title: Benefits of fresh-frozen plasma as a replacement fluid to neutralize ABO antibodies.
abstract: BACKGROUND
  ABO-incompatible organ transplantation requires pre-transplant conditioning to reduce ABO antibody levels in the recipients. With respect to replacement fluids used in plasma exchange, we intended to verify whether fresh-frozen plasma (FFP) containing soluble ABO substance (SAS) is more effective than albumin solution in reducing ABO IgG antibody levels.
  
  
  METHODS
  Apheresis data were retrospectively studied for in vivo effects, and in vitro plasma mixing studies were prospectively performed. The amount of ABO IgG antibodies bound to red cells was measured as the mean fluorescence intensity (MFI) using flow cytometry. Neutralization of ABO antibodies in the recipientst plasma by an ABO-incompatible donornc plasma was measured using the inhibition assay principle. The MFI value of the unneutralized control tube was divided by that of the neutralized test tube (neutralizing-capacity index, NCI).
  
  
  RESULTS
  The plasma exchange procedures replaced with group AB FFP showed a significantly greater decreased titer than those replaced with albumin (P = 0.010). The in vitro plasma mixing study simulating plasma exchange also produced consistent results. When the pooled group O plasma was neutralized for anti-A by individual group AB plasmas (AB-to-O, N = 30), the NCI was 12.8 ± 5.4 (6.5-29.5). When this group O plasma was neutralized by pooled group AB or A plasma, the repeatedly measured NCI (N = 5) of A-to-O (11.4 ± 1.4) was not significantly different from that of AB-to-O (9.7 ± 1.3, P = 0.074).
  
  
  CONCLUSIONS
  ABO antibody levels are reduced more effectively by group AB FFP than by albumin. Either group AB or donor type (group A or B) FFP can be infused to group O recipients. FFP units with higher SAS levels can be selected from multiple available candidate units using our protocol for measuring the neutralizing-capacity.
authors.affiliation: Department of Clinical Pathology, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Dong Il
authors.initials: DI
authors.lastname: Won
authors.affiliation: Department of Clinical Pathology, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Ji Yeon
authors.initials: JY
authors.lastname: Ham
authors.affiliation: Department of Internal Medicine, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Chan Duck
authors.initials: CD
authors.lastname: Kim
authors.affiliation: Department of Clinical Pathology, Kyungpook National University School of Medicine, Daegu, Republic of Korea.
authors.forename: Jang Soo
authors.initials: JS
authors.lastname: Suh
authors.affiliation: Department of Laboratory Medicine, Maryknoll Medical Center, Busan, Republic of Korea.
authors.forename: Byung Chang
authors.initials: BC
authors.lastname: Kim
mesh_terms: D000017:ABO Blood-Group System / Q000097:blood / Q000276:immunology*; D000372:Agglutination Tests; D000937:Antigen-Antibody Reactions; D001787:Blood Group Incompatibility / Q000276:immunology / Q000628:therapy*; D016238:Cytapheresis; D004912:Erythrocytes / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood* / Q000276:immunology; D066298:In Vitro Techniques; D007518:Isoantibodies / Q000097:blood* / Q000276:immunology; D016030:Kidney Transplantation; D010949:Plasma; D010951:Plasma Exchange / Q000379:methods*; D010952:Plasma Substitutes; D056910:Republic of Korea; D012189:Retrospective Studies; D012709:Serum Albumin / Q000008:administration & dosage / Q000494:pharmacology; D019172:Transplantation Conditioning
chemical_list: D000017:ABO Blood-Group System; D007074:Immunoglobulin G; D007518:Isoantibodies; D010952:Plasma Substitutes; D012709:Serum Albumin
keywords: ABO substance; flow cytometry; fresh-frozen plasma; plasma exchange