Killer-cell immunoglobulin-like receptor ligand mismatch cord blood transplantation in high-risk neuroblastoma

The prognosis of high-risk neuroblastoma stage 4 with bone marrow metastasis, MYCN amplified, or refractory neuroblastoma is poor. To date, no standard treatment has been established. In four selected cases, we challenged the killer-cell immunoglobulin-like receptor ligand mismatch cord blood transplantation in graft-versus-host disease (GVHD) with reduced-intensity conditioning.

Prior to this study, conventional chemotherapy, autologous peripheral blood stem cell transplantation with high-dose chemotherapy (busulfan and melphalan), surgery and radiation therapy were completed in every case. The status before cord blood transplantation in two cases was not complete remission (CR) and in the others it was CR. The primary site was the mediastinum, two adrenal glands and a retroperitoneum, respectively. Three patients had bone and bone marrow metastasis and one had MYCN amplification. In all cases, international neuroblastoma pathology classification was unfavorable histology. All patients were >2 years of age.

Relapse occurred only in one patient 17 months after the last transplantation, and the other three patients maintained disease-free survival for 74, 36, and 24 months, respectively. In one case of relapse the disease could be controlled by conventional chemotherapy. Except one, all patients had no severe complications, such as acute or chronic GVHD. One patient had gastric antral vascular ectasia and hemorrhagic cystitis.

This strategy might be feasible and should be investigated for efficacy in the future. No definite conclusion can be made, however, due to the very small number of patients. Further prospective studies are required to determine its efficacy.