RESUMO
BACKGROUND: MER2 (RAPH1), the only antigen of the RAPH blood group system, is located on the tetraspanin CD151. Only four examples of alloanti-MER2 are known. We report here two new examples of alloanti-MER2, in women of Pakistani and Turkish origin, one of whom showed signs of a hemolytic transfusion reaction (HTR) after transfusion of 3 units of red cells (RBCs). STUDY DESIGN AND METHODS: Standard serologic methods were used. A monocyte monolayer assay (MMA) was used to assess the potential clinical significance of one of the antibodies. All exons and flanking intronic sequences of CD151 were amplified and sequenced. A homology model for CD151 second extracellular loop (EC2) was constructed based on the crystal structure of CD81. RESULTS: RBCs of both patients did not react with alloanti-MER2, and neither of their antibodies reacted with MER2-negative RBCs. The MMA results suggested that the antibody that appeared to have caused an HTR had the potential to be clinically significant. Both patients were homozygous for a 511C>T mutation in CD151 encoding an Arg171Cys change. This change did not result in any significant structural rearrangement in the protein model. CONCLUSIONS: Two MER2-negative patients with anti-MER2 are homozygous for the same novel mutation encoding an amino acid substitution in the EC2 of CD151. One of the antibodies may have been responsible for an HTR, and crossmatch-compatible RBCs should be recommended for transfusion to patients with anti-MER2.
Assuntos
Antígenos CD/genética , Antígenos de Grupos Sanguíneos/genética , Mutação , Idoso de 80 Anos ou mais , Antígenos CD/química , Antígenos CD/metabolismo , Antígenos de Grupos Sanguíneos/imunologia , Feminino , Humanos , Isoanticorpos/imunologia , Modelos Moleculares , Polimorfismo Genético , Estrutura Secundária de Proteína , Tetraspanina 24 , Reação TransfusionalRESUMO
BACKGROUND: The Crawford antigen (RH43) was described in 1980. It occurred in African American people, as a low-prevalence Rhesus antigen, who were also VS+. STUDY DESIGN AND METHODS: Twelve blood samples were analyzed because of inquiries into discrepant reactions in routine anti-D typing. The RHCE alleles were determined by nucleotide sequencing from genomic DNA. The D epitope profile was determined with 60 monoclonal anti-D. The population frequency was estimated in four major US regional blood centers. RESULTS: The novel RHce(W16C, Q233E, L245V) allele, dubbed ceCF, was found to be occurring in the cde haplotype as cause of the reactivity with the immunoglobulin M anti-D GAMA401. The ceCF phenotype expressed few D epitopes resembling but not matching the reaction patterns observed with other RhCE variants, like R0 (Har), ceRT, and ceSL. The frequency of the ceCF phenotype was 0.056 percent among African American persons and 0.007 percent in the general US population. CONCLUSION: The novel RHce(W16C, Q233E, L245V) allele, which is a variant of the known ce(s) allele, RHce(W16C, L245V), occurs in a haplotype with the RHD deletion and represents the molecular basis of the Crawford antigen.
Assuntos
Alelos , Substituição de Aminoácidos , Frequência do Gene/genética , Mutação Puntual , Sistema do Grupo Sanguíneo Rh-Hr/genética , Negro ou Afro-Americano , Substituição de Aminoácidos/imunologia , Anticorpos Monoclonais/imunologia , Tipagem e Reações Cruzadas Sanguíneas , Análise Mutacional de DNA , Epitopos/genética , Epitopos/imunologia , Feminino , Frequência do Gene/imunologia , Haplótipos/genética , Haplótipos/imunologia , Humanos , Masculino , Fenótipo , Mutação Puntual/imunologia , Sistema do Grupo Sanguíneo Rh-Hr/imunologia , Estados UnidosRESUMO
Es descripto las tecnicas potenciadoras e substancias que se emplean en imunohematologia e banco de sangre para promover modificacion en el medios de prueba. Son considerados potenciadores de la aglutinacion la albumina bovina, soluciones de baja fuerza ionica y o polietilenglicol.
The techniques for Potentiators of reactions used in immunohematology and the blood bank to make clear an erytbrocytary antigen reaction are described in this report. Bovine albumin, low-ionic strength salt solution and polyethylene glycol are included within tbe potentiators.