Prolonged selective neutropenia after allogeneic bone marrow transplantation: Possible effect of presensitization by donor lymphocytes prior to transplant

Selective neutropenia lasting over five months occurred in a 17-year- old adolescent male who received all allogeneic bone marrow transplantation (BMT) from an HLA-identical sibling for severe aplastic anemia. Bone marrow specimens showed maturation arrest of myeloid precursor cells despite sustained engraftment. Cytogenetic analyses revealed complete donor-type chimerism in hematopoietic cells and mixed lymphoid chimerism. The patient received a second BMT from the same donor following more intensive conditioning, including total body irradiation. neutrophil recovery was rapid and complete donor-type hematopoietic and lymphoid chimerism was observed within three weeks of the second transplant. The present case suggests that prolonged selective neutropenia following BMT is due to residual host- derived immunity which is resistant to the standard immunosuppressive conditioning used prior to BMT for asplastic anemia.