[The specific erythrocyte adherence method in the study of ABH antigens on normal and neoplastic bladder epithelium].

The isoantigens A, B, and H, identical with those present in erythrocytes, are also present in epithelial cells of some normal tissues, included the transitional epithelium of the urinary bladder. The cell surface ABH antigens can be detected with the specific erythrocyte adherence method (SEA), but could not be detected when carcinoma developed in this tissue: with rare exceptions, the loss of demonstrable antigens paralleled morphological anaplasia. We studied retrospectively by SEA test 51 specimens of urinary bladder, including 36 primary transitional cell carcinomas at the time of initial biopsy, and 15 controls. The SEA reaction was strongly positive in normal bladder epithelium, in vascular endothelium and in erythrocytes already present in sections, while was negative in connective tissue. 21 were classified as grade 0 (papilloma): in 19 of them the ABH antigens were fully or partially preserved, and the follow up from 5 to 15 years demonstrated no recurrences; the other 2 patients with negative SEA recurred locally. The only one graded as I, with strongly positive SEA, had not recurred in at least 6 years, 5 were classified as grade II; in 2 of graded as III, the SEA reaction was weakly positive in 3, while in remaining 6 the antigens were absent. The usefulness of the detection of ABH antigens as a prognostic tool in low grade and stage bladder carcinomas is confirmed by our data establishing the correlation of antigens deletion with subsequent clinical behavior. An alteration of blood group substance synthesis occurs in malignant epithelium, but it is not known whether it causes or results from malignant changes. The SEA method resulted highly sensitive and specific; however, the test is cumbersome and time-consuming, requires special expertise and shows some limitations, particularly the frequency of the occurrence of false-negative or weakly positive results in blood group O patients.