Subgroups of A in the South African Bantu

Abstract

Summary Bantu blood samples of group A, when tested for agglutination with Dolichos anti‐A1 reagent, do not show the sharp differentiation into Al and A2 that is found in specimens from Caucasians. They may he classified as A1, reacting strongly with Dolichos reagent; an intermediate group reacting weakly; and two groups that do not react — A2 and a weak form named Abantu. None of these subgroups is rare. Intermediates, though they have mean A scores lying between A1 and A2, have higher mean agglutination titres against Ulex anti‐H than do A2 samples. The mean H level of intermediates, in fact, does not differ significantly from that of O cells. Bantu bloods of all ABO groups have far higher mean H levels against Ulex reagent than do Caucasian samples of corresponding group. The A bantu group shows an A3 pattern of agglutination with potent anti‐A reagents and with O serum, but there is no A substance in the secretor salivas examined and anti‐A1. active at room temperature, is regularly present in the serum. Résumé Des échantillons de sang de Bantous de groupe A lorsqu'ils sont testés avec un réactif anti‐A1 provenant de Dolichos ne démontrent pas la différenciation nette entre des échantillons A1 et A2 ainsi qu'on le trouve chez des échantillons de Caucasiens. Ces échantillons de Bantous doivent être classifiés en A1 réagissant très fortement avec le réactif Dolichos; en une forme intermédiaire réagissant faiblement; et en deux groupes qui ne réagissent pas dont l'un est le type A2 et l'autre une forme faible appelée Abantou. Aucun de ces sous‐groupes est rare. Les formes intermédiaires qui se situent entre la forme A1 et A2, ont un titre moyen d'agglutination plus élevé contre l'anti‐II Ulex que les échantillons A2. Le taux moyen de substance H des formes intermédiaires, en fait, ne diffère pas de manière significative de celui des érythrocytes O. On observe que les échantillons de sang de Bantous des groupes A, B, O ont un taux moyen de substance H mis en évidence au moyen du réactif Ulex plus élevé que les échantillons des Caucasiens provenant de groupes correspondants. Le groupe Abantou se comporte au point de vue agglutination comme des érythrocytes A3 avec des réactifs anti‐A puissants et avec les sérums O, mais il n'y a pas de substance A dans la salive des secréteurs examinés et de l'anti‐A1 actif à la température de chambre se trouve régulièrement dans le sérum de ces sujets. Zusammenfassung Bantu‐Blutproben der Gruppe A zeigen bei Prüfung mit Dolichos Anti‐A1‐Reagentien nicht die scharfe Unterteilung in A1 und A2, wie dies bei Kaukasiern üblich ist. Sie lassen sich vielmehr wie folgt gruppieren: A1 mit kräftiger Reaktion mit Dolichos‐Extrakt; A‐intermediär mit schwacher Reaktion; zwei Gruppen, welche nicht reagieren: nämlich A2 und eine schwache A‐Eigenschaft, die als Abantu bezeichnet wird. Keine dieser Untergruppen ist selten. Intermediärformen mit A‐Scores zwischen A1 und A2 zeigen im Ansatz mit Ulex Anti‐H höhere Durchschnittstiter als A2‐Zellen. Der mittlere H‐Gehalt dieser Intermediärformen weich...

Red Cell and Saliva Studies for the Evaluation of ABH and Lewis Factors Among the Caucasian and Aboriginal Populations of Western Australia

“…This somewhat reduced A antigen value, notably those who agglutinated seed extract to a dilution of 1:10 and 1:50 (see Table II) may very well be classified as A15 A2 intermediates. However they do appear to be quite different from the A Bantu subgroups recently re ported by Brain (1966) in th at they were all known secretors of blood group substances A II and did not possess any form of anli-Aj in the serum, a feature which is apparently characteristic for group A Bantu bloods.…”

“…The difference was statistically significant (*2 [1J = 10.67; P <0.001). Brain (1966) recently also reported the high incidence of II reactivity for Bantu group A red cells, and suggested th a t this finding might be of forensic value in the identification of Bantu bloods. From our observations it is now possible to conclude th a t this remarkable variation is probably not specific for Bantu bloods alone.…”

Determinants of ABH expression on human blood platelets

“…As expected, there was an inverse expression of A and H antigens on RBCs, whereas A and H were directly correlated on platelets (Figure 4F-G 41 The incidence of A 1H1 and A 1 int differs among various ethnic populations, ranging from 2.0% to 13.7%. [41][42][43] Like the ABH-HXP phenotype, family studies of A 1 H donors suggest autosomal dominant inheritance. 43 To ascertain whether our ABH-high-expressing platelet donors were of the A 1H1 or A 1 int phenotype, A and H were examined on RBCs and platelets from an ABH-HXP donor ( …”

Inherited Differences in Blood Group A Subtypes in Caucasians and Negroes

“…The lectins from Ulex europaeus and Dolichos biflorus were not used, as yet, at the time of the fore going studies. In a more recent study, the A intermediate was found to be relatively common in the African Bantu [1], Studies were conducted to determine the magnitude of variation in the A and H antigens among blood group A individuals of a Negro and a Cau casian population, and to establish the frequency and mode of inheritance of the A intermediate, designated as Aj hereafter.…”