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.

Background: B-cell chronic lymphocytic leukaemia (B-CLL) is a disease with a highly variable clinical course; some patients never need treatment, while others require intensive treatment early after diagnosis. Recently, some new prognostic factors, such as IgVH mutational status, ZAP-70 and the expression of CD38 in leukaemic cells were introduced to identify attenuated versus progressive types of CLL bearing the potential to facilitate risk-adapted treatment strategies. Patients and methods: To evaluate the clinical value of ZAP-70 and CD38 as predictors of disease progression we assessed the expression of these markers by the flow cytometry method in 156 B-CLL patients. Results and conclusions: Both ZAP-70 and CD38 expression were shown to predict the clinical course of the disease, while ZAP-70 expression appeared to be more predictive than CD38 expression and more relevant in defining the cases of B-CLL responsive or refractory to first line chemotherapy. A simultaneous evaluation of ZAP-70 and CD38 expression allowed distinguishing the patients groups with the most favourable prognosis as well as those with the worst. Taken together we recommend assessing both ZAP-70 and CD38 protein expression for the definition of prognostic subgroups in patients with B-CLL

Programmed death-1 (PD-1) is an immunoreceptor predominantly expressed on exhausted T cells, which through an interaction with its ligand (PD-L1), controls peripheral tolerance by limiting effector functions of T lymphocytes. qRT-PCR for PD-1, PD-L1 and their splicing forms as well as flow cytometric assessment of surface expression was performed in a cohort of 58 chronic lymphocytic leukemia (CLL) patients. In functional studies, we assessed the influence of the proliferative response of leukemic B-cells induced by IL-4 and CD40L on PD-1 transcripts and expression on the protein level. The median level of PD-1, but not PD-L1, transcripts in CLL patients was higher in comparison to healthy volunteers (HVs, n = 43, p = 0.0057). We confirmed the presence of PD-1 and PD-L1 on the CLL cell surface, and found the expression of PD-1, but not PD-L1, to be higher among CLL patients in comparison to HVs (47.2% vs. 14.8%, p<0.0001). The Kaplan-Meier curves for the time to progression and overall survival in groups with high and low surface expression of PD-1 and PD-L1 revealed no prognostic value in CLL patients. After stimulation with IL-4 and CD40L, protein expression of PD-1 was significantly increased in samples that responded and up-regulated CD38. PD-1, which is aberrantly expressed both at mRNA and cell surface levels in CLL cells might represent a novel immunotolerant molecule involved in the pathomechanism of the disease, and could provide a novel target for future therapies.