Background: Recent findings concerning the role of immunity in the eradication of residual malignant disease after autologous haematopoietic stem cell transplantation have led to extensive studies of T-cell and natural killer (NK) mediated anti-tumour effects. Interleukin 2 (IL-2) activation of autologous bone marrow (BM) or peripheral blood stem cells (PBSC) before transplantation is one of the methods of adoptive cell therapy.
Methods: Autologous BM of patients with chronic myelogenous leukaemia (n = 11) and PBSC of patients with multiple myeloma (n = 14) were activated by IL-2 in laboratory conditions with the aim of evaluating the feasibility of this method, the activation of T and NK cells, recovery of active progenitor cells, microbial contamination, and reduction of malignant cell content.
Results: Samples of BM (mean 2.6 x 10(6) cells) and PBSC (mean 10.3 x 10(6) cells) were cultured in complete culture medium with IL-2 (6000 Ul/ml) for 24 h. The recovery of CD34+ cells and CFU-GM was 82.5% and 51.5%, respectively, for BM, and 85% and 86%, respectively, for PBSC (mean values). No purging effect was detected by flow cytometry and a small decline in malignant cell contamination was observed by quantitative PCR in BM samples. No microbial contamination occurred during the sample processing.
Conclusions: The described in vitro activation of BM and peripheral blood stem cells using IL-2 was evaluated as a safe and reliable method suitable for clinical application.