Daniela Longoni

IL-10 prevents the differentiation of monocytes to dendritic cells but promotes their maturation to macrophages.

Human monocytes cultured with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and IL‐13 for 7 days differentiate into cells with the morphology and function of dendritic cells (DC). We have investigated the effect of IL‐10 on this differentiation pathway. In the presence of IL‐10 cells did not develop DC morphology, did not express CD1a and had lower levels of MHC class II. IL‐10 promoted the differentiation of large cells with the morphology, cytochemistry and membrane phenotype of macrophages, including staining for nonspecific esterase and high levels of CD14, CD16 and CD68. The effect of IL‐10 was dose dependent and was best appreciated when the cytokine was added at the initiation of the culture, as addition on day 3 was less inhibitory. When added to already differentiated DC on day 6, IL‐10 caused only a modest reduction of MHC class II and CD1a expression, and no acquisition of the macrophage markers CD14, CD16 and CD68. Prolonged incubation up to 5 days with IL‐10 did not induce a shift of differentiated DC to macrophages. On the other hand, the macrophages obtained by culturing for 7 days with GM‐CSF+IL‐13+IL‐10 did not shift to DC upon removal of IL‐10 for up to 3 days. Thus, the effect of IL‐10 on monocyte differentiation, occurs only at the precursor level and confers an irreversible phenotype. From a functional point of view, cells cultured in the presence of IL‐10 were poor stimulators of allogeneic cord blood T cells in mixed lymphocyte reaction (MLR) and presented tetanus toxin (TT) to specific T cell lines with much less efficiency than control DC. In contrast, IL‐10‐cultured DC showed 7 times greater endocytosis of FITC‐dextran. This increased endocytosis was mostly mediated via the mannose receptor, as demonstrated by blocking with unlabeled mannose. In conclusion, IL‐10 inhibits DC differentiation from monocytes and, in a substantial proportion of the cells, promotes the differentiation to mature macrophages. Intriguingly, IL‐10 inhibits antigen presentation while it stimulates endocytic activity.

Interleukin-17-Producing T-Helper Cells as New Potential Player Mediating Graft-Versus-Host Disease in Patients Undergoing Allogeneic Stem-Cell Transplantation

Objectives. Graft-versus-host disease (GVHD) is a major obstacle to safe allogeneic hematopoietic stem-cell transplantation, leading to significant mortality. Recently, T-helper (TH)-17 cells have been shown to play a central role in mediating several autoimmune diseases. The aim of our study was to investigate the relationship between TH-17 cells and GVHD occurring in transplanted patients. Methods. Blood samples were collected from 51 hematopoietic stem-cell transplantation patients and 15 healthy donors. Patients with GVHD were monitored for the presence of TH-17 cells by ELISPOT or flow cytometry in the peripheral blood and by confocal microscopy in GVHD lesions. Cytokine plasma levels were detected by ELISA. Results. An increased TH-17 population (up to 4.8% of peripheral blood CD4+T lymphocytes) was observed in patients with acute GVHD and (up to 2.4%) in patients with active chronic GVHD along with an inflammatory process. In contrast, the percentage of TH-17 cells drastically decreased in patients with inactive chronic GVHD. TH-17 cells consisted of both interleukin (IL)-17+/interferon (IFN)-&ggr;− and IL-17+/IFN-&ggr;+ subsets and expressed IL-23 receptor. Interestingly, IFN-&ggr;+TH-17 cells were able to infiltrate GVHD lesions as observed in liver and skin sections. Moreover, the proportion of TH-17 was inversely correlated with the proportion of regulatory T cells observed in the peripheral blood and tissues affected by GVHD. Finally, we demonstrated a strong correlation between TH-17 levels and the clinical status of patients with GVHD. Conclusions. These findings support the hypothesis that TH-17 are involved in the active phases of GVHD and may represent a novel cellular target for developing new strategies for GVHD treatment.

Treatment of Graft versus Host Disease with Mesenchymal Stromal Cells: A Phase I Study on 40 Adult and Pediatric Patients

This phase I multicenter study was aimed at assessing the feasibility and safety of intravenous administration of third party bone marrow-derived mesenchymal stromal cells (MSC) expanded in platelet lysate in 40 patients (15 children and 25 adults), experiencing steroid-resistant grade II to IV graft-versus-host disease (GVHD). Patients received a median of 3 MSC infusions after having failed conventional immunosuppressive therapy. A median cell dose of 1.5 × 10(6)/kg per infusion was administered. No acute toxicity was reported. Overall, 86 adverse events and serious adverse events were reported in the study, most of which (72.1%) were of infectious nature. Overall response rate, measured at 28 days after the last MSC injection, was 67.5%, with 27.5% complete response. The latter was significantly more frequent in patients exhibiting grade II GVHD as compared with higher grades (61.5% versus 11.1%, P = .002) and was borderline significant in children as compared with adults (46.7 versus 16.0%, P = .065). Overall survival at 1 and 2 years from the first MSC administration was 50.0% and 38.6%, with a median survival time of 1.1 years. In conclusion, MSC can be safely administered on top of conventional immunosuppression for steroid resistant GVHD treatment. Eudract Number 2008-007869-23, NCT01764100.

Risk factors and severe outcome in thrombotic microangiopathy after allogeneic hematopoietic stem cell transplantation

Background. Thrombotic microangiopathy (TMA) has been described as severe complication after hematopoietic stem cell transplantation (HSCT). The principal aim of this study was to focus the incidence and the outcome of TMA in the era of more complex HSCTs. Methods. We analyzed the role of some predicting factors for the incidence and the outcome of TMA after HSCT. We enrolled 539 consecutive patients (307 males, median age 31 years) undergoing HSCT from match or mismatch human leukocyte antigen family donor (314) or match/mismatch unrelated (195) and haploidentical donor (30) for malignant or nonmalignant diseases. TMA diagnosis was performed by homogeneous clinical and laboratory criteria. Results. Sixty-four of 539 patients presented TMA (11,87%) and the five-year cumulative incidence of TMA was 14% (HR=0.13). Fifty nine of 64 patients were affected by malignant and 5/64 by non-malignant diseases. On multivariate analysis, TMA occurrence was influenced by graft versus host disease >grade II (P=0.0001), donor type (P=0.029), gender (P=0.0233), total body irradiation based conditioning regimen (P=0.0041). Three factors for TMA outcome proved to be statistically significant by multivariate analysis: age (P=0.009), donor type (P=0.0187) and TMA index (P=0.029). The TMA mortality rate was 50%. The outcome was influenced by defibrotide (P=0.02 in univariate analysis). Conclusions. The study underlines the possibility of finding out which patients are more prone to developing post-HSCT TMA, and identifies which risk factors are more frequently associated with a dismal outcome after TMA.

Cyclosporin A response and dependence in children with acquired aplastic anaemia: a multicentre retrospective study with long-term observation follow-up.

Immunosuppressive therapy (IST) with antithymocyte globulin and cyclosporin A (CyA) is the standard treatment for children with acquired aplastic anaemia (AAA) lacking a matched donor. Survival rates of more than 80% at 5 years are achieved, but the response is drug‐dependent in 15–25% of cases. This study, of 42 consecutive children with AAA treated with IST, assessed the incidence of CyA‐dependence, CyA and granulocyte colony‐stimulating factor (G‐CSF) tapering schedules and the impact of drug accumulation on progression to myelodysplasia/acute myeloid leukaemia (MDS/AML). Overall survival was 83% at 10 years. CyA‐dependence without a predictive marker was observed in 18% of responders. Probability of discontinuing CyA was 60·5% at 10 years; a slow CyA tapering schedule was performed in 84% of patients; the cumulative incidence of relapse was 16% at 10 years. Relapse risk was significantly associated with rapid CyA discontinuation: 60% compared to 7·6% in the slow tapering group (P = 0·001). Cumulative incidence of MDS/AML was 8% at 10 years, with a significant correlation with both G‐CSF cumulative dose and second IST. This long‐term follow‐up of children with AAA shows that IST with a slow CyA tapering course is an effective treatment with a low‐relapse rate in these cases.

Diamond-Blackfan anemia: genotype-phenotype correlations in Italian patients with RPL5 and RPL11 mutations

Background Diamond-Blackfan anemia is a rare, pure red blood cell aplasia of childhood due to an intrinsic defect in erythropoietic progenitors. About 40% of patients display various malformations. Anemia is corrected by steroid treatment in more than 50% of cases; non-responders need chronic transfusions or stem cell transplantation. Defects in the RPS19 gene, encoding the ribosomal protein S19, are the main known cause of Diamond-Blackfan anemia and account for more than 25% of cases. Mutations in RPS24, RPS17, and RPL35A described in a minority of patients show that Diamond-Blackfan anemia is a disorder of ribosome biogenesis. Two new genes (RPL5, RPL11), encoding for ribosomal proteins of the large subunit, have been reported to be involved in a considerable percentage of patients. Design and Methods In this genotype-phenotype analysis we screened the coding sequence and intron-exon boundaries of RPS14, RPS16, RPS24, RPL5, RPL11, and RPL35A in 92 Italian patients with Diamond-Blackfan anemia who were negative for RPS19 mutations. Results About 20% of the patients screened had mutations in RPL5 or RPL11, and only 1.6% in RPS24. All but three mutations that we report here are new mutations. No mutations were found in RPS14, RPS16, or RPL35A. Remarkably, we observed a higher percentage of somatic malformations in patients with RPL5 and RPL11 mutations. A close association was evident between RPL5 mutations and craniofacial malformations, and between hand malformations and RPL11 mutations. Conclusions Mutations in four ribosomal proteins account for around 50% of all cases of Diamond-Blackfan anemia in Italian patients. Genotype-phenotype data suggest that mutation screening should begin with RPL5 and RPL11 in patients with Diamond-Blackfan anemia with malformations.

Human monocyte-derived and CD34+ cell-derived dendritic cells express functional receptors for platelet activating factor.

Dendritic cells (DC) are a heterogeneous population of specialized antigen presenting cells that exhibit complex trafficking properties. DC differentiated in vitro from both peripheral monocytes and CD34+ cells expressed mRNA for platelet activating factor (PAF) receptor. Expression of PAF receptor was increased by TNFα, a prototypic inflammatory cytokine that induces differentiation and in vivo mobilization of DC. PAF induced in vitro directional migration of DC obtained from both precursor cells through its specific receptor. Since DC are highly motile cells, protein chemoattractants as well as bioactive phospholipids are likely to contribute to tissue localization of DC, in vivo.

The outcome of children with Fanconi anemia given hematopoietic stem cell transplantation and the influence of fludarabine in the conditioning regimen: a report from the Italian pediatric group

Background and Objectives Hematopoietic stem cell transplantation (HSCT) still represents the only treatment potentially able to prevent/rescue the development of marrow failure and myeloid malignancies in patients with Fanconi anemia (FA). While in the past HSCT from an HLA-identical sibling was proven to cure many patients, a higher incidence of treatment failure has been reported in recipients of an unrelated donor (UD) or HLA-partially matched related allograft. Design and Methods We analyzed the outcome of 64 FA patients (age range, 2–20 years) who underwent HSCT between January 1989 and December 2005. Patients were transplanted from either an HLA-identical sibling (n=31), an UD (n=26), or an HLA-partially matched relative (n=7). T-cell depletion of the graft was performed in patients transplanted from an HLA-disparate relative. Results The 8-year estimate of overall survival (OS) for the whole cohort was 67%; it was 87%, 40% and 69% when the donor was an HLA-identical sibling, an UD and a mismatched relative, respectively (p<0.01). The outcome of recipients of grafts from an UD improved over time, the probability of survival being 10% and 72% for patients transplanted before and after 1998, respectively (p<0.05). The OS probability of children who did or did not receive fludarabine in preparation for the allograft was 86% and 59%, respectively (p<0.05). Interpretation and Conclusions These data, useful for counselling, provide support to the concept that a relevant proportion of FA patients undergoing HSCT can now be successfully cured, even in the absence of an HLA-identical sibling, especially if the conditioning regimen includes fludarabine.

Homozygosis for (12) CA repeats in the first intron of the human IFN‐γ gene is significantly associated with the risk of aplastic anaemia in Caucasian population

Interferon‐γ (IFN‐γ) mediates the final damage of the stem cell compartment in Aplastic Anaemia (AA). Normal subjects homozygous for 12 (CA) repeats of polymorphism variable number of dinucleotide (CA) repeat (VNDR) in position 1349 of the IFN‐γ gene (IFNG) were shown to overproduce IFN‐γin vitro. We studied the distribution of polymorphism VNDR 1349 of IFNG in 67 Caucasian AA patients and in normal controls. Genotype (CA)12‐12, (homozygosis for allele 2) and the single allele 12 were significantly more frequent (P = 0·005 and 0·004 respectively) in patients versus controls. The polymorphism was equally distributed in AA patients regardless of their response to immunosuppression. Homozygosity for 12 (CA) repeats of polymorphism VNDR 1349 of IFNG is strongly associated with the risk of AA in Caucasian subjects.

Mesenchymal stromal cells for the treatment of graft-versus-host disease: understanding the in vivo biological effect through patient immune monitoring

Mesenchymal stromal cells for the treatment of graft-versus-host disease: understanding the in vivo biological effect through patient immune monitoring