Cytodiagnosis of rheumatoid pleural effusions.

The stained smears of the deposits from one pericardial and 19 pleural effusions complicating rheumatoid arthritis were examined. On the basis of clinical and biochemical evidence it was considered that in six cases the effusions were due to the rheumatoid disease while in a further nine cases the association was considered likely. In the remaining five cases the association was considered to be due to chance as other causes for the effusions were diagnosed. On cytological examination, seven cases showed a characteristic picture of degenerating polymorphs with amorphous extracellular material and epithelioid cells many of which were multinucleate. Five others contained similar amorphous material without epithelioid cells; of these two had many plasma cells and a third numerous macrophages probably containing ;droplets' of rheumatoid factor complex. Thus in 12 of 15 cases a definite diagnosis of rheumatoid effusion could be made. In the remaining five cases cytological examination confirmed that the effusions were unrelated to the rheumatoid disease.The extracellular material gave a non-specific fluorescence with labelled anti-gamma globulin antisera, and since this reaction was not seen in control pleural fluid deposits, or with preparations of fibrin, it may have a confirmatory value. It is concluded that in many cases reliable cytological evidence can be found to confirm or refute a diagnosis of rheumatoid pleural or pericardial effusion. This may be helpful in the management of the rheumatoid disease.