Carole Green

Comparison of the proteome of adult and cord erythroid cells, and changes in the proteome following reticulocyte maturation

Cord blood stem cells are an attractive starting source for the production of red blood cells in vitro for therapy because of additional expansion potential compared with adult peripheral blood progenitors and cord blood banks usually being more representative of national populations than blood donors. Consequently, it is important to establish how similar cord RBCs are to adult cells. In this study, we used multiplex tandem mass tag labeling combined with nano-LC-MS/MS to compare the proteome of adult and cord RBCs and reticulocytes. 2838 unique proteins were identified, providing the most comprehensive compendium of RBC proteins to date. Using stringent criteria, 1674 proteins were quantified, and only a small number differed in amount between adult and cord RBC. We focused on proteins critical for RBC function. Of these, only the expected differences in globin subunits, along with higher levels of carbonic anhydrase 1 and 2 and aquaporin-1 in adult RBCs would be expected to have a phenotypic effect since they are associated with the differences in gaseous exchange between adults and neonates. Since the RBC and reticulocyte samples used were autologous, we catalogue the change in proteome following reticulocyte maturation. The majority of proteins (>60% of the 1671 quantified) reduced in abundance between 2- and 100-fold following maturation. However, ∼5% were at a higher level in RBCs, localized almost exclusively to cell membranes, in keeping with the known clearance of intracellular recycling pools during reticulocyte maturation. Overall, these data suggest that, with respect to the proteome, there is no barrier to the use of cord progenitors for the in vitro generation of RBCs for transfusion to adults other than the expression of fetal, not adult, hemoglobin.

A KEL gene encoding serine at position 193 of the Kell glycoprotein results in expression of KEL1 antigen

BACKGROUND: The KEL2/KEL1 (k/K) blood group polymorphism represents 578C>T in the KEL gene and Thr193Met in the Kell glycoprotein. Anti‐KEL1 can cause severe hemolytic disease of the fetus and newborn. Molecular genotyping for KEL*1 is routinely used for assessing whether a fetus is at risk. Red blood cells (RBCs) from a KEL:1 blood donor (D1) were found to have abnormal KEL1 expression during evaluation of anti‐KEL1 reagents.

Serology and genetics of an MNSs-associated antigen Dantu.

Dantu, a previously undescribed low‐incidence red cell antigen, is inherited as a Mendelian dominant character. The Dantu antigen is associated with very weak s antigen, protease resistant N antigen and either very weak or no U antigen. Two of the propositi had previously been shown to have an unusual hybrid MNSs sialoglycoprotein, and it is probably this which carries these unusual N, s and U antigens as well as the Dantu antigen. A study of the family of one propositus suggests, by conventional genetics, that Dantu is not controlled by the MNSs locus; a possible explanation is given. Several examples of anti‐Dantu are known, one was found to cause a positive direct antiglobulin reaction on neonatal red cells.

Molecular basis of the JAHK (RH53) antigen

BACKGROUND: The JAHK antigen was first described in 1995 as a low‐frequency red blood cell antigen. Family studies confirmed the association of the antigen with the rare rG phenotype of the Rh blood group system, which is associated with weak expression of C and e, but normal G expression. JAHK was allocated the Rh number RH53. The serologic findings indicated the location of the antigen on the RhCE protein, although the molecular basis for JAHK has not been known.

Different inactivating mutations in the LU genes of three individuals with the Lutheran-null phenotype

BACKGROUND: The null phenotype of the Lutheran blood group system, Lunull or Lu(a–b–), is characterized by the lack of all Lutheran system antigens. It can arise from three genetic backgrounds: recessive, dominant, or X‐linked. Lunull of the recessive type appears to result from homozygosity for an inactive LU gene.

Molecular bases of the antigens of the Lutheran blood group system

BACKGROUND: Lutheran is a complex blood group system consisting of 18 identified antigens. There are four pairs of allelic antigens, whereas others are independently expressed antigens of a high frequency. Lutheran antigens are carried by the Lutheran glycoproteins, which are a product of a single gene LU.

McLeod syndrome resulting from a novel XK mutation

Summary. McLeod Syndrome (MLS) is a rare X‐linked disorder characterized by haemopoietic abnormalities and late‐onset neurological and muscular defects. The McLeod blood group phenotype is typically associated with erythrocyte acanthocytosis, absence of the Kx antigen and reduced expression of Kell system antigens. MLS is caused by hemizygosity for mutations in the XK gene. We describe a patient with MLS who first showed symptoms in 1989 (aged 51 years). As the disease progressed, the patient developed a slight dementia, aggressive behaviour and choreatic movements. A cardiomyopathy was also diagnosed. An electroneuromyography showed neuropathic and myopathic changes. Liver enzymes were elevated and a blood smear showed acanthocytes. MLS was confirmed by serological analysis of the Kell antigens. Analysis of red blood cells by flow cytometry revealed the patient and his grandson to have reduced Kell antigen expression. The patients daughters had two populations of red cells, consistent with them being heterozygous for an XK0 allele. The molecular basis of MLS in this family is a novel mutation consisting of a 7453‐bp deletion that includes exon 2 of the XK gene. This confirms that the patients 7‐year‐old grandson, who is currently asymptomatic, also has the XK0 allele and is therefore likely to develop MLS.

Novel GYP(A-B-A) hybrid gene in a DANE+ person who made an antibody to a high-prevalence MNS antigen

BACKGROUND: The glycophorin (GP) molecule associated with the GP.Dane phenotype is a GP(A‐B‐A) hybrid that contains some amino acids encoded by the Pseudoexon 3 of GYPB and Asn45 of GPA and carries the low‐prevalence MNS antigens DANE and Mur. Serum from a woman of English ancestry contained an immunoglobulin M alloantibody to a high‐prevalence MNS antigen, and the purpose of this study was to identify the molecular basis of her phenotype.

Swa: a subdivision.

Abstract. For some time, anomalous serological reactions have been observed when the same anti‐Swa sera are tested against red cells from different individuals reported as Sw(a+). A comparative collaborative study using the same collection of Sw(a+) cells and anti‐Swa sera was undertaken by 4 reference laboratories, and it was found that Swa represents a heterogeneous group of antigens that can be subdivided into two categories. Both categories, Sw(a+) 700:41 and Sw(a+) 700:‐41, were shown to be inherited.

M9+ WINS Blood Group Phenotype: Further Observations

Red cells carrying the low‐frequency MNS antigen M8 reacted with the only example of anti‐DANE, an antibody which had previously defined the GP.Dane (Mi.IX) phenotype. Furthermore, Mg + cells reacted with the original anti‐Mur (serum of Mrs. Murrell), but with none of 14 other anti‐Mur. Therefore, M8 + cells carry both DANE antigen and an atypical Mur antigen. Immunoblotting of membranes from Mg + cells with anti‐M, and with eluates prepared from anti‐Mg and Mrs. Murrells serum demonstrated a glycophorin A (GPA) molecule whose mobility was increased by an apparent Mr of about 3,000 presumably due to the loss of the three O‐glycans known to be absent from Mg ‐active GPA.