STUDY OF THE MOLECULAR STRUCTURE OF HAPLOTYPE RH CARRIER OF THE ALLELE RHD*WEAK D TYPE 4

PRINCIPI, CINTIA; TRUCCO BOGGIONE, CAROLINA; MUFARREGE, NICOLÁS; LUJÁN BRAJOVICH, MELINA ELIANA; MATTALONI, STELLA MARIS; ENSINCK, MARÍA ALEJANDRA; GARCIA BORRAS, SILVIA; BIONDI, CLAUDIA; COTORRUELO, CARLOS

Rosario

Congreso; XX Congreso y XXXVIII Reunión Anual de la Sociedad de Biología de Rosario 2018; 2018

Sociedad de Biología de Rosario

The Rh blood group system is highly polymorphic and has a great clinical interest in Transfusion Medicine due to the participation ofits antibodies in the processes of immune destruction of the transfused red blood cells. The RH locus consists of two homologousgenes, RHD and RHCE. More than 400 alleles have been reported that generate Rh variant epitopes (partial and/or weak) andphenotypes lacking high prevalence antigens. The RH genes segregate as haplotypes and some RHD and RHCE alleles show geneticlinkage disequilibrium. The coexistence of aberrant allelic variants in cis in patients who are under therapy with chronic transfusionsmay be responsible for delayed transfusion hemolytic reactions due to the production of complex alloantibodies.Molecular studiesallow the characterization of the allele involved in the altered expression of Rh antigens, optimizing transfusional compatibility. Theaim of this work was to characterize the molecular structure of the RHhaplotype carrying the allelic variantRHD*WeakD type 4.Serologic and molecular analyses were performed in 39 blood samples carryng the RHD*Weak D type 4alelle. The samples wereobtained from unrelated patients from different health effectors of our country. D phenotype was investigated by haemagglutinationwith 4 anti-D monoclonal reagents: IgM / IgG (clones TH28 / MS26), IgM (clone MS201), IgM (clone RUM1) and IgM (clonesLDM1 and ESD1M). The complete Rh phenotype was also studied with anti-C (clone MS24), anti-c (clone MS33), anti-E (cloneMS258 / MS80) and anti-e (clones MS16 + MS21 + MS63) antibodies. Genomic DNA was obtained using the salting-out method.PCR-SSP strategiesallowed the detection ofc.733G, c.48C and c.48G polymorphisms in the RHCE gene. Serologic analysis in allsamples showed a weak D antigen expression and the presence of the c and e antigens only (complete Rh phenotype: Dweak type 4ccee).In 36 (92.31%) samples aberrant RHCE alleles were detected: 27 (75.00%) RHCE*ce(733G, 48C, 48G), 7 (19.44%) RHCE*ce(733G,48G) and 2 (5.56%) RHCE*ce(733G, 48C). The RHD*Weak D type 4allele is responsible for a partial D phenotype whereas thec.733G and c.48C mutations present in RHCE originate c and e partial antigens. The molecular characterization of the RHD-RHCEhaplotype in patients carrying the RHD*Weak D type 4allele results useful to determinetransfusional compatibility and avoid potentialanti-D, anti-c or anti-ealloimmunization, mainly in patients who carryRHCE*Ce,RHCE*cE orRHCE*ce(733G, 48C) alleles in transand require chronic transfusion therapy for the treatment of their primary pathology.