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

Abstract

A patient with aplastic anemia received an ABO incompatible bone marrow transplant (BMT) from an HLA identical sibling. Weekly HLA antibody screens were performed as part of the BMT protocol. At the time of transplant, a hemolytic anti-Le a was detected in the Le (a−b−) donor. The le (a−b+) recipient had no red cell or LCT antibody. A hemolytic anti-Le a was detected in the recipient on day 8, but no LCT reactivity was noted at this time. On day 15, the LCT panel demonstrated reactivity with 9 of 50 panel cells without apparent HLA specificity. Graft vs. host disease (GVHD) was present on the skin at this time. The dose of cyclosporin A was increased, but by day 20 the GVHD worsend and the LCT titers increased to 8. This strong reactivity was noted only in the Le (a+) panel members (12/50) and was neutralized with commercial Lewis substance. On day 34 there was no evidence of GVHD, but the lymphocytotoxic anti-Le a continued to be present. The patient began experiencing renal and gastrointestinal difficulties by day 48, and expired on day 60. In renal transplants the kidneys retain their Lewis type and secrete Lewis substance in the urine. In our experience BMT patients retain their Lewis type regardless of the type of the donor. The Lewis system has been linked to renal allograft rejection, and Lewis antigens may function as transplantation antigens in BMT patients as well. In addition, lymphocytotoxic Lewis antibodies can mask other significant HLA antibodies and must be identified when screening patients in need of plateletpheresis products.