IntroductionAdult bone marrow stromal cells supply the appropriate scaffold for hematopoiesis 1 and hematopoietic-cell homeostasis, 2 but can also differentiate in vitro in most, if not all, somatic cell types. 3,4 Due to their specific capability of generating multiple mesenchymal lineages, bone marrow-derived stromal progenitors have been designated mesenchymal stem cells (MSCs). 5 MSCs are clonogenic because they can be isolated from bone marrow and expanded ex vivo without any apparent modification in phenotype or loss of function. Based on these features, MSCs are considered a promising strategy for tissue engineering, repair of damaged tissues, and gene therapy, but their capacity to trans-differentiate also in vivo is still unresolved.Recently, another unforeseen feature of MSCs has been reported, namely, that MSCs can modulate many T-cell functions including cell activation. 6,7 Based on this, human MSCs (hMSCs) have been administered in vivo to improve the outcome of allogeneic transplantation by promoting hematopoietic engraftment 8 and to hamper graft-versus-host disease. 9 More recently, we have shown that systemic administration of MSCs to mice affected by experimental autoimmune encephalomyelitis (EAE), a prototypical disease mediated by self-reactive T cells, results in striking disease amelioration mediated by the induction of peripheral tolerance. 10 In addition, it has been shown that tolerance induction by MSCs may occur also through the inhibition of dendritic-cell maturation and function, 11-13 thus suggesting that activated T cells are not the only targets of MSCs. In contrast, the effects of hMSCs on B cells are unknown.B-cell development occurs in the bone marrow and is strictly dependent on close interaction of B-cell progenitors with stromal cells that produce cytokines capable of supporting B-cell survival and proliferation. 14,15 Thus, we investigated whether MSCs, which derive from the marrow stroma, affect mature B-cell functions. Here, we demonstrate that hMSCs significantly affect proliferation, differentiation, and chemotactic behavior of normal mature B cells, thus further supporting the possibility that administration of MSCs may represent a novel therapeutic strategy for immune-mediated disorders. Materials and methodsAliquots of bone marrow aspirates were obtained from healthy adult bone marrow donors and peripheral-blood (PB) samples were obtained from healthy adult blood donors after informed consent was obtained, per the Declaration of Helsinki. The ethical board of the G. Gaslini Institute approved the study. B-cell isolation and cultureMononuclear cells (MNCs) were isolated by Ficoll-Hypaque density gradient (Sigma Chemical, St Louis, MO) from the PB of 9 healthy donors. Cell suspensions were first depleted of lymphocytes forming rosettes with sheep red blood cells (T cells) and subsequently treated with magnetic activated cell sorting (MACS) CD19-conjugated microbeads, according to the instructions of the manufacturer (Miltenyi Biotech, Auburn, CA). (mAb). All cell cul...

The efforts of the expert panel members allowed to set up and share a common approach to the mobilization, enumeration, and collection issues in the field of both autologous and allogeneic peripheral blood SCT.

Although in recent years the use of purine analogues has increased the percentage of long-term complete response the effect on overall survival of patients with hairy cell leukemia (HCL) is not yet clear. This study aimed to evaluate the long-term outcome (mean follow up of 92 months) of 64 patients receiving IFN as first-line therapy. IFN was well tolerated and effective. The overall response rate was 91% (PR 65%, CR 13%, GPR 13%). Forty-one patients (63%) received IFN 3 MU/ wk as maintenance therapy. The 10-yr projected survival rate of responding patients (CR and GPR 100%; PR 95%) and non-responders (SD, PD 80%) clearly shows that type of response does not affect survival. Patients receiving IFN maintenance had a statistically higher PFS than those who did not (p <0.01). This study shows that IFN is still one of the standard therapies for this disease, that achieving CR has no primary relevance for the control of the disease, and that good utilization of therapeutic resources may assure HCL patients a survival rate comparable to that of a normal, healthy population.

Colony formation in agar (CFU-c) was studied in 20 patients with severe aplastic anaemia by three different assays: (1) cultures of light density untreated marrow cells; (2) cultures of marrow cells manipulated in order to enhance colony formation (pretreatment with antilymphocytic globulin, ALG, or 6-methylprednisolone, 6-MPr, T cell depletion, adherent cell (AC) depletion, depletion of both AC and T cells), and (3) co-culture of putative suppressor T cells with autologous T-depleted marrow cells. By the first assay, all patients showed poor colony formation (1 +/- 1.5 colonies/10(5) cells; normal controls 46 +/- 18 colonies/10(5) cells). By the second assay, ALG and 6-MPr had no significant effect on colony formation. Removal of adherent cells proved equally without effect on colony growth. On the contrary, removal of T cells enhanced significantly (P less than 0.001) colony formation in 10 out of 20 patients. By the third assay, colony formation of marrow cells (deprived of T lymphocytes) was inhibited by the addition of autologous T cells in six patients studied. All patients were given high dose bolus 6-MPr as first treatment on admission: only patients who had detectable suppressor T cells in their marrow achieved a complete autologous haematologic reconstitution after 6-MPr or after 6-MPr and ALG. The results of this study indicate the detection of CFU-c/suppressor T cells correlates with responses to immunosuppressive regimens, and may thus help to identify patients with immune mediated aplastic anaemia.

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