A Pediatric Case of Systemic Lupus Erythematosus Developed 10 Years after Cord Blood Transplantation for Juvenile Myelomonocytic Leukemia

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a most powerful immunotherapy for hematological malignancies. However, the impact of immunological disturbances as a result of allo-HSCT is not understood well. We experienced an 11-year-old boy who presented with systemic lupus erythemathosus (SLE) 10 years after unrelated cord blood transplantation of male origin for juvenile myelomonocytic leukemia (JMML) with monosomy 7. Bone marrow examination showed complete remission without monosomy 7. Genetic analysis of peripheral blood revealed mixed chimera with recipient cells consisting of <5% of T cells, 50–60% of B cells, 60–75% of NK cells, 70–80% of macrophages, and 50–60% of granulocytes. Significance of persistent mixed chimera as a cause of SLE is discussed.