Detection of A1A2 and A2AAm1 heterozygotes among human A blood group phenotypes.

From the variations of alpha-N-acetylgalactosaminyltransferases activities with the pH, evidence was obtained for the recognition of A1A2 heterozygotes in normal A blood group sera. Besides, unusual transferase properties associated with two A2 sera from individuals out of AAm1 siblings, lead to the identification of the very infrequent A2AAm1 genotypes. These results strongly support the simultaneous coexistence of both A1 and A2 transferases in heterozygotes' sera, and bring some new information on the genetical background of the Am phenotype.

An auto-anti-b in an a1b person. Serological studies.

The serum of a patient (Mr. Lat) with the regular blood group A1 B contains an anti-B reacting with all cells having a B antigen except Bx and cis AB. The anti-B reacts at 4 degrees C and occasionally at room temperature as shown by agglutination, absorption-eluction and by thermo-dynamic assays.

[Proposed practical classification of weak B phenotypes B 3, Bx, B el].

Although the first weak B phenotypes have been observed some thirty years ago, very few comparative studies have been done until now. In this work, different samples were analysed, using immunogenetic methods, thermodynamics, agglutination kinetics and agglutination profiles. Almost hundred weak B samples were tested, belonging to twenty nine families including cis AB but exclusing acquired B and Bh.

Quantitative and thermodynamic measurements on I and i antigens of human red blood cells.

Different homogeneous IgM cold agglutinins (two anti-I, two anti-i and one anti-Il cross-reacting antibodies) have been used to determine the antigen site densities of adult I and i erythrocytes and of cord red cells. The equilibirium constants and the thermodynamic constants of these reactions have been determined. The two anti-I antibodies, which did not combine with i or cord red blood cells, recognized two different determinants on I red cells.

Groups of alpha-D- galactosyltransferase activity in sera of individuals with normal B phenotype. II. Relationship between transferase activity and red cell agglutinability.

In the Paris population of blood donors with normal B phenotype, two groups can be formed owing to their respective serum alpha-D-galactosyltransferase activity and red cell agglutinability with an anti-B antibody. Both parameters are closely correlated. The agglutinability groups partially overlap.

Jk(a-b-) phenotype in a French family. Quantitative evidence for the inheritance of a silent allele (Jk).

A Caucasian French family was investigated including two Jk(a-b-) sibs who had developed anti-JkaJkb. The parents were first cousins. Quantitative study of Kidd antigens using titration scoring and HD50 assay clearly showed the parents and a maternal aunt, phenotypically Jk(a+b-), to have a weak expression of Jka documenting thereby the transmission of the postulated silent gene Jk.

Polyagglutinability associated with the cad antigen.

Various anti-Cad and anti-Sda reagents were tested against a panel of Cad red cells in order to determine whether Cad and Sda antigens were identical. According to the results, although strong Sda reactivity was always found in Cad red cells, the two antigen specificities are not identical. The polyagglutinability of Cad red cells seems to be related to an anti-Cad present in all human sera but Cad, and not with anti-Sda antibody.

An unusual Rh phenotype indicating heterogeneity of the Cw antigen.

A family is reported in which a new Cw antigen occurred in two generations. This was recognized by 17 anti-Cw sera, but by none of the 21 anti-C sera which were, however, shown to react strongly with common Cw+ cells. This unusual finding provides evidence that the Cw antigen is in fact heterogeneous.

Blood groups changes in preleukemic states.

Modifications of blood groups in the course of malignant hemopathies are related to the disease itself and appear to be essentially clonal. They refer not only to the glycolipidic ABH and associated antigens, but also to other blood group systems or other genetic markers. These multiple abnormalities are observed in the preleukemic states as well as in the actual leukaemias.

Cis AB blood groups. Immunologic, thermodynamic and quantitative studies of ABH antigens.

Fifteen samples of cis AB bloods belonging to six unrelated families were tested by serological and thermodynamic assay techniques. The B and H antigens of cis AB bloods differ significantly from those of trans AB bloods. Differences were found among unrelated samples, but identical results were obtained within a given family : this could mean that there had been as many mutations as there were families.

Acquired B antigen disappearance by in vitro acetylation associated with A1 activity restoration.

The chemical acetylation of RBC bearing the acquired B antigen led to the disappearance of the agglutinability by anti-B and restored the A1 specificity. The same results are obtained using RBC transformed in vitro by a Clostridium Tertium filtrate, where a deacetylase was reported.

Auto-anti-Pra: a 'second' example in a newborn.

A second example of anti-Pra was recognized in a newborn infant which exhibited several signs of development disease. The antibody was complement-fixing 19S IgM and showed a high thermal range but no detectable haemolytic anaemia was associated. It gave negative reactions with a panel of animal cells as well as with two samples of human En(a-) cells.

[Cold agglutinin with anti-B specificity in an A1B subject].

A high titre cold autoagglutinin with anti-B specificity was found in the serum of an A1B group individual. It was associated with a low titre anti-I. This anti-B agglutinated most cells having a B antigen (normal B, A1B, A2B, from adult and cord bloods, B3), but failed to agglutinate Bx Cis-AB and Bh cells.

[The Cis AB complex of the ABO system].

Members of six unrelated families from Japan, France, Belgium and Poland were studied in parallel. Major immunological features characteristic of the phenotype produced by the Cis AB complex are the following: 1) The red cell A reactivity is close to normal, is beyond the values of agglutination scores by Helix and by anti-A from B; likewise, with percent agglutination measurements, A reactive appears hiher than that of A2B cells; one sample only is slightly detected by anti-A from Dolichos. 2) The B reactivity, on the contrary, is lower than that of normal AB cells.

[Coagglutination in continuous flow. Techniques and applications].

The principle of coagglutination, the specific agglutination of uncoated red cells by antibody coated ones was applied to the two conventional continuous flow agglutination systems (bromelin-methylcellulose and polybrene-Na-citrate). The technique was used to study a large number of allo- and auto-antibodies of various specificities as well as some drug related antibodies. The sensitivity of the technique proved not to be higher than that of similar systems using free antibodies.

A1 weak B phenotypes found in two generations of a Romanian family: A1Bx versus cis AB complex.

Three 'A1 weak B' blood groups found in two generations of a Romanian family were studied with quantitative and thermodynamic assays in order to determine if they derive from 'A1Bx' or from 'cis AB' genotypes, what cannot be achieved by the genetics.

A cold auto-agglutinin of anti-B specificity in an A1B patient.

A high titre cold auto-agglutinin with anti-B activity was found in the serum of an A1B group individual. The B/anti-B reaction was thermodynamically investigated and quantitative analysis of the patient's B antigen revealed no abnormality.

Cad antigen: comparative study of 50 samples.

50 Cad (+) blood samples were tested using various anti-Cad reagents. Results demonstrated a wide Cad antigenic expression, even among the members of one family. In particular experimental procedures, almost all Cad (+) cells were polyagglutinable.