Expression of p75 chain of IL-2 receptor in the early immunological reconstitution after allogeneic bone marrow transplantation

Microenvironment in neuroblastoma: isolation and characterization of tumor-derived mesenchymal stromal cells

Background

It has been proposed that mesenchymal stromal cells (MSCs) promote tumor progression by interacting with tumor cells and other stroma cells in the complex network of the tumor microenvironment. We characterized MSCs isolated and expanded from tumor tissues of pediatric patients diagnosed with neuroblastomas (NB-MSCs) to define interactions with the tumor microenvironment.

Methods

Specimens were obtained from 7 pediatric patients diagnosed with neuroblastoma (NB). Morphology, immunophenotype, differentiation capacity, proliferative growth, expression of stemness and neural differentiation markers were evaluated. Moreover, the ability of cells to modulate the immune response, i.e. inhibition of phytohemagglutinin (PHA) activated peripheral blood mononuclear cells (PBMCs) and natural killer (NK) cytotoxic function, was examined. Gene expression profiles, known to be related to tumor cell stemness, Wnt pathway activation, epithelial-mesenchymal transition (EMT) and tumor metastasis were also evaluated. Healthy donor bone marrow-derived MSCs (BM-MSC) were employed as controls.

Results

NB-MSCs presented the typical MSC morphology and phenotype. They showed a proliferative capacity superimposable to BM-MSCs. Stemness marker expression (Sox2, Nanog, Oct3/4) was comparable to BM-MSCs. NB-MSC in vitro osteogenic and chondrogenic differentiation was similar to BM-MSCs, but NB-MSCs lacked adipogenic differentiation capacity. NB-MSCs reached senescence phases at a median passage of P7 (range, P5-P13). NB-MSCs exhibited greater immunosuppressive capacity on activated T lymphocytes at a 1:2 (MSC: PBMC) ratio compared with BM-MSCs (p = 0.018). NK cytotoxic activity was not influenced by co-culture, either with BM-MSCs or NB-MSCs. Flow-cytometry cell cycle analysis showed that NB-MSCs had an increased number of cells in the G0-G1 phase compared to BM-MSCs. Transcriptomic profiling results indicated that NB-MSCs were enriched with EMT genes compared to BM-MSCs.

Conclusions

We characterized the biological features, the immunomodulatory capacity and the gene expression profile of NB-MSCs. The NB-MSC gene expression profile and their functional properties suggest a potential role in promoting tumor escape, invasiveness and metastatic traits of NB cancer cells. A better understanding of the complex mechanisms underlying the interactions between NB cells and NB-derived MSCs should shed new light on potential novel therapeutic approaches.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5082-2) contains supplementary material, which is available to authorized users.

Haemophagocytic lymphohistiocytosis: proposal of a diagnostic algorithm based on perforin expression

Haemophagocytic lymphohistiocytosis (HLH) is a rare, fatal disorder of early infancy. Mutations of the PRF1 gene have been identified in a subset of patients. However, the distinction between the different genetically determined and environmental subtypes of the disease remains a major issue to be solved. This may result in delayed or inappropriate application of bone marrow transplantation (BMT). We propose an algorithm that uses a combination of three rapid laboratory tests, i.e. perforin expression by peripheral lymphocytes, assessment of the behaviour of the 2B4 lymphocyte receptor and natural killer (NK) cell activity, to identify the different subgroups of HLH. In 19 patients diagnosed according to current criteria, we tested perforin expression, 2B4 receptor function and NK cell activity. PRF1 mutations were found in all seven patients showing absent perforin expression. In one male with abnormal behaviour of the 2B4 receptor, SH2D1A mutation confirmed the diagnosis of X-linked lymphoproliferative disease. Four patients with normal NK cell activity had evidence of associated infections. Of the seven with impaired NK cell activity, two had a probable genetically determined subtype of HLH and five appeared as sporadic, infection-associated cases. Improving the diagnostic approach may restrict the use of BMT, the only recognized curative treatment, to HLH patients with a documented poor prognosis while patients with milder disorders may be treated less intensively. Our flow chart could also lead to better selection of patients for specific gene analysis.

Immune reconstitution following allogeneic stem cell transplantation in recipients conditioned by low intensity vs myeloablative regimen

We have investigated the immune status of patients with hematologic malignancies treated with a low intensity conditioning in preparation for allogeneic stem cell transplantation. Conditioning consisted of fludarabine, anti-T lymphocyte globulin and low-dose busulfan, followed by infusion of allogeneic blood stem cells. This protocol resulted in rapid engraftment and complete replacement of host with donor hematopoietic cells. Immunological parameters of these patients were compared to those patients who were conditioned by an aggressive myeloablative regimen. Distribution of cell surface markers of lymphocyte subsets from both groups of patients was similar, but different from that of normal control cells. Reduced intensity or non-myeloablative conditioning prior to allogeneic stem cell transplantation (NST), hardly lowered the normal T cell-dependent mitogenic response even during the early period following transplant, while the myeloablative treatments resulted in a suppressed mitogenic reaction and in slow immune recovery. Reactivity of non-MHC restricted cytotoxic T cells was also at a normal level in patients who were treated with NST. We conclude that stem cell engraftment following reduced conditioning may result in early reconstitution of immune responses assessed in vitro. We hypothesize that clinical application of NST may lead to faster development of effective immune responses against residual host-type malignant and abnormal non-malignant hematopoietic cells, although the role of fludarabine on post-transplant infections remains to be investigated in a larger cohort of patients.

Analysis of immune reconstitution in children undergoing cord blood transplantation

OBJECTIVE

The aim of this study was to investigate and compare immune reconstitution in allogeneic cord blood transplantation (CBT) and bone marrow transplantation (BMT) recipients.

MATERIALS AND METHODS

Twenty-three children underwent CBT from either human leukocyte antigen-identical siblings (11 cases) or unrelated donors (12 cases) were enrolled in the study, together with 23 matched children receiving BMT. Patients were analyzed 2-3 and 12-15 months after transplant. Recovery of T-, B-, and NK-lymphocyte subsets, proliferative in vitro response to mitogens, as well as cytotoxic activities, were investigated.

RESULTS

CBT recipients showed a marked increase in the number of B lymphocytes as compared with patients who underwent BMT (p < 0.001). The absolute number of CD3(+) and CD8(+) T cells, as well as the proliferative response to T-cell mitogens, recovered with time after transplantation, irrespective of the source of stem cells used. Recipients of unrelated CBT had a better recovery of CD4(+) T lymphocytes (p < 0.01). Among patients experiencing acute graft-versus-host disease (GVHD), children given CBT had a much greater production of CD4(+) CD45RA(+) T cells than BMT recipients (p < 0.005). Recovery of NK cell number and innate cytotoxic activities was fast, irrespective of the source of stem cells used.

CONCLUSIONS

Despite the much lower number of lymphocytes transferred with the graft, recovery of lymphocyte number and function toward normal in CBT recipients was rapid and comparable to that observed after transplantation of bone marrow progenitors. This prompt immune recovery possibly was favored by the reduced incidence and severity of GVHD observed in children who underwent CBT.

Unrelated peripheral blood stem cell transplantation with 'megadoses' of purified CD34+ cells in three children with refractory severe aplastic anemia

Three children with refractory severe aplastic anemia were transfused with high numbers of unrelated matched (n = 2) or C-locus haploidentical mismatched (n = 1) CD34-selected peripheral blood stem cells in the absence of an HLA-identical family donor. Two leukaphereses of the donors yielded a median number of 10.1 x 10(10) nucleated cells (range 9.7-15.4) with a median number of 9.89 x 10(8) CD34+ cells (range 7.46-26.1) and a median percentage of CD34+cells of 0.98% (range 0.77-1.7). After positive selection by magnetic cell sorting the patients received a median of 14.3 x 10(6) CD34+ cells/kg (range 11.7-24.3) and of 1.3 x 10(4) CD3+ cells/kg (range 0.57-5.8). Median time to ANC >/=0.5 x 10(9)/l was 7 days (range 7-12) and to platelets >/=20 x 10(9)/l 13 days (range 13-27). Chimerism analysis of peripheral blood after transplantation revealed permanent 100% donor hematopoiesis in all patients. The patient with the C-locus haploidentical mismatch presented with acute GVHD (grade III-IV) of the skin, liver and lower gastrointestinal tract (onset day +40) and died despite intensive immunosuppressive treatment on day +238. The two survivors developed lymphopoietic recovery of B and T lymphocytes within 3 months after transplantation. To our knowledge this experience represents the first report of transplantation with unrelated CD34+ enriched peripheral blood stem cell in children with refractory severe aplastic anemia. Bone Marrow Transplantation (2000) 25, 513-517.