Search

Among the novel biological therapeutics that will increase our ability to cure human cancer in years to come, adoptive cellular therapy is one of the most promising approaches. Although this is a complex and challenging field, there have been major advances in basic and translational research resulting in clinical trial activity that is now beginning to confirm this promise. The results obtained with tumor-infiltrating lymphocytes therapy for melanoma, and virus-specific CTLs for EBV-associated malignancies are encouraging in terms of both ability to obtain clinical benefit and limited toxicity profile. In both settings, objective responses were obtained in at least 50% of treated patients. However, improvements to the clinical protocols, in terms of better patient selection and timing of administration, as well as cell product quality and availability, are clearly necessary to further ameliorate outcome, and logistical solutions are warranted to extend T-cell therapy beyond academic centers. In particular, there is a need to simplify cell production, in order to decrease costs and ease preparation. Promising implementations are underway, including harnessing the therapeutic potential of T cells transduced with TCRs directed against shared tumor antigens, and delineating strategies aimed at targeting immune evasion mechanisms exerted by tumor cells. [ABSTRACT FROM AUTHOR]

Progressive multifocal leukoencephalopathy (PML) associated with polyomavirus JC (JCV) infection has been reported to be usually fatal in allogeneic hematopoietic SCT (HSCT) recipients. We present the case of a 19-year-old HSCT patient diagnosed with JCV-associated PML after prolonged immunosuppression for severe GVHD. No short-term neurological improvement was observed after antiviral treatment and discontinuation of immunosuppressive therapy. Donor-derived JCV Ag-specific CTLs were generated in vitro after stimulation with 15-mer peptides derived from VP1 and large T viral proteins. After adoptive CTL infusion, virus-specific cytotoxic cells were shown in the peripheral blood, JCV-DNA was cleared in the cerebrospinal fluid and the patient showed remarkable improvement. Adoptive T-lymphocyte therapy with JCV-specific CTLs was feasible and had no side effects. This case suggests that adoptive transfer of JCV-targeted CTLs may contribute to restore JCV-specific immune competence and control PML in transplanted patients. [ABSTRACT FROM AUTHOR]

Haematopoietic stem cell transplantation (HSCT) represents the treatment of choice for severe bone marrow failure in patients with Fanconi anaemia (FA). When the donor is a compatible relative, the chance of being cured with an allograft is in the order of 70%. However, for FA children lacking an HLA-identical sibling, the results of HSCT from an alternative donor are less satisfactory because of a higher risk of graft rejection, graft-versus-host-disease (GVHD) and regimen-related toxicity. We report on a 12-year-old girl with FA, who was treated by T-cell-depleted (TCD) peripheral blood HSCT from her haploidentical uncle, using a novel fludarabine-based preparative regimen without radiation. She had rapid engraftment with no toxicity and no GVHD. Progressive recovery of both numbers of lymphocyte and of proliferative response to polyclonal activators occurred over time. At 18 months after transplantation, she is well with 100% donor chimerism and has recovered normal immune function.Bone Marrow Transplantation (2003) 31, 437-440. doi:10.1038/sj.bmt.1703903 [ABSTRACT FROM AUTHOR]

The article presents the discussion on workshop on infections after stem cell transplantation (SCT) in children. Topics include children undergoing hematopoietic stem cell transplantation (SCT) being at risk of infectious complications during several months following SCT; and causing smoldering invasion of the tissues of the host during prolonged periods of granulocytopenia or granulocyte dysfunction.

The success of allogeneic hematopoietic stem cell transplantation from HLA-disparate donors depends on the development of new strategies for graft-versus-host disease prevention able to target specifically donor antihost alloreactivity, while preserving GVL and antiviral immune surveillance. Recent experimental and clinical work has shown the feasibility of an approach based on induction of anergy to host alloantigens through blockade of B7/CD28 costimulatory signal in donor T cells, but data on the impact of this strategy on the recovery of the immune system are still lacking. We devised an ex vivo method for induction of host alloantigen-specific unresponsiveness based on treatment with the B7/CD28 blocking agent CTLA4-Ig associated with CsA. We then proceeded to assess the maintenance of an effective immune response towards viral pathogens and tumor cells after CTLA4-Ig/CsA treatment, by measuring the frequency of CTL precursors directed against CMV- and EBV-infected targets, and against autologous leukemic blasts. We demonstrated that (1) CTLA4-Ig and CsA can act synergistically in inducing a state of unresponsiveness to alloantigens; (2) the number of leukemia-reactive, EBV-specific and CMV-specific CTLp is not impaired by CTLA4-Ig/CsA treatment. Our data provide the first direct in vitro evidence that it is possible to preserve antiviral and antileukemia effector cells after blockade of CD28/B7 interaction during MLR. Bone Marrow Transplantation (2001) 27, 1263–1273. [ABSTRACT FROM AUTHOR]

Allogeneic cord blood transplantation (CBT), especially from unrelated donors, is being increasingly used for treating paediatric patients with both malignant and non-malignant disorders. Recent clinical and experimental evidence suggests that human cord blood mononuclear cells (CBMC) may acquire in utero a state of tolerance towards non-inherited maternal antigens (NIMA). In order to better define this phenomenon, we measured, by means of a limiting dilution assay (LDA), the frequency of NIMA-specific CTL precursors (CTLp) in cord blood samples obtained from 13 healthy neonates. The immunophenotype of the effector cells recovered from LDA was also analysed. Data concerning both CTLp frequency and phenotype of effector cells were compared with those obtained stimulating CBMC with cells of paternal origin (NIPA) and adult PBMC with allogeneic targets. Results showed that cytotoxic cells directed towards cells of maternal origin could be detected in all cord blood samples tested. Phenotype analysis demonstrated that NIPA elicit the expansion of CD3+/CD8bright T cells, a phenotype associated with alloreactive CTL. By contrast, NIMA preferentially stimulated the expansion of CD3-/CD8dim+ cells, a phenotype associated with NK cells, which are known to be able, in certain clinical conditions, to kill allogeneic haematopoietic cells without causing GVHD. Thus, our results indicate that, when evaluated in a limiting dilution condition, NIMA-reactive cord blood cells are detectable and a preferential expansion of NK cells is observed. [ABSTRACT FROM AUTHOR]

The frequency of CTL precursors (CTLp) directed towards recipient-derived pre-transplant leukaemic blasts (LB) was measured in the peripheral blood of nine children with acute leukaemia and given BMT from either an HLA-identical sibling or a matched unrelated donor (MUD). Patients were evaluated at various time points between 1 month and more than 2 years after transplantation. A high frequency of donor-derived LB-reactive CTLp was detectable 2–6 months after BMT in all children and persisted for at least up to 18 months in the eight patients in haematological remission, while it rapidly declined in the only patient who relapsed. Generation of LB-reactive T cell clones obtained from some of these patients demonstrates that various T lymphocyte subsets, either HLA class I-restricted/TCR-dependent or HLA-unrestricted, contribute to this phenomenon. The in vitro GVL effect here described seems to be at least partially separated from GVHR, since no correlation was observed between the emergence of LB-reactive CTLp and the development and/or severity of GVHD. Development of LB-reactive CTL in the patients was independent of the frequency of these cells in the donor. These data suggest that donor-derived CTL activity specifically directed towards leukaemic blasts may develop in patients given allogeneic BMT and contribute to the maintenance of a state of haematological remission. [ABSTRACT FROM AUTHOR]

Allogeneic BMT has been reported to be the only curative therapy for children with juvenile autosomal recessive osteopetrosis. We report the case of a 14-month-old child in whom bone resorption was observed after cord blood transplantation (CBT). The patient was given CBT from an unrelated newborn matched for five of six HLA antigens. At the time of transplantation, the child presented with neurological symptoms, with feeding problems and visual impairment. A successful engraftment of donor hematopoiesis was demonstrated and the child experienced grade I acute GVHD. Progressive bone clearing was achieved and a bone marrow trephine demonstrated signs of osteoclast function. Despite full engraftment and bone resorption, neurologic deterioration did not improve. This experience documents that CBT can promote the correction of juvenile osteopetrosis. The shorter time needed both to identify an unrelated donor and to perform the transplant, as well as the lower incidence of GVHD make this procedure more appealing than BMT in children lacking an HLA-compatible relative. [ABSTRACT FROM AUTHOR]

We describe the case of a child affected by acute lymphoblastic leukaemia who received adoptive immunotherapy after cord blood transplantation (CBT). The patient, transplanted in second relapse resistant to chemotherapy, still showed lung and costal leukaemic nodular lesions 2 months after CBT. For this reason, three infusions of donor peripheral blood leukocytes 1 x 10(7)/kg each were administered on days +60, +80 and +100. The procedure was well tolerated by both patient and donor, and a complete disappearance of the lung lesions was documented 2 months after the last infusion. The patient remains in continuous complete haematological remission 13 months after CBT. This experience suggests that adoptive immunotherapy may be safely employed after CBT in order to increase the contribution of immune-mediated anti-leukaemia effect. [ABSTRACT FROM AUTHOR]

This paper reports the results of biological analyses (pigments, diatoms, chrysophyte cysts, cladocerans, chironomids and ostracods) of aca. 14 m-long sediment core recovered from Lake Albano (Central Italy) in the course of the EU-funded project PALICLAS (PALaeoenvironmental analysis of Italian Crater Lake and Adriatic Sediments).A reconstruction of the environmental evolution and ecosystem response of Lake Albano during the last ca. 30 kyr was possible. Additional information on lake level oscillation is obtained from benthic and planktonic palaeocommunities. Several oscillations in the productivity and the level of the lake were detected in the oldest sediment layers (from ca.30 kyr BP to ca. 17 kyr BP), followed by a long (ca. 5 kyr BP) period of low productivity in which cold, holomictic conditions prevailed.A period of high biological activity and, probably, meromictic conditions during the early-mid Holocene was detected. A clear impact of human activities in the catchment was found at ca. 4 kyr BP in the form of increased erosion, associated with a decline in the abundance ofbiological remains. Further signs of human impact on the lake ecosystem are recorded during the Roman period. Although large-scale environmental changes (e.g. regional climate changes) caused many of the observed biological changes, human activities were important during themid-late Holocene. [ABSTRACT FROM AUTHOR]