ALBERT

Description: Carboniferous–Permian coal seams in the Datong coalfield are intruded by Mesozoic magmatic dikes and sills. Our observations indicate that these dikes and sills have been seriously altered and have lost their original characteristics. Although this phenomenon has been mentioned in some studies, there is a lack of detailed research on the alteration mechanism. To fill this research gap, six dike samples were collected in this study to analyze their alteration characteristics and mechanisms. Petrographic analysis, scanning electron microscopy, and X-ray diffraction were used to determine the mineralogy of the altered igneous samples. The results suggest that the mineral alteration is associated with severe carbonation and clavization. The carbonation of mafic minerals is due to the release of CO2 generated from the coking of high volatile bituminous coals that may have occurred during the intrusive event. However, labradorite did not react with CO2. The water activity in the coal seam was enhanced by the dikes, and mafic minerals were converted into mixtures of chlorite and smectite group minerals. The water activity is especially high at the edges of the dike. Albite and clay minerals were formed due to the albitization of labradorite. Based on these effects, the dike can be divided into weak alteration, carbonation, and clavization bands. The alteration processes in the coal seam are described in detail in this work, and potential formation mechanisms are suggested.

Description: The level of minimal residual disease (MRD) is one of the most important prognostic indicators for acute lymphoblastic leukemia (ALL). In this study, the data about 390 cases of ALL patients who obtained MRD negative after chemotherapy or CART therapy underwent allogenic hematopoietic stem cell transplantation (HSCT) in our center were retrospectively analyzed. The MRD was detected by flow cytometry or molecular methods such as fusion genes or gene mutations. 235 were males and 155 were females. Median age was 15 years old (range 2-64). According to 2016 WHO classification, the diagnosis were Pro-B-ALL(n=24), Common B-ALL(n=113), Pre-B-ALL(n=17), Hyperdiploid (n=8), BCR-ABL positive B-ALL(n=51), MLL rearranged B-ALL (n=19), TEL-AML positive B-ALL (n=13), E2A-PBX B-ALL (n=16), BCR-ABL1-like B-All (n=4), Pro-T-ALL(n=8), Pre-T-AL(n=21), Cortical T-ALL(n=17), Medullary T-ALL (n=6) and ETP T-ALL(n=1). Other 5 patients have complex karyotypes and 67 patients cannot be grouped because of absence complete information about immunophenotypes or genetic profiles. Total number of B-ALL was 295 (54 of which received CART therapy before transplant.) and T-ALL was 92. Another one was T-B mixed lineage and remaining two's lineages was unknown. 14% of the patients had sibling identical donors (n=54), 66% of the patients had haplo-identical relative donors (n=258) and others are unrelated donor (n=77) or cord blood (n=1) transplantation. Disease status before transplant are CR1 (n=228), CR2(n=134) and ≥CR3(n=28). MNC dose was 8.30(2.50-22.60)×108/kg, CD34+cells dose was 4.51(0.89-19.61) ×106/kg and CD3+cells was 1.58(0.01-37.63) ×108/kg. Preparative regimens were based on TBI (n=352) or Bu (n=38). The median time to neutrophil and platelets engraftment was 14 and 12 days. Five-years OS and disease-free survival (DFS) for all patients were 71.7% and 71.1% . Univariate analysis showed difference of impact on overall survival about the patient' gender, age, T or B immunotype, WHO classification, whether or not receiving CART therapy before transplant, conditioning regimen based on TBI or Bu, years of transplant, and time from diagnosis to transplant (≤1year, 〉1year, ≤2year, 〉2year, ≤3year, 〉3year) was not statistically significant. 5-ys OS for CR1, CR2, 〉CR2 were 77.4%, 60.9%, 67.8% (p=0.0018). Five-years OS for sibling-identical , unrelated donor and haplo-identical transplant were 74.8%, 68.8% and 79.6% (p=0.026). The incidence of gradeⅠ-Ⅱ aGVHD and grade Ⅲ-ⅣaGVHD within 100 days were 1.5% and 2.1%. Limited cGVHD was 10.3% and extensive cGVHD was 9.2%. 5 years cumulative relapse rate was 12.2%. In summary, when MRD were negative before transplantation, the result of allo-HSCT for ALL is good. The factors affecting the survival rate are disease status and interval between diagnosis and transplant time rather than gender, age, WHO classification, immunotype, whether or not receiving CART therapy and conditioning regimen. Disclosures No relevant conflicts of interest to declare.

Description: Background: The outcomes of alternative donor haematopoietic stem cell Transplantation(HSCT)for Inherited bone marrow failure syndromes(IBMFS) have not been well described,especially the conditioning regimens are major challenges ,each disease type has different characteristics, whether engraftment can be achieved with less toxicity. Method : With this background,we retrospectively analyzed alternative donor HSCT for 42 patients with IBMFS in our single center from November 2012 to August 2018. Results: 27 cases were Fanconia anemia(FA),7 cases were dyskeratosis congenital(DC), 8 cases were severe congenital neutropenias(SCN). The median age at diagnosis and transplantation were 4(1 to 25 ) years and 10(1.9 to 26)years respectively. Male to female was 28 :14. All patients were confirmed to have BMF and disease-specific pathogenesis-related gene mutations. 16 cases had disease specific congenital anomalies, 10 patients had family history. Chromosomal fragility test was positive in 8 cases of FA group. Indication of HSCT for FA and DC patients which were 30 patients had BMF or transfusion dependency at transplantation;4 cases had clonal disease (2 cases myelodysplasia, 2 cases acute myeloid leukaemia). Indication of HSCT for SCN patients were uncontrollable severe infection .FA received low dose Busulfan (Bu;total dose of 6.4 mg/kg, IV), Fludarabine (Flu; total dose of 120 mg/m2, IV) , Cyclophosphamide (Cy; total dose of 2.0 g/m2, IV) based-reduced intensity conditioning(RIC) ; DC patients received low dose TBI (total 300cGy, Special position, supine) , Flu(total dose of 120 mg/m2, IV) , Cy( total dose of 3.0 g/m2, IV) based-RIC, while SCN patients had Bu(total dose of 12.8 mg/kg, IV),Cy( total dose of 3.6 g/m2, IV) or Flu(total dose of 160 mg/m2, IV) based -myeloablative conditioning(MA); and all patients combinated either of 2 different rabbit ATG ,ATG-T , rabbit anti-human thymocyte immunoglobulin, total dose 5.0 -10 mg/kg in 26 cases or ATG-F ,rabbit anti-human lymphocyte immunoglobulin, total dose 20 mg/kg in 14 cases. Campath-1, Anti-CD52 mAb was accepted with total dose 1mg/kg in 2 cases. Donor types were matched unrelated donor(MUD) in 22 patients ,Haploidentical donor (HID) in 17 patients,unrelated cord blood (UCB) in three cases. Unmanipulated stem cells were used for all patients. The Haplo-HSCT cohort received granulocyte colony-stimulating factor (G-CSF)-primed BM combined with peripheral blood stem cells (PBSCs) , The MUD HSCT cohort only received G-CSF PBSCs. The UCB HSCT cohort received one unit CB . No primary graft failure was observed. The median myeloid engraftment time was 14 (range, 10 to 21) days.Survivor median follow-up time was 38 months (range, 9-63 months), the overall survival in all patients was 76.1% ,in FA,DC,SCN were 72.4% ,100%,53.0% respectively. Cumulative incidence of 100 days acute graft-versus-host disease(GVHD) was 48.1%,Cumulative incidence 1 year and 3 years of chronic GVHD were 35.0% and 69.3% respectively. The positive chromosomal fragility test was the only independent adverse prognostic factor in multivariate analysis for FA patients rather than age ,donor type and graft source. Main causes of death were GVHD (50%) and infection (20%).No secondary malignancies occurred after HSCT till the last follow up time. Conclusion: In our study, alternative donor and disease-specific conditioning regimen HSCT for IBMFS showed promising prognosis especially for DC patients. Chromosomal fragility test positive was the only independent adverse prognostic factor in HSCT for FA patients. Disclosures No relevant conflicts of interest to declare.

Description: Introduction: CD19-CAR-T cells induce high rates of initial response among patients with refractory/relapsed and MRD positive high risk B-cell acute lymphoblastic leukemia (B-ALL). Afterwards allogeneic hematopoietic stem cell transplantation (HSCT) can further reduce relapse rate. Our previous results had shown that CR obtained by CD19 CAR-T had comparable significance to CR by chemotherapy before Allogeneic HSCT in B-ALL. Patients and Methods: Between July 2015 and Mar 2018, consecutive 135 patients with refractory/relapsed or high risk B-ALL obtained CR with CD19-CART therapy followed by allogeneic HSCT were retrospective analyzed. Median follow-up of survivors was 13 months (range, 3-32 months). Results: The median age was 11 (2-49) years. The median disease course before transplant was 21(4-143) months. The median time from CART therapy to HSCT was 69 (35-312) days. Disease status was 108 cases relapsed diseases, 11 cases refractory, and 16 persistent/recurrent measurable residual diseases (MRD). MRD pre-conditioning measured by flow cytometry and QT-PCR was positive in 20(14.8%) subjects. Donor source was haploidentical donors in 107(79.3%), identical sibling in 7(5.1%), and unrelated in 21(15.6%). Most subjects (87.4%) received conventional myeloablative pretransplant conditioning with total body radiation (TBI), the rest with busulfan (Bu). Antithymocyte globulin was used in haploidentical and unrelated transplants. Cyclosporine, short-term methotrexate, and mycophenolate mofetil were employed for GVHD prophylaxis. There were no cases of graft-failure except one early death on Day 0 for septic shock. The median time to neutrophil engraftment was 14 days (10, 26 days), and median time to platelet engraftment 14 days (5, 70 days). The incidences of non-relapse mortality within 100 days were 4.4% (0.8, 7.9%) The incidence of grades II-IV acute graft-versus-host disease (GvHD) were 32.1% (24.3, 39.9%) and grades III-IV GvHD 10.5% (5.4, 15.6%). Chronic GvHD and extensive chronic GvHD were 69.7% (60.7, 78.7%) and17.6% (10.7, 24.5%). Cumulative incidence of relapses (CIRs) at 2-year was 11.1% (5.4, 16.8%). There were totally 14 subjects relapsed after HSCT, among which 8 were CD19 negative relapse, 5 CD19 positive and 1 partial CD19 positive. And among the 8 CD19 negative relapse after transplant, 4 subjects had CD19 negative MRD before conditioning. Leukemia-free survival (LFS) was 76.5% (64.2, 88.8%) and overall survival (OS) was 80.8% (72.6, 89.0%) at two years after transplant. In multivariate analysis subjects who were MRD- positive pre-transplant had a higher 2-year CIR (43.5% [18.4, 68.6%] vs. 5.9% [1.2, 10.6%]; p=0.000) and worse 2-year OS (61.5% [35.6, 87.4%] vs. 83.6% [75, 92.2%]; p=0.034). Conclusions: Our clinical results showed that CART therapy followed by allogeneic HSCT was a promising modality for refractory/relapsed B-ALL. CD19 negative relapse accounted for most relapse after allogeneic HSCT. Figure. Figure. Disclosures No relevant conflicts of interest to declare.

Description: Introduction Current available treatments are limited once patients with B-ALL relapse following allogeneic hematopoietic stem cell transplantation (allo-HSCT). While chimeric antigen receptor (CAR) T-cell therapy offers a chance of remission, long-term outcomes for these patients remain poor. The benefit of bridging into a second transplant after CAR T-cell therapy remains inconclusive and available data are limited. Here, we report the long-term outcomes of 23 B-ALL patients who chose to undergo a second allo-HSCT after achieving complete remission (CR) from CAR T-cell therapy. Methods From April 2017 to April 2020, 23 R/R B-ALL patients (median age of 20 years, ranging from 3 to 58 years) who relapsed after first allo-HSCT received CAR T-cell therapy. The data were aggregated from seven different clinical trials (www.clinicaltrials.gov NCT03173417, NCT02546739 NCT03825718, NCT03825731, NCT03952923, NCT04100187 and www.chictr.org.cn ChiCTR1800016541). Patients' first transplant sources were HLA-identical sibling (n=5), matched-unrelated donor (MUD) (n=1), and haploidentical donors (haplo) (n=17). Eight of the 23 patients had disease relapse within 6 months following the first transplant. The median time from first transplant to CAR T-cell infusion was 261days (range: 117~2181 days). Before CAR T-cell infusion, patients' median bone marrow (BM) blasts by morphology were about 72.5% (1.5%-94.5%) including 12 patients with BM blasts 〉70% (5 with BM blasts 〉90%). Three of the 23 patients (13%) had received at least one prior donor lymphocyte infusion. No patients had active graft-versus-host disease (GVHD) prior to CAR T-cell therapy. Second generation CAR T-cells were generated by using purified T-cells from transplant donors (n=15) or patients (n=8). Twenty-two patients received T-cells modified with CD19-targeting CAR T-cells containing either a 4-1BB (n=18) or a CD28 co-stimulatory domain (n=4), and one patient received CD19-CD22 dual specificity CAR T-cells. All patients received a conditioning regimen of IV fludarabine (30mg/m2/d) and cyclophosphamide (250mg/m2/d) for 3 days followed by a single CAR T-cell infusion with a median dose of 3×105 cells/kg (1×105-6×105 cells/kg) in 21 patients. Two patients received a second CAR T-cell infusion in 2-3 months (1/3×105 cells/kg dose). Post CAR-T therapy, all patients bridged into a consolidation second transplantation with conventional myeloablative pre-transplantation conditioning regimens including 15 patients who received total body irradiation-based and 7 patients that received a busulfan-based conditioning regimen. Cyclosporin A, short-term methotrexate, and mycophenolate mofetil were used for GVHD prophylaxis. Results Patients' characteristics are shown in Table 1. On Day 30 post CAR-T-cell infusion, 23/23 (100%) patients achieved minimal residual disease (MRD)-negative CR. A total of 16/23 (69.6%) patients developed cytokine release syndrome (CRS) of which 14/23 (60.9%) had Grade I-II and 2/23 (8.7%) had Grade III CRS. Two patients had Grade III neurotoxicity. All patients with MRD-negative status subsequently bridged into a second transplant (2 from MUD and 21 from haplo donors) with a median interval time of 67 days (39- 329 days) from CAR T-cell therapy to a second transplant. At a median follow-up time of 258 days (84-978 days), no patients relapsed, which was encouraging. Five of 23 patients (21.7%) died from transplant-related mortality (TRM) at a median time of 295 days (103-372 days) (1 from GVHD and 4 from infection). The 1-year overall survival (OS) was 68.0% and 2-year OS was 54.4% (Fig.1). While there was a trend towards a more efficacious OS for patients whose CAR T-cells were derived from donors rather than from patients themselves but the number are too small to reach statistical significance (1-year OS 83.9% vs. 64.3%, 2-year OS 83.9% vs. 42.9%, P=0.739. Fig.2). After the 2nd transplant, four patients developed GVHD. Conclusions Our study demonstrates that even for R/R B-ALL patients who have relapsed following a first allo-HSCT , an MRD-negative CR status can still be achieved through CAR T-cell cell therapy without increasing CRS or neurotoxicity, making consolidation second allo-HSCT feasible for these patients. CAR T-cell therapy combined with a consolidation second HSCT are effective for these heavily pre-treated patients with an encouraging prospect for long-term survival. Disclosures No relevant conflicts of interest to declare.

Description: Introduction SIL-TAL1 rearrangement is relatively common among patients with T-cell acute lymphoblastic leukemia (T-ALL). Pediatric patients with SIL-TL1 positive T-ALL generally have a poor response to early intensive treatment and a lower median relapse-free survival (RFS) and overall survival (OS) rates compared to pediatric T-ALL patients who do not harbor the SIL-TAL1 gene fusion. Therefore, we explored the clinical effect of haploid transplantation among pediatric SIL-TAL1-gene fusion positive T-ALL and aimed to identify potential patient prognostic factors. M ethods We performed a retrospective analysis of 21 children with SIL-TAL1 gene fusion positive T-ALL who underwent haploidentical transplantation at the Lu Daopei Hospital in Langfang, China between July 2014 and June 2020. The median patient age was 9 years (range: 1.6 to 18 years), the male to female ratio was 19:2, and the median white blood cell count at initial onset was 193.65×109/L (range: 3.6-582.17×109/L). Prior to transplantation, 18 patients were bone marrow minimal residual disease (MRD) negative, three patients were bone marrow MRD-positive and the overall median value for MRD positivity by flow cytometry was 0.05% (range: 0.03%-0.35%). Eighteen patients were SIL-TAL1 gene fusion negative and three patients were SIL-TAL1 gene fusion positive prior to transplantation. The quantitative median number is 0.04% (range: 0.033%-0.05%). 13 patients with CR1 and 8 patients with CR2. 11 of 21 patients harbored the SIL-TAL1 gene fusion along with at least one other gene mutation. All patients were given myeloablative pretreatment, of which 17 patients received cyclophosphamide/total body irradiation (TBI/Cy) and 4 patients received Busulfan/cyclophosphamide (Bu/Cy). The median follow-up time was 9.5 months (range: 2 to 51 months). Results The white blood cells (WBCs) of 21 patients were all completely engrafted , two patients did not have platelet engraftment . At one month after transplantation, all patients were bone marrow MRD negative and the quantification of SIL-TAL1 fusion gene was 0% among all the patients. For 20 of these 21 patients, the chimerism rate of peripheral blood CD3+ cells and bone marrow was 100% donor type. The 4-year disease-free survival (DFS) and overall survival (OS) rate were 56.5% and 55.1%, respectively (Figure 1). Causes of death were recurrence (5 patients all of whom had bone marrow recurrence), infection (3 patients) and alveolar hemorrhage after reinfusion (1 patient). Six patients relapsed after transplantation with a median time to relapse of 90 days (range: 54-180 days). The OS rate following transplantation in the CR1 group was higher than in the CR2 groups (69.2% vs 31.3%, respectively) but there was no statistical difference between the two groups (P=0.147) (Figure 2). The OS rate of MRD-negative patients and MRD-positive patients prior to transplantation was 58.4% and 33.4% respectively, (P=0.287) (Figure 3). Prior to transplantation, the OS rate of SIL-TAL1 gene fusion-negative patients was 64.3%, while the OS rate of SIL-TAL1 gene fusion-positive patients was 0.0%--the difference between the two groups was statistically significant (P=0.001) (Figure 4). The OS rate of 11 patients that harbored the SIL-TAL1 gene fusion along with another gene mutation was 47.7% (Figure 5). Among these 11 patients, the OS rate of 9 patients who switched from SIL-TAL1 positive to SIL-TAL1 negative prior to transplantation was 58.3%. In contrast, two patients that remained SIL-TAL1 gene fusion positive had an OS rate of 0% (P=0.027) (Figure 6). Conclusion Pediatric T-ALL patients harboring the SIL-TAL1 gene fusion achieved a higher OS rate through haploid transplantation and were able to avoid extramedullary recurrence. We conclude that if patients with the SIL-TAL1 gene fusion do not switch to SIL-TAL1-negative prior to transplantation, we showed that even if the myeloablative pretreatment program is adopted, the survival rate cannot be improved, and the mortality rate is 100%. Harboring another gene mutation besides SIL-TAL1 at the initial onset of disease did not affect the prognosis in our cohort analysis. We conclude that for pediatric T-ALL patients, intensive chemotherapy should be adopted to make the bone marrow MRD negative and SIL-TAL1 gene fusion negative, and allogeneic hematopoietic stem cell transplantation should be performed as soon as possible to improve OS. Disclosures No relevant conflicts of interest to declare.