Allogeneic Donor Stem Cells Research Articles

N-803, an IL-15 Superagonist Complex as Maintenance Therapy After Allogeneic Donor Stem Cell Transplant for Acute Myeloid Leukemia or Myelodysplastic Syndrome; A Phase 2 Trial

Maintenance therapy may improve natural killer (NK) cell surveillance after allogeneic donor hematopoietic cell transplant (HCT) for myeloid malignancies and represents a potential approach to improve cure rates. Interleukin-15 (IL-15) enhances lymphocyte proliferation and antitumor activity. In a prior Phase 1 study of an IL-15 superagonist (N-803) in patients with AML who relapsed after HCT, we observed in vivo expansion of NK cells and antitumor responses. The primary objective of this Phase 2 trial was to determine if post-transplant N-803 could reduce relapse. We administered N-803 (n = 20) (dosed 6 mcg/kg subcutaneously [SQ] at day 60 after HCT to patients with myelodysplastic syndrome [MDS] or acute myeloid leukemia [AML] who were in complete remission [CR]). N-803 treatment was planned weekly, biweekly or every 4 weeks in 2 sequential cohorts. The most common adverse events after administration were self-limited injection sites skin rashes (n = 20). One week after an N-803 dose, we observed enhanced NK cell proliferation and improved antitumor cytotoxicity without inducing immune exhaustion. Five patients who developed acute graft versus host disease (aGVHD) after N-803 responded promptly to steroids and 4 patients developed chronic GVHD. Patients receiving >4 doses of N-803 had a 3-fold decrease in relapse at two years (P = .06). These findings support the safety, immune activation, and potential efficacy of N-803 to prevent relapse of AML/MDS after HSCT.

Cryopreservation of Growth Factor-Mobilized Peripheral Blood Stem Cells Does Not Compromise Major Outcomes after Allogeneic Hematopoietic Cell Transplantation: A Single-Center Experience

During the COVID-19 pandemic, cryopreservation of allogeneic donor stem cell products ensured availability of products at the start of conditioning for hematopoietic cell transplantation (HCT). Following recommendations from unrelated donor registries, including the National Marrow Donor Program (NMDP), many centers started to cryopreserve related donor peripheral blood stem cell (PBSC) products. Throughout the process, several centers have published outcomes with cryopreserved versus fresh products, some with conflicting results. Even though cryopreservation was initially considered only a temporary measure driven by the pandemic, potential advantages include greater flexibility of transplant timing. However, concern about detrimental effects of cryopreservation including increased risks of graft rejection, relapse and consequently mortality remained. The primary objective was to describe our center's experience comparing outcomes following PBSC transplantation with cryopreserved versus fresh grafts. This was an observational case study with retrospective review comparing cryopreserved grafts (N=213), to a recent historical cohort (controls) using fresh grafts (N=167). In multivariable analyses, the adjusted hazard ratio (fresh vs. cryo) we for overall mortality was HR= 1.20 (95% confidence interval (CI), 0.79-1.82; p=0.40), for non-relapse mortality HR=0.99 (95% CI, 0.55-1.77; p=0.98), and for relapse HR=0.94 (95% CI, 0.60 -1.48; p=0.80). The adjusted hazard ratio for platelet engraftment was HR=1.31 (95% CI, 1.05-1.63; p=.02) and the odds ratio of grades III-IV acute GVHD was OR=1.75 (95% CI 1.01-3.04; p=.05) with fresh compared to cryopreserved grafts. There was no demonstrable difference in the risk of chronic GHVD. Although longer-term follow-up is needed, these data provide preliminary reassurance that in the event of another pandemic or should the logistical need arise in individual patients, cryopreservation of PBSC products constitutes a reasonably safe alternative.

Donor-derived spermatogenesis following stem cell transplantation in sterile NANOS2 knockout males

Spermatogonial stem cell transplantation (SSCT) is an experimental technique for transfer of germline between donor and recipient males that could be used as a tool for biomedical research, preservation of endangered species, and dissemination of desirable genetics in food animal populations. To fully realize these potentials, recipient males must be devoid of endogenous germline but possess normal testicular architecture and somatic cell function capable of supporting allogeneic donor stem cell engraftment and regeneration of spermatogenesis. Here we show that male mice, pigs, goats, and cattle harboring knockout alleles of the NANOS2 gene generated by CRISPR-Cas9 editing have testes that are germline ablated but otherwise structurally normal. In adult pigs and goats, SSCT with allogeneic donor stem cells led to sustained donor-derived spermatogenesis. With prepubertal mice, allogeneic SSCT resulted in attainment of natural fertility. Collectively, these advancements represent a major step toward realizing the enormous potential of surrogate sires as a tool for dissemination and regeneration of germplasm in all mammalian species.

Long-Term Safety and Efficacy of Autologous or Allogeneic Donor Stem Cell Transplantation in Patients with Behçet's Syndrome

Background. Behçet's disease (BD) or syndrome is a rare chronic multisystem inflammatory condition with most manifestations attributed to vasculitis, including ulceration, skin lesions, with joint and other organ involvement. The poorest prognosis is reported in a small subgroup of BD patients with vascular, neurological, ocular, and gastrointestinal (GI) manifestations. The main aims of treatment are to suppress inflammatory exacerbations and recurrences, to prevent irreversible organ damage.1 There are few trial data supporting treatment options because of disease rarity and clinical heterogeneity. There are no previous or current clinical trials of hematopoietic stem cell transplantation (SCT) for BD, with only a few individual reported cases.Objective. To assess the safety and efficacy of SCT with the research question: “what is the overall survival and progression free survival (PFS) of patients with BD post autologous SCT (autoSCT) and allogeneic SCT (alloSCT), including those with the primary indication of refractory disease”.Design. Systematic review of reported cases, with updated data for 4 patients treated at our centre in Liverpool, UK.Data sources: PubMed, PubMed Central, Web of Science, OvidSP, Cochrane central register of controlled trials (CENTRAL), clinicaltrials.gov, eudract.ema.europa.eu, controlled-trials.com, free Google search, relevant conference proceedings, hand searching of reference lists, and contact with authors as necessary. Search terms were “behcet” and “transplant”. The search was last updated on 31 July 2018.Eligibility criteria. Cases of BD treated with autoSCT or alloSCT with available information on survival and PFS.Data extraction. Two reviewers independently assessed articles for inclusion, extracted data to assess patients, interventions, comparisons, and outcomes.Primary outcome measures. PFS and overall survival.Results. 32 patients with BD were reported in 25 identified articles, from Europe (47%), Asia (47%), and North America (6%). Median age was 36 years (range 6-60 years old), with 53% females, and 75% had had poor prognosis BD manifestations including vascular, neurological, ocular, and GI. Median time from BD diagnosis to SCT was 48 months (range 3-132), with a median of 3 (range 0-8) prior lines of BD-directed immune therapy.1 The primary indication for SCT was refractory BD in 41% of patients, and 59% of SCTs were primarily for other hematology indications. AlloSCT accounted for 59% of BD patients, the rest being autoSCT. Overall survival was 97% (Fig 1), after a median follow up of 31 months (range 0.2-135 months), with no difference between SCT types (p=0.36). The only death was from infection and sepsis prior to engraftment post alloSCT. ORR was 93%, and PFS was 112 months (95% CI 94-130) (Fig 2), with no difference by SCT donor types (p=0.46).Refractory BD was the main indication for autoSCT in 85%, and myeloma accounting for the remainder. Reported autoSCT conditioning regimens included melphalan 140-200 mg/m2 (54%), carmustine/etoposide/cytarabine/melphalan (BEAM) (23%), and cyclophosphamide combinations (23%), with 46% incorporating additional anti-thymocyte globulin (ATG). OOR was 92%, with complete remission (CR) achieved in 62%, partial remission (PR) in 31%, and stable disease (SD) in 8%.Refractory BD was the main indication for 11% of alloSCTs, and 5% had relapsed post autoSCT. Other hematology primary indications accounted for 89% of alloSCTs, with 69% for MDS, 11% AML, and 11% aplastic anemia. Trisomy 8 was recorded in 59%. Myeloablative conditioning was reported in 58%, with 26% using total body irradiation (TBI). OOR was 94%, with CR accounting of 84%. Acute or chronic graft versus host disease (GvHD) requiring therapy was poorly reported and lower than expected at 32%, with grade III-IV acute GvHD of 11%.Conclusion. SCT in BD appears to be safe and effective, with no clear difference in long-term survival or PFS by SCT type. AutoSCT is a beneficial treatment option for refractory BD. AlloSCT is also advantageous in BD, with less data in the refractory BD or post autoSCT salvage settings. Given the lack of a clinical trial, we present the most comprehensive evidence available supporting the practice changing role of SCT as a treatment option in BD.References. 1. Hatemi G, et al. 2018 update of the EULAR recommendations for the management of Behçet's syndrome. Annals of the Rheumatic Diseases 2018;77:808-18. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

The Development of Methods for High Purity Hematopoietic Lineage Cell Isolation and Lineage Chimerism Testing

Chimerism analysis has become an important tool for assessing the origin of hematopoietic cells after allogeneic donor stem cell transplantations. Particularly, lineage chimerism analysis provides crucial information regarding treatment progress. Donor chimerism status for certain lineages, such as T, NK and myeloid, during early stages following post-transplant is associated with long term engraftment success and the relapse risk. However, the accurate lineage chimerism result is highly contingent on obtaining lineage cell preparation purity. There are several challenges in the field relating to the isolation of high purity cell lineages, chiefly among which is extremely low cell counts during the early stages post-transplant. Our laboratory has developed a method based on a) sequential isolation of hematopoietic lineages; b) purity assessment by flow cytometry; and c) a correction algorithm substandard purity of isolated cells. First, myeloid, B, T, and NK cells are sequentially isolated by magnetic separation using lineage specific markers. Thus each lineage isolated is largely excluded from the sample as a potential contaminant in each subsequent step. A purity with >90% can be routinely achieved when isolating lineages accounting for as little as 0.5 % of total leukocytes. Second, the purity of each population is verified by Flow Cytometry using a 6-color antibody panel staining for T, B, NK, myeloid, and total leukocytes. This enables not only the determination of cell purity of each isolated lineage cells, but also the identification and quantification of any contaminating cells in each isolated lineage. Lastly, an algorithm was derived based on the assumption that total chimerism consists of the four main lineages, T, B, NK, and myeloid. This mathematical correction is reflexively applied when isolated lineage cells are of <90% purity, often occurred as the isolated lineage accounting for < 0.5% of total leukocytes in the sample. In summary, our methods enable generation of high purity of isolated lineage cells that lead to accurate and reliable single lineage chimerism results.

Mobilization of Hematopoietic Stem Cells with Lenograstim in Healthy Donors: Efficacy and Safety Analysis According to Donor Age

We reviewed and analyzed safety and efficacy data after mobilization with granulocyte colony-stimulating factor (G-CSF) according to healthy donor's (HDs) age as follows: <50 years (HDs-1, n = 161), aged 50 to 59 years (HDs-2, n = 62), and ≥60 years or over (HDs-3, n = 23). Two hundred forty-six HDs were evaluated, and their characteristics were well balanced among age groups: most were male, siblings, and HLA matched. According to age group, the median numbers of CD34+ cells in the peripheral blood for HDs-1, HDs-2, and HDs-3 were, respectively, 44.5, 34.5, and 26 (HDs-1 versus HDs-2, P = .002; HDs-1 versus HDs-3, P = .036; HDs-2 versus HDs-3, P = n.s.) at day 4 and 65.5, 58, and 46 (HDs-1 versus HDs-2, P = .039; HDs-1 versus HDs-3, P = .002; HDs-2 versus HDs-3, P = n.s.) at day 5. With a median apheresis session of 1, the number of CD34+ cells/kg recipient body weight collected was not significantly different (6.4 in HDs-1, 6.0 in HDs-2, and 5.7 in HDs-3, P = n.s.). Short- and long-term safety did not differ among age groups. Bone pain was reported as the most frequent short-term adverse event (76.5%). After a median follow-up of 7.8 years, the observed rate of solid tumors, hematological malignancies, and cardiovascular and autoimmune events was similar to the expected incidence for these diseases in Western countries. These results show that G-CSF is effective in the mobilization of older HDs. Moreover, our data contribute to the growing body of evidence in support of the long-term safety of G-CSF for allogeneic donor stem cell mobilization also for elderly HDs.

Safety and efficacy of healthy volunteer stem cell mobilization with filgrastim G‐CSF and mobilized stem cell apheresis: results of a prospective longitudinal 5‐year follow‐up study

G-CSF-mobilized peripheral blood stem cells have long replaced marrow as the major source for allogeneic transplants. Conclusive evidence questioning the long-term safety of G-CSF for donors has not been provided, but the cumulative number of followed donors remains insufficient to rule out rare adverse events. A long-term active follow-up study of G-CSF-mobilized healthy volunteer donors was therefore performed. Two hundred and three successive donors were evaluated pre-apheresis, subjected to G-CSF-mobilization/apheresis, and actively followed for 5 years by the same physicians and laboratories. Follow-up laboratory work included standard biochemical/haematological tests and T-cell phenotyping. Donor epidemiology was typical for reported stem cell donor cohorts. Acute adverse effects of G-CSF and apheresis were mild and transient, consistent with the previous reports. Mean circulating CD34(+) cells after nine doses of G-CSF were 124 per μl. Other biochemical/haematological parameters were also altered, consistent with G-CSF treatment. Spleen enlargement was modest. At first follow-up, all clinical and laboratory parameters had normalized. Leucocyte/lymphocyte counts and CD4/CD8 ratios were the same as during premobilization work-up and remained unchanged throughout. A single severe but likely unrelated adverse event, a case of papillary thyroid carcinoma, was reported. The studies add an observation time of almost 500 donor years to the growing body of evidence of the long-term safety of G-CSF for allogeneic donor stem cell mobilization.

Unrelated donor allogeneic transplantation for adult acute lymphoblastic leukemia: a review

Acute lymphoblastic leukemia is highly sensitive to induction chemotherapy; however, long-term survival in adults has been less than 35%, primarily as a result of high relapse rate. Treatment for relapsed disease is even less successful. The optimal post-remission therapy in the first complete remission offers the best opportunity for leukemia-free survival. Allogeneic donor stem cell transplantation can offer a unique anti-leukemia effect and a potential for extended survival. We will discuss advances in unrelated donor (URD) stem cells transplantation, improvements in transplantation process and supportive care along with growing experience with umbilical cord blood (UCB) allografts.

Effective treatment of leptomeningeal multiple myeloma with total craniospinal irradiation supported by second allogeneic donor stem cell infusion

Effective treatment of leptomeningeal multiple myeloma with total craniospinal irradiation supported by second allogeneic donor stem cell infusion

Anti-CD45–mediated cytoreduction to facilitate allogeneic stem cell transplantation

The CD45 antigen is present on all cells of the hematopoietic lineage. Using a murine model, we have determined whether a lytic CD45 monoclonal antibody can produce persistent aplasia and whether it could facilitate syngeneic or allogeneic stem cell engraftment. After its systemic administration, we found saturating quantities of the antibody on all cells expressing the CD45 antigen, both in marrow and in lymphoid organs. All leukocyte subsets in peripheral blood were markedly diminished during or soon after anti-CD45 treatment, but only the effect on the lymphoid compartment was sustained. In contrast to the prolonged depletion of T and B lymphocytes from the thymus and spleen, peripheral blood neutrophils began to recover within 24 hours after the first anti-CD45 injection and marrow progenitor cells were spared from destruction, despite being coated with saturating quantities of anti-CD45. Given the transient effects of the monoclonal antibody on myelopoiesis and the more persistent effects on lymphopoiesis, we asked whether this agent could contribute to donor hematopoietic engraftment following nonmyeloablative transplantation. Treatment with anti-CD45 alone did not enhance syngeneic engraftment, consistent with its inability to destroy progenitor cells and permit competitive repopulation with syngeneic donor stem cells. By contrast, the combination of anti-CD45 and an otherwise inactive dose of total-body irradiation allowed engraftment of H2 fully allogeneic donor stem cells. We attribute this result to the recipient immunosuppression produced by depletion of CD45(+) lymphocytes. Monoclonal antibodies of this type may therefore have an adjunctive role in nonmyeloablative conditioning regimens for allogeneic stem cell transplantation.

Synthesis of C4 by C4 Deficient NIH-Albany Strain Guinea Pig Radiation Chimeras: Restoration of the Classical Pathway of Complement

Abstract We have detected significant hemolytic C4 activity after transplant of normal guinea pig bone marrow into lethally irradiated guinea pigs genetically deficient in C4. Each of five C4-deficient guinea pigs received 640 rads total body irradiation. They were immediately injected intracardially with 93 to 200 × 106 allogeneic nucleated marrow cells from Albany strain normal guinea pigs. The recipients were followed by sequential white cell counts and titrations of total complement, C1, C4, and C2. C4 activity, initially undetectable, was present as early as 24 days after transplantation and reached maximum levels by 45 to 60 days. C4 protein was also identified by using monospecific anti-guinea pig C4 serum. Amounts of C4 were sufficient to restore classical pathway function. C1 activity, initially 2 S.D. below normal, rose dramatically to normal or greater than normal levels. C2 activity also increased. These data demonstrate that allogeneic donor stem cells protected the lethally irradiated C4-deficient recipients and these allogeneic radiation chimeras subsequently synthesize circulating functional C4.