Beta₂Microglobulin in Pleural Effusions

Abstract

ABSTRACT. Beta 2 microglobulin (β 2 m) concentrations in serum and pleural fluid from 64 patients with pleural effusion were studied. The level of β 2 m in pleural fluid was generally twice that in serum. The ratio of pleural fluid β 2 m to serum β 2 m in patient groups defined according to the final diagnosis showed an interestingly high value in tuberculous pleuritis and in patients with rheumatoid arthritis with pleural effusion. There was a positive correlation between the β 2 m and lysozyme contents in pleural fluid, suggesting local and simultaneous activation of different cell lines when the pleura is involved. We suggest that pleural fluid and concomitant serum β 2 m measurements should be taken into consideration when pleural effusion of tuberculous origin is suspected. Furthermore, β 2 m determination might help to differentiate between rheumatoid pleural fluid and pleural involvement due to other systemic diseases.