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Bisphosphonates, especially nitrogen-containing bisphosphonates (N-BPs), are widely used to block bone destruction in cancer patients with bone metastasis because they are effective inhibitors of osteoclast-mediated bone resorption. In addition to their antiresorptive effects, preclinical evidence strongly suggests that N-BPs have anticancer activity. Some of the activities associated with N-BPs are observed in human T cells that straddle the interface of innate and adaptive immunity and have potent anti-tumour activity. This review examines the molecular and cellular mechanisms through which N-BPs stimulate the expansion and cytotoxic activity of human T cells. In addition, we discuss the emerging clinical evidence that N-BPs have a role in cancer immunotherapy.

Tumor necrosis factor-alpha (TNF) is a cytokine that displays a pleomorphic array of effects on different cell populations. Evidence is presented that TNF may be constitutively produced by B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia (HCL) cells and that it may play a relevant role in these diseases. These conclusions are based on the presence of circulating levels of TNF in the serum of 20 of the 24 patients tested (83.3%), while undetectable values were found in normal sera. The suggestion that the increased serum levels were due to the leukemic cell population is strengthened by the evidence that purified B-CLL and HCL cells may constitutively release variable degrees of TNF. These levels markedly increase after incubation with interferon gamma or phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). The cellular release of TNF by primary B-CLL cells was significantly (P less than .001) higher in B-CLL stage O-I patients compared with stage II-III patients. The demonstration that, in B-cell chronic lymphoproliferative disorders, the pathologic cells may release TNF was further confirmed by the presence of the mRNA for this cytokine in primary and/or in pre-activated cells. Recombinant TNF was capable of inducing a proliferative signal only in a minority of cases (4/24); in most cases it was ineffective, and, in a few, it reduced the degree of proliferation. Furthermore, in costimulatory experiments with interleukin-2 and PHA plus PMA, TNF was ineffective. On the other hand, when primary B-CLL cells were incubated in the presence of an anti-TNF antibody, in 8 of 12 independent experiments a 2- to 15-fold increase in thymidine uptake was documented. Taken together, these results suggest that TNF may play a regulatory role in the progression of the neoplastic clone in B-cell chronic lymphoproliferative disorders and may be implicated in some of the side effects associated with these diseases.

The characteristics of a human cell line (LP-1) derived from the peripheral blood of a patient with IgG-lambda myeloma in leukemic transformation are described. The cells resemble immature plasma cells in that they exhibit a membrane phenotype that is intermediate between late B lymphocytes and plasma cells, even though they secrete IgG- lambda chains. Treatment of LP-1 cells with 12–0 tetradecanoylphorbol- 13-acetate (TPA) or pokeweek mitogen (PWM) induces the appearance of surface markers and ultrastructural features typical of mature plasma cells but does not affect their proliferative activity. Molecular analysis of the cell line showed an increased expression of the c-myc protooncogene and the presence of abnormally sized transcripts. Conventional cytogenetics and pulsed-field gel electrophoresis showed no structural rearrangements of the c-myc gene, suggesting that the abnormal c-myc expression may be due to point mutations or small deletions within the gene. The LP-1 cell line is a useful model in which to study the process of B-cell maturation; such study may lead to the uncovering of unusual mechanisms of c-myc activation. Furthermore, the LP-1 cell is a potential partner in the generation of human hybridomas.

We have recently shown that peripheral blood T cells of multiple myeloma (MM) patients are very susceptible to stimulation of the T-cell receptor/CD3 complex with anti-CD3 monoclonal antibodies (MoAbs). CD3 stimulation is currently under clinical investigation as a nonspecific approach to boost antitumor effector mechanisms. The aim of this study was to determine whether the hyperreactivity of MM T cells to CD3 stimulation could be exploited to generate antitumor activity. Bone marrow mononuclear cells (BMMCs) from 65 MM patients were stimulated with the anti-CD3 MoAb OKT3 and the effect of this stimulation on autologous T cells and plasma cells was evaluated. The number of CD3+ CD25+ cells on day 6 was significantly higher in MM than the controls (30 normal individuals) (P = .001). Kinetic studies showed that 3H- thymidine incorporation peaked on day 3 and that the T-cell expansion peaked on days 5 and 6. In MM, T-cell activation markedly affected the survival of autologous plasma cells; their number in OKT3-treated cultures was significantly lower than in unstimulated cultures (P < .0001). T-cell activation and plasma cell decrease were not observed when T cells were removed from BMMC preparations. MM produced significantly higher levels of interferon-gamma (P = .005) and tumor necrosis factor-beta (P = .001), but lower levels of tumor necrosis factor-alpha (P < .001) than normal individuals. Interferon-gamma only was partially involved in CD3-induced plasma cell killing. Transwell cultures showed that the main mechanism by which CD3+ CD25+ cells affected plasma cells was direct cell-to-cell contact rather than cytokines. In conclusion, T cells in MM BMMCs possess distinct features in terms of susceptibility to CD3 stimulation and cytokine production compared with normal bone marrow T cells that can be exploited to generate antiplasma cell activity.

We have previously reported the presence of activated (HLA-DR+) T cells in multiple myeloma (MM) patients. These cells produce high amounts of interleukin (IL)-2 and interferon (IFN)-gamma and generate a potent antiplasma cell activity after appropriate in vitro stimulation, but they are unable in vivo to hold in check the disease. Activated T cells are highly susceptible to apoptosis, a form of programmed cell death involved in the modulation of immune responses and regulated by molecules such as Fas (CD95) and bcl-2. The aim of this study was to determine the expression of Fas and bcl-2 antigens and the susceptibility to apoptosis in T cells of MM patients. Fas+ cells were significantly higher, whereas bcl-2+ cells were significantly lower in MM patients than in the controls. MM patients with the highest number of HLA-DR+ T cells showed the highest Fas and the lowest bcl-2 expression. Two-color cytofluorometric analysis confirmed in individual cells that HLA-DR+ T cells coexpressed Fas and lacked bcl-2. Susceptibility to apoptosis was then investigated to evaluate the consequence of dysregulated Fas and bcl-2 expression. The percentage of apoptotic cells after incubation in medium alone (spontaneous apoptosis) or in the presence of methylprednisolone (MP) or anti-Fas monoclonal antibody (triggered apoptosis) was significantly higher in MM and mainly restricted to HLA-DR+ T cells. Spontaneous apoptotosis was reverted by exogenous IL-2. In conclusion, MM T cells have a dysregulated expression of Fas and bcl-2 antigens that is associated with an enhanced susceptibility to apoptosis. These data may unravel a novel mechanism by which activated MM T cells are weakened in their ability to exert an effective antitumor activity in vivo.

Cellular immunity was investigated in 43 patients with multiple myeloma (MM) by assessing 3HTdR uptake induced by monocyte-dependent [CD3 monoclonal antibodies (MoAbs), phytohemagglutinin (PHA)] and monocyte- independent (CD2 MoAbs, ionomycin + phorbolester) stimulations. The former were evaluated in peripheral blood mononuclear cells (PBMNC) and purified T cells; the latter were evaluated in purified T-cell preparations only. MM showed significantly lower PBMNC responses to PHA (P less than .001), soluble OKT3 (CD3) (P = .01), and immobilized OKT3 MoAbs (P = .01). On purification of T cells, MM responses were still defective to soluble T11(2) + T11(3) (CD2) MoAbs (P = .004), phorbol myristate acetate (PMA) plus ionomycin (P less than .001), but significantly higher to plastic-immobilized OKT3 (P = .004). In some MM, 3HTdR uptake, interleukin-2 (IL-2) receptor (CD25) expression, and IL-2 production were as high on stimulation with plastic-immobilized OKT3 as that observed in normal subjects under optimal conditions (ie, plastic-immobilized OKT3 plus accessory signals). CD3 hyperreactivity correlated with the number of CD8+ HLA-DR+ cells in MM T-cell preparations. MM patients with more than 10% CD8+ HLA-DR+ cells had significantly higher responses to immobilized OKT3 (P less than .001), but lower responses to T11(2) plus T11(3) (P = .01), and PMA plus ionomycin (P = .03) than patients with less than 10% CD8+ HLA-DR+ cells. Phenotyping of CD45RA (naive) and CD45R0 (memory) expressions in resting MM T cells showed a lower ratio of CD45RA to CD45R0 in both CD4 (P less than .05) and CD8 (P less than .001) subpopulations. These data indicate that (a) some MM T cells require significantly fewer accessory signals (if any) to express the IL-2 receptor fully, secrete IL-2, and proliferate on multivalent cross-linking of the CD3/TCR complex; and (b) this peculiar state of activation is associated with high HLA-DR expression in CD8+ lymphocytes.

Ecto-5'nucleotidase (5'NT) activity of peripheral blood (PB) lymphocytes was determined in 31 patients with serum monoclonal gammopathies (MG). Twenty-one patients had a diagnosis of multiple myeloma (MM), and ten patients had monoclonal gammopathy of undetermined significance (MGUS). The proliferative activity of the bone marrow plasma cells (LI%) was investigated in 28 of these MG patients by means of tritiated thymidine uptake evaluated by simultaneous autoradiography and cytoplasmic immunofluorescence. 5'NT activity was significantly lower in MG patients as compared with normal controls. MM patients had lower 5'NT activity than MGUS patients, but the difference was not significant. By contrast, MM had significantly higher LI% than MGUS patients. There was a linear regression of 5'NT on LI% which was statistically significant: the higher the LI%, the lower the 5'NT. Because the LI% is an accurate prognostic and monitoring factor in MG, this correlation indicates that 5'NT may be of assistance in predicting the clinical progress of MG patients. In seven MGs, the PB T and B lymphocytes were studied separately. The T cell subpopulation was 5'NT deficient compared to the normal controls, shown as a significant linear regression of T cell 5'NT on the LI%. This suggests that in MG there may be an alteration of nonneoplastic T lymphocytes correlated with tumor growth. The OKT8+ lymphocytes were mainly responsible for the 5'NT deficiency of unseparated T lymphocytes.

The phenotypic pattern of peripheral blood T (PBT) lymphocytes was correlated with diagnosis and clinical status in 63 patients with monoclonal gammopathies (MGs). The numbers of lymphocytes expressing activation and CD11 determinants were significantly increased in suppressor/cytotoxic and helper/inducer subpopulations of patients with multiple myeloma (MM) and MG of undetermined significance (MGUS). The number of activated suppressor/cytotoxic cells was closely correlated with diagnosis and disease status. These cells were significantly higher in MM at diagnosis (160 +/- 88) than MGUS patients (61 +/- 79; P less than .01). Their number decreased to MGUS levels in MM in stable remission (58 +/- 53), but not in MM with tumor progression (172 +/- 102; P less than .001). In individual patients, part of these cells specifically adhered to dishes precoated with the related M-protein. No monoclonal T-beta gene rearrangement was detected in PBT and cytotoxic/suppressor subpopulations from two patients with a large proportion of activated cells.

The tritiated thymidine labeling index (LI%) of peripheral B lymphocytes was studied in eight myeloma patients using simultaneous immunofluorescence and autoradiography. The LI% values were low (0.3%- 5.1%), but significantly increased as compared to normal controls. In addition, there was excellent correlation between the LI% values and myeloma disease activity: lowest LI% values were observed in remission patients and the highest at the time of relapse. Simultaneous LI% evaluation of bone marrow myeloma cells in five patients gave concordant results, indicating the same kinetic behavior in both these compartments, particularly in the relapse phase. These data indicate both that circulating B lymphocytes include the neoplastic clone and that these B lymphocytes and bone marrow myeloma cells have similar kinetics.

ABSTRACTMultiple myeloma (MM) derives from malignant transformation of plasma cells (PC), which accumulate in the bone marrow (BM), where microenvironment supports tumor growth and inhibits anti-tumor immune responses. Adenosine (ADO), an immunosuppressive molecule, is produced within MM patients' BM by adenosinergic ectoenzymes, starting from ATP (CD39/CD73) or NAD+[CD38/CD203a(PC-1)/CD73]. These ectoenzymes form a discontinuous network expressed by different BM cells. We investigated the expression and function of ectoenzymes on microvesicles (MVs) isolated from BM plasma samples of patients with MM, using asymptomatic forms of monoclonal gammopathy of undetermined significance (MGUS) and smoldering MM (SMM) as controls.The percentage of MVs expressing ectoenzymes at high levels was higher when derived from MM patients than controls. BM CD138+PC from MM patients expressed high levels of all ectoenzymes. Paired MVs samples confirmed a higher percentage of MVs with high ectoenzymes expression in MM patients than controls. Pooled MVs from MM patients or controls were tested for ADO production. The catabolism of ATP, NAD+, ADPR and AMP to ADO was higher in MVs from MM patients than in those from controls.In conclusion, our results confirmed the hypothesis that MVs in MM niche are main contributor of ADO production. The ability of MVs to reach biological fluids strongly support the view that MVs may assume diagnostic and pathogenetic roles.

The concept of genetic randomisation has been applied to assess clinical outcomes between patients with hematological cancers treated with allografting or other therapies. Though not universally accepted, the comparison by the intention-to-treat principle between patients with HLA-identical siblings, who can be assigned to allografting, and those without, who cannot receive an allograft, is used as a surrogate for an unbiased randomisation. We previously published the results of a study where the treatment assignment of 162 newly diagnosed patients younger than 65 years was based only on the presence/absence of an HLA-identical sibling (Bruno et al, N Engl J Med). First-line treatment plans included a cytoreductive autograft followed by a nonmyeloablative allograft (Tandem auto-allo) or a second melphalan-based autograft (Double-auto). Primary endpoints were overall (OS) and event-free (EFS) survivals by intention-to-treat analysis. The 80 patients with a sibling donor were offered a Tandem auto-allo and the 82 without a Double-auto after high (140–200 mg/m2) or intermediate dose melphalan (100 mg/m2). After a median follow up of 45 (range 21–90) months, OS and EFS were significantly longer in patients with donors: 80 versus 54 months (p=0.01) and 35 versus 29 months (p=0.02). Median OS was not reached in the 58 (out of 60 enrolled, 97%) patients who completed Tandem auto-allo and was 58 months in the 46 (out of 59 enrolled, 78%) who completed high-dose double-auto (p=0.03). Here, we report a update analysis. At a median follow up of 56 months, OS was not reached for the 80 patients with an HLA-identical sibling and was 56 months for those without (HR 0.53, CI 95% 0.33–0.86, p=0.009). EFS remained significantly longer in patients with HLA-identical siblings: 35 versus 29 months (HR: 0.61; 95% Cl: 0.42–0.88, p=0.008). Median OS was not reached in the 58 patients who completed Tandem auto-allo and was 63 months in the 46 who completed high-dose double-auto (HR 0.47, CI 95% 0.25–0.86, p=0.016). EFS was 43 and 33 months (HR 0.64, CI 95% 0.40–1.02, p=0.06). By multivariate analysis, the presence of HLA-identical siblings was significantly correlated with longer OS and EFS. We carried out a stratified analysis, on the intent-to-treat population, that defined a patient subgroup at high risk in the light of high b -2-microglobulin levels or presence of del(13). The adjusted HRs by Cox models were 0.34 for OS and 0.52 for EFS similar to those obtained in the whole series. Though this exploratory analysis has low statistical power, its results indicate that del(13) does not offset the advantage in OS and EFS for patients with an HLA-identical sibling, but do not exclude an impact of del(13) in those patients undergoing an allograft. Attal et al. (N Engl J Med) previously reported median OS and EFS of 58 and 30 months, respectively, after double autologous transplantation, consistent with our results (OS: 63 months; EFS: 33 months). However, the EFS after Tandem auto-allo also indicates that long-term disease control is an issue. Allografting and new drugs with molecular targets should not be viewed as mutually exclusive. Thus, it is imperative to thoroughly explore their roles in increasing the response rates and their duration in Tandem auto-allo.

The concept of genetic randomisation has been applied to assess clinical outcomes between patients with hematological cancers treated with allografting or other therapies. Though not universally accepted, the comparison by the intention-to-treat principle between patients with HLA-identical siblings, who can be assigned to allografting, and those without, who cannot receive an allograft, is used as a surrogate for an unbiased randomisation. We previously published the results of a study where the treatment assignment of 162 newly diagnosed patients younger than 65 years was based only on the presence/absence of an HLA-identical sibling (Bruno et al, N Engl J Med). First-line treatment plans included a cytoreductive autograft followed by a nonmyeloablative allograft (Tandem auto-allo) or a second melphalan-based autograft (Double-auto). Primary endpoints were overall (OS) and event-free (EFS) survivals by intention-to-treat analysis. The 80 patients with a sibling donor were offered a Tandem auto-allo and the 82 without a Double-auto after high (140–200 mg/m2) or intermediate dose melphalan (100 mg/m2). After a median follow up of 45 (range 21–90) months, OS and EFS were significantly longer in patients with donors: 80 versus 54 months (p=0.01) and 35 versus 29 months (p=0.02). Median OS was not reached in the 58 (out of 60 enrolled, 97%) patients who completed Tandem auto-allo and was 58 months in the 46 (out of 59 enrolled, 78%) who completed high-dose double-auto (p=0.03). Here, we report a update analysis. At a median follow up of 56 months, OS was not reached for the 80 patients with an HLA-identical sibling and was 56 months for those without (HR 0.53, CI 95% 0.33–0.86, p=0.009). EFS remained significantly longer in patients with HLA-identical siblings: 35 versus 29 months (HR: 0.61; 95% Cl: 0.42–0.88, p=0.008). Median OS was not reached in the 58 patients who completed Tandem auto-allo and was 63 months in the 46 who completed high-dose double-auto (HR 0.47, CI 95% 0.25–0.86, p=0.016). EFS was 43 and 33 months (HR 0.64, CI 95% 0.40–1.02, p=0.06). By multivariate analysis, the presence of HLA-identical siblings was significantly correlated with longer OS and EFS. We carried out a stratified analysis, on the intent-to-treat population, that defined a patient subgroup at high risk in the light of high b -2-microglobulin levels or presence of del(13). The adjusted HRs by Cox models were 0.34 for OS and 0.52 for EFS similar to those obtained in the whole series. Though this exploratory analysis has low statistical power, its results indicate that del(13) does not offset the advantage in OS and EFS for patients with an HLA-identical sibling, but do not exclude an impact of del(13) in those patients undergoing an allograft. Attal et al. (N Engl J Med) previously reported median OS and EFS of 58 and 30 months, respectively, after double autologous transplantation, consistent with our results (OS: 63 months; EFS: 33 months). However, the EFS after Tandem auto-allo also indicates that long-term disease control is an issue. Allografting and new drugs with molecular targets should not be viewed as mutually exclusive. Thus, it is imperative to thoroughly explore their roles in increasing the response rates and their duration in Tandem auto-allo.

Allogeneic approaches employing low dose TBI nonmyeloablative conditionings reported a dramatic reduction of transplant-related mortality (TRM) compared to conventional high dose regimens in newly diagnosed multiple myeloma (MM) (Maloney et al, Blood, 2003). The role of allografting, however, compared to autologous HCT remains to be determined. From September 1999 to July 2004, 241 consecutive MM patients, up to the age of 65, were diagnosed at five academic Italian Institutions. Overall, 194/241 had natural siblings (Table 1): 158/194 (81%) were HLA typed, while 36/194 (19%) were not typed for the following reasons: patients not eligible for high dose chemotherapy (n. 14); siblings not eligible for peripheral hematopoietic cell (PHC) donation (n.11); patient refusal to high dose chemotherapy (n. 9), unknown (n.2). Seventy-six/158 (48%) with a matched donor were offered a tandem autologous- nonmyeloablative allogeneic HCT approach. Eventually, 56/76 (73%), the “auto-allo group”, were enrolled while 20 did not enter the tandem program as 5 siblings (5/76, 7%) were not eligible for PHC donation, 5 patients refused an allogeneic HCT, and 10 patients preferred allografting as a possible salvage treatment. Of 102 patients without matched donors or after refusal to allografting, 73, “double-auto group”, underwent a standard double autologous transplant while 29 received less intense treatments because of clinical conditions or patient preference. Table 1 Newly diagnosed pts 241 With sibs/without sibs 194 /47 (total 241) HLA typed /not HLA typed 158 /36 (total 194) Matched sibs /No matched sibs 76 /82 (total 158) Auto-Allo”/“Double Auto”/Other”“ 56 /73 /29 (total 158) After induction chemotherapy, patients of both groups underwent G-CSF mobilised autografting with high dose melphalan (200 mg/m2). In the “auto-allo” group, the autologous HCT was followed, 2-4 months later, by low dose (2.0 Gy) TBI, allogeneic PHC infusion, and post transplant mycophenolate mofetil and cyclosporin. In the “double-auto group”, patients received a second autologous HCT. Patients characteristics were as follows: age: 54 (range 34–65) vs 53 (range 33–64) (p=ns); stage III myeloma: 77% vs 64% (p=0.03); beta 2 microglobulin > 2,5 mg/dl: 75% vs 59% (p=0.005), for the “auto-allo group” and for “the double-auto group”, respectively. At the time of this analysis, 56/56 of the “auto-allo group” and 55/73 of “the double-auto group” had completed the transplant programs. After median follow up of 3 years (range 11–80 months), TRM was 11% vs 4% (p=0.09); complete remission rates, defined as the disappearance of the monoclonal paraprotein by immunofixation, were 46% vs 16% (p=0.0001); overall survivals were 84% versus 62% (p=0.003); progression free survivals were 75% vs 41% (p=0.00008); event free survivals were 61% (34/56)% vs 38% (30/73) (p=0.006) in the “auto-allo group” and in the “double-auto” group, respectively. Longer follow up is needed, however data suggest that the “auto- non myeloablative allo” approach is not inferior to “double autologous” HCT in newly diagnosed MM.

Allogeneic approaches employing low dose TBI nonmyeloablative conditionings reported a dramatic reduction of transplant-related mortality (TRM) compared to conventional high dose regimens in newly diagnosed multiple myeloma (MM) (Maloney et al, Blood, 2003). The role of allografting, however, compared to autologous HCT remains to be determined. From September 1999 to July 2004, 241 consecutive MM patients, up to the age of 65, were diagnosed at five academic Italian Institutions. Overall, 194/241 had natural siblings (Table 1): 158/194 (81%) were HLA typed, while 36/194 (19%) were not typed for the following reasons: patients not eligible for high dose chemotherapy (n. 14); siblings not eligible for peripheral hematopoietic cell (PHC) donation (n.11); patient refusal to high dose chemotherapy (n. 9), unknown (n.2). Seventy-six/158 (48%) with a matched donor were offered a tandem autologous- nonmyeloablative allogeneic HCT approach. Eventually, 56/76 (73%), the “auto-allo group”, were enrolled while 20 did not enter the tandem program as 5 siblings (5/76, 7%) were not eligible for PHC donation, 5 patients refused an allogeneic HCT, and 10 patients preferred allografting as a possible salvage treatment. Of 102 patients without matched donors or after refusal to allografting, 73, “double-auto group”, underwent a standard double autologous transplant while 29 received less intense treatments because of clinical conditions or patient preference.