A and B blood group antigen expression on mixed colony cells and erythroid precursors: relevance for human allogeneic bone marrow transplantation.

Using anti-A and anti-B blood group monoclonal antibodies and fluorescent activated cell sorting of human bone marrow, A (or B) blood group antigen was shown to be on 5.2 +/- 5.9 (mean +/- SD) % of CFU-GEMM and 12.5 +/- 19.6% of the erythroid burst forming cells (designated BFU-GEMM) as defined by the mixed colony assay, and 49.5 +/- 20% of the BFU-E and 83.5 +/- 9.9% of the CFU-E as defined by the erythroid colony assay. This antigen expression on the BFU-GEMM is consistent with the concept that erythroid bursts stimulated by leucocyte conditioned medium are less mature, and are closer in development to the pluripotent stem cell than the BFU-E. These results help to explain the delayed erythropoiesis, and perhaps impaired engraftment of all cell lineages, that may occur in some recipients of ABO incompatible bone marrow transplants with persistent and high anti-A titres.