<qa>  How many subjects will be screened to identify?Thirty subjects will be screened to identify 20 subjects with severe persistent asthma. The following data andor samples will then be obtained within three weeks of the clinical assessment: 1 the percentages of LDG will be quantified by flow cytometry; 2 a blood sample will be collected into a PAXgene Blood tube and stored until shipped to Genentech for gene profiling analysis; and 3 a serum sample will be collected for measurement of total immunoglobulin E IgE and for future confirmation of potential biomarkers identified in the gene profiling analyses. 