R2 randomisation: R2 was activated in November 2006 (13-cis retinoic acid +/- chimeric ch14.18/CHO antibody), modified in July 2009 and suspended in August 2013. R2 randomisation tested the hypothesis that immunotherapy with chimeric 14.18/CHO and subcutaneous aldesleukin (IL-2, Proleukin®), following MAT and autologous stem cell transplantation, in addition to differentiation therapy with 13-cis retinoic acid, will improve 3-year EFS in patients with high-risk neuroblastoma.