1. ¹Department of Hematooncology, Medical University of Lublin, Lublin, Poland
2. ²Department of Internal Medicine III, University of Ulm, Ulm, Germany
3. ³Department of Clinical Immunology, Medical University of Lublin, Lublin, Poland

Correspondence: Professor M Schmitt, Department of Internal Medicine III, University of Ulm, Robert-Koch-Str. 8, Ulm 89081, Germany. E-mail: michael.schmitt@uniklinik-ulm.de

⁴These authors contributed equally to this work

Received 26 November 2007; Revised 16 January 2008; Accepted 28 January 2008; Published online 6 March 2008.

Abstract

Recently, we described that vaccination with allogeneic dendritic cells (DCs) pulsed with tumor cell lysate generated specific CD8+ T cell response in patients with B-cell chronic lymphocytic leukemia (B-CLL). In the present study, the potential of autologous DCs pulsed ex vivo with tumor cell lysates to stimulate antitumor immunity in patients with B-CLL in early stages was evaluated. Twelve patients at clinical stage 0–2 as per Rai were vaccinated intradermally up to eight times with a mean number of 7.4 10⁶ DCs pulsed with B-CLL cell lysate. We observed a decrease of peripheral blood leukocytes and CD19+/CD5+ leukemic cells in five patients, three patients showed a stable disease and four patients progressed despite DC vaccination. A significant increase of specific cytotoxic CD8+ T lymphocytes against the leukemia-associated antigens RHAMM or fibromodulin was detected in four patients after DC vaccination. In patients with a clinical response, an increase of interleukin 12 (IL-12) serum levels and a decrease of the frequency of CD4+CD25⁺FOXP3+ T regulatory cells were observed. Taken together, the study demonstrated that vaccination with autologous DC in CLL patients is feasible and safe. Immunological and to some extend hematological responses could be noted, justifying further investigation on this immunotherapeutical approach.