Massimo Degan

CD38/CD31, the CCL3 and CCL4 Chemokines, and CD49d/Vascular Cell Adhesion Molecule-1 Are Interchained by Sequential Events Sustaining Chronic Lymphocytic Leukemia Cell Survival

CD38 and CD49d are associated negative prognosticators in chronic lymphocytic leukemia (CLL). Despite evidence that both molecules are involved in interactions occurring between CLL and normal cells in the context of CLL-involved tissues, a functional link is still missing. Using gene expression profiles comparing CD38(+)CD49d(+) versus CD38(-)CD49d(-) CLL cells, we showed overexpression of the CCL3 and CCL4 chemokines in cells from the former group. These chemokines were also up-regulated by CD38 signals in CLL; moreover, CCL3 was expressed by CLL cells from bone marrow biopsies (BMB) of CD38(+)CD49d(+) but not CD38(-)CD49d(-) cases. High levels of CCR1 and, to a lesser extent, CCR5, the receptors for CCL3 and CCL4, were found in CLL-derived monocyte-macrophages. Consistently, CCL3 increased monocyte migration, and CD68(+) macrophage infiltration was particularly high in BMB from CD38(+)CD49d(+) CLL. Conditioned media from CCL3-stimulated macrophages induced endothelial cells to express vascular cell adhesion molecule-1 (VCAM-1), the CD49d ligand, likely through tumor necrosis factor alpha overproduction. These effects were apparent in BMB from CD38(+)CD49d(+) CLL, where lymphoid infiltrates were characterized by a prominent meshwork of VCAM-1(+) stromal/endothelial cells. Lastly, CD49d engagement by VCAM-1 transfectants increased viability of CD38(+)CD49d(+) CLL cells. Altogether, CD38 and CD49d can be thought of as parts of a consecutive chain of events ultimately leading to improved survival of CLL cells.

Molecular and clinical features of chronic lymphocytic leukaemia with stereotyped B cell receptors: Results from an Italian multicentre study

A fraction of chronic lymphocytic leukaemia (CLL) cases carry highly homologous B‐cell receptors (BCR), i.e. characterized by non‐random combinations of immunoglobulin heavy‐chain variable (IGHV) genes and heavy‐chain complementarity determining region‐3 (HCDR3), often associated with a restricted selection of IGVK/L light chains. Such ‘stereotyped’ BCR occur more frequently in CLL with unmutated (UM) than mutated (M) IGHV genes. We analysed 1426 IG rearrangements (from 1398 CLL cases) by a clustering driven by HCDR3 similarities. Molecular findings were correlated to time‐to‐treatment (TTT) and presence of known prognosticators. Sixty‐nine clusters (319 IG‐rearrangements, 22·4%) with stereotyped BCR were identified. Among 30 confirmed clusters (≥3 IG‐rearrangements/cluster), we found 14 novel clusters, of which 11 had M IG rearrangements (M clusters) and predominantly (8/11) used IGHV3 subgroup genes. Recurrent cluster‐biased amino acid changes were found throughout IGHV sequences of these ‘M clusters’. Regarding clinical outcome: (i) UM CLL from the IGHV1‐2/1‐3/1‐18/1‐46/7‐4‐1/IGKV1‐39 cluster had poorer prognosis than UM/M cases, or UM cases using the same IGHV genes but not in clusters; (ii) M CLL from the IGHV3‐21/IGLV3‐21 cluster had TTT similar to UM CLL, and shorter than M CLL expressing IGHV3‐21 but not in cluster. Altogether, our analysis identified additional molecular and clinical features for CLL expressing stereotyped BCR.

Consolidation and maintenance immunotherapy with rituximab improve clinical outcome in patients with B-cell chronic lymphocytic leukemia†

Rituximab in sequential combination with fludarabine (Flu) allowed patients with B‐cell chronic lymphocytic leukemia (B‐CLL) to achieve higher remission rates and longer response duration. Based on their recent experience in indolent non‐Hodgkin lymphomas, in this study, the authors attempted to demonstrate whether consolidation/maintenance therapy with rituximab could prolong the response duration in this patient population.

Hyaluronan–CD44 interaction hampers migration of osteoclast-like cells by down-regulating MMP-9

Osteoclast (OC) precursors migrate to putative sites of bone resorption to form functionally active, multinucleated cells. The preOC FLG 29.1 cells, known to be capable of irreversibly differentiating into multinucleated OC-like cells, displayed several features of primary OCs, including expression of specific integrins and the hyaluronan (HA) receptor CD44. OC-like FLG 29.1 cells adhered to and extensively migrated through membranes coated with fibronectin, vitronectin, and laminins, but, although strongly binding to HA, totally failed to move on this substrate. Moreover, soluble HA strongly inhibited OC-like FLG 29.1 cell migration on the permissive matrix substrates, and this behavior was dependent on its engagement with CD44, as it was fully restored by function-blocking anti-CD44 antibodies. HA did not modulate the cell–substrate binding affinity/avidity nor the expression levels of the corresponding integrins. MMP-9 was the major secreted metalloproteinase used by OC-like FLG 29.1 cells for migration, because this process was strongly inhibited by both TIMP-1 and GM6001, as well as by MMP-9–specific antisense oligonucleotides. After HA binding to CD44, a strong down-regulation of MMP-9 mRNA and protein was detected. These findings highlight a novel role of the HA–CD44 interaction in the context of OC-like cell motility, suggesting that it may act as a stop signal for bone-resorbing cells.

Association between molecular lesions and specific B-cell receptor subsets in chronic lymphocytic leukemia.

Genetic lesions and B-cell receptor (BCR) signaling are both oncogenic drivers in chronic lymphocytic leukemia (CLL). However, scant data are available on preferential associations between specific genetic alterations and stereotyped BCR subsets. By analyzing 1419 cases, 2 CLL subsets (2 and 8) harboring stereotyped BCR are enriched in specific molecular alterations influencing disease course. SF3B1 mutations are the genetic hallmark of IGHV3-21-CLL belonging to subset 2 (52%) but are evenly represented in nonstereotyped IGHV3-21-CLL. Trisomy 12 (87%) and NOTCH1 mutations (62%) characterize IGHV4-39-CLL belonging to subset 8 but occur with the expected frequency in IGHV4-39-CLL with heterogeneous BCR. Clinically, co-occurrence of SF3B1 mutations and subset 2 BCR configuration prompts disease progression in IGHV3-21-CLL, whereas cooperation between NOTCH1 mutations, +12, and subset 8 BCR configuration invariably primes CLL transformation into Richter syndrome. These findings provide a proof of concept that specific stereotyped BCR may promote or select molecular lesions influencing outcome.

Analysis of IgVH gene mutations in B cell chronic lymphocytic leukaemia according to antigen-driven selection identifies subgroups with different prognosis and usage of the canonical somatic hypermutation machinery

Cases of B‐cell chronic lymphocytic leukaemia (B‐CLL) with mutated (M) IgVH genes have a better prognosis than unmutated (UM) cases. We analysed the IgVH mutational status of B‐CLL according to the features of a canonical somatic hypermutation (SHM) process, correlating this data with survival. In a series of 141 B‐CLLs, 124 cases were examined for IgVH gene per cent mutations and skewing of replacement/silent mutations in the framework/complementarity‐determining regions as evidence of antigen‐driven selection; this identified three B‐CLL subsets: significantly mutated (sM), with evidence of antigen‐driven selection, not significantly mutated (nsM) and UM, without such evidence and IgVH gene per cent mutations above or below the 2% cut‐off. sM B‐CLL patients had longer survival within the good prognosis subgroup that had more than 2% mutations of IgVH genes. sM, nsM and UM B‐CLL were also characterized for the biased usage of IgVH families, intraclonal IgVH gene diversification, preference of mutations to target‐specific nucleotides or hotspots, and for the expression of enzymes involved in SHM (translesion DNA polymerase ζ and η and activation‐induced cytidine deaminase). These findings indicate the activation of a canonical SHM process in nsM and sM B‐CLLs and underscore the role of the antigen in defining the specific clinical and biological features of B‐CLL.

CD49d in B-cell chronic lymphocytic leukemia: correlated expression with CD38 and prognostic relevance.

CD49d in B-cell chronic lymphocytic leukemia: correlated expression with CD38 and prognostic relevance

A scoring system based on the expression of six surface molecules allows the identification of three prognostic risk groups in B‐cell chronic lymphocytic leukemia

We have previously identified 12 surface antigens whose differential expression represented the signature of B‐cell chronic lymphocytic leukemia (B‐CLL) subsets with different prognosis. In the present study, expression data for these antigens, as determined in 137 B‐CLL cases, all with survivals, were utilized to devise a comprehensive immunophenotypic scoring system of prognostic relevance for B‐CLL patients. In particular, univariate z score was employed to identify the markers with greater prognostic impact, while maximally selected log‐rank statistics were chosen to define the optimal cut‐off points capable to split patients into two groups with different survivals. A weighted immunophenotypic scoring system was developed by integrating results from these analyses. Six antigens were selected: three positive prognosticators (CD62L, CD54, CD49c) and three negative prognosticators (CD49d, CD38, CD79b), with cut‐off values ranging from 30% to 50% of positive cells. By weighing the expression of each marker according to its statistical power, a complete scoring system, with point values comprised between 0 (complete absence of phenotypic conditions associated with good prognosis) and 9 (all the phenotypic conditions associated with good prognosis fulfilled), allowed to split the whole set of B‐CLL patients, into three distinctive prognostic groups (P = 4.78 × 10−11) with high‐ (score 0–3), intermediate‐ (score 4–6), and low‐ (score 7–9) risk of death. The three risk groups showed different distribution of cases as for Rais stages, IgVH mutations, and ZAP‐70 expression. The proposed immunophenotypic scoring system may be an additional useful tool in routine diagnostic/prognostic procedures for B‐CLL. J. Cell. Physiol. 207: 354–363, 2006.

Expression of Functional Interleukin-3 Receptors on Hodgkin and Reed-Sternberg Cells

The human interleukin-3 receptor (IL-3R) is a heterodimeric complex consisting of an IL-3-specific alpha chain (IL-3Ralpha) and a common beta chain (beta(c)), this latter shared with the receptors for granulocyte-macrophage colony-stimulating factor and IL-5. Despite extensive research on cytokine circuitries regulating proliferation and survival of tumor cells in Hodgkins disease (HD) the functional expression of IL-3Rs in this pathobiological entity has not yet been investigated. In the present study, we demonstrate that the great majority (>90%) of malignant Hodgkin and Reed-Sternberg cells of classic HD (19 of 19 analyzed cases) express IL-3Ralpha by immunostaining of frozen sections and cell suspensions from involved lymph nodes. Accordingly, HD cell lines (L428, KMH2, HDLM2, L1236) expressed the alpha and beta chains of IL-3R both at the mRNA and protein level, with a molecular size of IL-3Ralpha identical (70 kd) to that expressed by human myeloid cells. Exogenous IL-3 promoted the growth of cultured Hodgkin and Reed-Sternberg cells, such effect being potentiated by IL-9 co-stimulation, and was able to partially rescue tumor cells from apoptosis induced by serum deprivation. This data suggests an involvement of IL-3/IL-3R interactions in the cellular growth of HD through paracrine mechanisms.

ZAP‐70 expression in B‐cell chronic lymphocytic leukemia: Evaluation by external (isotypic) or internal (T/NK cells) controls and correlation with IgVH mutations

Expression of T cell specific zeta‐associated protein 70 (ZAP‐70) by B‐cell chronic lymphocytic leukemia (B‐CLL) cells, as investigated by flow cytometry, has both prognostic relevance and predictive power as surrogate for immunoglobulin heavy chain variable region (IgVH) mutations, although a standardization of the cytometric protocol is still lacking.