RNASE3 and chronic obstructive pulmonary disease: Simultaneously elevated nitric oxide and serum-eosinophil cationic protein have also been linked to asthma exacerbations.50 Some biomarkers such as immunoglobulin E (IgE), sputum or peripheral blood eosinophil count and FENO have also been suggested as helpful when choosing treatment and assessing the prognosis of COPD,51 identifying COPD patients with possible synchronous asthma.