Systemic AL amyloidosis is associated with nearly 15% of cases of multiple myeloma, but data on the frequency and significance of amyloid deposits in the bone marrow of patients affected by multiple myeloma without clinical signs of systemic amyloidosis are scanty. Bone marrow smears of 166 unselected patients affected by multiple myeloma (126 at diagnosis and 40 after treatment) were stained with Congo red and studied by transmission and birefringence microscopy. Both focal and diffuse storages were considered positive. Overall, 67 patients were positive and 99 were negative to Congo red and apple-green birefringence. In particular, 51 of the 126 patients studied at diagnosis and 16 of the 40 patients with advanced disease were positive. Seventeen patients were reassessed after a mean follow-up of 32 months (range: 6-91): disappearance of amyloid deposits was verified in three cases, all responsive to bortezomib-based regimens. The preliminary data available suggest that amyloid deposition in the marrow of myeloma patients is frequent, as it can be traced in nearly 40% of cases. We failed to find correlations between bone marrow amyloid deposits and immunoglobulin type, disease stage, plasma cells percentage, hemoglobin, calcium, creatinine, albumin, or beta(2)microglobulin. Significantly higher incidence of moderate/severe peripheral neuropathy was found in patients with marrow amyloid exposed to potentially neurotoxic antineoplastic agents. Further studies and prolonged follow-up are needed to validate our findings and to define possible prognostic aspects.

Previous observational studies suggest that rituximab may be useful in the treatment of primary immune thrombocytopenia (ITP). This randomized trial investigated rituximab efficacy in previously untreated adult ITP patients with a platelet count of 20 x 10(9)/L or less. One hundred three patients were randomly assigned to receive 40 mg/d dexamethasone for 4 days with or without 375 mg/m(2) rituximab weekly for 4 weeks. Patients who were refractory to dexamethasone alone received salvage therapy with dexamethasone plus rituximab. Sustained response (ie, platelet count > or = 50 x 10(9)/L at month 6 after treatment initiation), evaluable in 101 patients, was greater in patients treated with dexamethasone plus rituximab (n = 49) than in those treated with dexamethasone alone (n = 52; 63% vs 36%, P = .004, 95% confidence interval [95% CI], 0.079-0.455). Patients in the experimental arm showed increased incidences of grade 3 to 4 adverse events (10% vs 2%, P = .082, 95% CI, -0.010 to 0.175), but incidences of serious adverse events were similar in both arms (6% vs 2%, P = .284, 95% CI, -0.035 to 0.119). Dexamethasone plus rituximab was an effective salvage therapy in 56% of patients refractory to dexamethasone. The combination of dexamethasone and rituximab improved platelet counts compared with dexamethasone alone. Thus, combination therapy may represent an effective treatment option before splenectomy. This study is registered at http://clinicaltrials.gov as NCT00770562.

The literature provides scant data concerning infectious complications and their effect on the outcome of patients with multiple myeloma (MM) treated with new drug combinations. Despite no substantial myelotoxic effect, thalidomide increases the risk of severe infections in patients with MM. We studied 202 patients who received regimens containing thalidomide in order to assess the time, type, outcome, and factors affecting development of severe infections, role of antibiotic prophylaxis, and effect of severe infections on final outcome. Thirty-eight patients (19%) developed a severe infection early during induction therapy and most infections were pneumonia. Only one patient died due to septic shock during neutropenia. No significant differences were reported in terms of progression-free survival (PFS) and overall survival (OS) between patients developing a severe infection and those who did not. Multivariate analysis determined a monoclonal component >3 g/dL and platelets <130 ,000/μL as factors associated with increased risk of severe infection. Primary antibiotic prophylaxis significantly decreased the probability of severe infection only in patients having both the above risk factors. Patients with MM receiving thalidomide combinations with high tumor burden are at high risk of developing severe infections and require primary antibiotic prophylaxis, whereas in other patients it is questionable. However, patient final outcome was not affected by infection development.

Background: Multiple myeloma (MM)-osteolytic bone disease occurs in about 70% of newly diagnosed patients, and up to 90% at relapse. It is characterized by an unbalanced bone remodelling, due to increased osteoclast (OC) activity and impaired osteoblast repair. Osteoclastogenesis is regulated by members of TNF superfamily. Among these, there is LIGHT/TNFSF14 recently implicated in the pathogenesis of joint diseases with increased bone resorption, as the rheumatoid arthritis. LIGHT is expressed by activated T-cells, monocytes, granulocytes, spleen cells, and immature dendritic cells, and it is described as a potent T-cell co-stimulatory molecule. Aims: Here, we purposed to investigate a possible role of LIGHT in the mechanisms of the enhanced osteoclastogenesis occurring in MM-osteolytic bone disease. Methods: Peripheral blood (PB) and bone marrow (BM) aspirates were obtained from 40 patients (23M/17F, median age: 64 years), newly diagnosed as having symptomatic MM with or without osteolytic bone disease, smoldering MM (sMM) or Monoclonal Gammopathy of Undetermined Significance (M.G.U.S.). Osteolytic lesions were detected by skeleton standard radiography, and in some cases also by spine and pelvis nuclear magnetic resonance. The control group included PB and BM aspirates from 15 patients with nonneoplastic disease without any skeletal involvement as well as PB from 25 healthy donors matching for age and sex with the patients’ group. Patients and controls gave their written informed consent to the study, approved by the local Ethical Committee and performed according to the Declaration of Helsinki. By means of flow cytometry, Western Blotting and real-time PCR, LIGHT expression was evaluated in freshly purified CD14+ monocytes, CD2+ T-cells and neutrophils from PB and BM aspirates of patients and controls. OCs were obtained from unfractionated PB mononuclear cells (PBMCs) cultured in the presence or in the absence of an anti-LIGHT neutralizing monoclonal antibody (mAb). Mature OCs were identified as multinucleated tartrate-resistant acid phosphatase (TRAP) positive cells. Results: In the CD14+ monocytes, CD2+ T-cells and neutrophils isolated from PB and BM of patients with MM-osteolytic bone disease, at both protein and mRNA levels LIGHT was found more expressed than in the cells isolated from the patients with symptomatic MM without bone disease, sMM, M.G.U.S, nonneoplastic disease without any skeletal involvement, and healthy donors. The in vitro effect of the anti-LIGHT mAb on osteoclastogenesis resulted in a significant reduction of the OC formation (p<0.001). Summary and Conclusions: Our findings support a possible involvement of LIGHT in the mechanisms of the osteoclastogenesis occurring in MM-osteolytic bone disease.

Wingless-type (Wnt) signaling through the secretion of Wnt inhibitors Dickkopf1, soluble frizzled-related protein-2 and -3 has a key role in the decreased osteoblast (OB) activity associated with multiple myeloma (MM) bone disease. We provide evidence that another Wnt antagonist, sclerostin, an osteocyte-expressed negative regulator of bone formation, is expressed by myeloma cells, that is, human myeloma cell lines (HMCLs) and plasma cells (CD138+ cells) obtained from the bone marrow (BM) of a large number of MM patients with bone disease. We demonstrated that BM stromal cells (BMSCs), differentiated into OBs and co-cultured with HMCLs showed, compared with BMSCs alone, reduced expression of major osteoblastic-specific proteins, decreased mineralized nodule formation and attenuated the expression of members of the activator protein 1 transcription factor family (Fra-1, Fra-2 and Jun-D). Moreover, in the same co-culture system, the addition of neutralizing anti-sclerostin antibodies restored OB functions by inducing nuclear accumulation of β-catenin. We further demonstrated that the upregulation of receptor activator of nuclear factor κ-B ligand and the downregulation of osteoprotegerin in OBs were also sclerostin mediated. Our data indicated that sclerostin secretion by myeloma cells contribute to the suppression of bone formation in the osteolytic bone disease associated to MM.

Abstract n. 2564

Schnitzler's syndrome is characterized by recurrent urticarial rash and monoclonal gammopathy, associated with clinical and biological signs of inflammation and a long-term risk of AA amyloidosis and overt lymphoproliferation. An extensive literature review was performed, and the following questions were addressed during an expert meeting: In whom should Schnitzler's syndrome be suspected? How should the diagnosis of Schnitzler's syndrome be established? How should a patient with Schnitzler's syndrome be treated? How should a patient with Schnitzler's syndrome be followed up?. A diagnosis of Schnitzler's syndrome is considered definite in any patient with two obligate criteria: a recurrent urticarial rash and a monoclonal IgM gammopathy, and two of the following minor criteria: recurrent fever, objective signs of abnormal bone remodeling, elevated CRP level or leukocytosis, and a neutrophilic infiltrate on skin biopsy. It is considered probable, if only 1 minor criterion is present. In patients with monoclonal IgG gammopathies, diagnosis is definite if three minor criteria are present and possible if two are present. First-line treatment in patients with significant alteration of quality of life or persistent elevation of markers of inflammation should be anakinra. Follow-up should include clinical evaluation, CBC and CRP every 3 months and MGUS as usually recommended.

Sclerostin, an osteocyte-expressed negative regulator of bone formation, is one of the inhibitors of Wnt signaling that is a critical pathway in the correct process of osteoblast differentiation. It has been demonstrated that Wnt signaling through the secretion of Wnt inhibitors, such as DKK1, sFRP-2, and sFRP-3, plays a key role in the decreased osteoblast activity associated with multiple myeloma (MM) bone disease. We provide evidence that sclerostin is expressed by myeloma cells that are human myeloma cell lines and plasma cells (CD138(+) cells) obtained from the bone marrow (BM) of a large number of MM patients with bone disease. Moreover, we show that there are no differences in sclerostin serum levels between MM patients and controls. Thus, our data indicate that MM cells, as a sclerostin source in the BM, could create a microenvironment with high sclerostin concentration that could contribute toward inhibiting osteoblast differentiation.

Abstract 22

Sclerostin, an osteocyte-expressed negative regulator of bone formation, is one of the inhibitors of Wnt signaling that is a critical pathway in the correct process of osteoblast differentiation. It has been demonstrated that Wnt signaling through the secretion of Wnt inhibitors, such as DKK1, sFRP-2, and sFRP-3, plays a key role in the decreased osteoblast activity associated with multiple myeloma (MM) bone disease. We provide evidence that sclerostin is expressed by myeloma cells that are human myeloma cell lines and plasma cells (CD138(+) cells) obtained from the bone marrow (BM) of a large number of MM patients with bone disease. Moreover, we show that there are no differences in sclerostin serum levels between MM patients and controls. Thus, our data indicate that MM cells, as a sclerostin source in the BM, could create a microenvironment with high sclerostin concentration that could contribute toward inhibiting osteoblast differentiation.

Soluble decoy receptor 3 (DcR3), a member of the tumor necrosis factor receptor superfamily, has recently been reported to increase osteoclast (OC) differentiation. Its impact on the skeleton was reinforced by a study on DcR3 transgenic mice showing a decreased bone mass through the elevation of OC number, providing some initial evidence of DcR3 involvement in bone diseases. In this study we show that malignant plasma cells and T lymphocytes from myeloma patients directly produce DcR3, and this molecule supports the elevated formation of OCs in both peripheral blood and bone marrow from the patients. We also show that serum DcR3 levels in myeloma patients are significantly higher compared to controls.