RESUMEN
BACKGROUND: The Rh blood group antigens are encoded by the RHD and RHCE genes, which possess a remarkable degree of polymorphism owing to their high homologous structures. These variants of the RH genes can lead to absence or weak expression of antigens. METHODS: Analysis of RHCE genotyping by Polymerase Chain Reaction (PCR-SSP) method specific to detect c.48G, c.48C, 109 bp insertion of IVS2, c.201A and c.307C and RhCE phenotyping, were conducted in 316 Chinese patients in previous study. One patient with discrepancy typing result was collected for further RhCE serologic typing using microcolumn gel method and tube method in saline using monoclonal antibodies. PacBio sequencing was performed for RHCE, RHD and RHAG complete sequence analysis. 3D molecular models of the protein with the wild-type and mutant residue were generated using the DynaMut web server. The effect of the mutation on the protein function was predicted by PolyPhen-2 software. RESULTS: One male patient of Chinese Han was detected with RHCE*C allele showed by PCR-SSP method but ccEE phenotype. Further PacBio sequencing identified one normal RHCE*cE allele and one RHCE*Ce allele carried a novel c.829G > A (p.Gly277Arg) variant, which the encoded amino acid located in the ninth transmembrane segment of RhCE protein. Crystallisation analysis of 3D molecular models revealed that the substitution at Arg277 leads to the formation of additional hydrogen bonds, including weak hydrogen bonds between multiple atoms. It also results in hydrophobic ion interactions between Arg277 and Ala244. This mutation is predicted to have a damaging effect on protein function. CONCLUSION: One novel RHCE*Ce allele with c.829G > A (p.Gly277Arg) variant was identified to resulting in the absence or weak expression of C and e antigens.
RESUMEN
【Objective】 To evaluate the interference of anti-CD47 monoclonal antibody on transfusion compatibility detection, in order to establish methods for removing interference and evaluate its efficacy. 【Methods】 Blood samples from 8 patients in our clinical trial who were treated with anti-CD47 monoclonal antibody from Tianjing and Xinda were collected. ABO and Rh blood group antigen identification, direct anti-human globulin test, unexpected antibody screening test and cross-matching test were performed by ZZAP, Gamma-clone(an anti-globulin reagent lacking IgG4) and Immucor Capture-R solid phase agglutination kit. 【Results】 ABO blood group identification of 5 subjects were interfered after treatment with anti-CD47 monoclonal antibody. All 8 subjects showed 2+ to 4+ agglutination intensity on direct anti-human globulin test and 3+ to 4+ on unexpected antibody screening. The results of unexpected antibody screening by Gamma-clone and Immucor Capture-R solid phase agglutination kit were all negative, while the cross-matching test were compatible. Patients with anemia caused by CD47 monoclonal antibody treatment were transfused with 2 U suspension red blood cells, and the evaluation showed that the transfusion was effective. 【Conclusion】 The CD47 monoclonal antibody can interfere with transfusion compatibility detection, and the use of antiglobulin reagents lacking IgG4 and Immucor Capture-R solid phase agglutination kit can remove the interference, with good transfusion efficacy in patients.