title: Posttransplant immune-mediated hemolysis.
abstract: BACKGROUND
  Immune-mediated hemolysis is a well-recognized complication of transplantation, but few reports have drawn together the different mechanisms that could be involved.
  
  
  METHODS
  The clinical and laboratory records of three patients are used to illustrate different types and complexities of posttransplant immune-mediated RBC destruction.
  
  
  RESULTS
  Patient 1 received bone marrow from an HLA-matched, unrelated donor. At 7 months after transplant, his Hb level fell to 50 g per L. The serum contained warm autoantibodies, and the DAT was strongly positive for IgG, IgM, and C3d; an eluate yielded IgG and IgM autoantibodies. Autoimmune hemolytic anemia was diagnosed. Patient 2, blood group A, experienced severe hemolysis 14 days after receiving a lung from a group O donor. The DAT was positive for IgG. Serum and RBC eluate contained anti-A produced by immunocompetent B cells in the transplanted lung-this was the passenger lymphocyte syndrome. Patient 3 experienced posttransplant hemolysis caused by two different immune mechanisms. Originally group A, D- with anti-C, -D, -E, she received a peripheral blood progenitor cell (PBPC) transplant from her HLA-identical group A, D+ son. Six months later, chimerism was evident; the remaining recipient marrow was still producing antibodies that destroyed D+ RBCs made by the transplant. Later, autoimmune hemolytic anemia also developed; the DAT became positive for IgG, and warm autoantibodies were eluted from D- RBCs.
  
  
  CONCLUSIONS
  An understanding of the causes and circumstances under which posttransplant immune hemolysis arises is required for proper management. As more patients become long-term survivors of unrelated bone marrow and/or PBPC transplants, chimerism and complex serologic problems will become more common.
authors.affiliation: National Blood Service, Trent Center, Sheffield, UK. carol.mitchell@nbs.nhs.uk
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Sokol
authors.forename: Robert
authors.initials: R
authors.lastname: Stamps
authors.forename: David J
authors.initials: DJ
authors.lastname: Booker
authors.forename: Fiona M
authors.initials: FM
authors.lastname: Scott
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Laidlaw
authors.forename: Elisabeth A
authors.initials: EA
authors.lastname: Vandenberghe
authors.forename: Helen F
authors.initials: HF
authors.lastname: Barker
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology; D000328:Adult; D000744:Anemia, Hemolytic, Autoimmune / Q000175:diagnosis / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood; D001402:B-Lymphocytes / Q000276:immunology; D001787:Blood Group Incompatibility; D016026:Bone Marrow Transplantation / Q000009:adverse effects*; D003176:Complement C3 / Q000032:analysis; D003298:Coombs Test; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation / Q000009:adverse effects*; D006461:Hemolysis / Q000276:immunology*; D006358:Hot Temperature; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D016040:Lung Transplantation / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D012204:Rh-Hr Blood-Group System / Q000276:immunology; D018183:Transplantation Chimera
chemical_list: D000017:ABO Blood-Group System; D001323:Autoantibodies; D003176:Complement C3; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012204:Rh-Hr Blood-Group System