[Show abstract][Hide abstract]ABSTRACT: Blood and Marrow Transplantation (BMT) is a standard curative therapy for patients with non-malignant genetic diseases. Myeloablative conditioning has been associated with significant regimen related toxicity (RRT), while reduced intensity conditioning regimens have been associated with graft failure. In this prospective pilot trial conducted at two-centers between 2006 and 2013, we report the outcome of patients with non-malignant genetic diseases (n=22) who were conditioned with a novel reduced toxicity regimen: intravenous busulfan (16mg/kg), alemtuzumab (52mg/m2), fludarabine (140mg/m2) and cyclophosphamide (105mg/kg). The median age of the study population was 3.5 years (5 months to 26 years). There were no reported cases of sinusoidal obstruction syndrome (SOS), severe or chronic graft-versus-host-disease (GVHD) or primary graft failure. Median (range) time to neutrophil engraftment (>500 cells/μL) and platelet engraftment (>20K cells/microliter) were 19 (12-50) and 23.5 (14-134) days respectively. The median (range) length of follow-up was 3 (0.2- 6.3) years. Overall survival (OS) was 95% at 100 days (95% confidence interval (CI): 0.72-0.99) and 90% (95% CI: 0.68-0.98) at 6 years. RRT and chronic GVHD are significant barriers to BMT for patients with non-malignant genetic diseases. This alemtuzumab-based reduced toxicity regimen appears promising with durable engraftment, effective cure of clinical disease, low rates of regimen related toxicity and no observed chronic GVHD.
No preview · Article · Nov 2014 · Biology of Blood and Marrow Transplantation
[Show abstract][Hide abstract]ABSTRACT: Outcomes have improved for pediatric patients undergoing autologous bone marrow transplantation for refractory or relapsed Hodgkin Lymphoma.•Cyclophosphamide, Carmustine (BCNU), and etoposide (VP-16) is an appropriate therapy for patients <21 years old with relapsed or refractory Hodgkin Lymphoma.•Post-transplantation consolidative radiation therapy may improve outcomes following autologous bone marrow transplantation for relapsed or refractory Hodgkin Lymphoma.•Improved outcomes may be due to factors other than improvements in transplant conditioning regimen.
No preview · Article · Oct 2014 · Biology of Blood and Marrow Transplantation
[Show abstract][Hide abstract]ABSTRACT: Allogeneic hematopoietic stem cell transplantation (HSCT) for patients with a hemoglobinopathy can be curative but is limited by donor availability. While positive results are frequently observed in those with a HLA matched sibling donor, the use of unrelated donors has been complicated by poor engraftment, excessive regimen-related toxicity and graft-versus-host disease (GVHD). As a potential strategy to address these obstacles, a pilot study was designed that incorporated both a reduced intensity conditioning (RIC) and mesenchymal stromal cells (MSCs). Six patients were enrolled including four with high risk Sickle Cell Disease (SCD) and two with transfusion dependent thalassemia major. Conditioning consisted of Fludarabine (150mg/m2), Melphalan (140mg/m2), and Alemtuzumab (60mg for patients weighing >30kg and 0.9mg/kg for patients weighing <30kg). Two patients received a HLA 7/8 allele matched bone marrow and four received 4-5/6 HLA matched umbilical cord blood (UCB) as the source of HSCs. MSCs were of bone marrow origin and derived from a parent in one patient and unrelated third party donor in the remaining five patients. GVHD prophylaxis consisted of cyclosporine A (CSA) and mycophenolate mofetil (MMF). One patient had neutropenic graft failure, two had autologous hematopoietic recovery and three had hematopoietic recovery with complete chimerism. The two SCD patients with autologous hematopoietic recovery are alive. The remaining four died either from opportunistic infection, GVHD, or intracranial hemorrhage. While there was no infusion-related toxicity, the co-transplantation of MSCs was not sufficient for reliable engraftment in patients with advanced hemoglobinopathy. While poor engraftment has been observed in nearly all such trials to date in this patient population, there was no evidence to suggest that MSC had any positive impact on engraftment. Due to lack of improved engraftment and unacceptably high transplant-related mortality, the study was prematurely terminated. Further investigations into understanding the mechanisms of graft resistance and development of strategies to overcome this barrier are needed to move this field forward.
Full-text · Article · Dec 2013 · Biology of blood and marrow transplantation: journal of the American Society for Blood and Marrow Transplantation
[Show abstract][Hide abstract]ABSTRACT: The Primary Immune Deficiency Treatment Consortium (PIDTC) is a network of 33 centers in North America that study the treatment of rare and severe primary immunodeficiency diseases. Current protocols address the natural history of patients treated for severe combined immunodeficiency (SCID), Wiskott-Aldrich syndrome, and chronic granulomatous disease through retrospective, prospective, and cross-sectional studies. The PIDTC additionally seeks to encourage training of junior investigators, establish partnerships with European and other International colleagues, work with patient advocacy groups to promote community awareness, and conduct pilot demonstration projects. Future goals include the conduct of prospective treatment studies to determine optimal therapies for primary immunodeficiency diseases. To date, the PIDTC has funded 2 pilot projects: newborn screening for SCID in Navajo Native Americans and B-cell reconstitution in patients with SCID after hematopoietic stem cell transplantation. Ten junior investigators have received grant awards. The PIDTC Annual Scientific Workshop has brought together consortium members, outside speakers, patient advocacy groups, and young investigators and trainees to report progress of the protocols and discuss common interests and goals, including new scientific developments and future directions of clinical research. Here we report the progress of the PIDTC to date, highlights of the first 2 PIDTC workshops, and consideration of future consortium objectives.
Full-text · Article · Oct 2013 · The Journal of allergy and clinical immunology
[Show abstract][Hide abstract]ABSTRACT: Multi-center evaluations of pediatric patients with juvenile systemic sclerosis (jSSc) have suggested that the pathogenesis of jSSc may differ from that of systemic sclerosis (SSc) in adult patients. Therefore, we undertook to identify abnormalities in the T lymphocytes of jSSc patients and to determine if they differed from the abnormalities reported in the T lymphocytes of adult SSc patients. We identified decreases in the frequency of resting regulatory T lymphocytes and an increased frequency of CD45RA expressing effector memory (EMRA) CD4 T lymphocytes, which were characterized by an increased frequency of CCR7 protein expressing cells. Neither the increases in the EMRA subpopulation nor the increased CCR7 protein expression have been reported in adult SSc patients. The decrease in resting regulatory T lymphocytes in jSSc patients may permit the expansion of the disease initiating CD4 T lymphocytes present in the CCR7 expressing EMRA CD4 T lymphocyte subpopulation.
Full-text · Article · Aug 2013 · Clinical Immunology
[Show abstract][Hide abstract]ABSTRACT: Besides its cooperating effects on stem cell proliferation and survival, Kit ligand (KL) is a potent chemotactic protein. While transwell assays permit studies of the frequency of migrating cells, the lack of direct visualization precludes dynamic chemotaxis studies. In response, we utilize microfluidic chambers that enable direct observation of murine bone marrow-derived mast cells (BMMC) within stable KL gradients. Using this system, individual Kit+ BMMC were quantitatively analyzed for migration speed and directionality during KL-induced chemotaxis. Our results indicated a minimum activating threshold of ∼3 ng ml(-1) for chemoattraction. Analysis of cells at KL concentrations below 3 ng ml(-1) revealed a paradoxical chemorepulsion, which has not been described previously. Unlike chemoattraction, which occurred continuously after an initial time lag, chemorepulsion occurred only during the first 90 minutes of observation. Both chemoattraction and chemorepulsion required the action of G-protein coupled receptors (GPCR), as treatment with pertussis toxin abrogated directed migration. These results differ from previous studies of GPCR-mediated chemotaxis, where chemorepulsion occurred at high ligand concentrations. These data indicate that Kit-mediated chemotaxis is more complex than previously understood, with the involvement of GPCRs in addition to the Kit receptor tyrosine kinase and the presence of both chemoattractive and chemorepellent phases.
No preview · Article · Jul 2013 · Integrative Biology
[Show abstract][Hide abstract]ABSTRACT: Thymic involution during aging is a major cause of decreased production of T cells and reduced immunity. Here we show that inactivation of Rb family genes in young mice prevents thymic involution and results in an enlarged thymus competent for increased production of naive T cells. This phenotype originates from the expansion of functional thymic epithelial cells (TECs). In RB family mutant TECs, increased activity of E2F transcription factors drives increased expression of Foxn1, a central regulator of the thymic epithelium. Increased Foxn1 expression is required for the thymic expansion observed in Rb family mutant mice. Thus, the RB family promotes thymic involution and controls T cell production via a bone marrow-independent mechanism, identifying a novel pathway to target to increase thymic function in patients.
Full-text · Article · May 2013 · Journal of Experimental Medicine
[Show abstract][Hide abstract]ABSTRACT: We conducted a gene therapy trial in 10 patients with adenosine deaminase-deficient severe combined immunodeficiency (ADA-deficient SCID) using two slightly different retroviral vectors for the transduction of patients' bone marrow CD34+ cells. Four subjects were treated without pre-transplant cytoreduction and remained on ADA enzyme replacement therapy (ERT) throughout the procedure. Only transient (months), low level (<0.01%) gene marking was seen in peripheral blood mononuclear cells (PBMC) of two older subjects (15 and 20 years old), whereas some gene marking of PBMC has persisted for the past nine years in two younger subjects (4 and 6 years). Six additional subjects were treated using the same gene transfer protocol, but after withdrawal of ERT and administration of low-dose busulfan (65-90 mg/m(2)). Three of these remain well, off ERT (5, 4, and 3 years post-procedure), with gene marking in PBMC of 1-10%, and ADA enzyme expression in PBMC near or in the normal range. Two subjects were restarted on ERT due to poor gene marking and immune recovery and one had a subsequent allogeneic hematopoietic stem cell transplant. These studies directly demonstrate the importance of providing non-myeloablative pre-transplant conditioning to achieve therapeutic benefits with gene therapy for ADA-deficient SCID.