Patients with tuberculous pleurisy tended to have significantly higher concentrations of hyaluronic acid and adenosine deaminase in their pleural fluid (tuberculous pleurisy patients vs. other infective pleurisy patients: hyaluronic acid (× 103 ng/mL); 42.9 ± 23.3 vs. 16.8 ± 17.9, P = 0.003, adenosine deaminase (IU/L); 89.7 ± 33.3 vs. 74.0 ± 90.9, P = 0.032). The gene discussed is ADA; the disease is pleural tuberculosis.