-2) gene expression were observed in the recovery sample. In children classified by post-bronchiolitis wheezing, LTC4 remains elevated in the NPA supernatant. CONCLUSIONS: After bronchiolitis, cytokines and biomarkers linked to innate immune response in NPA decrease significantly in the recovery period accompanied by a drop in LTC4 levels; however, this reduction was lower in infants with post-bronchiolitis wheezing.