Expression of HLA-G in patients with B-cell chronic lymphocytic leukemia (B-CLL).

The expression of HLA-G was reported in certain malignancies and its role in escaping from immunosurveillance in cancers was proposed since HLA-G is a nonconventional HLA class I molecule that protects fetus from immunorecognition during pregnancy. Recent studies proposed HLA-G as novel prognostic marker for patients with B-CLL. HLA-G was showed to bear even better prognostic information compared to Zeta-chain associated protein of 70kDa (ZAP-70) and CD38 although some other authors did not find HLA-G expression in CLL. Therefore in this study we characterized the expression of HLA-G on both RNA and protein level. In most of 20 B-CLL patients we were able to detect signal from HLA-G using flow cytometry analysis. The expression of HLA-G was confirmed on messenger level by real-time RT-PCR experiments. No correlation between HLA-G expression and expression of well established prognostic factors such as ZAP-70 and CD38 was detected. These results confirm that HLA-G is expressed on CLL leukemic cells. Furthermore the expression of HLA-G on CLL cells suggests that this molecule might be involved in escaping of CLL cells from immunosurveillance

Programmed Death-1 and Its Ligand Are Novel Immunotolerant Molecules Expressed on Leukemic B Cells in Chronic Lymphocytic Leukemia

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

The Mysterious Actor—γδ T Lymphocytes in Chronic Lymphocytic Leukaemia (CLL)

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia among adults. It is the clonal expansion of B cells expressing CD19 and CD5. Despite significant progress in treatment, CLL is still incurable. γδ T cells comprise an important subset of the cytotoxic T cells. Although γδ T cells in CLL are dysfunctional, they still can possibly be used for immunotherapy. The current paper reviews our understanding of γδ T lymphocytes in CLL