Matthew Kim

Hello, fellow blood bankers. I recently got a DAT positive result; poly 4+ IgG 4+ IgA 2+ IgM1+ C3c 1+ C3d 2+ control 1+ using Bio-rad DAT card. Antibody identification revealed pan-reactivity at the IAT. I thought this result might be caused by spontaneous agglutination of heavily IgG-coated patient's red cells. According to AABB technical manual 18th ed, removing autoantibody by warm saline wash (method 2-17) is recommended for ABO, RhD cell typing. I guess warm saline washing is done to remove cold agglutinins, not IgG antibody. Is there an appropriate method to have a valid DAT result in this case? Please help me. Forgive my ignorance.

Thank you very much. Now I understand why. Your comment helps me a lot.

Wow. Now I understand the cause of C-negative phenotype. Malcolm, I am sorry for my mistake about Dw. I meant that the patient has the weak D phenotype. However, there is one thing I cannot fully understand. CdeS type has (RHD-CE(3-7)-D) on his RHD gene capable of causing altered C antigen. You previously mentioned that Trp16Cys is a source of weakened C antigen expression. Do you think that both mutated RHD and RHCE genes affect altered C antigen expression? Thank you for such a great answer.

Hello. I've tried to come up with an answer over and over, but I've failed so far. Can I ask a question here? Our patient was identified to harbor DAR/Cdes (compound heterozygote) in our commercial kit. His Rh phenotype is Dwce. (c,e antigens are strongly positive) If his Cdes (RHD-CE(3-7)-D) allele is true, the patient's phenotype should Cces. But why ce? I am looking at blood group antigen factsbook and other papers, but I cannot find an answer. Any help would be appreciated.

Thank you, Malcolm I admire you clear answer. I also appreciate your recommendation on the book, Immune Hemolytic Anemias. I will definitely read it.

Anti-C and anti-e were identified in our patient and his DAT was 3+positive for IgG without previous transfusion history. His RBCs were typed as R1R2. Therefore, we suspect that auto-anti-C+e were present in his blood. I heard his antibodies could be autoantibodies mimicking anti-C and anti-e. Does anyone know the concept of autoantibodies mimicking specificity and the effective method to differentiate from just autoantibodies in detail? Any help would be appreciated. Thanks