Clinical Study Of Relationship Between Granulocyte,HDAC2 And Severe Asthma

Bronchial asthma is a chronic inflammatory airway disease which involves a variety of cells and components.Most of these patients could be under control with inhaling corticosteroids,but there are still 5-10% patients who can be controlled or is still without control although large dosages of inhaled or oral glucocorticoid,which known as severe asthma(SA).The incidence of severe asthma is low,but the disease burden can be more than 50% of the total cost of asthma.Due to the poor efficacy of traditional therapy methods,patients suffer from the lower quality of life,poor prognosis and high risk of death.If progress trend of SA could be found exactly and treated promptly.the prognosis of SA would be improved obviously.It was found that the recruitment and activation of polymorphonuclear neutrophils(PMN)and eosinophils(EOS)of the airway mucosa and the low activity of histone deacetylase 2(HDAC2)were closely related to severe asthma in many domestic and abroad research conducted in recent years.This study intends to detect the concentrations of the serum granulocyte activation markers of the myeloperoxidase(MPO),matrix metalloproteinase 9(MMP9),neutrophil elastase(NE)and eosinophil cationic protein(ECP)and the activity of HDAC2 in peripheral bloodmononuclear cells(PBMCs)of the subjects,to understand their relationships with SA and find out simple biomarkers to evaluate the phenotypes of severe asthm.Objective:To investigate the relationships between granulocyte activation markers,HDAC2 expression and severe asthma,and to explore the biomarkers for the early prediction and identification of severe asthma.Methods:Collected fasting venous blood samples of 18 subjects with severe asthma(male 8,aged from20-64);and 18 patients with mild-and-moderate asthma(male 9,aged from19-66)and 18 healthy subjects(male 10,aged from 24-50).Got the plasma anticoagulated with EDTAK2 and separated the blood cells to get PBMCs.Detected the concentrations of granulocyte activation markers of the MPO,MMP9,NE and ECP in serum by ELISA and the HDAC2 expression levels in PBMCs by Western-blot,and the results are expressed as HDAC2/GAPDH.Results:1.The difference of granulocyte activation markers among 3 groups: The concentrations of MPO,MMP-9,NE and ECP in severe asthma subjects group(102.43 ±28.19ng/ml,992.97 ± 176.44pg/ml,9.40 ± 0.99ng/ml and 232.85 ± 48.37ng/ml,respectively)were significantly higher than that in mild-and-moderate asthma subjects group(48.56 ± 8.78ng/ml,554.35 ± 99.03pg/ml,8.01 ± 1.27ng/ml,105.30 ± 26.93ng/ml,respectively,p<0.05)and healthy subjects group(37.46 ± 9.93ng/ml,374.00 ± 79.08pg/ml,4.66 ± 0.64ng/ml,40.87 ± 15.35ng/ml,respectively,p<0.05).There was no significant difference in MPO level between the mild-and-moderate asthma group and the healthy control group(p > 0.05).2.The difference of the HDAC2 expression level among 3 groups: The expression level of HDAC2 in PBMCsin severe asthma group(HDAC2/GAPDH: 0.19 ± 0.09)was significantly lower than that in mild-and-moderate asthma group(0.60 ± 0.08)and healthy control group(1.09 ± 0.26),the difference was significant statistically(p<0.05).HDAC2 expression in mild-and-moderate asthma group was lower than that in healthy controlgroup,and the difference was apparent(p < 0.05).3.The relationship between the granulocyte activation markers and pulmonary function,asthma control test: The level of MPO,MMP-9,NE and ECP were significantly negatively correlated with FEV1%pred.,and the difference was significant(r values were-0.60,-0.75,-0.43 and-0.67,respectively,p < 0.01).And a significantly negatively correlated with FEV1%FVC,the difference was significant(r values were-0.52?-0.60?-0.42 and-0.50,respectively,p < 0.05).There was also a significant negative correlation between ACT and the concentration of MPO,MMP-9,NE and ECP(-0.69,-0.67,-0.50and-0.70,respectively,p < 0.01).4.The relationship between the expression of HDAC2 in PBMCs and pulmonary function,asthma control test: There was a significant positive correlation between FEV1%pred.,FEV1%FVC and the expression of HDAC2,and the difference was marked in the bilateral Pearson test(r values were 0.68 and 0.61,respectively,p < 0.01).A significant positive correlation between HDAC2 activity and ACT was observed(r=0.68,p < 0.01).Conclusion:The elevation of serum levels of the MPO,MMP-9,NE and ECP in patients with severe asthma indicated the activation in neutrophil and eosinophilic granulocytes,and was significantly higher than that in patients with mild-and-moderate asthma.The activity of PBMCs HDAC2 in severe asthma group was decreased markedly,implying the possibility of the decrease of glucocorticoid sensitivity,and poor therapeutic effect in severe asthma.