MIF and Pleural effusion: Interestingly, the data suggested that patients with cavitary lesion and pleural effusion had significantly higher serum levels of MIF than that of the other patients [27.5(23.2–30.5) vs. 21.6(18.0–26.5) ng/ml, P < 0.001 and 26.5(22.1–29.5) vs. 21.9 (18.5–26.9) ng/ml, P = 0.001].