The aim is to examine whether the interleukin-1β (IL-1β), IL-2, IL-6, tumor necrosis factor-α (TNF-α), plasminogen activator inhibitor type-1 (PAI-1), and tissue plasminogen activator (t-PA) levels were different in pleural effusions of tuberculous pleurisy and tuberculous empyema. The gene discussed is IL1B; the disease is pleural tuberculosis.