TY - JOUR T1 - Sputum gene expression of mast cell tryptase and carboxypeptidase A3 are increased in eosinophilic asthma JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p4746 AU - Katherine Baines AU - Jodie Simpson AU - Lisa Wood AU - Rodney Scott AU - Peter Gibson Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p4746.abstract N2 - Rationale: Little is known regarding the presence and activity of mast cells in the airway lumen across asthma inflammatory phenotypes. Sputum gene expression of the mast cell specific proteases may serve as markers of mast cell activation in asthma.Objective: To investigate if sputum gene expression of mast cell specific proteases is associated with asthma inflammatory phenotype.Methods: Induced sputum was collected from participants with asthma (n=59; eosinophilic n=17; neutrophilic n=12; mixed granulocytic n=12; and paucigranulocytic n=18) and healthy controls (n=17). Gene expression profiles were generated (Illumina Humanref-8 V2) from sputum RNA. Mast cell tryptase (TPSAB1), carboxypeptidase A3 (CPA3) and chymase (CMA1) data were extracted and investigated for their relationship to asthma phenotype.Results: Gene expression of tryptase and carboxypeptidase A3 was significantly different among the 5 groups (p<0.0001). There was no difference in chymase expression. Tryptase mRNA was increased (p<0.01) in eosinophilic asthma compared to neutrophilic asthma, paucigranulocytic asthma and healthy controls. Carboxypeptidase A3 mRNA was increased (p<0.01) in eosinophilic asthma compared to neutrophilic asthma, mixed granulocytic asthma, paucigranulocytic asthma and healthy controls. Tryptase (r=0.58 p<0.0001) and carboxypeptidase A3 (r=0.59 p<0.0001) expression was strongly correlated with sputum eosinophils.Conclusions: Gene expression of mast cell tryptase and carboxypeptidase A3 is increased in eosinophilic asthma. Airway mast cells are important in eosinophilic asthma and have a unique phenotype associated with expression of tryptase and carboxypeptidase A3 but not chymase. ER -