Early occurrence of nephrotic syndrome associated with cord blood stem cell transplantation

Nephrotic syndrome (NS) associated with hematopoietic stem cell transplantation (HSCT) is usually related to chronic graft-versus-host disease (GVHD) and invariably occurs later than 100 days after transplantation. Here, we report the case of a 6-year-old boy who presented with NS only 61 days after cord blood stem cell transplantation (CBSCT). At 4 years old he was diagnosed with acute lymphoblastic leukemia and underwent bone marrow transplantation. Six months later, a recurrence was noted in the thymus, which required CBSCT at the age of 6. Acute GVHD and hemophagocytic syndrome occurred on day +13 and day +15, respectively, and were successfully treated with tacrolimus and a steroid. After tacrolimus was switched from intravenous infusion to oral administration, NS occurred on day +61. Complete remission was achieved in 3 weeks by resuming steroid treatment. Dry erythema with pigmentation and elevation of Th2 cytokine level suggest that NS in this case was also related to chronic GVHD. To our knowledge, this is the earliest occurrence of NS after HSCT. Hematologists and nephrologists should be aware that this condition may occur even in early periods after HSCT.