Gerbich System Research Articles

A GE:-13 (GECT-) HETEROZIGOUS AND GE:-14 (GEAR) HOMOZIGOUS PHENOTYPE DETECTED BY RANDOM SCREENING FOR GE:-2 BLOOD DONORS IN BRAZIL

We report a rare case of GE:-13 and GE:-14 phenotype blood donor identified by random screening during blood bank routine. This is a descriptive work using immunohematology data from immunohematology reference laboratory (LRI) where samples were tested. A 29 year old blood donor, woman, self-declared as african american from the São Paulo city with no history of previous transfusions or pregnancies. Her blood was typed as O RhD+ (C-E+c+e+) and K- and the antibody screening was negative in gel cards. The phenotypes identified as Ge:-2,3 were confirmed by screening for GE:-2 blood group performed by hemagglutination in DG Gel cards using in house anti-Ge2 and others anti-Ge2 and anti-Ge3 from our inventory. Genomic DNA was isolated from donor whole blood and GE genotyping was performed by PCR-SSP techniques for analysis of exons 2, 3 and exon 4. The genetic variations that influence the expression of high-incidence antigens are deletions that involve exons 2, 3, 4 and the single nucleotide exchange (SNVs) in exons regions of the GYPC gene. These mutations, if not studied by molecular tests, may result in serological interpretation errors. Thus, sequencing by Sanger method of GE gene was performed and revealed a nucleotídeo change 59C>T (Pro20Leu in GPC) in Exon 2 in heterozygous and a nucleotide change 333A>C (non-coding) (Gly19Arg in GPD) in Exon 4 in homozigous state. No other nucleotide changes were identified. One of the criteria for AABB reference laboratory certification in immunohematology is the screening for blood donors with rare phenotypes. For this reason, donors from the Hospital Israelita Albert Einstein are tested with anti-Ge2 antiserum. The aim is detect the rare phenotype Ge:-2, for compatibility tests in patients with anti-Ge2 alloantibody. The antigens of the Gerbich System are located on glycophorins C (GPC), D (GPD) or both. There are eight highly prevalent antigens known as Ge2, Ge3, Ge4, GEPL, GEAT, GETI, GECT, GEAR. Polymorphisms that involve high incidence antigens such as deletions in introns and single nucleotide exchange (SNVs) in exons regions of the GYPC gene, if not studied by molecular tests, may result in serological interpretation errors. The fact of donor has a GECT allele (GE*01.-13) in heterozygosity does not imply the development of antibodies. The homozygous GEAR allele (GE*01-14) could result in the production of a rare anti-GEAR antibody in case of transfusion or pregnancy, however the clinical importance of this antibody is still unknown. Few articles report that these mutations can lead to loss of epitopes and the phenotypes can be interpreted as Ge:-2 or Ge:-3 in serological screening. This case showed that the molecular sequencing was crucial to determine the correct mutations present in the GYPC gene and consequently the correct deduction of the phenotype.

Recombinant forms of glycophorin C as a tool for characterization of epitopes for new murine monoclonal antibodies with anti-glycophorin C specificity.

Glycophorin C (GPC) and glycophorin D (GPD) are minor but important components of human RBC membranes. They carry the high-frequency antigens Ge2, Ge3 and Ge4 of the Gerbich blood group system. The epitopes for five new monoclonal antibodies (MoAbs) with anti-GPC specificity were characterized. Two antibodies (4G11 and 5B11) reacted with glycosylated N-terminal epitopes, and three reacted with internal epitopes of GPC. Pepscan analysis showed that the MoAb RB11 required for binding the EPDP sequence, occurring twice in GPC polypeptide chain. The MoAb 7F11 recognized the sequence 13PLSLEPDP20, and the MoAb RB8 did not react with synthetic peptides. Further characterization of the internal epitopes was performed in fluorescence-activated cell sorter (FACS) with the use of recombinant GPC and its variant forms transiently expressed on COS-7 cells. The results indicated that the MoAb RB11 recognized distinctly its target sequence EPDP only in a normal GPC molecule. The reactivity of the MoAb 7F11 with the PLSLEPDP sequence was confirmed and found to be enhanced by the O-glycan at the Ser15 residue. The MoAb RB8 recognized the glycopeptidic epitope in proximity to the Ser15 residue, requiring the presence of O-glycan. The combination of immunochemical techniques with the use of the recombinant forms of GPC has made it possible to define the role of sugar chains in the recognition of peptidic epitopes in glycosylated antigen and sheds new light on the Gerbich system antigens.

A Novel Human Alloantibody in the Gerbich System

A Gerbich-negative Leach phenotype individual was identified on the basis of distinct morphological, biochemical, and serological characteristics of her red blood cells. This individual has produced an antibody which was reactive with the various Gerbich phenotypes including Ge:-2,3 (Yus type) and Ge:-2,-3 (Ge type) cells; only her own and Leach phenotype cells were non-reactive. It is suggested that this antibody represents an example of a new specificity, one which defines the Leach phenotype, in the Gerbich system.

A Novel Human Alloantibody in the Gerbich System

A Novel Human Alloantibody in the Gerbich System

A case report: unusual Gerbich antibody in a patient with sickle cell anemia

Abstract A patient whose red blood cells (RBCs) typed as Ge:2,3 produced an alloantibody to a high-frequency antigen in the Gerbich system. This antibody was shown to be nonreactive with Ge: −2, −3 RBCs using adsorption-elution studies. A monocyte monolayer assay (MMA) suggested that transfusion of Ge:2,3 RBCs to this patient would have reduced in vivo survival.

Linguistic and genetic differentiation in New Guinea

Results of genetic marker studies for populations in various parts of New Guinea have been analysed for the relationship between genetic differentiation, linguistic differences and geographic distance. Single-locus markers, such as the Gm groups, the Gc and the Gerbich systems do not give consistent differences between speakers of Austronesian and Non-Austronesian languages. Similarly, genetic distance techniques applied to gene frequency data do not allow a clear-cut separation based on language alone. A more detailed study of 17 populations in the northern areas of Papua New Guinea suggest that populations cluster together genetically on the basis of geography rather than language. Partial correlation coefficients were obtained for genetic kinship, geographical distance and cognate frequency for populations in the Bogia Subprovince. Kinship is significantly correlated with distance when cognate frequency is held constant. It is concluded that linguistic studies do not provide an infallible guide to ancestral relationships and that postulates of past migrations based on language may be in error unless genetic studies also are taken into account.