The effects of zoledronate on monocyte-derived dendritic cells from melanoma patients differ depending on the clinical stage of the disease.

Zoledronic acid has shown indirect anticancer effects on angiogenesis, the tumor microenvironment and immune responses. Its immunological action is exerted, at least in part, via its modulating properties. The aim of this study was to investigate the in vitro effects of zoledronic acid on the dendritic cells of melanoma patients. Peripheral blood samples were collected from 26 patients with melanoma and 11 healthy donors. Dendritic cells were derived from purified monocytes, and zoledronic acid (ZA) was added on the first day of culture. The phenotype and function of the generated cells were evaluated by flow cytometry. The ZA-treated monocytes from patients with early-stage disease generated DCs characterized by reduced endocytic activity and increased allostimulatory capacity compared with the untreated samples, allowing restoration of the DC function observed in normal subjects. In contrast, the ZA-treated monocytes from patients at stage III generated cells with higher CD14 antigen expression and endocytosis than the untreated samples. Therefore, in melanoma patients, the in vitro ZA effects differ according to the progression of the disease. In addition, our preliminary results appear to suggest that ZA effects are also influenced by the expression of CD14 antigen, indicating that the DC phenotype together with clinical characteristics must be considered in the choice of patients to be treated with ZA. Our work focus on the effect of ZA on monocyte-derived DCs from melanoma patients, showing that the effects of therapeutic doses of this drug might be mediated at least in part by modulation of myeloid cell function

Combined antiretroviral therapy reduces hyperimmunoglobulinemia in HIV-1 infected children

Objective: To evaluate the effect of combined antiretroviral therapy on serum immunoglobulin (Ig) levels in HIV-1 perinatally infected children. Methods: Data from 1250 children recorded by the Italian Register for HIV Infection in Children from 1985 to 2002 were analysed. Since Ig levels physiologically vary with age, differences at different age periods were evaluated as differences in z-scores calculated using means and standard deviations of normal population for each age period. Combined antiretroviral therapy has become widespread in Italy since 1996, thus differences in Ig z-scores between the periods 1985-1995 and 1996-2002 were analysed. Data according to type of therapeutic regimen were also analysed. Results: Between the two periods 1985-1995 and 1996-2002, significant (P < 0.0001) decreases in IgG (6.29 ± 4.72 versus 4.44 ± 4.33), IgM (9.25 ± 13.32 versus 5.61 ± 7.93), and IgA (10.25 ± 15.68 versus 6.48 ± 11.56) z-scores, together with a parallel significant (P < 0.0001) increase in CD4 T-lymphocyte percentages, were found. These decreases were confirmed regardless of whether the children were receiving intravenous Ig or not. Ig z-scores were significantly higher in children receiving mono-therapy than in those receiving double-combined therapy (IgC, P < 0.0001; IgM, P = 0.003; IgA, P = 0.031) and in the latter children than in those receiving three or more drugs (P < 0.0001 for all z-scores). Ig z-scores correlated inversely with CD4 T-lymphocyte percentages and, directly, with viral loads. Conclusions: Our data show that in HIV-1 infected children combined antiretroviral therapy leads to reduction of hyperimmunoglobulinemia which parallels restoration of CD4 T-lymphocyte percentage and viral load decrease, which it turn probably reflects improved B-lymphocyte functions. © 2004 Lippincott Williams & Wilkins

EFFETTI DI CITOCHINE SULLA CRESCITA DI PRECURSORI CELLULARI B UMANI PURIFICATI E IN PRESENZA DI COMPONENTE (CD13+) STROMALE

As reproducible models for examining human early B-cell progenitors (BCPs) are poorly developed, the cells and molecules regulating their growth and differentiation are still incompletely characterized. We used a recently published short term culture system, using immunomagnetic beads and negative selection, in order to isolate an early BCPs enriched population from human fetal tissues that support further studies on B cell proliferation or differentiation events. This purified population was incubated with or without human recombinant Interleukin-4 (rIL4), and its capability to proliferate and differentiate was followed. We found that rIL4 did not induce either proliferation or differentiation of purified human BCPs. Furthermore in the presence of stromal cells (CD13+) it was able to enhance cy mu + cells and to induce the expression of surface Ig (sIg), surface CD22 on in vitro TdT + CD19 + CD10 + sIg-fetal liver cells. Human recombinant interleukin-7 (rIL-7) promoted the proliferation and the clonal growth of Tdt + CD19 + CD10 + fetal BCPs, confirming its critical role at early stages of human B lymphopoiesis. Furthermore rIL7 also induced growth of CFU-GM when unseparated fetal tissues or myeloid/monocytic contaminated BCPs were used as a target populations, probably by indirect mechanism. Transforming growth factor -beta (TGF-beta 1) partially inhibited the stromal cell-dependent rIL4 induced differentiation and rIL7 clonal growth and proliferation of fetal BCPs. Our study contributes to elucidate the growth factor requirements that characterize normal human B-cell ontogeny, suggesting another mechanism for the linkage between lymphopoiesis and myeloid/macrophagic micro-environment. The in vivo implications of this study are discussed

[The hematopoietic stem cell: biology and clinical applications] La cellula staminale emopoietica: biologia e applicazioni cliniche (Editoriale)

The hematopoietic stem cells (HSCs) are defined as cells that are able of both self-renewal and multilineage reconstitution of the hematopoietic system. Their biological properties and, similarly, the gene regulation, the positive and negative factors of the hematopoietic progenitor cells and the models of the hematopoietic amplification in the murine system are described. The clinical relevance of HCS has been obtained by the characterization and function of the CD34 cell surface molecule. The methods of isolation, selection and purification of HCS, the clinical use (particularly the mobilization of peripheral CD34+ cells) are detailed. Finally the potential advantages and use of HCS in vivo expansion are described

Generation of Dendritic Cells: A Critical Comparison of Different Methodological Approaches

Dendritic cells (DCs) represent the most important antigen presenting cells (APCs). In vivo they originate from bone marrow myeloid and lymphoid precursors. In a first stage, the so-called immature DCs stay into nonlymphoid tissues and show high capacity of antigen capture and processing, but low T cell stimulatory capacity. After the internalization of the antigen, in the presence of inflammatory mediators, DCs mature and migrate out of nonlymphoid tissues into the blood or lymph, reaching secondary lymphoid organs. In this second stage the mature DCs lose the ability to capture antigens and increase the capacity to stimulate T cells, controlling the immune responses. Indeed, DCs are a family of heterogeneous cells and each subset exerts control over a different area of immunity, activating innate and acquired systems or maintaining the tolerance to antigens. For in vitro studies, dendritic cells can be isolated directly from peripheral blood through blood dendritic cell antibodies (BDCA), but they have been difficult to obtain due to their low concentration. So a wide variety of methods to have DCs has been performed, including the generation from circling CD14+ monocytes or from CD34+ progenitors. A multitude of systems have been carried out also to obtain these precursor cells

B cell colony assay improves the sensitivity of the cytogenetic analysis in common acute lymphoblastic leukemia.

The recognition and identification of subtle chromosomal changes in leukemic cells has greatly been facilitated since the advent of high-resolution banding techniques. However efficient utilization of these methods is often hampered by the paucity of leukemic cells during clinical remission, the variability of cell cycle length and tissue culture conditions. Therefore the detection of minimal residual disease in acute lymphoblastic leukemia by cytogenetic methods requires a preselection of material to be examined. In this preliminary report analyzable metaphases could be obtained in cultured cells from a colony assay for malignant peripheral B cell progenitors, whereas in marrow samples direct or 24 hours G-banding technique had failed to reveal metaphases in common Acute Lymphoblastic Leukemia patients during complete remission. It is believed that in common Acute lymphoblastic Leukemia patients this B cell colony assay permits the clonal expansion of residual circulating cells linked to malignant clone that are not detectable by classic hematologic and cytologic methods. In addition, this culture procedure substantially improves the sensibility of cytogenetic approach to the study of minimal residual disease in acute lymphoblastic leukemia during complete remission

THYMIC DYSFUNCTION IN CHILDHOOD T-ACUTE LYMPHOBLASTIC-LEUKEMIA - A POSSIBLE LINKAGE WITH A PRIMARY THYMUS INVOLVEMENT

Experimental models, clinical and histopathological observations suggest a thymic origin of childhood T acute lymphoblastic leukemia (T-ALL). We studied thymic epithelial function in childhood T-ALL as compared to normal controls in order to improve our understanding of the cellular immunodeficiency mechanisms operating in a thymus-linked malignant process. The levels of Facteur Thymique Serique (FTS) were measured in 9 patients at diagnosis, according to the rosette inhibition assay of Dardenne & Bach (1975). This method is based on the capacity of human serum containing FTS activity to confer on rosette-forming cells (RFC) from adult thymectomized mice a sensitivity to azathioprine identical to that of normal mouse RFC. All patients presented low age-corrected titres of FTS. No zinc deficiency was found, suggesting that low FTS levels are not related to unexpressed FTS biological activity. Plasma from all the children studied contained factors capable of inhibiting the biological activity of FTS in vitro. However, the nature of this inhibitor has not yet been elucidated. Our study shows the presence of a thymic dysfunction in childhood T-ALL, which could partially explain the immunodeficiency described in these patients. The linkage of the leukemic process with a primitive thymic involvement is discussed