Alteration of Blood Group Antigens in Leukemic Lymphocytes.

The purpose of this investigation was to delineate the presence of ABH blood group antigens on the surface of normal and leukemic lymphocytes and to determine whether this genetically directed and supposedly constant characteristic (1) is altered in the neoplastic cell. The study was an extension and synthesis of the following previously recorded observations. 1) The recent demonstration that red cells and lymphocytes share common cellular antigens (2) implied this might also be the case for more specific antigenic determinants. 2) Blood group substances are found not only in erythrocytes but are widely distributed in a multiplicity of body tissues and fluids (3) so that their suspected presence in the lymphocyte was credible. 3) The observation that carcinomatous epithelia lose their blood group identity (4) suggested the possibility that a similar alteration might occur in the malignant lymphocyte. The lymphocyte's tendency to clump spontaneously and its avidly adsorbing surface lead to interpretive difficulties when a number of immunologic methods, such as conventional agglutination, antibody consumption, and fluorescent labeling are used to define this cell's more exact antigenic structure. The technic (5, 6) of specific mixed cell agglutination (SMCA), as employed and described in this study, largely circumvents these problems since the only circumstance under which the lymphocyte may be linked to the indicator red cells of known blood group by type-specific anti-