Assessment of chimerism and immunomodulation to prevent post-transplantation relapse in childhood acute myeloblastic leukemia: is it the right approach?
Pediatric hematology and oncology. 2020;:1-10
Relapse of acute myeloblastic leukemia (AML) after first allogenic hematopoietic stem-cell transplantation (allo-HSCT) is a fatal complication. Sixty-five children transplanted for AML were included in a prospective national study from June 2005 to July 2008 to explore the feasibility of preemptive immune modulation based on the monitoring of blood chimerism. Relapse occurred in 23 patients (35%). The median time between the last complete chimerism and relapse was 13.5 days (2-138). Prompt discontinuation of cyclosporin and the administration of donor lymphocyte infusions (DLIs) based on chimerism monitoring failed as a preemptive tool, either for detecting relapse or certifying long-term remission.
Prediction, management, and prognosis of mixed chimerism after hematopoietic stem cell transplantation in transfusion-dependent pediatric thalassemia patients
Pediatric transplantation. 2020;:e13876
BACKGROUND Early-onset mixed chimerism (MC) with a high proportion of residual host cells is considered a signal of graft rejection in patients undergoing allogenic hematopoietic stem cell transplantation for transfusion-dependent thalassemia. In order to prevent graft rejection and minimize the risk of treatment-related graft-versus-host disease (GVHD), we established a hierarchical management system based on chimerism analysis. METHOD This retrospective study provides a comprehensive review of the characteristics, interventions, and outcomes of the 38 patients who developed MC after transplantation among the 144 pediatric thalassemia patients between July 2007 and January 2019 at our center. RESULTS A sibling donor, a blood type-matched donor, conditioning regimens without fludarabine, and transplants containing <10 × 10(8) total nucleated cells/kg were identified to be associated with the development of MC. Among the 38 patients developing MC, only four patients rejected the grafts. The response rate to donor lymphocyte infusion (DLI, only for patients receiving sibling donor transplantation) and cytokine immunomodulation without DLI was 70.6% and 42.9%, respectively. Patients that developed GVHD after DLI or cytokine therapy had a more significant increase in donor cell chimerism (16%, range 0%-35%) than those without (8.5%, range -21% to 40%, P = .049). However, even when treatment-related GVHD was included, patients with MC had a lower cumulative incidence of total acute GVHD than patients with complete donor chimerism (29.2% vs 48.0%, P = .030). CONCLUSIONS Interventions based on chimerism analysis were effective in preventing graft rejection and did not increase treatment-related GVHD in thalassemia patients with MC.
The incidence, clinical outcome and protective factors of mixed chimerism following hematopoietic stem cell transplantation for severe aplastic anemia
Clinical transplantation. 2020;:e14160
OBJECTIVES The aim of our study was to determine possible predictors and clinical course of mixed chimerism (MC) in aplastic anemia after transplantation. METHODS A total of 207 transplants were obtained from haploidentical donors (HID) using busulfan (Bu), cyclophosphamide (Cy) and anti-thymocyte globulin (ATG) regimens, and 69 transplants from matched related donors (MRD) and 29 transplants from unrelated donors (URD) using Cy/ATG regimens were obtained. RESULTS Incidences of MC were 1.93±0.01%, 20.29±0.01%, and 35.71±0.01% in HID, MRD and URD transplantation (P<0.001). In multivariate analysis, incidence of MC was significantly higher in patients without adding Bu in conditioning (P<0.001) and receiving a lower number of CD3+ cells in graft (P = 0.042). MC was associated with significantly lower II-IV aGvHD (3.70% vs. 27.7%, P = 0.007), but higher secondary graft rejection rates (14.8% vs. 0.4%, P<0.001) and poorer overall survival (72.7±8.9% vs. 89.6±2.0%, P = 0.011) than those of donor chimerism cohort. CONCLUSIONS MC was an unsettling status even in non-malignancy. Haploidentical transplantation with more intense regimen by adding Bu to Cy and ATG was associated with reduced MC following HSCT for SAA. An intensified regimen should be explored in matched related or unrelated donors.
The impact of chimerism on DNA-based human identification from skin surface cells of post-allogenic hematopoietic stem cell transplantation (HCST) patients
Forensic science international. 2020;318:110636
The use of biological traces recovered from touched or handled items increased with the advance of the forensic analysis system. Thus, DNA profiles obtained from touch DNA became a useful tool in forensic investigation. However, a chimeric person with more than one chromosomal population can be challenging for a forensic analyst. We investigated the genetic profile in blood, buccal swab, and skin swabs from twenty-four recipients aged 21-63 years who underwent a matched sibling allogeneic hematopoietic stem cell transplantation with no sign of skin graft versus host disease. Autosomal short tandem repeats genotyping was performed to evaluate chimerism status at 15 loci along with gender marker Amelogenin. According to our results, donor chimerism was detected in all recipient's blood samples, while in buccal swabs, five recipients showed no presence of donor-derived cells in their genotype. Epithelial cells swabbed from hand fingertips were not devoid of donor-derived cells since all recipients showed high chimerism (39.69%-96.66%) in their genotypes. A significant change in chimerism was seen among various types of biological samples (p<0.05). No correlations were observed between chimerism and recipient age, gender, or time after transplant (p> 0.05). The loci D21S11, D8S1179, and FGA were the most informative, whereas D13S317, Vwa, and TOPX were the least informative STR markers. We concluded that touch DNA from a person who has undergone a successful allogeneic HSCTs should not be considered as reliable evidence for human identifications. Therefore, necessary precautions must be taken to avoid false identification and miscarriage of justice.
Adoptive immunotherapy with CB following chemotherapy for patients with refractory myeloid malignancy: chimerism and response
Blood advances. 2020;4(20):5146-5156
We conducted a prospective evaluation of cord blood (CB)-derived adoptive cell therapy, after salvage chemotherapy, for patients with advanced myeloid malignancies and poor prognosis. Previously, we reported safety, feasibility, and preliminary efficacy of this approach. We present updated results in 31 patients who received intensive chemotherapy followed by CB infusion and identify predictors of response. To enhance the antileukemic effect, we selected CB units (CBU) with shared inherited paternal antigens and/or noninherited maternal antigens with the recipients. Twenty-eight patients with acute myeloid leukemia (AML), 2 with myelodysplastic syndrome, and 1 in chronic myeloid leukemia myeloid blast crisis were enrolled; 9 had relapsed after allogeneic transplant. Response was defined as <5% blasts in hypocellular bone marrow at 2 weeks after treatment. Thirteen patients (42%) responded; a rate higher than historical data with chemotherapy only. Twelve had CBU-derived chimerism detected; chimerism was a powerful predictor of response (P < .001). CBU lymphocyte content and a prior transplant were associated with chimerism (P < .01). Safety was acceptable: 3 patients developed mild cytokine release syndrome, 2 had grade 1 and 2 had grade 4 graft-versus-host disease. Seven responders and 6 nonresponders (after additional therapy) received subsequent transplant; 5 are alive (follow-up, 5-47 months). The most common cause of death for nonresponders was disease progression, whereas for responders it was infection. CB-derived adoptive cell therapy is feasible and efficacious for refractory AML. Banked CBU are readily available for treatment. Response depends on chimerism, highlighting the graft-versus-leukemia effect of CB cell therapy. This trial was registered at www.clinicaltrials.gov as #NCT02508324.
Full Donor Chimerism After Allogeneic Hematopoietic Stem Cells Transplant For Myelofibrosis: The Role Of The Conditioning Regimen
American journal of hematology. 2020
The aim of this retrospective study, was to assess the rate of full donor chimerism (F-DC) in patients with myelofibrosis, prepared for an allogeneic stem cell transplant, with one or two alkylating agents. We analyzed 120 patients with myelofibrosis, for whom chimerism data were available on day +30. There were two groups: 42 patients were conditioned with one alkylating agent (ONE-ALK), either thiotepa or busulfan or melphalan, in combination with fludarabine, whereas 78 patients were prepared with two alkylating agents, thiotepa- busulfan and fludarabine (TBF). Patients receiving TBF were older (57 vs 52?years), were less frequently splenectomized pre-HSCT (31% vs 59%), had more frequently intermediate-2/high DIPSS scores (90% vs 74%), were grafted more frequently from alternative donors (83% vs 33%) and received more frequently ruxolitinib pre-HSCT (26% vs 7%). The proportion of patients with F-DC on day +30, in the TBF vs the ONE-ALK group, was respectively 87% vs 45% (p<0.00001). The 5-year cumulative incidence of relapse was 9% in the TBF group, versus 43% for the ONE-ALK group (p<0.0001). The 5-year actuarial disease free survival was 63% for TBF and 38% for the ONE-ALK group (p=0.004). In conclusion, early full donor chimerism is a prerequisite for long term control of disease in patients with myelofibrosis, undergoing an allogeneic HSCT. The combination of two alkylating agents in the conditioning regimen, provides a higher chance of achieving full donor chimerism on day+30, and thus a higher chance of long term disease free survival. This article is protected by copyright. All rights reserved.
Myelofibrosis patients, with chimerism data available on day +30 (n=120)
Patients conditioned with one alkylating agent (ONE-ALK, n=42)
Patients conditioned with two alkylating agents (TBF, n=78)
The proportion of patients with F-DC on day +30, in the TBF vs the ONE-ALK group, was respectively 87% vs 45%. The 5-year cumulative incidence of relapse was 9% in the TBF group, versus 43% for the ONE-ALK group. The 5-year actuarial disease free survival was 63% for TBF and 38% for the ONE-ALK group.
Evaluation of EuroFlow minimal residual disease measurement and donor chimerism monitoring following tandem auto-allogeneic transplantation for multiple myeloma
Bone marrow transplantation. 2020
Prognostic factors for multiple myeloma (MM) after allogeneic haemopoietic stem cell transplantation (alloHSCT) are poorly characterised. Two potential factors include minimal residual disease (MRD) and CD3(+) donor-specific chimerism. We retrospectively examined 93 consecutive patients who received upfront or deferred tandem auto-alloHSCT. Bone marrow (Euroflow) MRD was assessed pre-alloHSCT and 3-monthly post-alloHSCT. CD3(+) donor chimerism was assessed at D30, D60, D90, 6?m and 12?m post-alloHSCT. There was no statistical difference between upfront and deferred transplants in progression free survival (PFS) (34?m vs. 15?m respectively, p?=?0.20) and overall survival (OS) (75.5?m vs. 62.7?m respectively, p?=?0.56). Patients who were MRD-positive post-alloHSCT had inferior PFS to MRD-negative patients from 6?m (6?m HR 3.32, p?=?0.02; 9?m HR 4.08, p?=?0.003; 12?m HR 4.47, p?=?0.008). Attainment or maintenance of MRD-negativity predicted reduced relapse risk (23.5% vs. 62.5%, p?=?0.04). However, there was no significant difference in OS between the MRD-negative and positive groups. Full CD3(+) donor chimerism at early time points (D30 and D90) was associated with increased risk of acute GVHD (D30 p?0.001, D90 p?=?0.006) and extensive chronic GVHD (D90 p?=?0.04), but not PFS or OS. These data support the use of sequential MRD evaluation post-alloHSCT to inform intervention to eradicate persistent or emergent MRD-positive disease.
A SNP panel for early detection of artificial chimerism in HSCT patients using TaqMan technology
International journal of legal medicine. 2020
The monitoring of chimerism status in a hematopoietic stem cell transplantation patient is a crucial process and is performed periodically in a short time interval. A short tandem repeat marker is widely used for chimerism analysis due to its high discrimination power. However, the sensitivity of this approach was limited to 5% of a minor contributor and the interpretation is usually interrupted with PCR stochastic phenomena. Here, we developed an SNP panel for chimerism analysis using TaqMan technology. A set of SNPs was selected from Thai ancestry informative markers and open-access databases with proper criteria. We examined the 30 recipient-donor pairs that underwent HSCT and showed that the panel can provide an informative marker from 90% of all pairs. An early detection of artificial chimerism in post-HSCT samples was observed when compared with STR analysis. In addition, the detail of cases was discussed.
Cord blood maternal microchimerism following unrelated cord blood transplantation
Bone marrow transplantation. 2020
Cord blood transplantation (CBT) is associated with low risk of leukemia relapse. Mechanisms underlying antileukemia benefit of CBT are not well understood, however a previous study strongly but indirectly implicated cells from the mother of the cord blood (CB) donor. A fetus acquires a small number of maternal cells referred to as maternal microchimerism (MMc) and MMc is sometimes detectable in CB. From a series of 95 patients who underwent double or single CBT at our center, we obtained or generated HLA-genotyping of CB mothers in 68. We employed a technique of highly sensitive HLA-specific quantitative-PCR assays targeting polymorphisms unique to the CB mother to assay CB-MMc in patients post-CBT. After additional exclusion criteria, CB-MMc was evaluated at multiple timepoints in 36 patients (529 specimens). CB-MMc was present in seven (19.4%) patients in bone marrow, peripheral blood, innate and adaptive immune cell subsets, and was detected up to 1-year post-CBT. Statistical trends to lower relapse, mortality, and treatment failure were observed for patients with vs. without CB-MMc post-CBT. Our study provides proof-of-concept that maternal cells of the CB graft can be tracked in recipients post-CBT, and underscore the importance of further investigating CB-MMc in sustained remission from leukemia following CBT.
Donor-derived DNA variability in fingernails of acute myeloid leukemia patients after allogeneic hematopoietic stem cell transplantation detected by direct PCR
Bone marrow transplantation. 2020