Review: the Diego group system

The purpose of this article is to review the literature Caribe Indian admixture. The fifth example was a nat- about the Diego blood group system and to highlight urally occurring anti-Dia in a Caucasian woman, anthropological studies, genetic studies, serologic whose serum agglutinated RBCs from a Di(a+) blood characteristics of Diego antigens and , and donor. Four of her relatives of Irish origin were their clinical importance in certain ethnic groups. Di(a+). The next example of anti-Dia in an Austrian family, caused HDN and was the first example in History and Anthropological Studies which alloimmunization occurred during a first preg- In 1956 a low-incidence red cell antigen responsi- nancy.1,2,5-7 It was concluded from these studies that ble for hemolytic disease of the newborn (HDN) was Dia is not exclusive to Mongoloids but occurs also as described with the aid of an produced by a a low-incidence antigen in Caucasians. mother living in Caracas, Venezuela. This antigen was Since American Indians are considered to be named Diego (Dia) after the proposita, and the corre- anthropologically related to the Mongoloid people, sponding antibody was named anti-Dia.1 A study of individuals of Chinese and Japanese descent living in the Diego family showed that the antigen was present Venezuela were studied. The presence ofDia in six in 10 of 33 members in four generations (see Fig. South American Indian populations studied, as well 1).1-3 During this study it was observed that some as in Chinese and Japanese, suggests that this gene is family members showed physical features of admix- Mongoloid rather than American Indian. Further find- ture with native Indians, many of whom are Di(a+).4 ings of the Dia antigen in Chippewa Indians in The Dia antigen may not be completely absent in a Northern Minnesota and in Japanese in Winnipeg also Caucasian population free from admixture with suggested that Dia may be an Asiatic (Mongoloid) Indians, since the second example of anti-Dia was characteristic.3 The phenotype and genotype fre- found in the serum of the mother of an infant with quencies of the Diego system in Mongoloid, HDN from a Polish family living in New York.1,2,5 Caucasian, Negroid, and hybrid Venezuelan popula- Some believe that the finding of anti-Dia in a Polish tions are given in Table 1.3,8 mother and the Dia antigen on the red cells of her In 1956 it came as a surprise when no Di(a+) per- husband, who is also Polish, is indicative of son was found among 156 Eskimos tested in the Mongoloid admixture, and the high incidence of the Eastern Canadian Arctic.9 Further studies on Eskimo B gene in the Polish population is supportive evidence populations showed a very low incidence of Dia.10-12 of this admixture.3,4It was proposed that if the genet- The Alaska Indians are the only American Indians that ically related Dib and anti-Dib exist, the antibody do not have at least 5 percent Di(a+) person13 In should be sought among the homozygotes of geno- the study of the Canadian Indian population by type DiaDia of the Caribe Indians.' Buchanan et aI.,13 the Dia antigen incidence The third example of anti-Dia also caused HDN, this decreased from 3 percent in northern Alberta to 0 per- time in a family of Spanish ancestry, "Mart," living in cent in Inuvik in far northern Canada. Other studies the Dallas, Texas, area. The fourth example of anti-Dia found that the incidence of Dia was 3-4 percent in was described in a Puerto Rican woman, whose pre- northern Japan and 5-7 percent in southern maturely born twins did not develop HDN, although All of these studies suggest that Dia is an their red blood cells (RBCs) were direct antiglobulin Asiatic characteristic. test (DAT) positive. In this family there were six Nearly 1374 Australian aborigines and 1741 New Di(a+) members in four generations, and there was Guineans were tested for Dia from 1967 to 1970 and