Hepatitis B virus-related cryogobulinemic vasculitis. The role of antiviral nucleot(s)ide analogues: a review.

Cryoglobulinemic vasculitis (CV) can develop in 1.2-4% of hepatitis B virus (HBV)-infected patients. HBV infection affects about 350 million people worldwide. It can progress from acute or fulminant hepatitis to chronic hepatitis, cirrhosis or hepatocellular carcinoma. Twenty per cent of HBV patients may develop extra-hepatic manifestations, such as polyarteritis nodosa, glomerulonephritis, dermatitis, polyarthralgias and arthritis, lung disease, aplastic anaemia. Our review focuses on the role of antiviral agent nucleot(s)ide analogues (NAs) in treatment of HBV-related CV. The studies in literature have demonstrated that NAs therapy in HBV-related CV yields high virological and satisfying clinical responses in most patients with mild-and-moderate CV, but a low response in severe CV. Overall, NAs represent a promising therapeutic option for HBV-related CV. Obtaining early suppression of HBV viral load should be the main virological and clinical goal in order to prevent organ complications and lymphoproliferative disorders.

A new freezing and storage procedure improves safety and viability of haematopoietic stem cells and neutrophil engraftment: a single institution experience.

BACKGROUND AND OBJECTIVES: Autologous peripheral blood stem cell transplantation has recently become a standard therapeutic approach to virus-related or infected haematological malignancies. Collection, manipulation, storage and thawing of leukapheresis products in this subset of patients require strict monitoring to prevent infection risk for operators and risk of contamination for other stored bags. MATERIALS AND METHODS: This is a non-randomized retrospective observational study. In the 2000-2002 period, a single bag freezing procedure was used for autologous peripheral blood stem cell transplantation. Bags were stored in tanks containing liquid and gas phase nitrogen. In 2002, the processing procedure was revised, and a second additional safety bag and a new storage tank containing jacketed liquid nitrogen have been used. RESULTS: A total of 524 bags were thawed, of which 121 processed with the single bag method and 403 with the double bag method. Forty-nine and 109 patients were infused respectively. The observed rupture rate with the single bag in liquid and gas phase nitrogen was 17 and 2.5%, respectively, against a rupture rate as little as 0.24% with the new methodology. Viability revealed levels of 84.4% +/- 6.1% and 96.9% +/- 2.4% for the single and double-bag respectively. This statistically significant (P < 0.0001) difference correlated with better neutrophil engraftment. CONCLUSIONS: The new proposed method, based on a double bag and storage freezer without liquid or gas phase nitrogen into a cryogenic chamber, significantly reduces bag rupture and bio-hazard and improves stem cell viability and neutrophil engraftment remarkably.

Phorbol ester induced osteoclast-like differentiation of a novel human leukemic cell line (FLG 29.1).

Studies on human osteoclast formation have been hampered by lack of a defined isolated progenitor cell population. We describe here the establishment of a human leukemic cell line (designated FLG 29.1) from bone marrow of a patient with acute monoblastic leukemia. The cultured cells are predominantly undifferentiated leukemic blasts, but addition of 12-o-tetradecanoylphorbol 13-acetate (TPA; 0.1 microM) induces irreversible differentiation into adherent, non-dividing, multinucleated cells. TPA-treated cells bear surface antigens typical of fetal osteoclasts, degrade 45Ca-labeled devitalized bone particles, display tartrate-resistant acid phosphatase in both mononuclear and multinuclear cells and receptors for calcitonin. Calcitonin increases intracellular cAMP accumulation in TPA-treated cells. TPA-treated cells show some ultrastructural features of osteoclasts as evidenced by transmission EM. These results indicate that FLG 29.1 cells may represent an osteoclast committed cell population, which upon induction with TPA acquire some morphological, phenotypical, and functional features of differentiated osteoclasts.

Preclinical ex vivo expansion of peripheral blood CD34+ selected cells from cancer patients mobilized with combination chemotherapy and granulocyte colony-stimulating factor.

BACKGROUND AND OBJECTIVES: Ex vivo peripheral blood progenitor cell (PBPC) expansion has been proposed as a strategy to increase the number of haematopoietic progenitors available for cell transplantation. We have expanded CD34+ cells from PBPCs obtained from four patients with haematological malignancies and one patient with an Ewing's sarcoma. MATERIALS AND METHODS: Cells were expanded in the Dideco 'Pluricell system'. After 12 days in culture, we evaluated cell phenotype, total nucleated cells, CD34+ fold increase, cell apoptosis and colony assay of expanded cells. Cell engraftment has been evaluated by transplanting two groups of irradiated non-obese diabetic/severe combined immunodeficient (NOD-SCID) mice with expanded and non-expanded cell populations. RESULTS: Total nucleated cells and CD34+ cells increased 59.5 and 4.0 times, respectively. The expanded cells were mainly constituted of myeloid and megakaryocytic cells. A significant increase in the number of colony-forming unit-granulocyte macrophage (CFU-GM) was observed in the CFU assay. Ten mice transplanted with expanded cells showed a best overall survival (80%) compared to 10 mice transplanted with non-expanded cells (20%). Human CD45+ cells were detected by flow cytometry and polymerase chain reaction in bone marrow and spleen of transplanted animals. The relative low engraftment level obtained with the expanded cells suggests a loss of SCID repopulating cells maybe due to cell differentiation during expansion. CONCLUSIONS: We have demonstrated the feasibility of the ex vivo expansion of mobilized PBPCs from cancer patients, evidencing a clonal expansion of CFUs and the ability of the expanded cells to engraft the bone marrow and spleen of immunosuppressed mice. The differentiation of the CD34+ stem cell compartment could be further minimized by ameliorating the expansion conditions.

Telomerase expression in B-cell chronic lymphocytic leukemia predicts survival and delineates subgroups of patients with the same igVH mutation status and different outcome.

Activation of telomerase reverse transcriptase (hTERT) is essential for unlimited cell growth and plays a critical role in tumorigenesis. We investigated hTERT gene expression in 134 B-cell chronic lymphocytic leukemia (B-CLL) cases and evaluated its prognostic value with other prognostic markers (IgVH mutation status, CD38 and ZAP-70 expression). Real-time PCR assays to quantify either all hTERT transcripts (AT) or only the full length (FL) transcript encoding the functional protein were developed. hTERT-AT levels strongly correlated with hTERT-FT levels (r=0.743, P<0.0001); both inversely correlated with the percentage of IgVH mutation (P<0.005) and were significantly higher in unmutated than in mutated cases (P=0.004 and P=0.001, respectively). The hTERT values which best discriminated between the unmutated and mutated IgVH cases were 150 and 40 copies for hTERT-AT and hTERT-FL, respectively. Using these cut-off values, there was a significant difference in the survival of patients with high or low hTERT levels (P<0.0001). Unmutated cases with low hTERT levels had an overall survival close to mutated cases with high hTERT levels. Thus, this work identifies hTERT-RNA level as a new prognostic marker in B-CLL, and may be used to identify previously unrecognized patient groups with the same IgVH mutation status and different disease outcomes.

NOTCH1 mutations are associated with high CD49d expression in chronic lymphocytic leukemia: link between the NOTCH1 and the NF-κB pathways.

In chronic lymphocytic leukemia (CLL), stabilizing mutations of NOTCH1, affecting up to 10-15% of cases, have been associated to poor prognosis, disease progression and refractoriness to chemotherapy. NOTCH1 mutations are significantly overrepresented in trisomy 12 CLL, a disease subset frequently expressing CD49d, the α4 chain of the very-late-activation-4 integrin, a well-known key regulator of microenviromental interactions, and negative prognosticator in CLL. In the present study, by analysing a wide cohort of 1180 CLL, we observed a very strong association between the presence of NOTCH1 mutations and the expression of CD49d (P<0.0001), occurring also outside the trisomy 12 CLL subset. Using both the MEC-1 CLL-like cells stably transfected with the NOTCH1 intracellular domain and primary CLL cells bearing a mutated or wild-type NOTCH1 gene configuration, we provide evidence that triggering of the NOTCH1 pathway resulted in a positive CD49d expression regulation, which was driven by a NOTCH1-dependent activation of nuclear factot-κB (NF-κB). Consistently, pharmacological inhibition of the NOTCH1 and/or of the NF-κB pathways resulted in impaired NF-κB nuclear translocation with consequent down-modulation of CD49d expression. Altogether, our data link for the first time NOTCH1 mutations to CD49d expression regulation through the involvement of the NF-κB pathway in CLL.

Differences between BCL2-break positive and negative follicular lymphoma unraveled by whole-exome sequencing.

Depending on disease stage follicular lymphoma (FL) lack the t(14;18) in ~15-~50% of cases. Nevertheless, most of these cases express BCL2. To elucidate mechanisms triggering BCL2 expression and promoting pathogenesis in t(14;18)-negative FL, exonic single-nucleotide variant (SNV) profiles of 28 t(14;18)-positive and 13 t(14;18)-negative FL were analyzed, followed by the integration of copy-number changes, copy-neutral LOH and published gene-expression data as well as the assessment of immunoglobulin N-glycosylation sites. Typical FL mutations also affected t(14;18)-negative FL. Curated gene set/pathway annotation of genes mutated in either t(14;18)-positive or t(14;18)-negative FL revealed a strong enrichment of same or similar gene sets but also a more prominent or exclusive enrichment of immune response and N-glycosylation signatures in t(14;18)-negative FL. Mutated genes showed high BCL2 association in both subgroups. Among the genes mutated in t(14;18)-negative FL 555 were affected by copy-number alterations and/or copy-neutral LOH and 96 were differently expressed between t(14;18)-positive and t(14;18)-negative FL (P<0.01). N-glycosylation sites were detected considerably less frequently in t(14;18)-negative FL. These results suggest a diverse portfolio of genetic alterations that may induce or regulate BCL2 expression or promote pathogenesis of t(14;18)-negative FL as well as a less specific but increased crosstalk with the microenvironment that may compensate for the lack of N-glycosylation.

The kinetics of reduction of minimal residual disease impacts on duration of response and survival of patients with acute myeloid leukemia.

UNLABELLED: We assessed by multiparametric flow cytometry the levels of minimal residual disease (MRD) in 100 adult patients with acute myelogenous leukemia (AML) achieving complete remission after intensive chemotherapy. The aim of the study was to determine the optimal threshold, in terms of residual leukemic cells, and the time point of choice, that is, post-induction (post-Ind) or post-consolidation (post-Cons), able to better predict outcome. By applying the maximally selected log-rank statistics, the threshold discriminating MRD- from MRD+ cases was set at 3.5 x 10(-4) residual leukemic cells, a level that allowed the identification of distinct subgroups of patients, both at post-Ind and post-Cons time points. Post-Cons MRD- patients had a superior outcome in terms of relapse rate, overall survival (OS) and relapse-free survival (RFS) (P<0.001, for all comparisons), regardless of the MRD status after induction. In particular, patients entering MRD negativity only after consolidation showed the same outcome as those achieving early negativity after induction. Multivariate analysis, including karyotype, age, MDR1 phenotype, post-Ind and post-Cons MRD levels, indicated that the post-Cons MRD status independently affected relapse rate, OS and RFS (P<0.001, for all comparisons). IN CONCLUSION: (1) the threshold of 3.5 x 10(-4) is valid in discriminating risk categories in adult AML and (2) post-Cons MRD assessment is critical to predict disease outcome.

Outside inside signalling in CD40-mediated B cell activation.

CD40 is a member of the growing tumor necrosis factor receptor (TNF-R) family of molecules, and has been shown to play important roles in T cell-mediated B lymphocyte activation. Ligation of B cell CD40 by CD154 expressed on activated T cells stimulates B cell proliferation, differentiation, isotype switching, upregulation of surface molecules contributing to antigen presentation, development of the germinal center, and the humoral memory response. The present review will summarize recent literature data on the various CD40 signalling pathways, which involve both the TNF-R associated factors (TRAFs) and additional signalling proteins, and lead to activation of kinases and transcription factors.

NOTCH1-mutated chronic lymphocytic leukemia cells are characterized by a MYC-related overexpression of nucleophosmin 1 and ribosome-associated components.

In chronic lymphocytic leukemia (CLL), the mechanisms controlling cell growth and proliferation in the presence of NOTCH1 mutations remain largely unexplored. By performing a gene expression profile of NOTCH1-mutated (NOTCH1-mut) versus NOTCH1 wild-type CLL, we identified a gene signature of NOTCH1-mut CLL characterized by the upregulation of genes related to ribosome biogenesis, such as nucleophosmin 1 (NPM1) and ribosomal proteins (RNPs). Activation of NOTCH1 signaling by ethylenediaminetetraacetic acid or by coculture with JAGGED1-expressing stromal cells increased NPM1 expression, and inhibition of NOTCH1 signaling by either NOTCH1-specific small interfering RNA (siRNA) or γ-secretase inhibitor reduced NPM1 expression. Bioinformatic analyses and in vitro activation/inhibition of NOTCH1 signaling suggested a role of MYC as a mediator of NOTCH1 effects over NPM1 and RNP expression in NOTCH1-mut CLL. Chromatin immunoprecipitation experiments performed on NOTCH1 intracellular domain (NICD)-transfected CLL-like cells showed the direct binding of NOTCH1 to the MYC promoter, and transfection with MYC-specific siRNA reduced NPM1 expression. In turn, NPM1 determined a proliferation advantage of CLL-like cells, as demonstrated by NPM1-specific siRNA transfection. In conclusion, NOTCH1 mutations in CLL are associated with the overexpression of MYC and MYC-related genes involved in protein biosynthesis including NPM1, which are allegedly responsible for cell growth and/or proliferation advantages of NOTCH1-mut CLL.

Venetoclax: Bcl-2 inhibition for the treatment of chronic lymphocytic leukemia.

Venetoclax (ABT-199) is a small-molecule selective oral inhibitor of the antiapoptotic protein Bcl-2 that promotes programmed cell death of chronic lymphocytic leukemia (CLL) cells regulating the release of proapoptotic factors, such as Smac/Diablo, apoptosis-inducing factor (AIF) and cytochrome c. In April 2016, the U.S. Food and Drug Administration (FDA) granted accelerated approval to venetoclax for patients diagnosed with CLL with 17p deletion, as detected by an FDA-approved test, who have received at least one prior therapy. This review will focus on the mechanism of action, preclinical studies and clinical development of venetoclax both as a monotherapy and in combination with other drugs for CLL in the current milieu of therapy dominated by novel tyrosine kinase inhibitors such as ibrutinib and idelalisib.

NOTCH1 mutations associate with low CD20 level in chronic lymphocytic leukemia: evidence for a NOTCH1 mutation-driven epigenetic dysregulation.

In chronic lymphocytic leukemia (CLL), NOTCH1 mutations have been associated with clinical resistance to the anti-CD20 rituximab, although the mechanisms behind this peculiar behavior remain to be clarified. In a wide CLL series (n=692), we demonstrated that CLL cells from NOTCH1-mutated cases (87/692) were characterized by lower CD20 expression and lower relative lysis induced by anti-CD20 exposure in vitro. Consistently, CD20 expression by CLL cells was upregulated in vitro by γ-secretase inhibitors or NOTCH1-specific small interfering RNA and the stable transfection of a mutated (c.7541-7542delCT) NOTCH1 intracellular domain (NICD-mut) into CLL-like cells resulted in a strong downregulation of both CD20 protein and transcript. By using these NICD-mut transfectants, we investigated protein interactions of RBPJ, a transcription factor acting either as activator or repressor of NOTCH1 pathway when respectively bound to NICD or histone deacetylases (HDACs). Compared with controls, NICD-mut transfectants had RBPJ preferentially complexed to NICD and showed higher levels of HDACs interacting with the promoter of the CD20 gene. Finally, treatment with the HDAC inhibitor valproic acid upregulated CD20 in both NICD-mut transfectants and primary CLL cells. In conclusion, NOTCH1 mutations are associated with low CD20 levels in CLL and are responsible for a dysregulation of HDAC-mediated epigenetic repression of CD20 expression.

CD49d prevails over the novel recurrent mutations as independent prognosticator of overall survival in chronic lymphocytic leukemia.

CD49d, the alpha-chain of the integrin heterodimer α4ß1, was identified among the strongest predictors of overall survival (OS) in chronic lymphocytic leukemia (CLL), along with IGHV mutational status and deletion of the 17p chromosome involving TP53. In addition to TP53, the clinical relevance of NOTCH1, SF3B1 and BIRC3 gene mutations has been recently emphasized. By analyzing a cohort of 778 unselected CLL patients, we assessed the clinical relevance of CD49d as an OS predictor in subgroups defined by mutation/deletion of the TP53, NOTCH1, SF3B1 and BIRC3 genes. In this context, CD49d emerged as an independent predictor of OS in multivariate Cox analysis (Hazard ratio =1.88, P<0.0001). Consistently, high CD49d expression identified CLL subsets with inferior OS in the context of each category of a previously reported hierarchical risk stratification model. Moreover, by evaluating the relative importance of biological prognosticators by random survival forests, CD49d was selected among the top-ranked OS predictor (variable importance =0.0410), along with IGHV mutational status and TP53 abnormalities. These results confirmed CD49d as an independent negative OS prognosticator in CLL also in comprehensive models comprising the novel recurrent mutations. In this context, TP53 disruption and NOTCH1 mutations retained prognostic relevance, in keeping with their roles in CLL cell immuno-chemoresistance.

In vitro and in vivo effects of 5-aza-2'-deoxycytidine (Decitabine) on clonogenic cells from acute myeloid leukemia patients.

5-Aza-2'-deoxycytidine (Decitabine) is an analog of deoxycytidine now entering clinical trials in acute myeloid leukemia (AML) owing to a defined antileukemic activity mediated at least in part by DNA hypomethylation, altered gene expression, and induction of cell differentiation. In the present study, we examined the relationship between the in vitro sensitivity to Decitabine of blast progenitors and the clinical outcome, in nine AML patients treated in vivo with Decitabine within a phase II trial carried out at two different institutions. Leukemic blast progenitors in acute myeloid leukemia (AML) undergo terminal divisions giving rise to colonies in methylcellulose. The self-renewal capacity of blast progenitors is conversely reflected by a secondary methylcellulose assay after exponential growth of clonogenic cells in suspension cultures. Three out of four patients, in which clonogenic cells in methylcellulose were strongly suppressed by Decitabine and clonogenic growth of blasts cultured in suspension was only slightly affected, failed on Decitabine treatment in vivo. Two subjects, whose blast progenitors in suspension culture were significantly inhibited by Decitabine, obtained a positive hematological response (complete or partial remission, CR or PR) and an additional patient showing a similar in vitro pattern died in induction with an hypoplastic marrow without morphological evidence of persistant leukemia. Interestingly two patients displaying an unfavourable in vitro pattern (i.e. a minor suppression of self-renewal mitoses as evinced from suspension cultures) achieved a hematological response (CR and PR) upon in vivo therapy with Decitabine. The in vitro response to Decitabine of clonogenic progenitors from both these patients shifted to a favourable pattern (i.e. major suppression of self-renewal versus terminal mitoses) following manipulation of culture conditions by the addition or removal of exogenous growth factors. In addition, in a further patient refractory to treatment with Decitabine in vivo, similar alterations of the culture conditions were unable to modify the unfavourable pattern of response to the drug in vitro. Our results indicate that the sensitivity of blast progenitors in suspension cultures strongly correlates with the remission outcome of the patients. From our data, it also appears that alterations of culture microenvironment are able to modify the response of AML blasts to Decitabine, unveiling the 'hidden' sensitivity of leukemic progenitors to the drug in cases characterized by a discrepancy between in vivo and in vitro results, i.e. apparent in vitro resistance and favourable clinical outcome.

5-Aza-2'-deoxycytidine (Decitabine) induces trilineage response in unfavourable myelodysplastic syndromes.

The preliminary results of a disease-oriented phase I-II study aimed at evaluating the clinical activity of 5-aza-2'-deoxycytidine (Decitabine) in patients affected by advanced myelodysplastic syndromes (MDS) are reported. Two patients affected by refractory anemia with excess of blasts (RAEB) and eight with RAEB in transformation (RAEB-T) were treated with Decitabine at a daily dose of 45 mg/m2, divided into three 4 h infusions for 3 days (six patients) or as continuous infusion of 50 mg/m2 for 3 days (four patients). Treatment with Decitabine resulted in a significant increase in circulating neutrophils, platelets, and hemoglobin with respect to pretreatment values in over 50% of patients. These changes were accompanied by the improvement of the marrow myeloid relative differentiation index (median fivefold increase in the whole group of patients) and of the myeloid to erythroid cell ratio (median twofold increase) in most of the patients. In four out of ten patients a complete normalization of peripheral blood (PB) and bone marrow (BM) picture (complete hematologic response) was obtained. The evaluation of the percentage of CD34-positive BM cells showed a slow but progressive reduction of early leukemic progenitors in most of the patients. A transient slight BM hypoplasia was obtained in less than 50% of patients while a severe marrow aplasia was never observed in our group of MDS patients during treatment with Decitabine. Extra-hematological toxicity was very mild in all the patients. The preliminary results of our study indicate that Decitabine is able to induce trilineage hematological responses in advanced MDS patients along with a stable normalization of the PB and BM picture in some of the subjects. Decitabine appears an active agent in advanced MDS and this deserves careful investigation in this heterogeneous group of disorders.

Pilot study of 5-aza-2'-deoxycytidine (Decitabine) in the treatment of poor prognosis acute myelogenous leukemia patients: preliminary results.

5-Aza-2'-deoxycytidine (Decitabine) is a new cytosine analog with potent antileukemic activity and able to induce in vitro gene activation and cellular differentiation by a mechanism probably involving DNA hypomethylation. The aim of this pilot study was to evaluate the efficacy and the toxicity of Decitabine, used as single induction agent, in the treatment of poor prognosis acute myeloid leukemia (AML) patients, and to explore its mechanism of action. A total of 12 patients were treated with Decitabine at 90-120 mg/m2 as a four hour intravenous infusion, three times daily for three consecutive days every four to six weeks. A minimum of two courses were required for response evaluation and to consider a patient as therapeutic failure. A total of 10/12 patients were fully evaluable for response; three patients achieved a complete remission (CR) and one a partial remission (PR). Extra-hematological toxicity was generally mild. As for the mechanism of action, both a differentiation induction effect and a cytotoxic mechanism have been observed. In particular, CRs and PRs were probably obtained through the induction of leukemia cell differentiation as shown by the kinetic of remission and immunotyping studies. The preliminary results of this ongoing study suggest that Decitabine may have a prominent role in the treatment of those AML patients with poor general conditions and/or advanced age.

The enzymatic activities of CD38 enhance CLL growth and trafficking: implications for therapeutic targeting.

The ecto-enzyme CD38 is gaining momentum as a novel therapeutic target for patients with hematological malignancies, with several anti-CD38 monoclonal antibodies in clinical trials with promising results. In chronic lymphocytic leukemia (CLL) CD38 is a marker of unfavorable prognosis and a central factor in the pathogenetic network underlying the disease: activation of CD38 regulates genetic pathways involved in proliferation and movement. Here we show that CD38 is enzymatically active in primary CLL cells and that its forced expression increases disease aggressiveness in a xenograft model. The effect is completely lost when using an enzyme-deficient version of CD38 with a single amino-acid mutation. Through the enzymatic conversion of NAD into ADPR (ADP-ribose) and cADPR (cyclic ADP-ribose), CD38 increases cytoplasmic Ca(2+) concentrations, positively influencing proliferation and signaling mediated via chemokine receptors or integrins. Consistently, inhibition of the enzymatic activities of CD38 using the flavonoid kuromanin blocks CLL chemotaxis, adhesion and in vivo homing. In a short-term xenograft model using primary cells, kuromanin treatment traps CLL cells in the blood, thereby increasing responses to chemotherapy. These results suggest that monoclonal antibodies that block the enzymatic activities of CD38 or enzyme inhibitors may prove therapeutically useful.

Bispecific antibodies targeting tumor-associated antigens and neutralizing complement regulators increase the efficacy of antibody-based immunotherapy in mice.

The efficacy of antibody-based immunotherapy is due to the activation of apoptosis, the engagement of antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity (CDC). We developed a novel strategy to enhance CDC using bispecific antibodies (bsAbs) that neutralize the C-regulators CD55 and CD59 to enhance C-mediated functions. Two bsAbs (MB20/55 and MB20/59) were designed to recognize CD20 on one side. The other side neutralizes CD55 or CD59. Analysis of CDC revealed that bsAbs could kill 4-25 times more cells than anti-CD20 recombinant antibody in cell lines or cells isolated from patients with chronic lymphocytic leukemia. The pharmacokinetics of the bsAbs was evaluated in a human-SCID model of Burkitt lymphoma. The distribution profile of bsAbs mimics the data obtained by studying the pharmacokinetics of anti-CD20 antibodies, showing a peak in the tumor mass 3-4 days after injection. The treatment with bsAbs completely prevented the development of human/SCID lymphoma. The tumor growth was blocked by the activation of the C cascade and by the recruitment of macrophages, polymorphonuclear and natural killer cells. This strategy can easily be applied to the other anti-tumor C-fixing antibodies currently used in the clinic or tested in preclinical studies using the same vector with the appropriate modifications.

CD30L up-regulates CD30 and IL-4 expression by T cells.

CD30L is frequently expressed on acute myeloid leukemia (AML) blasts. Its presence is associated with the co-expression of interleukin-4 (IL-4) receptor and with the expansion of specific T-helper 2 (Th2) cell subsets producing IL-4 and expressing CD30. Recombinant CD30L-bearing cells up-regulated the expression of surface CD30 and increased the production of IL-4 and soluble (s) CD30 by co-cultured T cells. These findings were confirmed with AML blasts expressing surface CD30L, where blocking anti-CD30 antibodies completely abolished the release of sCD30 and reduced the production of IL-4. Our data indicates a direct role of CD30L(+) neoplastic cells in driving the immune response toward a Th2-polarized non-protective state.