[Cellular changes in malignant pleural effusion induced by intrapleural injection of BCG-CWS]

The intrapleural injection of BCG cell wall skeleton (BCG-CWS) is thought to be beneficial in the treatment of malignant pleural effusion. The study of cancer cells in pleural effusion after the intrapleural injectin of CWS showed that nuclear damage to cancer cells was slight and delayed compared to findings obtained after the intrapleural injection of Mitomycin C. After the intrapleural injection of CWS, the ratio of granulocytes in pleural effusion was rapidly elevated. This suggests that CWS induces an inflammatory response in the pleural cavity. After the inflammatory reaction, adhesive pleuritis was induced, the pleural space was reduced, leading to the disappearance of effusion. On the other hand, after the intrapleural injection of CWS, no elevation of the ratio of macrophages, and no increase of macrophage and cancer cell adherence were observed. This suggests that the immunopotentiating effect of CWS is not high.