Anti-A and/or anti-B is not detectable in some patients who underwent ABO-incompatible bone marrow transplantation

Recently, anti-A and/or anti-B produced by B cells from donor marrow could not be detected for more than 20 weeks in some patients who had undergone ABO-incompatible bone marrow transplantation (BMT).

Twelve to 72 weeks after 11 patients underwent ABO-incompatible BMT, titers of anti-A and anti-B were assayed, A and B antigens were identified by routine methods and flow cytometry, direct and indirect antiglobulin tests were performed, and the red cell antibody was eluted.

In some patients who underwent ABO-incompatible BMT, anti-A and/or anti-B produced by the B cells from the donor marrow could not be detected after BMT when red cells taken from the patients before BMT carried the corresponding antigen--that is, when hematopoiesis had already changed the cells to the donor's type according to ABO blood typing. Furthermore, some blood samples from those patients gave positive results in direct antiglobulin tests. Blood typing of patients after BMT showed mixed-field agglutination. In one patient, the half-life of red cells assayed with 51Cr was 22.4 days (30.0 +/- 4.0 days for normal controls).

Although many hypotheses could be considered to explain the present data, the possibility is proposed that anti-A and/or anti-B in the sera must have been consumed in some patients who underwent ABO-incompatible BMT. This may lead to problems such as difficulty of ABO typing, positive direct antiglobulin tests, and a relatively short life span of red cells.