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Background: Gene therapy (GT) with hematopoietic stem cells is a promising treatment for inherited immunodeficiencies. Objectives: Limited information is available on the relative contribution of de novo thymopoiesis and peripheral expansion to T-cell reconstitution after GT as well as on the potential effects of gene transfer on hematopoietic stem cells and lymphocyte replicative lifespan. We studied these issues in patients affected by adenosine deaminase severe combined immune deficiency after low-intensity conditioning and reinfusion of retrovirally transduced autologous CD34+ cells. Methods: Immunophenotype, proliferative status, telomere length, and T-cell receptor excision circles were investigated at early and late time points (up to 9 years) after GT treatment. Control groups consisted of pediatric healthy donors and patients undergoing allogeneic bone marrow transplantation (BMT). Results: We observed no telomere shortening in the bone marrow compartment and in granulocytes, whereas peripheral blood naive T cells from both GT and BMT patients showed a significant reduction in telomere length compared with healthy controls. This was in agreement with the presence of a high fraction of actively cycling naive and memory T cells and lower T-cell receptor excision circles. Conclusion: These data indicate that T-cell homeostatic expansion contributes substantially to immune reconstitution, like BMT, and is not associated with senescence in the stem cell compartment. [ABSTRACT FROM AUTHOR]

Abstract: The failure of allogeneic stem cell transplant (allo-SCT) is cumbersome. We analyzed our experience in a second allo-SCT. Between the years 1981 and 2007, 144 patients underwent 2 or more allo-SCT. The first to second transplant interval ranged from 18 days to 13.25 years (median 98 days). The most frequent indications for the second SCT were activity of the basic disease (78), rejection (37), and engraftment failure (25). Twenty-nine of the 144 (20%) patients transplanted survived more then a year with treatment-related mortality of 45.5% as the leading cause of death. Interestingly, despite the low rate of graft-versus-host disease (GVHD) prophylaxis used, only 51 and 16 of the patients developed acute and chronic GVHD (aGVHD, cGVHD), respectively. Factors indicating higher likelihood for survival were nonmalignant disease, a nonrelapse indication for the second SCT, full HLA-matching, and the use of reduced-intensity conditioning (RIC). Age at transplantation, time interval between transplants, the development of GVHD, conditioning regimen, GVHD prophylaxis, or graft source were not shown to influence the prognosis. With a median follow-up of 4.5 years, 25 patients (17.2%) are alive, and 18 are disease-free. We conclude that although toxic, a second allo-SCT can lead to long-term survival. [Copyright &y& Elsevier]

Abstract: The effect of ABO-incompatibility on transplantation outcome remains a controversial issue, with many of the reported studies showing conflicting results. In this study, we evaluate: the association between ABO-incompatibility and myeloid engraftment; the incidence and severity of acute and chronic graft-versus-host disease (GVHD); non-relapse mortality (NRM); GVHD-associated mortality, relapse and overall survival (OS). Our study includes 221 patients with malignant diseases treated in the same institution with the same reduced intensity regimen. Other variables known to affect the transplantation outcome such as age, disease, disease risk, and donor characteristics were well-balanced between ABO-matched and ABO-mismatched transplants. Analysis of our data shows increased incidence of NRM during the first months after transplantation in the groups of patients with major and minor ABO-incompatibility. Although neither incidence nor severity of GVHD differed significantly among the different groups, we found increased mortality associated with GVHD in the major ABO-incompatible groups. Long-term OS and relapse rate were not different, although we observed a trend for decreased OS during the first year post transplantation in the group of patients with major ABO-incompatibility. Our study showed that ABO-incompatibility has an adverse impact on the transplantation outcome. [Copyright &y& Elsevier]

Background: Hepatic grafr-versus-host disease (GVHD) is associated with significant morbidity and mortality. Standard therapy includes systemically administered immunosuppressive drugs. More recent reports have described catheter-directed intrahepatic arterial (IHA) delivery of low-dose methotrexate (MTX) and methylprednisolone in the treatment of corticosteroid-resistant severe hepatic GVHD.Objective: This article reports on MTX toxicity and the variability in plasma drug concentrations after IHA administration of low-dose MTX in patients with severe hepatic GVHD.Methods: In this open-label, uncontrolled pilot study, MTX and methylprednisolone were administered via the hepatic artery in patients with corticosteroid-resistant grade III or IV GVHD of the liver. Patients also received standard therapy. MTX concentrations were measured in the hepatic artery 5 and 10 minutes after injection and in peripheral venous blood at 1, 2, and 24 hours.Results: Six patients (5 males [83.3%], I female [16.7%]; median age, 32 years; range, 8–42 years) were enrolled in the study. No hepatotoxicity was observed after IHA administration of MTX. In 5 patients with normal renal function, plasma drug concentrations 24 hours after administration of MTX ranged from 0.01 to 0.12 μmol/L (mean [SD], 0.043 [0.042] μmol/L). In 1 patient with renal failure, plasma MTX concentrations were 1.0 μmol/L 24 hours after administration and 0.07 μmol/L 5 days after administration. The severe hematologic and renal toxicity observed in this patient may have contributed to his death. Adverse events in patients with GVHD and normal renal function, who had normal plasma MTX concentrations, were comparable to those that have been reported after administration of an intravenous infusion.Conclusions: In patients with GVHD and normal renal function, IHA administration of low-dose MTX was not associated with liver or bone marrow toxicity. Further study is needed to determine the optimal protocols for treating corticosteroid-resistant hepatic GVHD. [Copyright &y& Elsevier]