Sibling Donor Recruitment Based on the NIMA Hypothesis

Abstract

Based on the hypothesis that long-term microchimerism of fetal or maternal cells in the donor circulation might be an indicator of acquired immunological hyporesponsiveness to non-inherited maternal HLA antigens (NIMA) or inherited paternal HLA antigens (IPA), several groups have recently reported the feasibility of non-T-cell-depleted blood and marrow transplantation between HLA-haploidentical and NIMA or IPA mismatched family members. To evaluate the safety and efficacy of mother donor superiority over father donor, we performed a nationwide retrospective analysis on the clinical outcomes of 452 patients who received the first allogeneic stem cell transplantation from their mother or father, registered when the bone marrow transplantation committee of the Japanese Society of Pediatric Hematology since 1983 to 2001. Mother versus father donor was not a significant factor in the over-all survival of pediatric allo-SCT patients. The retrospective study revealed NIMA mismatched sibling donors' efficacy and safety; the NIMA concept could be applied to select HLA mismatched relatives at better compatibility.