Urinary eosinophil protein X in childhood asthma: relation with changes in disease control and eosinophilic airway inflammation

Relationship between airway inflammation and airflow limitation in elderly asthmatics

Background

The prevalence of asthma in elderly population has been increasing. Previous studies have demonstrated clinical characteristics of elderly asthmatics (EA). However, little is known regarding the influence of immunological change on the physiological status of EA.

Objective

We investigated the relationship between inflammatory mediators and the pulmonary function (PF) of EA.

Methods

Eligible adult asthmatics recruited from the Allergy Center of Saitama Medical University Hospital were classified into a non-EA group (<40 years old, n = 15) and an EA group (≥60 years old, n = 43). Sputum induction and PF tests were performed. Concentrations of an eosinophil-derived neurotoxin (EDN) and neutrophil elastase (NE) in sputum supernatants were measured by enzyme-linked immunosorbent assay and a fluorometric assay using a commercial assay kit, respectively. Cell counts and EDN and NE concentrations in sputum were compared between the 2 groups. The association among those parameters and PF were analyzed in each group.

Results

The EA group had a significantly higher severe asthmatics proportion (p = 0.01), a lower current smokers proportion (p = 0.002), lower sensitization rate to aeroallergens (p = 0.012), several PFs deterioration (p < 0.0001) and lower total IgE levels (p = 0.001) than the non-EA group. Sputum neutrophil counts and NE concentrations were significantly higher in the EA group than those in the non-EA group (median neutrophil: 4.11 vs. 2.74 ×10⁵/mL, p = 0.03; NE: 2.0 vs.1.6 µg/mL, p < 0.05, respectively), whereas sputum eosinophil counts and EDN concentrations were not. Sputum EDN concentrations were significantly positively correlated with sputum neutrophil counts (r = 0.39, p = 0.031) and NE concentrations (r = 0.57, p < 0.0001) only in the EA group. Eosinophil-related parameters were negatively correlated with several PFs in the 2 groups. Neutrophil-related parameters were negatively correlated with PFs only in the non-EA group.

Conclusion

This study determines that in EA, persistent active eosinophilic airway inflammation is accompanied by advanced neutrophilic inflammation, which may contribute to deteriorated PF. This distinct airway inflammation may increase the severity of asthma in EA.

[Clinical significance of peripheral blood neutrophil-lymphocyte ratio and platelet- lymphocyte ratio in patients with asthma]

OBJECTIVE

To investigate the changes of peripheral blood neutrophil-lymphocyte ratio (NLR) and platelet- lymphocyte ratio (PLR) in patients in acute stage of bronchial asthma and their clinical significance.

METHODS

A total of 262 patients with acute asthma, including 97 critical and 175 non-critical patients, were recruited from our hospital between January, 2013 and May, 2016, with 130 healthy individuals as the control group. The absolute neutrophil count, absolute lymphocyte count, platelet, NLR and PLR were compared among different groups, and their diagnostic values were evaluated using the area under the receiver-operating characteristic (ROC) curve.

RESULTS

The absolute neutrophil count, absolute lymphocyte count, PLR and NLR (P<0.0001), but not platelet count (P=0.971), differed significantly among the 3 groups. The absolute lymphocyte count was significantly lower while the absolute neutrophil count, NLR and PLR were significantly higher in asthmatic patients in critical condition than in patients in non-critical condition and the control subjects (P<0.0001), and these parameters showed no significant differences between latter two groups (P>0.05). The areas under the curve of absolute neutrophil count, absolute lymphocyte count, NLR and PLR for the diagnosis of acute exacerbation of bronchial asthma were 0.802, 0.784, 0.873 and 0.795, respectively (all P<0.01); the optimal cut-off value of NLR was 2.58 for the diagnosis with a sensitivity of 82.8% and a specificity of 81.1%.

CONCLUSIONS

Peripheral blood NLR and PLR are increased in asthmatic patients, and their variations offer assistance in the diagnosis and assessment of bronchial asthma.

Fixed airflow obstruction relates to eosinophil activation in asthmatics

BACKGROUND

Some asthmatics develop irreversible chronic airflow obstruction, for example, fixed airflow obstruction (fixed-AO). This is probably a consequence of airway remodelling, but neither its relation to inflammation nor which asthma biomarkers can be clinically useful are elucidated. We hypothesized that the presence of type 2 inflammation relates to fixed-AO.

OBJECTIVES

To evaluate the presence of four markers for type 2 inflammation in fixed airflow obstruction among asthmatics.

METHODS

This was a cross-sectional study of 403 participants with asthma, aged 17-75 years, from three Swedish centres. Fixed airflow obstruction was defined as forced expiratory volume during the first second (FEV₁ ) over forced vital capacity (FVC) being below the lower limit of normal (LLN). The following type 2 inflammation markers were assessed: exhaled nitric oxide (FeNO), serum periostin, serum eosinophil cationic protein (S-ECP), and urinary eosinophil-derived neurotoxin (U-EDN).

RESULTS

Elevated U-EDN (values in the highest tertile, ≥65.95 mg/mol creatinine) was more common in subjects with fixed-AO vs. subjects without fixed-AO: 55% vs. 29%, P < 0.001. Elevated U-EDN related to increased likelihood of having fixed-AO in both all subjects and never-smoking subjects, with adjusted (adjusted for sex, age group, use of inhaled corticosteroids last week, atopy, early-onset asthma, smoking history, and packyears) odds ratios (aOR) of 2.38 (1.28-4.41) and 2.51 (1.04-6.07), respectively. In a separate analysis, having both elevated S-ECP (>20 μg/L) and U-EDN was related to having the highest likelihood of fixed-AO (aOR (95% CI) 6.06 (2.32-15.75)). Elevated serum periostin or FeNO did not relate to fixed-AO.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings support that type 2 inflammation, and in particular eosinophil inflammation, is found in asthma with fixed-AO. This could indicate a benefit from eosinophil-directed therapies. Further longitudinal studies are warranted to investigate causality and relation to lung function decline.

Eosinophil protein X and childhood asthma: A systematic review and meta-analysis

Background: There are no reference guidelines for health care providers regarding appropriate use and interpretation of urine eosinophil protein X (u‐EPX) in clinical practice. Currently, there are no clear‐cut clinical or laboratory parameters to diagnose asthma in young children. Objective: In this study, we (1) systematically reviewed and qualitatively appraised the epidemiological evidence to determine diagnostic u‐EPX cut points for pediatric asthma, and (2) performed a meta‐analysis to provide u‐EPX estimates for diagnosing pediatric asthma. Methods: Research articles in literature were identified from PubMed/Medline and Web of Science databases from 1966 to August 2015. Children <18 years of age were included. Both serum and urine EPX were included. Twenty‐seven studies met the inclusion criteria for the systematic review and nine studies for the meta‐analysis. Details regarding EPX analyses, treatment efficacy, and outcomes were assessed. For meta‐analyses, effect estimates were abstracted using standardized means. Results: Over 70% of studies found a significant relationship between u‐EPX and childhood asthma. There was 1.94 times higher standardized means of u‐EPX among acute asthmatics compared to healthy controls (confidence interval [CI]: 1.67–2.22). Similarly, the difference in standardized means between asymptomatic asthmatics and healthy controls was 1.58 times higher (CI: 1.27–1.88). Conclusions and Clinical Relevance: Despite differences in sample sizes, EPX processing and measurement, and ages of children, a consistent trend of higher EPX levels with childhood asthma was revealed.