Immunocytochemical analysis of ascitic fluid due to cirrhosis : a contribution to understanding the origin of markedly atypical cells

: In some cases of ascitic fluid due to cirrhosis, benign mesothelial clusters may be observed, accompanied by markedly atypical cells that have been proposed to be abnormal macrophages, mesothelial cells or necrotic cells of hepatic origin. The aim of this study was to determine the origin of these cells with the use of a panel of monoclonal antibodies (MAbs) against cell surface antigens. Furthermore, the lymphocyte subpopulations were analyzed for a possible correlation with the presence of abnormal cells. Markedly atypical cells were found in 4 of 12 cases. They showed no phagocytosis of latex particles and were negative for MAbs My4 (CD14), HLE-1 (CD45), Leu M1 (CD15), CEA 3-13 and HEA-125. They reacted positively with BMA-120 and HLA-1. This staining pattern demonstrated the mesothelial origin of the markedly atypical cells. The profile of the lymphocyte subpopulations in the cases with markedly atypical cells was not different from the other cases. We propose that these cells are abortive cluster formations of mesothelial cells.