Constitutive and Stimulated Production of Vegf by Human Megakaryoblastic Cell Lines: Effect on Proliferation and Signaling Pathway

Release of vascular endothelial growth factor (VEGF) and other candidate angiogenic factors such as basic fibroblast growth factor and transforming growth factor β, may play a role in sustaining neoplastic cell proliferation and tumor growth. We evaluated VEGF expression and synthesis in the two erythro-megakaryocytic cell lines B1647, HEL and one megakaryocyte cell line MO7 expressing erythroid markers. In this study RT-PCR was performed to evaluate VEGF expression and that of its receptor KDR; VEGF production was assayed by Elisa test and western blot analysis; sensitivity to VEGF was tested by thymidine incorporation. VEGF and its receptor KDR were expressed in B1647 and HEL, both as mRNAs and as proteins, while only KDR transcript was found in MO7 cells. Only B1647 and HEL cells showed a strong spontaneous proliferating activity. In fact, measurable amounts of VEGF were present in the unstimulated cell medium, thus suggesting an autocrine production of VEGF by B1647 and HEL cells, but not by MO7, which was inhibited in mRNA-silencing conditions. This production could not be further boosted by other growth factors, whereas it was inhibited by TGF-β1. Finally, analysis of She signal transduction proteins following stimulation with VEGF indicated that only p46 was tyrosine phosphorylated. These data indicate that leukemic cells may be capable of autocrine production of VEGF which, in turn, maintains cell proliferation, possibly mediated by She p46 phosphorylation.

Delayed diagnosis of abdominal mass due to morbid obesity

Obesity has become an increasing problem in developed countries. Obesity is associated with many of the most common causes of morbidity and mortality, including diabetes mellitus, coronary artery diseases, sleep apnoea, and many types of cancers. Not only is morbid obesity associated to a greater extent to the many medical problems related to obesity, but the body habitus of a morbidly obese patient causes limitation to physical examination, radiologic evaluations, and therapeutic interventions that can delay diagnosis and treatment of the patient. We present a case of a morbidly obese patient whose diagnosis of liposarcoma was delayed for over a year as his obesity hindered proper diagnosis and medical treatment.

Comparable kinetics of myeloablation between fludarabine/full-dose busulfan and fludarabine/melphalan conditioning regimens in allogeneic peripheral blood stem cell transplantation

Fludarabine was utilized in the conditioning regimen of 30 adult patients undergoing an allogeneic hematopoietic stem cell transplant. In 18 patients it was combined with full-dose busulfan (FluBu) as a myeloablative regimen and in 12 cases with melphalan (FluMel) as a reduced intensity conditioning (RIC) regimen. Patients in the FluBu group were younger than in the FluMel group (P=0.03). Of 30 patients, 24 received peripheral blood stem cells (PBSC) whereas six patients in the FluBu group received bone marrow cells. The hematological toxicity of each regimen was evaluated by analyzing the kinetics of the neutropenia induced by preparative regimens and the time to recovery of the absolute neutrophils count (ANC) and platelets post transplantation. In PBSC transplants, the median day of severe neutropenia (<500 ANC/microl) occurred on day +6 after the FluBu regimen and on day +3 after FluMel (P=ns), whereas both groups had a duration of severe neutropenia of 9 days and a comparable time for ANC and platelet engraftment. Extra-hematological toxicities were also comparable in the two groups. These findings suggest that the hematological and extra-hematological toxicities induced by fludarabine/full-dose i.v. busulfan are similar to those induced by a standard RIC regimen such as fludarabine/melphalan.

Prolonged responses after autologous stem cell transplantation in African-American patients with multiple myeloma

Multiple myeloma (MM) has a double incidence in African-American (AA) than in non-AA patients and previous studies have shown a higher mortality in the former patient population. Here, we retrospectively analyzed the results of autologous stem cell transplantation (ASCT) in 38 AA and 32 non-AA consecutive patients. The two groups were comparable at diagnosis for age, stage of the disease, cytogenetic abnormalities, beta(2) microglobulin and albumin blood levels, and plasma cell marrow infiltration. The rates of complete and partial response observed in AA and non-AA patients after induction chemotherapy (9 and 42 vs 13 and 33%) and at 2 months (31 and 25 vs 30 and 20%) following ASCT were similar. At 6 months after ASCT, a greater relapse rate was observed in non-AA patients (P=0.009). At a median follow-up of 26 months, AA patients had a greater event-free survival (P=0.02) than non-AA patients, whereas overall survival was comparable in the two groups. The initial finding that AA patients with MM, compared to non-AA patients, had more prolonged responses and comparable survival after ASCT suggests that intensified chemotherapy is equally effective in patients of various ethnicities.

Different reconstitution of peripheral blood lymphocytes and dendritic cells in liver and kidney transplant patients

T cells and dendritic cells are responsible for immune alloreactivity or tolerance after transplantation. In this study, we compared the levels of circulating T, B, and NK lymphocytes, as well as monocytes, plasmacytoid dendritic cells, and myeloid dendritic cells, in adult patients undergoing a liver transplant or kidney transplant. Our findings show that candidates for liver transplant had significantly lower levels of circulating T, B, and dendritic cells than candidates for kidney transplant. Nevertheless, liver transplant patients showed a greater T-cell recovery, despite the use of thymoglobulin, as compared with kidney transplant patients who were induced with Daclizumab. In four kidney transplant patients with allograft rejection we observed a dramatic drop of circulating T and dendritic cells at the time of rejection, and while myeloid dendritic cells and CD4(+) and CD8(+) cells rapidly recovered after 1 month, plasmacytoid dendritic cells and CD4(+)CD25(+) T-cell numbers remained significantly lower than in patients without rejection. Future studies will evaluate the monitoring of circulating CD4(+)CD25(+) T cells and myeloid dendritic cell:plasmacytoid dendritic cell ratio as potential biomarkers for rejection or, alternatively, for withdrawal of immune suppression.

Severe hemolytic anemia due to passenger lymphocytes after living-related bowel transplant

BACKGROUND

Hemolytic anemia following solid organ transplant may be caused by 'passenger' lymphocytes producing antibodies against erythrocytes. This phenomenon has never been described after intestinal transplant.

MATERIALS AND METHODS

We report a case of severe, immune-mediated hemolysis due to symptomatic passenger lymphocyte syndrome (PLS) in a 4-yr-old recipient of living donor small bowel transplant. The Coombs'-positive hemolysis was caused by anti-A,B antibodies derived from donor lymphocytes in an ABO-compatible donor-recipient pair (O into A).

RESULTS

This complication was successfully and efficiently treated by the novel combined use of group O RBC transfusion, plasmapheresis and rituximab (anti-CD20).

CONCLUSIONS

A severe hemolytic anemia due to PLS can occur in bowel transplantation. This complication should be considered when performing ABO-incompatible bowel transplant with a blood group O donor and an A or B recipient. Treatment with plasmapheresis, blood group O transfusion and rituximab has proved successful in our case.

Reduced incidence of GVHD without increase in relapse with low-dose rabbit ATG in the preparative regimen for unrelated bone marrow transplants in CML

SUMMARY

Antithymocyte globulin (ATG) treatment prevents graft failure and results in a low incidence of GVHD, but an increased risk of relapse could be expected as a consequence of reduced GVHD. From September 1995 to June 2001, 28 consecutive chronic myeloid leukemia (CML) patients underwent unrelated bone marrow transplants: 21 were in chronic phase (CP) and seven in advanced phase (AP). Median age was 35.5 years (range 20-50). HLA typing was based on high-resolution molecular techniques; in eight cases there were one or more allele mismatches. The preparative regimen consisted of TBI, EDX 120 mg/kg and rabbit ATG 15 mg/kg. All patients engrafted and no rejection occurred. Acute GVHD grade III-IV occurred in six patients (21%). Chronic GVHD occurred in 10 (40%) and it was extensive in one. Four out of seven patients transplanted in AP had a hematological relapse. Of 21 in CP, there was one cytogenetic and one molecular relapse: these two patients are now in complete remission with imatinib mesylate. With a median follow-up of 45.7 months, the 5-year survival is 76.2% for those transplanted in CP. These data demonstrate that transplants performed in CP, with low-dose ATG, are associated with a good outcome, low incidence of GVHD and no increase of relapse.

Use of anti-BDCA-2 antibody for detection of dendritic cells type-2 (DC2) in allogeneic hematopoietic stem cell transplantation

TH2-inducing dendritic cells (DC2) are commonly identified as negative for lineage markers and positive for HLA-DR and CD123 expression. More recently, normal blood DC2 were shown also to be positive for BDCA-2 and BDCA-4 antigens. The aim of this study was to evaluate whether BDCA-2 expression on DC2 is impaired in patients undergoing an allogeneic hematopoietic stem cell transplantation (HSCT) and in healthy donors treated with G-CSF for HSC mobilization. Flow cytometry assays for DC2 detection using either a triple staining with anti-HLA-DR PerCP, anti-Lin(+) anti-CD34 FITC and anti-CD123 PE monoclonal antibodies (mAbs), or a double staining with anti-HLA-DR PE and anti-BDCA-2 FITC mAbs were compared in blood samples from patients who underwent an allogeneic HSCT (n = 30) or from healthy donors before (n = 11) and after (n = 8) G-CSF mobilization, as well as in healthy donors' leukapheresis products (n = 12) or bone marrow (n = 4). Staining of BDCA-2(+) cells with other markers such as anti-CD38, anti-CD54 and anti-CD58 were also performed. Median values of CD123(+) DC2 and BDCA-2(+) DC2 were not statistically different in the blood of patients previously treated with chemotherapy, nor in the blood or bone marrow of heathy donors. Also, a 5 day G-CSF treatment did not affect BDCA-2 or adhesion molecule expression on healthy donors' blood DC2 significantly. A correlation between all the results (n = 65) obtained with the two assays was demonstrated in a linear regression curve (r = 0.914) (P = 0.00001). BDCA-2 is a marker highly specific for DC2 that is not downregulated by chemotherapy or G-CSF treatment. Therefore, the anti-BDCA-2 mAb can be efficiently combined with other mAbs and used in studies addressing the role of DC2 in the allogeneic HSCT setting.

Expression of P21(WAF1/CIP1/SID1) cyclin-dependent kinase inhibitor in hematopoietic progenitor cells

P21(Waf1/Cip1/Sid1) is a critical component of biomolecular pathways leading to the G(1) arrest evoked in response to DNA damage, growth arrest signals and differentiation commitment. It belongs to the Cip/Kip class of cyclin-dependent kinase inhibitors and is at least partly regulated by p53. P21(Waf1/Cip1/Sid1) functional inactivation possibly resulting from mutations of the gene itself or, more likely, from p53 mutations may be critical for either the cell fate following DNA-damaging insults or clonal evolution toward malignancy. In the study presented here we describe a competitive polymerase chain reaction (PCR) strategy whose sensitivity and reproducibility enable us to attain a precise quantitation of p21(Waf1/Cip1/Sid1) expression levels in hematopoietic progenitors, the cell compartment which mostly suffers from the side effects of genotoxic drugs in use for cancer cure. The strategy was set in the M07 factor-dependent hematopoietic progenitor cell line. We confirmed that its p21(waf1/cip1/sid1) constitutive expression level is very low and up-modulated by DNA-damaging agents: ionizing radiations and ultraviolet light. Gene up-modulation resulted in checkpoint activation and, in particular, in a significant G(1) arrest, required for either the repair of damaged DNA sequences or apoptotic cell death. Our competitive PCR strategy was further validated in CD34(+) purified hematopoietic progenitors from healthy donors mobilized into the peripheral blood by granulocyte colony-stimulating factor and intended for allogeneic bone marrow transplantation. The constitutive p21(WAF1/CIP1/SID1) expression levels, measured in three separate harvests, were very low and no significant differences were apparent. Our results support the use of a competitive PCR strategy as a useful tool for clinical purposes, to assess the individual biomolecular response of early hematopoietic progenitors to antiblastic drugs.

CD56 antigenic expression in acute myeloid leukemia identifies patients with poor clinical prognosis

CD56 antigen, a 200-220 kDa cell surface glycoprotein, identified as an isoform of the neural adhesion molecules (NCAM), has been found frequently expressed in several lympho-hematopoietic neoplasms including acute myeloid leukemias (AML). In fact, in these latter diseases it has been reported that the presence of CD56 antigen on the blasts of AML patients with t(8;21) (q22;q22), and in those with M3 subtype, identifies a subgroup of patients with a more unfavorable prognosis. On the basis of these findings, we evaluated in 152 newly diagnosed AML patients CD56 surface expression, and results were correlated with morphology, immunophenotype, cytogenetic pattern and clinical outcome. CD56 antigen was recorded in 37 out of 152 cases (24%) and particularly in those with M2 and M5 cytotypes. Moreover, CD56 expression was significantly associated with P-glycoprotein (PGP) hyperexpression (P = 0.007), unfavorable cytogenetic abnormalities (P = 0.008) and with a reduced probability of achieving complete remission (CR) (36% vs 68%) (P = 0.035) as well as with a shorter survival (6 vs 12 months) (P = 0.032). In conclusion, CD56 antigenic expression on AML cells represents an important adverse prognostic factor and therefore its presence should be regularly investigated for a better prognostic assessment of AML patients at diagnosis.

Acute lung injury associated with 5-fluorouracil and oxaliplatinum combined chemotherapy

Diarrhoea, T-CD4+ lymphopenia and bilateral patchy pulmonary infiltrates developed in a male 60 yrs of age, who was treated with oxaliplatinum and 5-fluorouracil for unresectable rectum carcinoma. The findings from transbronchial lung biopsy and bronchoalveolar lavage (BAL) were consistent with an organizing diffuse alveolar damage pattern. Once extensive microbiological studies proved negative, corticosteroids were given and a complete remission of clinical and radiological abnormalities was achieved. It is concluded that the aforementioned pathological manifestations were due to chemotherapy and included a pulmonary adverse reaction, a feature never previously associated with oxaliplatinum and 5-fluorouracil regimens.

Acute lung injury associated with 5-fluorouracil and oxaliplatinum combined chemotherapy

Diarrhoea, T-CD4+ lymphopenia and bilateral patchy pulmonary infiltrates developed in a male 60 yrs of age, who was treated with oxaliplatinum and 5-fluorouracil for unresectable rectum carcinoma. The findings from transbronchial lung biopsy and bronchoalveolar lavage (BAL) were consistent with an organizing diffuse alveolar damage pattern. Once extensive microbiological studies proved negative, corticosteroids were given and a complete remission of clinical and radiological abnormalities was achieved. It is concluded that the aforementioned pathological manifestations were due to chemotherapy and included a pulmonary adverse reaction, a feature never previously associated with oxaliplatinum and 5-fluorouracil regimens.

Different immune reconstitution in multiple myeloma, chronic myeloid leukemia and acute myeloid leukemia patients after allogeneic transplantation of peripheral blood stem cells

In this study we compared the lymphocyte reconstitution in 13 multiple myeloma (MM), nine acute myeloid leukemia (AML) and 10 chronic myeloid leukemia (CML) patients after allogeneic G-CSF-mobilized PBSC transplantation from HLA-identical siblings. Conditioning regimens included standard total body irradiation + cyclophosphamide (CY), or busulphan + CY, whereas VP-16 was added in patients with advanced disease. Overall comparable numbers of mononuclear cells, CD34+ cells and CD3+ T cells were infused in each group. A significantly higher CD3+ T cell number was observed in MM and AML than in CML patients 1 month after transplant. However, MM patients showed a faster and better recovery of CD4+ T cells than both AML and CML patients at 3 months (P = 0.01 and P = 0.01, respectively) and 12 months (P = 0.01 vs AML, while P = NS vs CML) after transplant, and had a CD4:CD8 ratio > 1 with a median CD4+ T cell value > 400/microl 1 year after transplant. Development of acute graft-versus-host disease (GVHD) did not affect CD4:CD8 ratios but patients who experienced acute GVHD > grade I had lower CD4+ and CD8+ T cell numbers at all time points. However, after excluding patients with GVHD > grade I, MM patients still showed a significantly higher CD4+ T cell value than patients with myeloproliferative diseases 1 year after transplant. These findings suggest that although allogeneic PBSC transplantation induces rapid immune reconstitution, different kinetics may occur among patients with hematological malignancies. In particular, the rapid reconstitution of CD4+ T cells in MM patients may contribute to the low transplant-related mortality achieved in this disease.

Antitumor vaccination: where we stand

BACKGROUND AND OBJECTIVES

Vaccination is an effective medical procedure of preventive medicine based on the induction of a long-lasting immunologic memory characterized by mechanisms endowed with high destructive potential and specificity. In the last few years, identification of tumor-associated antigens (TAA) has prompted the development of different strategies for antitumor vaccination, aimed at inducing specific recognition of TAA in order to elicit a persistent immune memory that may eliminate residual tumor cells and protect recipients from relapses. In this review characterization of TAA, different potential means of vaccination in experimental models and preliminary data from clinical trials in humans have been examined by the Working Group on Hematopoietic Cells.

EVIDENCE AND INFORMATION SOURCES

The method employed for preparing this review was that of informal consensus development. Members of the Working Group met four times and discussed the single points, previously assigned by the chairman, in order to achieve an agreement on different opinions and approve the final manuscript. Some of the authors of the present review have been working in the field of antitumor immunotherapy and have contributed original papers to peer-reviewed journals. In addition, the material examined in the present review includes articles and abstracts published in journals covered by the Science Citation Index and Medline.

STATE OF THE ART

The cellular basis of antitumor immune memory consists in the generation and extended persistence of expanded populations of T- and B-lymphocytes that specifically recognize and react against TAA. The efficacy of the memory can be modulated by compounds, called "adjuvants", such as certain bacterial products and mineral oils, cytokines, chemokines, by monoclonal antibodies triggering co-stimulatory receptors. Strategies that have been shown in preclinical models to be efficient in protecting from tumor engraftment, or in preventing a tumor rechallenge, include vaccination by means of soluble proteins or peptides, recombinant viruses or bacteria as TAA genes vectors, DNA injection, tumor cells genetically modified to express co-stimulatory molecules and/or cytokines. The use of professional antigen-presenting cells, namely dendritic cells, either pulsed with TAA or transduced with tumor-specific genes, provides a useful alternative for inducing antitumor cytotoxic activity. Some of these approaches have been tested in phase I/II clinical trials in hematologic malignancies, such as lymphoproliferative diseases or chronic myeloid leukemia, and in solid tumors, such as melanoma, colon cancer, prostate cancer and renal cell carcinoma. Different types of vaccines, use of adjuvants, timing of vaccination as well as selection of patients eligible for this procedure are discussed in this review.

PERSPECTIVES

Experimental models demonstrate the possibility of curing cancer through the active induction of a specific immune response to TAA. However, while pre-clinical research has identified several possible targets and strategies for tumor vaccination the clinical scenario is far more complex for a number of possible reasons. Since experimental data suggest that vaccination is more likely to be effective on small tumor burden, such as a minimal residual disease after conventional treatments, or tumors at an early stage of disease, better selection of patients will allow more reliable clinical results to be obtained. Moreover, a poor correlation is frequently observed between the ability of TAA to induce a T-cell response in vitro and clinical responses. Controversial findings may also be due to the techniques used for monitoring the immune status. Therefore, the development of reliable assays for efficient monitoring of the state of immunization of cancer patients against TAA is an important goal that will markedly improve the progress of antitumor vaccines. (ABSTRACT TRUNCATED)

Long-term follow-up after fludarabine treatment in pretreated patients with chronic lymphocytic leukemia

BACKGROUND AND OBJECTIVES

A study update to assess long-term survival following fludarabine salvage treatment in previously treated patients with chronic lymphocytic lymphoma (CLL).

DESIGN AND METHODS

From September 1992 to December 1995, 74 patients with advanced, relapsing B-cell CLL were enrolled in the study. Fludarabine was given for 5 consecutive days at the dose of 25 mg/m2/day in a 30 min infusion. Treatment was repeated every 28 days for a maximum of 6 courses.E RESULTS. Nineteen (26%) patients achieved a complete response (CR) and 20 (27%) patients had a partial response (PR), giving an overall response rate of 53%. The median overall survival was 68 months, and there was a strong negative correlation with the number of previous treatments. The median time to progression was 18 months for patients who achieved a CR and 12 months for those with a PR.

INTERPRETATION AND CONCLUSIONS

The results obtained with fludarabine alone in this subset of CLL patients indicate the existence of a conspicuous disease-free survival period. This time window could be used to consolidate the initial response with either biological approaches or high-dose therapeutic strategies such as autologous bone marrow transplantation, with the aim of eventual eradication of the disease.

Tolerance and hematopoietic stem cell transplantation 50 years after Burnet's theory

OBJECTIVE

In 1949, the original formulation of Burnet's theory on the mechanisms responsible for the capacity of the immune system to discriminate between foreign antigens (i.e., the "non-self") and the cells of its own body (i.e., the "self") was published. Since then, further refinements and reconsiderations of the basic concepts underlying the achievement of a state of tolerance toward a certain antigen have been reported. Here, we attempt to analyze critically new clinical and experimental strategies aimed at inducing alloantigen-specific unresponsiveness.

DATA SOURCES

The data discussed in this review are drawn from articles and abstracts published in journals covered by the Science Citation Index and Medline.

STATE OF THE ART

Induction of tolerance toward alloantigens still remains one of the most elusive goals of clinical immunology. Until now, nonspecific immunosuppressive drugs have been used to successfully perform both solid organ and hematopoietic stem cell transplantation. However, using this approach, patients given an allograft are exposed to the threat of infections, tumors, and other side effects. Moreover, in solid organ transplant recipients, permanent tolerance toward the graft's alloantigens is never achieved. Recently, considerable progress has been made in expanding our knowledge of transplant tolerance. The traditional model of central tolerance, derived from Burnet's concept, has been complemented by knowledge of mechanisms of peripheral tolerance.

CONCLUSIONS

New experimental and therapeutic trials based on the blockade of costimulatory molecules, as well as on generation and infusion of either regulatory or nonimmunogenic cells, have been recently proposed for inducing alloantigen-specific tolerance.The achievements obtained in understanding the mechanisms of unresponsiveness toward non-self antigens are fundamental prerequisites for successful allogeneic transplants, and they could open a new exciting era of specific, immunosuppressive therapies.

Cell therapy: achievements and perspectives

BACKGROUND AND OBJECTIVE

Cell therapy can be considered as a strategy aimed at replacing, repairing, or enhancing the biological function of a damaged tissue or system by means of autologous or allogeneic cells. There have been major advances in this field in the last few years. This has prompted the Working Group on Hematopoietic Cells to examine the current utilization of this therapy in clinical hematology.

EVIDENCE AND INFORMATION SOURCES

The method employed for preparing this review was that of informal consensus development. Members of the Working Group met three times, and the participants at these meetings examined a list of problems previously prepared by the chairman. They discussed the single points in order to reach an agreement on different opinions and eventually approved the final manuscript. Some of the authors of the present review have been working in the field of cell therapy and have contributed original papers in peer-reviewed journals. In addition, the material examined in the present review includes articles and abstracts published in journals covered by the Science Citation Index and Medline.

STATE OF THE ART

Lymphokine-activated killer (LAK) and tumor-infiltrating lymphocytes (TIL) have been used since the '70s mainly in end-stage patients with solid tumors, but the clinical benefits of these treatments has not been clearly documented. TIL are more specific and potent cytotoxic effectors than LAK, but only in few patients (mainly in those with solid tumors such as melanoma and glioblastoma) can their clinical use be considered potentially useful. Adoptive immunotherapy with donor lymphocyte infusions has proved to be effective, particularly in patients with chronic myeloid leukemia, in restoring a state of hematologic remission after leukemia relapse occurring following an allograft. The infusion of donor T-cells can also have a role in the treatment of patients with Epstein-Barr virus (EBV)-induced post-transplant lymphoproliferative disorders. However, in this regard, generation and infusion of donor-derived, virus specific T-cell lines or clones represents a more sophisticated and safer approach for treatment of viral complications occurring in immunocompromised patients. Whereas too few clinical trials have been performed so far to draw any firm conclusion, based on animal studies dendritic cell-based immunotherapy holds promises of exerting an effective anti-tumor activity. Despite leukemic cells not being immunogenic, induction on their surface of co-stimulatory molecules or generation of leukemic dendritic cells may induce antileukemic cytotoxic T-cell responses. Tumor cells express a variety of antigens and can be genetically manipulated to become immunogenic. The main in vitro and in vivo functional characteristics of marrow mesenchymal stem cells (MSCs) with particular emphasis on their hematopoietic regulatory role are reviewed. In addition, prerequisites for clinical applications using culture-expanded mesenchymal cells are discussed

PERSPECTIVES

The opportuneness of using LAK cells or activated natural killer (NK) cells in hematologic patients with low tumor burden (e.g. after stem cell transplantation) should be further explored. Moreover the role of new cytokines in enhancing the antineoplastic activity of NK cells and the infusion of selected NK in alternative to CTL for graft versus leukemia (GVL) disease (avoiding graft versus host disease (GvHD) seems very promising. Separation of GVL from GvHD through generation and infusion of leukemia-specific T-cell clones or lines is one of the most intriguing and promising fields of investigations for the future. Likewise, strategies devised to improve immune-reconstitution and restore specific anti-infectious functions through either induction of unresponsiveness to recipient alloantigens or removal of alloreactive donor T-cells might increase the applicability and success of hematopoietic stem cell transplantation. (ABSTRACT TRUNCATED)

Selection and transplantation of autologous CD34+ B-lineage negative cells in advanced-phase multiple myeloma patients: a pilot study

The feasibility of sequential positive and negative selection of mobilized CD34+ B-lineage negative cells to achieve tumour-free autografts in multiple myeloma (MM) patients was evaluated. Peripheral blood stem cells (PBSC) of 14 patients with advanced disease were mobilized. CD34+ cells were enriched in 12 of the patients by the avidin-biotin immunoabsorption technique. Subsequently, CD10+, CD19+, CD20+ and CD56+ cells (B-lin cells) were removed by immunomagnetic depletion. Minimal residual disease (MRD) was detected by flow cytometry and PCR-based molecular analysis of the patient specific IgH complementary-determining region III (CDRIII). Positive selection of stem cells produced a median recovery of 54.7% of the initial content of CD34+ cells (median purity 71.9%). Negative depletion of B-lineage cells reduced the number of CD34+ cells to 33.3% of the baseline value (median purity 72.7%). However, long-term culture assays showed the recovery of >60% of primitive haemopoietic progenitor cells after depletion of the B-lineage-positive cells. All evaluable patients had detectable disease in PBSC collections. The first step of positive selection of CD34+ cells resulted in >2 logs of tumour cell purging. However, molecular assessment showed the persistence of the disease in 6/7 cases. Immunofluorescence analysis demonstrated 1 additional log of B-cell purging by negative depletion. More importantly, molecular evaluation of IgH CDRIII region showed the disappearance of myeloma cells in 6/7 patients. 12 patients received a median of 3.9 x 106 CD34+ B-lin- cells/kg after conditioning with high-dose melphalan and showed a rapid reconstitution of haemopoiesis. These results were similar to two similar cohorts of patients who received either unmanipulated PBSC or positively selected CD34+ cells after the same conditioning regimen. Severe extrahaematological toxicity was limited to mucositis; no late infections were observed. We concluded that autotransplantation of purified CD34+ B-lin- cells was associated with a rapid and sustained recovery of haemopoiesis and low peritransplant morbidity. Sequential positive and negative enrichment of stem cells reduced tumour cell contamination in B-cell malignancies below the lower limit of detection of molecular analysis.

Rapid induction of CD40 on a subset of granulocyte colony-stimulating factor-mobilized CD34(+) blood cells identifies myeloid committed progenitors and permits selection of nonimmunogenic CD40(-) progenitor cells

CD40 antigen is a costimulatory molecule highly expressed on dendritic cells (DC) and activated B cells, which induces T-cell proliferation through the binding with CD40L receptor. In this study, we evaluated CD40 expression on normal CD34(+) blood cells and functionally characterized CD34(+)CD40(+) and CD34(+)CD40(-) cell subsets. CD40, CD80, and CD86 antigens were constitutively expressed on 3.2% +/- 4.5%, 0%, and 1.8% +/- 1.2% CD34(+) blood cells, respectively. However, after 24 hours in liquid culture with medium alone, or with tumor-necrosis-factor-alpha (TNF-alpha), or with allogeneic mononuclear cells 10.8% +/- 3.8%, 75.3% +/- 15.0% and 53. 7% +/- 17.0% CD34(+) blood cells, respectively, became CD40(+). After incubation for 24 hours with TNF-alpha CD34(+)CD40(+) blood cells expressed only myeloid markers and contained less than 5% CD86(+) and CD80(+) cells. Also, a 24-hour priming with TNF-alpha or ligation of CD40 significantly increased the CD34(+) blood cells alloantigen presenting function. Finally, purified CD34(+)CD40(+) blood cells stimulated an alloreactive T-cell response in MLC, were enriched in granulocytic, monocytic, and dendritic precursors, and generated high numbers of DC in 11-14 d liquid cultures with GM-CSF, SCF, TNF-alpha and FLT-3L. In contrast, CD34(+)CD40(-) cells were poorly immunogenic, contained committed granulocytic and erythroid precursors and early progenitors, and differentiated poorly toward the DC lineage. In conclusion, a short incubation with TNF-alpha allows the selection of CD40(+) blood progenitors, which may be a useful source of DC precursors for antitumor vaccine studies, and also a CD34(+)CD40(-) blood cell fraction that could be exploited in innovative strategies of allogeneic transplantation across HLA barriers.

Discrepancy between serological complete remission and concomitant new bone lytic lesions after infusion of escalating low doses of donor lymphocytes in multiple myeloma: a case report

A graft-versus-myeloma effect has been previously induced by infusing high numbers of donor lymphocytes after allogeneic stem cell transplantation in relapsed/refractory multiple myeloma (MM) patients. A 43-year-old patient with MM refractory to standard chemotherapy and autologous transplantation received an allogeneic HLA-matched T cell-depleted marrow transplant from his sister after conditioning with single dose total-body irradiation, melphalan and cyclophosphamide. Twenty-four months after transplant neither a significant reduction of serum M protein nor evidence of acute or chronic graft-versus-host disease (GVHD) were observed. The patient was then treated with four escalating low doses of donor lymphocyte infusions (DLI) (0.1, 1.0, 5.0 and 5.0 x 106 CD3+ T cells/kg, respectively) over a 13 month period. Following the second infusion a mild liver acute GVHD and a partial, but transient, response occurred. After the last DLI the patient achieved a complete remission and developed extensive chronic GVHD. However, concomitant with the disappearance of clonal plasma cells from the marrow and of serum M protein, two new bone lytic lesions appeared requiring treatment with radiotherapy. In conclusion, escalating low doses of DLI may be effective in MM and may prevent severe acute but not chronic GVHD. However, the efficacy of DLI in extramedullary MM lesions is still unclear.