Immune Reconstitution Following Autologous Stem Cell Transplantation in Patients with High-Risk Neuroblastoma at the Time of Immunotherapy

Outcomes for patients with high-risk neuroblastoma (HR-NBL) are significantly improved with the addition of immunotherapy (dinutuximab + cytokines) following autologous hematopoietic stem cell transplantation (auto-HSCT). We hypothesized that the immune system is not fully reconstituted at the initiation of immunotherapy. To test this hypothesis, we evaluated hematologic and immune subsets in 34 patients with HR-NBL before and after auto-HSCT. We found that absolute T, B, and NK cell counts at the time of immunotherapy were below normal in 80% of patients. Patients with residual disease at the time of transplantation had significantly lower absolute lymphocyte counts (ALC; P = .008), lower CD16+ cell counts (P = .009), and an abnormal ratio of cytokine-releasing to cytotoxic NK cells at the time of dinutuximab treatment. In addition, the preparative regimen used for auto-HSCT predicted immune recovery. Finally, higher total white blood cell count (P = .013) and ALC (P = .013) at 3 months after completion of therapy were measured in patients who remained in remission compared with those who relapsed. Our results indicate that most patients with HR-NBL do not have full immune reconstitution at the time of dinutuximab treatment after auto-HSCT, and that immune recovery may correlate with disease-related outcomes in patients with high-risk disease.