Lectin binding properties of cells from serous effusion and peritoneal washing specimens

The diagnostic value of staining cells from serous effusion and peritoneal washing specimens with a panel of four lectins was investigated and the results compared with those achieved with polyclonal anti-carcinoembryonic antigen (anti-CEA) sera. Cell blocks from 42 pleural effusions, 25 peritoneal effusions, and 14 peritoneal washing specimens were stained with Con A (D-mannosyl, D-glucosyl), WGA (n-acetyl glucosamine), UEA-1 (L-fucose), SBA (n-acetyl galactosamine) and anti-CEA. Con A and WGA were not useful in discriminating mesothelial cells from adenocarcinomas. In contrast, UEA-1 and SBA binding was present in 30 of 46 (65%) and in 31 of 46 (67%), respectively, of adenocarcinomas tested, but negative in 21 cases with reactive mesothelial cells, 10 cases with benign mesothelial cells, and one case of mesothelioma. All mesothelial cells were also negative for CEA, but 24 of 46 (52%) of adenocarcinomas were positive. All three cases of lymphoma were negative with UEA-1, SBA, and anti-CEA. UEA-1 and SBA lectins identified a higher proportion of metastatic adenocarcinomas than CEA and stained most cases of adenocarcinomas metastatic from sites which usually fail to express CEA. Combination of staining results for UEA-1, SBA, and anti-CEA produced a test with high sensitivity and specificity, identifying 40 of 46 (87%) of adenocarcinomas tested, with no false positive results. It is concluded that UEA-1 and SBA staining of effusion specimens warrants further study, and may provide a useful adjunct to CEA staining.