Rheumatoid arthritis cells in experimental pleuritis in mice.

In mice immunized with bovine fibrin, the same antigen was applied to the pleural cavity. A granulomatous pleuritis appeared affecting both the visceral and the parietal pleura, especially located around the antigen particle. Rheumatoid arthritis (RA) cells were constantly found in the pleural cavity when pleural lesions were present. This immunological, granulomatous pleuritis is the first experimental model for the study of RA cell-positive types of pleurisy in humans.