On the incidence of antibodies to the Rh antigens G, rhi(Ce), C, and CG in sera containing anti‐CD or anti‐C

In tests on 50 single‐donor sera containing anti‐CD or anti‐CDE, it was found that 37 of them reacted with rG red Mood cells. However, adsorption‐elution experiments showed that only 15 of the sera contained anti‐G. Those sera that reacted with rG red blood cells d but which lacked anti‐G, apparently contained anti‐C that accounted for their reactions with the C‐,D‐,G+,CG+, rG red blood cells used. In all, only 30 per cent of the singledonor anti‐CD and anti‐CDE antibodies contained anti‐G. In muked contrast, a11 of 11 commercially prepared anti‐CD and anti‐CDE typing reagents contained potent anti‐G. In tests on 46 anti‐CD and 9 anti‐C sera, it was found that most of them contained anti‐rhi (anti‐Ce) component. However, only 2 of the 55 sera (1 anti‐CD and 1 anti‐C, both single‐donor sera) failed to react with ry red blood cells, showing that 53 of the anti‐C antibodies would detect C in the absence of rhi. These findings are discussed in terms of some statements that exist in the literature about anti‐G, and in term of the relative immunogenicity of D, C, G, CG and rhi.