Successful treatment with T depleted autologous peripheral blood stem cell transplantation of refractory chronic autoimmune thrombocytopenic purpura

Autoimmune thrombocytopenia (AITP) is a disorder due to specific platelet auto-antibodies directed against platelet surface glycoproteins. AITP in adults is usually chronic, idiopathic and frequently refractory to conventional treatments. Myelo- and immuno- suppressive chemotherapy followed by autologous peripheral blood stem cell (PBSC) transplantation is an experimental approach for severe chronic refractory AITP. We report a case of a woman with AITP, refractory to the conventional therapy, submitted to T-cell-depleted autologous PBSC transplantation, which obtained long term stable response on platelet count. We deem that the positive outcome of our patient depends on T-cells depletion of the graft, which reduces autoreactive T clones

Role of α1 Acid Glycoprotein in the In Vivo Resistance of Human BCR-ABL+ Leukemic Cells to the Abl Inhibitor STI571

Background: Chronic myeloid leukemia is caused by a chromosomal translocation that results in an oncogenic fusion protein, Bcr-Abl. Bcr-Abl is a tyrosine kinase whose activity is inhibited by the antineoplastic drug STI571. This drug can cure mice given an injection of human leukemic cells, but treatment ultimately fails in animals that have large tumors when treatment is initiated. We created a mouse model to explore the mechanism of resistance in vivo. Methods: Nude mice were injected with KU812 Bcr-Abl+ human leukemic cells. After 1 day (no evident tumors), 8 days, or 15 days (tumors >1 g), mice were treated with STI571 (160 mg/kg every 8 hours). Cells recovered from relapsing animals were used for in vitro experiments. Statistical tests were two-sided. Results: Tumors regressed initially in all STI571-treated mice, but all mice treated 15 days after injection of tumor cells eventually relapsed. Relapsed animals did not respond to further STI571 treatment, and their Bcr-Abl kinase activity in vivo was not inhibited by STI571, despite high plasma concentrations of the drug. However, tumor cells from resistant animals were sensitive to STI571 in vitro, suggesting that a molecule in the plasma of relapsed animals may inactivate the drug. The plasma protein α1 acid glycoprotein (AGP) bound STI571 at physiologic concentrations in vitro and blocked the ability of STI571 to inhibit Bcr-Abl kinase activity in a dose-dependent manner. Plasma AGP concentrations were strongly associated with tumor load. Erythromycin competed with STI571 for AGP binding. When animals bearing large tumors were treated with STI571 alone or with a combination of STI571 and erythromycin, greater tumor reductions and better long-term tumor-free survival (10 of 12 versus one of 13 at day 180; P<.001) were observed after the combination treatment. Conclusion: AGP in the plasma of relapsed animals binds to STI571, preventing this compound from inhibiting the Bcr/Abl tyrosine kinase. Molecules such as erythromycin that compete with STI571 for binding to AGP may enhance the therapeutic potential of this dru

IRON CHELATION THERAPY WITH DEFERASIROX IN THE MANAGEMENT OF IRON OVERLOAD IN PRIMARY MYELOFIBROSIS

Deferasirox (DSX) is the principal option currently available for iron-chelation-therapy (ICT), principally in the management of myelodysplastic syndromes (MDS), while in primary myelofibrosis (PMF) the expertise is limited. We analyzed our experience in 10 PMF with transfusion-dependent anemia, treated with DSX from September 2010 to December 2013. The median dose tolerated of DSX was 750 mg/day (10 mg/kg/day), with 3 transient interruption of treatment for drug-related adverse events (AEs) and 3 definitive discontinuation for grade 3/4 AEs. According to IWG 2006 criteria, erythroid responses with DSX were observed in 4/10 patients (40%), 2 of them (20%) obtaining transfusion independence. Absolute changes in median serum ferritin levels (Delta ferritin) were greater in hematologic responder (HR) compared with non-responder (NR)  patients, already at 6 months of ICT respect to baseline. Our preliminary data open new insights regarding the benefit of ICT not only in MDS, but also in PMF with the possibility to obtain an erythroid response, overall in 40 % of patients. HR patients receiving DSX seem to have a better survival and a lower incidence of leukemic transformation (PMF-BP). Delta ferritin evaluation at 6 months could represent a significant predictor for a different survival and PMF-BP.  However, the tolerability of the drug seems to be lower compared to MDS, both in terms of lower median tolerated dose and for higher frequency of discontinuation for AEs. The biological mechanism of action of DSX in chronic myeloproliferative setting through an independent NF-κB inhibition could be involved, but further investigations are required

GOOD OUTCOME FOR VERY HIGH RISK ADULT B-CELL ACUTE LYMPHOBLASTIC LEUKAEMIA CARRYING GENETIC ABNORMALITIES t(4;11)(q21;q23) or t(9;22)(q34;q11), IF PROMPTLY SUBMITTED TO ALLOGENEIC TRANSPLANTATION, AFTER OBTAINING A GOOD MOLECULAR REMISSION.

Background and Objectives: Acute lymphoblastic leukaemia (ALL) carrying t(9;22) or t(4;11) genetic abnormalities represents a very high risk subtype of disease (VHR-ALL). Hematopoietic stem cell transplantation (HSCT) still remains the only curative option also in the Imatinib era. In the last years low molecular level of minimal residual disease (MRD) before HSCT was reported as one of the best favourable indexes for survival in ALL. Here we observed that even these patients can show a favourable outcome, if submitted to HSCT with very low MRD. Methods: We considered 18 consecutive VHR-ALL patients eligible to HSCT. 16 of them were transplanted upon first remission, as soon as possible, employing myelo-ablative conditioning regimens. Molecular MRD has been evaluated before and after HSCT.Results: Immediately before HSCT MRD revealed: complete molecular remission (MRDneg) for 5 patients and a level <1x10-3 for 7 patients; 100 days after HSCT we had: MRDneg for 7 patients and a decrease for all the others after HSCT. After tapering of immunosuppressive drugs, 13 patients reached the MRDneg in a median time of 8 months (range 3-16); Based on intention to treat analysis: 14/18 patients are alive and disease free at the time of analysis, overall survival and event free survival is of 78% and 66% respectively, with an average follow-up of 45 months (range 6-84) since HSCT. Conclusion: Early transplantation with low MRD level seems to be correlated with a favourable outcome also in VHR-AL

Influence of Donor and Recipient Gender on Telomere Maintenanceafter Umbilical Cord Blood Cell Transplantation: A Study by the GruppoItaliano Trapianto Di Midollo Osseo

Physiological loss of telomerase activity in adult life determines progressive telomere length (TL) shortening. Inflammation and oxidative damage are established causes of TL loss; moreover, males have shorter telomeres compared to females. Despite these notions, mechanisms regulating TL maintenance are poorly defined. As umbilical cord blood (UCB) cells harbor very long telomeres, not yet exposed to environmental damages, UCB transplantation (UCB-T) provides a unique experimental setting to study determinants of TL in humans. TL dynamics was analyzed on peripheral blood mononucleated cells (MNCs) from 36 patients (median age: 42 yrs.) undergoing UCB-T. TL was studied at a median of 20 months since UCB-T. A significantly longer TL (mean 8,698 bp, range 6521-11960) was documented in UCB-T recipients compared to age-matched healthy controls (mean 7,396 bp, range 4,375-11,108) (p<0.01). Among variables potentially influencing TL maintenance, including recipient features, graft type, transplant procedure, and engraftment kinetics, only donor/recipient gender combination was associated to TL, with longest TL in females receiving a male UCB (mean 10,063 bp, range 8,381-11,960). To further investigate this trend, telomerase activation was assessed in vitro. Experiments showed that telomerase subunits were preferentially up-regulated in male-derived bone marrow MNCs exposed ex-vivo to estradiol as compared to female MNCs. This implies an increased sensitivity of male-derived MNCs to telomerase activation induced by estradiol. The results suggest that extrinsic and modifiable factors such as hormonal status and female milieu could be major determinants of TL in humans providing the rationale for investigating hormonal-based approaches to counteract telomere erosion and aging-related diseases