Abstract: To study the value of combined determinations of surfactant -associated protein-D(SP-D) and -A (SP-A) in the pleural fluid in distinguishing lung adenocarcinoma and tubercular pleurisy. Methods SP-A and SP-D were determined in the pleural effusions from 36 patients with lung adenocarcinoma and 28 with tubercular pleurisy by western blotting. Results SP-A concentrations in pleural effusions due to lung adenocarcinoma and tubercular pleurisy were 265.1±141.16 and 180.0±64.1 respectively, and SP-D concentrations were 299.9±140.6 and 206.8±86.8, respectively. SP-A＞250 was found in 23 of 36 lung adenocarcinomas，SP-D＞250 in 16 of 36 lung adenocarcinomas， while increased values of SP-A and/or SP-D were found in pleural effusions from 29 of 36 lung adenocarcinomas. SP-A and -D values did not exceed 250 in any of 28 patients with tubercular pleurisy. Conclusions SP-A is a useful immunohistochemical marker for lung adenocarcinoma, and SP-A in pleural effusion is valuable in diagnosis of primary lung adenocarcinoma and tubercular pleurisy, however, a combination of SP-D and -A assays in pleural effusions will be better for discriminating lung adenocarcinoma from tubercular pleurisy.

Key words: Pleural effusion, Tuberculosis, pleura, Lung neoplasms, SP-A, SP-D