Serum Levels of Soluble FLT3 Ligand in Patients with Active Multiple Myeloma Constitute Marker of Bone Marrow Plasma Cell Proliferative Activity.

The FLT3-ligand is a molecule implicated in hematopoiesis. The aim of the present study was to detect any possible connections between serum levels of FLT3-L and multiple myeloma (MM) proliferation markers, such as serum levels of interleukin-6 (IL-6), B-cell activating factor (BAFF), beta-2 microglobulin (B2M), CRP and LDH, as well the percentage of bone marrow infiltration and the plasma cells' proliferation marker Ki-67 PI. We measured the above parameters in 58 patients with active MM. All circulating markers were significantly higher in MM patients compared to controls (p < 0.001 for all cases), and all values were increasing in parallel with disease stage (p < 0.001 for all cases). Positive correlations between FLT3-L were noted with serum levels of BAFF (p < 0.003), IL-6 (p < 0.002), CRP (p < 0.0001), LDH (p < 0.001), and BM Ki-67 PI (p = 0.012), whereas only trends of correlation were noted with the B2M value and the percentage of infiltration. It seems that the increased serum levels of circulating FLT3-L, in parallel with MM activity, reflect their increased presence in the bone marrow microenvironment, probably as an effect of increased angiogenesis and myelosuppression. Consequently, they are potential markers of disease activity.

New insights into monoclonal B-cell lymphocytosis.

Monoclonal B-cell lymphocytosis (MBL) is a premalignant condition characterized by the presence of less than 5000/µL circulating clonal B cells in otherwise healthy individuals. Three subcategories have been identified according to the immunophenotypic features: CLL-like, CD5(+) atypical, and CD5(-) MBL. CLL-like MBL is by far the most frequent and best studied category and further divided in low-count [LC] and high-count [HC] MBL, based on a cutoff value of 500/µL clonal B cells. LC-MBL typically remains stable and probably does not represent a truly premalignant condition, but rather an age-related immune senescence. On the other hand, HC-MBL is closely related to CLL-Rai0, bearing similar immunogenetic profile, and is associated with an annual risk of progression to CLL requiring therapy at a rate of 1.1%. Currently there are no reproducible factors for evaluating the risk of progression to CLL. CD5(-) MBL is characterized by an immunophenotype consistent with marginal zone origin and displays many similarities with marginal zone lymphomas (MZL), mainly the splenic MZL. The cutoff value of 5000/µL clonal B cells cannot probably be applied in CD5(-) MBL, requiring a new definition to describe those cases.

Clinical aspects of malt lymphomas.

Extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT) is an indolent lymphoma arising in extranodal sites. Several infectious agents and autoimmune disorders have been implicated in its pathogenesis. The stomach represents the most common and best-studied organ involved by MALT lymphoma and its development is strongly associated with Helicobacter pylori (Hp) infection. MALT lymphomas are characterized by an indolent clinical course and excellent survival in most cases, independently of the treatment delivered. Recent progress in the knowledge of the etiology and the cellular and molecular pathological events related to MALT lymphomas allowed us to improve our clinical understanding of this disease entity and to better define treatment strategies.

Circulating levels of soluble Fas ligand reflect disease progression in multiple myeloma.

Multiple myeloma (MM) plasma cells are apoptosis resistant. The system of Fas with its ligand (Fas-L) participates actively in the extrinsic apoptotic system. In oncology, its role is controversial, since it has been reported both to suppress and promote tumor growth. The aim of this study was to measure serum levels of soluble Fas-L (sFas-L) in patients with active MM and to correlate them with markers of disease activity. We studied 57 patients with active MM, along with 22 healthy controls. We measured serum levels of sFas-L and interleukin-6 (IL-6) by enzyme-linked immunosorbent assays, as well of beta-2 microglobulin (B2M), C-reactive protein (CRP) and lactate dehydrogenase (LDH). We also measured the degree of bone marrow infiltration. All parameters were increased in patients, compared with controls (p < 0.001 for all cases) and also in parallel with disease stage (p < 0.001 for all cases). Positive correlations were noted between serum levels of sFas-L with IL-6, infiltration (p < 0.001 for both cases) and LDH (p < 0.04), but not with CRP and B2M. We suggest that the system of Fas/Fas-L participates actively in MM progression in a complex manner and that serum levels of sFas-L may reflect disease progression. Further studies are needed to determine its usefulness as a marker of disease activity.

Increased serum levels of MIP-1alpha correlate with bone disease and angiogenic cytokines in patients with multiple myeloma.

Many cytokines possess variable roles in the pathogenesis of multiple myeloma. Macrophage inflammatory protein-1alpha (MIP-1alpha) is an osteoclast-activating factor with a major role in myeloma bone disease. The aim of the study was to examine its participation in the angiogenic process of the disease. We measured, by enzyme-linked immunosorbent assays, its serum levels in 56 newly diagnosed myeloma patients, in several skeletal grades and stages of the disease and in 25 healthy controls. Concurrently, we measured serum levels of the angiogenic cytokines basic-fibroblast growth factor, hepatocyte growth factor and interleukin-18. All the above cytokines were higher in myeloma patients (p < 0.001 for all cases) and were increasing in parallel with disease stage (p < 0.001 for all cases) and skeletal grade (p < 0.04 for MIP-1alpha and p < 0.001 for the other cases). Moreover, positive correlations between MIP-1alpha and all the angiogenic cytokines were noted (p < 0.001 for all cases). MIP-1alpha seems to be a predominant factor responsible for the enhancement of bone resorption and increased angiogenesis. The positive correlation between MIP-1alpha and the angiogenic chemoattractants supports the involvement of these factors in the biology of myeloma cell growth. Moreover, they could be used as possible therapeutic targets as well as markers of disease activity.

The relationship between soluble receptor of interleukin-6 with angiogenic cytokines and proliferation markers in multiple myeloma.

Soluble interleukin-6 receptor (sIL-6R) is part of IL-6 receptor that may stimulate cells that do not express the whole molecule. It may enhance myeloma cell proliferation and furthermore angiogenesis. The aim of the study was to evaluate the clinical significance and the relationship between serum levels of sIL-6R, with various stimulators of angiogenesis, such as hepatocyte growth factor (HGF) and interleukin-18 (IL-18) and with markers of proliferation, such as beta-2 microglobulin (B2M) levels and plasma cell Ki-67 proliferation index in the bone marrow, in patients with multiple myeloma (MM). We studied 45 newly diagnosed MM patients. Serum levels of sIL-6R, HGF, IL-18, and B2M and Ki-67 proliferation index (Ki-67 PI) in bone marrow's plasma cells were determined. The mean concentrations of sIL-6R, HGF, IL-18, and B2M and the value of Ki-67 were significantly higher in the patients compared to controls and with increasing disease stage. sIL-6R was strongly positively correlated with HGF, IL-18, B2M, and Ki-67 PI. There is a positive correlation between plasma cell growth, as determined by Ki-67 PI, and different angiogenic cytokines, such as HGF and IL-18, with sIL-6R. This relationship suggests the significant role of these cytokines in the proliferation and disease activity in MM patients.