Unmutated CLL derives from unmutated mature CD5+ B cells and mutated CLL derives from CD5+CD27+ post–germinal center B cells.

Prognostic predictions in B-cell chronic lymphocytic leukemia (B-CLL) at early clinical stage are based on biological disease parameters, such as ZAP-70 and CD38 protein levels, genomic aberrations as well as immunoglobulin variable heavy chain gene (IgV H ) mutation status. In the current study, ZAP-70 and CD38 expressions were examined by flow cytometry in 252 patients with B-CLL. Cytoplasmic ZAP-70 expression in more than 20% (ZAP-70 þ ) and surface CD38 expression on more than 30% (CD38 þ ) of B-CLL cells were associated with an unfavorable clinical course. The levels of ZAP-70 and CD38 did not change over time in the majority of patients where sequential samples were available for analysis. Combined analysis of ZAP-70 and CD38 yielded discordant results in 73 patients (29.0%), whereas 120 patients (47.6%) were concordantly negative and 59 patients (23.4%) were concordantly positive for ZAP-70 and CD38 expression. Median treatment-free survival times in patients whose leukemic cells were ZAP-70 þ CD38 þ was 30 months as compared to 130 months in patients with a ZAP-70À status. In patients with discordant ZAP-70/CD38 results, the median treatment-free survival time was 43 months. Thus, ZAP-70 and CD38 expression analyses provided complementary prognostic information identifying three patient subgroups with good, intermediate and poor prognosis. Over-representation of high-risk genomic aberrations such as 17p deletion or 11q deletion and distribution of the IgV H mutation status in B-CLL discordant for ZAP-70/ CD38 pointed toward a distinct biologic background of the observed disease subgroups. This finding was also supported by microarray-based gene expression profiling in a subset of 35 patients. The expression of 37 genes differed significantly between the three groups defined by their expression of ZAP-70 and CD38, including genes that are involved in regulation of cell survival and chemotherapy resistance.

Bcl-2 plays a key role in the regulation of apoptosis. We investigated the role of a novel regulatory single-nucleotide polymorphism (؊938C>A) in the inhibitory P2 BCL2 promoter in B-cell chronic lymphocytic leukemia (B-CLL

Soluble or membrane-anchored ligands of NKG2D and their receptor have a critical role in the elimination of tumor cells and disease progression. Plasma samples of 98 patients with B-cell chronic lymphocytic leukemia (CLL) were analyzed with specific ELISA systems for soluble major histocompatibility complex class I-related chains (sMICA and sMICB) and UL-16-binding proteins (ULBP1, 2, and 3). The flow cytometric analysis of MICA on CLL cells and natural killer group 2 member D (NKG2D) receptors on NK cells was performed after thawing of frozen peripheral blood lymphocytes of CLL patients (N ¼ 51). Levels of sMICA, sMICB, and sULBP2 were significantly increased (Po0.001) compared with 48 controls, whereas sULBP1 3 were not detectable in patients and controls. Levels of sMICA4990 pg/ml (P ¼ 0.014), sMICB4200 pg/ml (P ¼ 0.0001), and sULBP24105 pg/ml (Po0.0001) were associated with poor treatment-free survival (TFS). Neither MICA nor NKG2D expression could be related to clinical parameters. In multivariate analysis Binet stage (P ¼ 0.002), sULBP2 (P ¼ 0.002) and ZAP-70 (P ¼ 0.002) were independent predictive factors for TFS. In patients with Binet stage A, sULBP2 levels4105 pg/ml were strongly associated (P ¼ 0.0025) with poor TFS. Our data show that soluble but not membrane-anchored NKG2D ligands or receptors are of prognostic significance in CLL. Moreover, sULBP2 seems to be useful to identify early-stage patients with risk of disease progression.

B-cell chronic lymphocytic leukaemia (B-CLL) is a heterogenous disease with a highly variable clinical course and analysis of zeta-associated protein 70 (ZAP-70) and CD38 expression on B-CLL cells allowed for identification of patients with good (ZAP-70 À CD38 À ) and poor (ZAP-70 þ CD38 þ ) prognosis. DNA microarray technology was employed to compare eight ZAP-70 þ CD38 þ with eight ZAP-70 À CD38 À B-CLL cases. The expression of 358 genes differed significantly between the two subgroups, including genes involved in B-cell receptor signaling, angiogenesis and lymphomagenesis. Three of these genes, that is, immune receptor translocation-associated protein 4 (IRTA4)/Fc receptor homologue 2 (FcRH2), angiopoietin 2 (ANGPT2) and Pim2 were selected for further validating studies in a cohort of 94 B-CLL patients. IRTA4/FcRH2 expression as detected by flow cytometry was significantly lower in the poor prognosis subgroup as compared to ZAP-70 À CD38 À B-CLL cells. In healthy individuals, IRTA4/FcRH2 protein expression was associated with a CD19 þ CD27 þ memory cell phenotype. ANGPT2 plasma concentrations were twofold higher in the poor prognosis subgroup (Po0.05). Pim2 was significantly overexpressed in poor prognosis cases and Binet stage C. Disease progression may be related to proangiogenic processes and strong Pim2 expression.

We here describe a novel xenograft model of chronic lymphocytic leukemia (CLL) generated by infusion of human primary CLL cells into immunodeficient nonobese/severe combined immunodeficient (NOD/SCID) mice. Combined i.v. and i.p. injection of peripheral blood mononuclear cells (PBMC) from 39 patients with CLL resulted in highly reproducible splenic (37 of 39) and peritoneal (35 of 39) engraftment, which remained stable over a time span of 4 to 8 weeks. By comparison, recovery of leukemic cells from bone marrow (21 of 39) or peripheral blood (8 of 22) was substantially lower. The engraftment pattern of CLL PBMC 4 weeks posttransplant was correlated with clinical disease activity: infusion of PBMC from donors with Binet stage A, lymphocyte doubling time of >12 months, and normal lactate dehydrogenase (LDH) serum levels led to marked engraftment of T cells whereas comparably few tumor cells could be detected. In contrast, NOD/SCID mice receiving PBMC from donors with advanced stage Binet C, lymphocyte doubling time of <12 months, and elevated LDH serum levels exhibited predominant engraftment of tumor cells and comparably low numbers of T cells. These results suggest that this model reflects the heterogeneity and important clinical characteristics of the disease, and thus may serve as a tool for preclinical drug testing and investigation of the pathophysiology of CLL. [Cancer Res 2007;67(18):8653-61]

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B-cell chronic lymphocytic leukemia (B-CLL) is a heterogenous disease with a highly variable clinical course. Recent studies have shown that expression of lipoprotein lipase (LPL) and ADAM29 may serve as novel prognostic markers in B-CLL. To investigate the prognostic value of these genes, we quantified their expression in peripheral blood mononuclear cells using quantitative reverse transcriptase-polymerase chain reaction (RQ-PCR) in a cohort of 133 B-CLL patients and correlated the results with clinical outcome, and other known prognostic factors. LPL, ADAM29, LPL and ADAM29 ratios, as well as CD38 and ZAP-70 protein expression determined by multiparameter flow cytometry, were predictive of treatment-free survival. Multivariate Cox regression analysis identified LPL, ADAM29 and CD38 as independent prognostic markers. Evaluation of several disease characteristics in association with the LPL expression status of the patients' B-CLL cells showed highly significant differences for CD38 and ZAP-70 expression, suggesting a correlation of LPL expression with these established adverse prognostic factors. Sequential RQ-PCR analyses in a subset of 22 patients revealed that LPL mRNA expression was relatively stable in the majority of patients, whereas ADAM29 expression levels varied substantially over time. Furthermore, in a subgroup analysis, LPL provided prognostic information in both early stage (Binet A) and patients with more advanced disease (Binet B and C). Conversely, high ADAM29 expression was predictive of a long treatment-free interval in Binet stage A but did not retain its prognostic significance in Binet B and C patients. The LPL/ADAM29 expression ratio was not found to be an independent prognostic factor and did not offer any advantages over the use of LPL alone. Collectively, our data confirm a role for LPL as a novel prognostic indicator in B-CLL.