Geoff Daniels

Identification, by Immunoblotting, of the Structures Carrying Lutheran and Para-Lutheran Blood Group Antigens

Abstract. Immunoblotting was performed, after sodium dodecyl sulphate polyacrylamide gel electrophoresis of solubilised red cell membranes under non‐reducing conditions, with human Lutheran antibodies, anti‐Lua, ‐Lub, ‐Lu3, ‐Lu6 and ‐Lu8, and with human para‐Lutheran antibodies, ‐Lu4, ‐Lu12 and ‐Lu17. On antigen‐positive red cells all antibodies revealed two components of apparent molecular weight (Mr) 83,000 and 76,000. Anti‐Lua and ‐Lub gave no bands with Lu(a‐b+) or Lu(a+b‐) cells, respectively. With the exception of anti‐Lu17, which reacted normally, and anti‐Lu3, which reacted weakly, none of the antibodies showed bands with membranes from Lu(a‐b‐) cells of the In(Lu) type. Treatment of the red cells with sialidase led to a small reduction in the apparent Mr of the Lutheran glycoproteins which, therefore, appear to contain sialic acid bearing O‐linked oligosaccharides.

Cromer-Related Antigens – Blood Group Determinants on Decay-Accelerating Factor

Abstract. Cromer‐related antigens, a series of blood group antigens phenotypically related to each other through various serological characteristics, have recently been shown to be carried on the complement regulatory glycoprotein decay‐accelerating factor (DAF). Cromer‐related antigens, therefore, represent a number of inherited variants and polymorphisms of DAF. The Inab phenotype, a ‘Cromer‐null’ phenotype in which the red cells lack all Cromer‐related antigens, appears to be an inherited DAF deficiency.

Evidence that the Auberger Blood Group Antigens Are Located on the Lutheran Glycoproteins

Abstract. Immunoblots of red cell membranes stained with eluates of alloanti‐Aua and alloanti‐Aub show that these antibodies recognize 2 membrane components from Au(a+) and Au(b+) cells, respectively. These structures, of apparent molecular weight (Mr) 79,000 and 85,000, are identical in appearance and mobility on a 10% SDS polyacrylamide gel to the Lutheran glycoproteins identified by alloanti‐Lub. Like the Lutheran glycoproteins, they showed a reduction in apparent Mr of about 1,500 after sialidase treatment. Red cell membrane components immunoprecipitated by a Lutheran‐related monoclonal antibody, were analysed with Lutheran and Auberger antibodies by immunoblotting. The Lutheran glycoproteins were revealed by anti‐Lub in precipitates from Au(a+b‐) Lu(a‐b+) and Au(a‐b+) Lu(a‐b+) cells, by anti‐Aua in precipitates from Au(a+b‐) Lu(a‐b+) cells and by anti‐Aub in precipitates from Au(a‐b+) Lu(a‐b+) cells. The same components were also recognized by anti‐Lua in precipitates from Lu(a+b‐) cells. Thus Aua and Aub antigens appear to be carried on the same red cell membrane structures as those carrying the Lutheran determinants. These results are particularly significant in the light of the very close phenotypic association between the Auberger and Lutheran blood groups which have been shown, by one family, to be controlled by genes at separate loci.

A Japanese family with two sisters apparently homozygous for Mk

Abstract. Two Japanese sisters with consanguineous parents have M‐N‐ En(a‐) Wr(a‐b‐) S‐s‐U‐ red cells and are therefore apparently homozygous for Mk; the third reported family with members of this genotype. The serum of the proposita (ORCMK) contained anti‐EnaTS, anti‐EnaFR and possibly anti‐Wrbwhereas the serum of her MkMksister contained no atypical antibodies. Total absence of sialoglycoproteins α and δ from red cell membranes of an Mkhomozygote was demonstrated by lactoperoxidase‐catalysed radioiodination of accessible tyrosine residues with subsequent SDS polyacrylamide gel electrophoresis and autoradiography, and by use of a monoclonal antibody directed at the cytoplasmic portion of α‐sialoglycoprotein.

Human Alloantibodies Detecting a Red Cell Antigen Apparently Identical to MER2

Abstract. Three examples of an antibody were found to be detecting a red cell polymorphism probably identical to MER2. The antibodies were made by Jews originating from India and living in Israel. Two of them were sibs and the third was unrelated. All 3 had kidney disease requiring renal dialysis and regular blood transfusion. In 2 cases the antibodies were detected before dialysis was started and before the patients had been transfused. The human antibodies reacted with red cells of 90% of Israeli blood donors tested. In tests on selected blood donors, 82 English and 56 Israeli, one of the human antibodies gave almost identical reactions to those given by monoclonal anti‐MER2. Anomalous reactions were probably due to anti‐Bga. Two of the human antibodies completely blocked, and one partially blocked, the reaction of monoclonal anti‐MER2 with MER2+ red cells.

The Rare Phenotype En(a‐) in a French‐Canadian Family

Abstract. A French‐Canadian En(a‐) propositus, whose red cells are phenotypically like the three previously reported, differs in the mode of reaction of this antibody which is apparently not immune. His consanguineous parents and 2 of this 4 sibs are heterozygous EnaEn, the other 2 being EnaEna. Sialic acid levels and the MN glycoprotein content of the red cells of the family and the PAS‐stained patterns of the red cell membranes of the propositus confirm the serological findings.

SAT, a ‘new’ low frequency blood group antigen, which may be associated with two different MNS variants

Summary. A new private blood group antigen, SAT, was identified in an NFLD‐Japanese woman as a result of testing 10,480 blood donors with a serum containing anti‐NFLD and anti‐SAT. Three other sera were subsequently also shown to contain anti‐SAT. The donors family showed that SAT is inherited as a dominant character and may be associated with a weak M antigen. Serological and immunochemical analysis revealed no other aberrations in the MNS system.

Miltenberger Class IX of the MNS Blood Group System

Mi.IX is a new phenotype in the Miltenberger series of the MNS blood group system with a frequency of 0.43% in Denmark. Mi.IX red cells are Mur+ but do not express any of the other established Miltenberger determinants. They react with a new antibody, anti‐DANE, which defines a determinant present on Mi.IX cells but not on cells of other Miltenberger phenotypes. Four Mi.IX propositi have been found. Their families show that MiIX is inherited with a MS complex (lod score 3.69 at θ = 0.00) which produces a trypsin‐resistant M antigen. DANE has been allotted the ISBT number 002032 (MNS32). Serological and immunochemical studies with human and monoclonal antibodies to various determinants on glycophorin A (GPA) suggest that Mi.IX is associated with an aberrant GPA molecule that lacks the trypsin cleavage site at amino‐acid residue 39, retains the chymotrypsin cleavage site at residue 34 and has an apparent Mr of about 1,000 less than normal GPA. It is proposed that this Mi.IX molecule has an amino acid and possibly also a glycosylation change in the region of amino‐acid residues 35–39.

Transient reduction in erythrocyte membrane sialoglycoprotein β associated with the presence of elliptocytes

Erythrocyte membranes from an anaemic patient receiving gold therapy for rheumatoid arthritis had reduced β‐sialoglycoprotein (β‐SGP) content but normal expression of sialoglycoproteins α, δ and γ. Elliptocytes were present in the peripheral blood. The serum of the patient contained anti‐β‐SGP which did not appear to bind to her own cells. It reacted with all erythrocytes apart from β‐SGP deficient Leach phenotype cells. The antibody was inhibited by purified β‐SGP from normal red cells, bound to β‐SGP on immunoblots and also reacted with the abnormal β‐related‐SGP in erythrocyte membranes of both the Gerbich type and Yus type of Gerbich negative. Two years later the patient was no longer anaemic, no elliptocytes were seen in her peripheral blood film and her erythrocyte membranes had normal β‐SGP content. Antibody was no longer present in her serum and antibody from the earlier sample now reacted with the patients erythrocytes.

A ‘New’ Cromer-Related High Frequency Antigen Probably Antithetical to WES

Abstract. An antibody to a high frequency antigen, made in a WES+ Black antenatal patient (Wash.), failed to react with the red cells of a presumed WES+ homozygote and is, therefore, probably antithetical to anti‐WES. Like anti‐WES, it reacted with papain, ficin, trypsin or neuraminidase treated cells but not with α‐chymotrypsin or pronase treated cells and was specifically inhibited by concentrated serum. It also reacted more strongly in titration with WES‐ cells than with WES+ cells. The antibody is Cromer‐related as it failed to react with Inab phenotype (IFC‐) cells and reacted only weakly with Dr(a‐) cells. Wash, cells and those of the other possible WES+ homozygote are Cr(a+) Tc(a+b‐c‐) Dr(a+) IFC+ but reacted only very weakly with anti‐Esa.