Full Blood Count Parameters For The Detection Of Asthma Inflammatory Phenotype In Uncontrolled Asthma And The Characteristics And Airway Inflammatory Phenotypes Of Refractory Asthma

BackgroundBronchial asthma (asthma) is a chronic airway disease in which many cells (eosinophils, mast cells, T lymphocytes, neutrophils, dendritic cells, airway epithelial cells) and cellular elements play an important role. The disorder of the airway is characterized by airway hyperresponsiveness (AHR), airway inflammation, and airway remodeling. Different airway inflammatory phenotypes have different clinical findings, chooses and responses for therapy. Induced sputum cell counts are the gold standard test for defining inflammatory phenotypes. There is a need to find simpler methods to assess airway inflammation.Some studies confirmed the relationship between blood eosinophils and sputum eosinphils, however, others questioned the point and the accurancy of it. So our study selected uncontrolled asthmatic patients as the research subjects, and tested the blood cells and other parameters to predict the eosinophilic asthma and neutrophilic asthma. Refractory asthma is another clinical type of asthma. The induced sputum can help us to differential diagnosis and adjust therapy in refractory asthma. There is no report about the characteristics and airway inflammatory phenotypes of refractory asthma in China.Objective1. To investigate the role of blood eosinophils to detect sputum eosinophils in uncontrolled asthma.2. To investigate the role of blood neutrophils to predict sputum neutrophils in uncontrolled asthma.3. To obtain the clinical features and airway inflammatory phenotypes of refractory asthmatic patients in China.MethodsA cross-sectional study was carried out in this study. We recruited uncontrolled asthmatic patients and refractory asthma respectively. Every participants were taken the history of asthma, blood, sputum samples and lung functions. The data were analyzed using SPSS20.0software package. Means and standard errors were calculated for measurement data. Median and interquartile ranges were preferred for skewed distributions. For categorical variables the number of observations and percentages were given in each category. The receiver-operating characteristic curve was constructed to evaluate the relationship between the blood cells and sputum cells. Analysis of variance or nonparametric statistics were used to compare statistical differences of variables. Chis-square test was used to compare statistical differences of prevalence rates. P value less than0.05was considered statistically significant.Results1. There was a significant positive relationship between blood eosinophil parameters and the percentage sputum eosinophil count. ROC curve analysis identified that blood eosinophil percentage count was the best predictor for eosinophilic asthma, with an AUC of0.907(p=0.000). The optimum cut-point for blood eosinophil percentage was2.7%, and this yielded a sensitivity of92.2%, a specificity of73.6%. The eosinophil lymphocyte ratio (ELR) was elevated in eosinophilic asthma and the neutrophil lymphocyte ratio (NLR) was elevated in neutrophilic asthma.2. A weak but still significant correlation was found between sputum neutrophil percentage and blood neutrophil percentage (r=0.219, p=0.005). Neutrophilic asthma could also be detected by blood neutrophil percentages and NLR, but with less accuracy.3. A total of35asthmatic patients were involved in this study with the mean age of41.4years and the disease duration of14.3years with male tendency.8.6%patients attended the activity of training programs for asthmatic patients.65.7%of the asthmatics ever used systemic corticosteroids and about22thousands in expending in the past one year.61.1%(21/35) asthmatics had the complication of allergic rhinitis, followed by the complication of chronic rhinosinusitis31.4%(11/35), nasal polyp20.0%(7/35), gastroesophageal reflux disease. The total rate of current smoking and ever smoked was37.2%. The mean FEVi%was63.9%,60%of participants show the negative reaction in bronchial reversibility test that means most of patients in this study had incompletely reversible airflow limitations.50.0%of refractory asthmatics were eosinophilic asthma,28.1%and21.9%patients were neutrophilic asthma and mixed granulocytic asthma. The rest of patients were mixed granulocytic asthma.45.7%patients took oral corticosteroid.Conclusions1. Blood eosinophil counts and derived ratios can accurately predict sputum eosinophil percentages in uncontrolled asthma, but blood neutrophil percentages and NLR are poor surrogates for the proportion of sputum neutrophils. Blood counts may be a useful aid in the monitoring of uncontrolled asthma.2. The clinical features associated with refractory asthma are male, smoking, persistant airway limitation, combination of allergic rhinitis, chronic rhinosinusitis, nasal polyp and gastroesophageal reflux disease. The rate of systemic corticosteroids use is high and the cost of therapy is more as well. The eosinophilic asthma is the main inflammatory phenotype in refractory asthma. The percentages of neutrophilic asthma and mixed granulocytic asthma are increased either in refractory asthma.