Development and validation of antibody screening cells specifically designed for Asian populations - the first example of the addition of peptide antigens to human red cells using KODE technology
Background: Alloantibodies to antigens displayed on variant glycophorins are common in many Asian populations and have been shown to cause both transfusion reactions and haemolytic disease of the foetus and newborn new born. The detection of these antibodies is problematic as commercially available panels for antibody screening do not include the antigens necessary for detection of these antibodies. The use of naturally-occurring phenotype-positive cells is also problematic because not all antibodies detected are clinically significant, the specific epitope reactivity cannot be identified, and the RBC types required for full epitope analysis are of very limited availability.
Aim: To use KODETM technology to add peptide epitopes to screening cells and to evaluate their stability and suitability for use in the detection of alloantibodies. The peptides investigated represented a series of defined variant MNS (Miltenberger) epitopes. These were used for the detection, identification and investigation of clinically significant alloantibodies, particularly alloantibodies found in Asian populations.
Methods: Candidate carrier molecules were constructed and peptides attached. The epitope specificity of anti sera with generic anti-Mi(a) reactivity were characterized by ELISA. The candidate constructs were inserted into red cells and reactions in routine anti globulin test platforms were investigated. The stability of the transformed cells was also investigated.
Results: There was no abnormal lysis of RBC expressing KODE -peptide antigens and the expression of these peptides on the transformed cells was stable with time. Detection of antibodies to other rbc antigens by IAT was the same for transformed and untransformed cells. Antibodies to variantMNS (Miltenberger) epitopes that have been reported to be clinically significant were detected for almost all serums for which a previous ELISA specificity had been defined.
Summary: Various different KODE systems are suitable for addition of carbohydrate or protein antigens to human red blood cells. Under optimal conditions there is no change in the expression of other rbc blood group antigens. KODE technology allows for sensitive detection of clinically significant antibodies to vMNS antigens well as identification of their specific epitope reactivity.