Turpentine- and fibrin-induced pleuritis in nude mice. Histopathological, cellular and biochemical changes.

Turpentine was injected into the right pleural cavity of nude immune-incompetent mice, causing a temporary irritative exudative pleuritis. A transient occurrence of so-called rheumatoid arthritis cells was observed in the pleural fluid together with parallel characteristic biochemical changes. In similar experiments in nude mice, however, immunization followed by intrapleural application of bovine fibrin showed irritative "dry" pleuritis without the presence of rheumatoid arthritis cells. This is in contrast with previous results from similar experiments done using normal mice. The conclusion from the present experiments is that in nude immune-incompetent mice only the non-immunological, turpentine-induced pleuritis will generate cellular and biochemical changes typical of the rheumatoid disease in patients, while the fibrin-induced pleuritis fails to show similar changes. This suggests that the rheumatoid-like pleural changes described in the present experiments in nude mice have a non-immunological basis.