A method for demonstrating blood group isoantigens in permanent tissue sections

Several techniques have been used to demonstrate ABH isoantigens in tissue sections. The first, the Specific Red Cell Adherence (SRCA) test (Kovarik et al. 1968) involves adsorbing type-specific human erythrocytes (i.e. indicator erythrocytes) onto paraffin tissue sections which have been coated with multivalent anti-blood group substance antibody. Secondly, immunofluorescence and immunoperoxidase techniques have been used (Dabelsteen 1972). These techniques are limited in their applicability since anti-H serum is not available for the demonstration of the tissue antigen in patients who are blood group O. This limitation is circumvented with the SRCA test by the use of the lectin, Ulex, which cross reacts with blood group antigen O and tissue antigen H. To overcome the major deficiencies of the SRCA test as described by Kovarik et al. (1968), a modified procedure was developed so that the final product of the SRCA test is a permanent hematoxylin and eosin stained section to which type-specific indicator erythrocytes are bound. The procedure has been described. Staining characteristics and histopathological detail of the sections are excellent. It is noteworthy that indicator erythrocytes can be readily distinguished from erythrocytes within sections on the basis of position, shape, and staining characteristics. Typically, the indicator erythrocytes rest on the section, are spheres, and stain bright orange-red.