Auto-antibody Showing $Anti-Fy^b$ Specificity as Proven by the Dilution Method in the Presence of Warm Autoantibodies: A Case Report

Several approaches have been introduced to detect allo-antibodies in the presence of warm auto-antibodies, and these methods include warm autoadsorption, cysteine-activated papain and dithiothreitol (ZZAP), and polyethylene glycol (PEG) and dilution of the patient‘s serum. Among them, the dilution technique is a simple and rapid method. During pretransfusion testing of a 33 year-old systemic lupus erythematosus (SLE) patient with warm auto-antibodies, antibody identification was done by the dilution technique with using serum diluted 1-in-8. The patient demonstrated an anti- pattern of reactivity in his sera. Contrary to our expectations, the phenotypeof the erythrocytes was Fy(a+/b+) and the genotype, as assessed by performing PCR-restriction fragment length polymorphism (RFLP), was . These results suggest that the antibody is an autoantibody showing anti- specificities. An antibody identification test using undiluted serum showed the same result when 40 days had passed. We report here on a case with auto-anti- proven by the dilution method in the presence of warm autoantibodies.