In a series of papers (1-3), clinical cases of hemolytic transfusion reaction and erythroblastosis fetalis have been reported involving patients with Rh-positive blood (two with standard P, h0 factor, one with Rh0 variant factor) who had become sensitized and produced antibodies resembling anti-Rh0 in specificity. Similar cases had been encountered by other observers (4--6). Since the antibodies in our patients' serums were shown to be different from anti-PJao and from one another, they have been assigned the symbols anti-Rh A, anti-Rh B, and anti-Rh c. Recently, a fourth such antibody was encountered to which the symbol anti-Rh D has been assigned (7). Evidently, "standard" Rh-positive blood has besides factor Rh0 all the factors Rh A, Rh B, Rh c, and Rh D. However, rare Rh-positive individuals have been found with blood lacking one or more of the associated factors, and who can be sensitized to the missing blood factor (8, 9). The resulting antibody resembles anti-Rh0 in specificity except for its failure to clump the patient's own cells and the ceils of certain other rare Rh-positive (or ~h-positive) individuals. ~The original paper of Wiener and Geiger reported the results of tests for Rh A factor on a random series of Rh-positive Caucasians and Negroes, and a higher incidence was noted of the very rare Rh-positive bloods lacking factor Rh A among Negroes as compared with Caucasians. In previous papers (8, 11) the present authors extended this investigation to a larger series of individuals, confirmed the initial observations, and also noted especially the higher frequency of specimens lacking Rh x factor among blood with an Rh0 variant as x In this paper, in conformity with the recommendation of the Committee on Medicolegal Problems of the American Medical Association (10), symbols for agglutinogens, phenotypes, and blood group systems are printed in regular type, symbols for blood factors and their corresponding antibodies in boldface type, and symbols for genes and genotypes in ira/its. One should note that "agglutinogen Rh" is an inclusive term for all agglutinogens having factor ~ namely, aggintinogens Rh0, Rhl, Rh2, and Rh,. Similarly, "agglutinogen ~h" refers to all agglutinogens with an Rho variant factor, namely, ~ho, ~h~, etc. The symbol Rh • refers to Rh-positive blood locking factor Rh A, e.g., type Rh]th is indistingnishable from ordinary type Rh~rh blood except for its failure to react with anti-gh A serum, etc. Similar rules apply for agglutinogens and phenotypes designated as Rh b, Rh e, Rh a°, etc., and genes designated R°% R l~b,/~d, etc. Symbols using Greek superscript letters, such as Rh ~, Rh ~, and Rh ~, signify that the factors 1Lh A, Rh B, Rh c, are present but are variants, that is, the avidity and titer of the reactions axe less than that of "standard" Rh-positive blood.
Materials and MethodsThe methods used in these investigations have already been described in detail (11,12), and only the essential facts are repeated here. The antiserums used were bivalent anti-Rho. univalent ant...
