A bone marrow transplant with an acquired anti-Le(a): a case study

Area of Science:

• Immunology
• Transplantation Science
• Hematology

Background:

• Bone marrow transplantation (BMT) involves complex immunological considerations, including HLA compatibility and antibody screening.
• Lewis antigens, typically expressed on epithelial cells and secreted in bodily fluids, play a role in immune responses and transplant outcomes.
• Aplastic anemia patients undergoing BMT require rigorous monitoring for complications such as graft-versus-host disease (GVHD) and antibody formation.

Observation:

• A patient with aplastic anemia receiving an ABO incompatible BMT developed anti-Lewis a antibodies.
• The patient exhibited worsening graft-versus-host disease (GVHD) coinciding with rising titers of lymphocytotoxic antibodies specific for Lewis a.
• These Lewis a antibodies were neutralized by Lewis substance, confirming their specificity and masking potential HLA antibodies.

Findings:

• Hemolytic anti-Lewis a antibodies were detected in the donor and subsequently in the recipient post-BMT.
• Lymphocytotoxic anti-Lewis a antibodies emerged and increased in titer, correlating with GVHD severity.
• The patient experienced renal and gastrointestinal complications, suggesting a potential link between Lewis antibodies and transplant-related morbidity.

Implications:

• Lewis antigens may act as transplantation antigens in BMT, contributing to immune reactions and allograft rejection.
• The presence of lymphocytotoxic Lewis antibodies can obscure the detection of clinically significant HLA antibodies, necessitating careful identification.
• Routine screening for Lewis antibodies in BMT patients, particularly those requiring platelet transfusions, is recommended to optimize patient management and outcomes.