Lymphocytotoxic anti-LewisbH antibody

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

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 worsened 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-Lea 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.

Specific removal of anti-red cell blood group activity from anti-HLA lymphocytotoxic sera and purification of anti-A and anti-B antibodies with lymphocytotoxic activity

Lymphocytotoxic antibodies to the red cell blood groups A and B were purified from human sera by elution from synthetic immunoadsorbents (Synsorbs from Chembiomed). The lymphocytotoxic activity of the eluted antibodies was better preserved when elution was carried out at pH 11, whereas it was less stable when elution was performed at pH3. In addition, complete removal of anti-red cell blood group activity from an anti-HLA serum was easily obtained by adsorption on the corresponding Synsorb without loss of anti-HLA activity.

The role of the Lewis antigen system in renal transplantation and allograft rejection

The recent literature on the technologic and clinical progress being made in renal transplantation has not emphasized applicable advances in blood group serology. Accumulated data on the Lewis blood group system, however, seem to implicate Lewis incompatibilities between kidney donors and recipients as contributing factors in allograft rejection. Lewis antigens may be capable of inciting both cell-mediated and humoral immune responses of a cytotoxic nature, and such antigens are expressed on cell surfaces of the renal parenchyma in Lewis-positive persons. Hence, this serologically defined system could be the source of diminished allograft survival in recipients who are mismatched with their organ donors for Lewis antigens, despite compatibility within other histocompatibility antigen systems. This premise is still open to question, and future, controlled, clinical studies will be necessary to establish a definite role for the Lewis antigen system in renal transplant rejection.