Abstract 3112: Prospective immune phenotyping of neuroblastoma children at diagnosis reveals specific immune defects related to the aggressiveness of the disease

CONTEXT: Neuroblastoma is the most common extracranial solid tumor in children. Patients with low- and intermediate-risk neuroblastoma (LIRNB) have favorable prognosis and an excellent five-year survival rate of more than 90%. However, in the case of high-risk neuroblastoma (HRNB; ~50% of cases), the prognosis of treatment remains unfavorable and the five-year survival rate remains under 40% despite aggressive multi modal therapy. QUESTION: We wanted to know if there was a defect in immune surveillance that could explain part of the aggressive phenotype of HRNB. METHODS: We performed a prospective multi-center study on thirty two new cases of neuroblastoma at all stages. We performed a wide phenotyping of immune cells by flow cytometry in fresh whole blood, and fresh whole bone marrow at diagnosis of children diagnosed for neuroblastoma. Cell counts were performed in order to be able to reason in absolute values (G/L) rather than only percentages. RESULTS: Blood and bone marrow from 20 LIRNB and 12 HRNB were prospectively analyzed. We found that specific subsets of circulating immune cells such as myeloid dendritic cells BDCA-1+, plasmacytoid dendritic cells, Teff/Treg CD4+ T-cells, were decreased in HRNB blood compared to LIRNB groups as opposed to other subsets (e.g iNKT, g9d2 T-cells,⋯). More surprisingly, these differences were not due to defects in cell production as there was no difference found for the same cell populations in the bone marrow between LIRNB and HRNB children. CONCLUSION: Specific immune cell defects are found in the blood from High risk neuroblastoma children that are not present in the blood of low & intermediate risk neuroblastoma children. These defects are not due to bone marrow production impairment. These results suggest that high risk neuroblastoma disease generates an impairment in the immune homeostasis of children. Gene expression analysis of cytokine/chemokine from these neuroblastoma tumors is underway (NCT01295762). Citation Format: Sandrine Susini, Isabelle Rochet, Estelle Verronèse, Christine Bardin, Chantal Rigal, Cécile Conter, Perrine Marec-Bérard, Christophe Bergeron, Audrey Lardy-Cleaud, Séverine Neymarc, Séverine Metzger, Jean-Louis Stephan, Dominique Plantaz, Christophe Caux, Christine Ménétrier-Caux, Aurelien Marabelle. Prospective immune phenotyping of neuroblastoma children at diagnosis reveals specific immune defects related to the aggressiveness of the disease [abstract]. In: Proceedings of the American Ass