The development of multiple myeloma (MM) bone disease is mediated by increased number and activity of osteoclasts (OCs). Using an in vitro osteoclastogenesis model consisting of unstimulated and unfractionated peripheral blood mononuclear cells (PBMCs) from patients with MM, we showed that T cells support the formation of OCs with longer survival. Different from T-cell–depleted MM PBMC cultures, exogenous macrophage-colony stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL) were necessary for the formation of OCs; however, they did not exhibit longer survival. We found up-regulated production of RANKL, osteoprotegerin (OPG), and TNF-related apoptosis-inducing ligand (TRAIL) by fresh MM T cells. Despite high OPG levels, the persistence of osteoclastogenesis can be related to the formation of the OPG/TRAIL complex demonstrated by immunoprecipitation experiments and the addition of anti-TRAIL antibody which decreases OC formation. OCs overexpressed TRAIL decoy receptor DcR2 in the presence of MM T cells and death receptor DR4 in T-cell–depleted cultures. In addition, increased Bcl-2/Bax (B-cell lymphoma-2/Bcl2-associated protein X) ratio, following Bcl-2 up-regulation, was detected in OCs generated in the presence of T cells. Our results highlight that MM T cells support OC formation and survival, possibly involving OPG/TRAIL interaction and unbalanced OC expression of TRAIL death and decoy receptors.
Autoimmune hemolytic anemia (AIHA) is a well-known complication of chronic lymphocytic leukemia (CLL). In recent years the anti-CD20 monoclonal antibody rituximab has been used for the therapy of steroid-refractory AIHA and autoimmune thrombocytopenia, either idiopathic or in association with CLL. We report the results of rituximab treatment for 14 patients suffering from CLL-associated AIHA. They developed a direct antiglobulin test positive AIHA at a mean time of 47 months (range 0-135 months) from the diagnosis of CLL. In 3 cases AIHA was diagnosed at the same time as CLL. Only 1 patient had fludarabine-related AIHA. All patients received steroids as first-line treatment. At a mean time of 46 days (range 1-210 days) from the diagnosis of AIHA all patients received rituximab at a dosage of 375 mg/m 2 /weekly for 4 weeks. All patients except 3 (2 died of cardiac failure or sepsis soon after the third cycle and 1 HCV-positive patient experienced a rise in serum amino transferases) completed the scheduled four programmed cycles. First injection side effects of rituximab were minimal. All but 2 patients showed an increase in hemoglobin levels in response to rituximab (mean value 3.6 g/dl; range 0.7-10 g/dl) and a reduction in the absolute lymphocyte count and lymph nodes and spleen volume. Nine patients required packed red cell transfusions before starting rituximab; 5 no longer needed transfusions just after the second cycle and another patient after the fourth cycle. Three patients (22%) were considered to fully respond and 7 (50%) only responded partially. At a mean follow-up of 17 months, 8 patients were still alive, 6 of them transfusion-free. Our results prove that the anti-CD20 monoclonal antibody is an effective and well-tolerated alternative treatment for CLL-associated AIHA. Am. J. Hematol. 81:598-602, 2006. V V C 2006 Wiley-Liss, Inc.
The results of our prospective study have revealed great diversity in the treatment regimens used to manage MM in real-life practice. This diversity was linked to factors such as novel agent accessibility and evolving treatment recommendations. Our results provide insight into associated clinical benefits.
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