Osteopontin and C-reactive protein in Egyptian patients affected with tuberculous and malignant pleural effusion.

Background: The first step in the evaluation of patients with pleural effusion is to determine whether the effusion is a transudate or an exudate. Osteopontin (OPN) is a pleiotropic integrin-binding protein with many functions. We assessed pleural effusion and serum concentrations of OPN and C-reactive protein (CRP) in patients with different types of pleural effusions.