Search for specific endotype biomarkers must focus on homogenous group of patients according to underlying disease mechanisms described by histological features (e.g. eosinophilia, M2 polarized macrophages), cytokine signatures (e.g. TGFβ1, IL4, IL-5) and responsiveness to anti-cytokine and glucocorticoid therapy. The gene discussed is TGFB1; the disease is Increased total eosinophil count.