In COPD, an obstructive inflammatory disease with some features similar to asthma, PTX3 expression was found to be reduced in lung sections of patients which correlated with FEV1 (a marker for small airway obstruction); while the PTX3 expression in induced sputum in COPD patients did not have any correlation with FEV1 [45]. Here, PTX3 is linked to chronic obstructive pulmonary disease.