Disease–Free Remission Exceeding 37 Years in Patients Treated as Children for Acute Leukemia (AL) with Immunotherapy Using Viable (Cryopreserved) Allogeneic Leukemic Cells
Pages 254-264
Tatiana I. Bulycheva, Svetlana A. Mayakova and Simon V. Skurkovich

DOI: http://dx.doi.org/10.6000/1929-2279.2013.02.04.4

Published: 31 October 2013

Abstract: At present time in spite of great achievements in modern chemotherapy of acute leukemia (AL) the issue of eradication of residual leukemic cells (MRD) is still relevant. Since 1971 we included specific immunotherapy in the treatment of children with acute lymphoblastic leukemia in remission using viable cryopreserved allogeneic leukemic cells. 67 children in remission were divided into 2 groups: 27 constituted the control group (only continued standard-for-that-time chemotherapy) and 40 children – the treatment which received immunotherapy in addition to standard chemotherapy. In 3 years all children in the control group relapsed. The median length of remission was 15 months. In the treatment group we observed stabilization of remission only in children over 7 years of age when immunization was initiated after 6 or more months of remission and in children younger than 7 if it was initiated after 1-1,5 years of remission. The median length of remission was 60 months which significantly exceeded (4 times) that parameter in the control group of children. Cytotoxic antibodies against leukemic cells appeared in the serum of effectively immunized children at a higher titer than against donor lymphocytes. Intrathecal administration of this hyperimmune serum to patients with neuroleukemia resistant to chemotherapy led to a sharp decrease in the amount of leukemic cells in the spinal fluid. After 5 years of remission (and 3-5 years of immunotherapy) all treatment in these patients was stopped. Out of 19 patients who received immunotherapy on time, 8 patients (42%) have been in event-free remission for 37 to 41 years (median – 38 years) through the present time and enjoy high quality of life. Our results indicate that immunotherapy initiated during remission period of AL can lead to creation of anti-leukemic immunity with subsequent eradication of MRD and complete recovery.