Mimic of Anti-f (IgM) by Combination of Anti-c (IgM) and Anti-e (IgM) for Comparison with Reported Patient’s Anti-f (IgM/IgG or IgG)

Abstract

The f (ce) antigen is a compound antigen in Rh blood group system expressing on red blood cells when c and e antigens are formed by genes on the same chromosome. Anti-f alloimmunization occurs when a patient without the f antigen is transfused with blood carrying the f antigen. Anti-f is concerned in hemolytic transfusion reaction. The majority of anti-f found is IgG while the minority is IgM. A low frequency anti-f has been reported in a patient in Thailand. The objective of this work was to produce mimic of anti-f (IgM) by combination of anti-c (IgM) and anti-e (IgM), and compare the reaction pattern with the reported patient’s anti-f (IgM/IgG or IgG). The mimic of anti-f (IgM) was studied with antibody screening, antibody identification, adsorption-elution technique followed by antibody screening and antibody identification of eluate, antibody distinguishing with dithiothreitol and potency testing. The results showed that antibody screening of mimic of anti-f (IgM) presented 4+ for all screening cells O1-4 with antigen c and/or e (R1R1, R1R2, rr) whereas patient’s anti-f (IgM/IgG or IgG) was reported 3+ with only O4 with ce antigen (rr). Antibody identification of mimic of anti-f (IgM) revealed 4+ for all panel cells 1-11 (P1-11) with antigen c and/or e (R1R1, R1R2, R2R2, R1Rz, R1r, rr, r’r, r’’r) whereas patient’s anti-f (IgM/IgG or IgG) was reported 2-3+ with P4, P9-11 carrying antigen ce (R1r, rr, r’r, r’’r). Antibody screening and antibody identification of eluate demonstrated 1+ with O1-4 and 1+ with P1-11 at RT, 37ºC and AHG the reaction pattern of which was identical with mimic of anti-f (IgM) and mimic of anti-f (IgM) exhibited the potency of 128. This research indicated that mimic of anti-f (IgM) had different characteristics from patient’s anti-f which was antibody to compound antigen f (ce) and not to either antigen e or c. Reaction pattern of mimic of anti-f (IgM) could be a practical way of antibody identification to separate patients’ anti-f from anti-c + anti-e which might be found in the future.