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Key Points Question Is there an association between dynamic measurable residual disease, treatment, and outcomes among adults with intermediate-risk acute myeloid leukemia? Findings In this registry-based cohort study that included 549 younger patients (aged 14-60 years) with intermediate-risk acute myeloid leukemia, 154 received chemotherapy, 116 received an autologous stem cell transplant, and 279 received an allogeneic stem cell transplant. Results showed that making a postremission treatment choice based on dynamic measurable residual disease was associated with improved outcomes in subgroup analyses. Meaning This study suggests that clinical decisions based on dynamic measurable residual disease might be associated with improved therapy stratification and optimized postremission treatment for patients with intermediate-risk acute myeloid leukemia., Importance Measurable residual disease (MRD) is widely used as a therapy-stratification factor for acute myeloid leukemia (AML), but the association of dynamic MRD with postremission treatment (PRT) in patients with intermediate-risk AML (IR-AML) has not been well investigated. Objective To investigate PRT choices based on dynamic MRD in patients with IR-AML. Design, Setting, and Participants This cohort study examined 549 younger patients with de novo IR-AML in the South China Hematology Alliance database during the period from January 1, 2012, to June 30, 2016, including 154 who received chemotherapy, 116 who received an autologous stem cell transplant (auto-SCT), and 279 who received an allogeneic SCT (allo-SCT). Subgroup analyses were performed according to dynamic MRD after the first, second, and third courses of chemotherapy. The end point of the last follow-up was August 31, 2020. Statistical analysis was performed from December 1, 2019, to September 30, 2020. Exposures Receipt of chemotherapy, auto-SCT, or allo-SCT. Main Outcomes and Measures The primary end points were 5-year cumulative incidence of relapse and leukemia-free survival. Results Subgroup analyses were performed for 549 participants (314 male participants [57.2%]; median age, 37 years [range, 14-60 years]) according to the dynamics of MRD after 1, 2, or 3 courses of chemotherapy. Comparable cumulative incidences of relapse, leukemia-free survival, and overall survival were observed among participants who had no MRD after 1, 2, or 3 courses of chemotherapy. Participants who underwent chemotherapy and those who underwent auto-SCT had better graft-vs-host disease–free, relapse-free survival (GRFS) than those who underwent allo-SCT (chemotherapy: hazard ratio [HR], 0.35 [95% CI, 0.14-0.90]; P = .03; auto-SCT: HR, 0.07 [95% CI, 0.01-0.58]; P = .01). Among participants with MRD after 1 course of chemotherapy but no MRD after 2 or 3 courses, those who underwent auto-SCT and allo-SCT showed lower cumulative incidence of relapse (auto-SCT: HR, 0.25 [95% CI, 0.08-0.78]; P = .01; allo-SCT: HR, 0.08 [95% CI, 0.02-0.24]; P, This registry-based cohort study investigates postremission treatment choices and outcomes based on dynamic measurable residual disease in adults with intermediate-risk acute myeloid leukemia (AML).

Air pollutant emissions from agricultural burning are observed every year after harvest in China. While agriculture is not the main contributor to air pollution in China, agricultural activities can cause severe pollution events. Recognizing the key mechanisms involved in this process offers an opportunity to minimize pollution events caused by agricultural burning. In this paper, we review the meteorological conditions present during a selected air pollution episode and discuss those conditions using standard meteorological observations. The spatio-temporal variations of PM2.5 concentrations following agricultural burning in Beijing were measured from October 4 to October 7, 2013. This time period coincides with a Chinese public holiday and was selected because the influence of other anthropogenic emissions on air quality was strongly reduced during those days. As a result, we were able to identify the key sources and progress of a severe air pollution event. On October 4, average PM_(2.5) concentration in Beijing continuously increased from 49.7 μg m^(-3) at 1:00 to 302.5 μg m^(-3) at 23:00. Heavily polluted air (＞ 300 μg m^(-3)) initially appeared in southeastern Beijing on the afternoon of October 4. On October 5 and in the early morning of October 6, heavily polluted air masses moved into central Beijing, the inner suburbs, and the suburbs. From 0:00 on October 6 to 15:00 on October 7, the average PM_(2.5) concentration in Beijing decreased from 291.6 μg m^(-3) to 19.2 μg m^(-3). Active fire information derived from the MODIS sensors and back trajectory analysis show that field burning of agricultural residues after a harvest triggered and massively contributed to this severe air pollution event. The results improve our understanding of PM_(2.5) air pollution development processes, and they provide scientific support for the Chinese government to accelerate emission reductions from the field burning of agricultural residues.

Background : Autologus hematopoietic stem cell transplantation (auto-HSCT) has now been widely used in treatment ofhematologic malignancies, some solid tumor, and autoimmune diseases and so on. Engraftment failure (EF) is a severe complication after auto-HSCT, and is occurring in 2% to 9.5% of patients. Although this complication is becoming increasingly uncommon with the wide application of mobilized peripheral blood stem cells (PBSCs) instead of bone marrow (BM), it is still associated with considerable morbidity and mortality related to an increasing risk of hemorrhagic complications and infections. In this study, we retrospectively analyzed risk factors of primary EF after auto-HSCT. Method: For the purpose of this study, EF was defined as an absolute neutrophil count (ANC)≦0.5×109/L and a platelet (PLT) count≦20×109/L for at least 35 consecutive days post-transplantation, with hypoplastic BM and without primary disease relapse. Two hundred and five patients undergoing auto-HSCT from Nanfang Hospital of Southern Medical University, Guangzhou General Hospital of Guangzhou Military Command and Zhongshan City People’s Hospital of Guangdong Province, were included in this study between March 2004 and March 2014. They were divided into two groups according to the presence (EF group) or absence (non-EF group) of primary EF. The clinical and transplantation-related characteristics were collected and compared between groups. Then we would choose some factors to perform a risk analysis for EF. Results: The median age of 205 patients was 39 years (range 14 to 60 years). Primary diseases included acute myelogenous leukemia (n=120), non-Hodgkin lymphoma (n=49), multiple myeloma (n=36). Eighteen patients (8.78%) developed primary EF after auto-HSCT. There were significant differences regarding infection during the period from transplantation to hematopoietic reconstruction or EF, and the doses of CD34+ cells infused between groups (P values were 0.010 and 0.044). Results of univariate models of binary logistic regression analysis showed that the number of chemotherapy cycles, infection during the period from transplantation to hematopoietic reconstruction or EF and the doses of CD34+ cells infused were related to primary EF after auto-HSCT (P values were 0.017, 0.040 and 0.018). The results of multivariate analysis for the above 3 factors showed that too much chemotherapy cycles pre-transplantation (P=0.032, odds ratio [OR] = 3.140, 95% confidence interval [CI], 1.101 to 8.956) was a risk factor for primary EF after auto-HSCT and the number of CD34+ cells transfused was a protective factor for it (P=0.035, OR= 3.249, 95% CI, 1.088 to 9.704). The 5-year overall survival, disease-free survival and cumulative incidence of tumor relapse post-transplantation were 68.3% (95% CI, 60.6%-76.0%), 63.0% (95% CI, 58.0%-68.0%) and 37.0% (95% CI, 32.0%-42.0%). Conclusion: The number of chemotherapy cycles is a risk factor for primary EF after auto-HSCT, which may be due to the damaged BM microenvironment by chemotherapy drugs. However, the number of CD34+ cells transfused is a protective factor for it. Disclosures Liu: It was supported by National Natural Science Foundation of China (81270647, 81300445, 81200388); National High Technology Research and Development Program of China (863 Program) (2011AA020105); National Public Health Grand Research Foundation (201202017);: Research Funding; It was supported by Natural Science Foundation of Guangdong Province (S2012010009299); the project of health collaborative innovation of Guangzhou city (201400000003-4, 201400000003-1);: Research Funding; It was supported by the Technology Plan of Guangdong Province of China (2012B031800403); the project of the Zhujiang Science & Technology Star of Guangzhou city (2013027).: Research Funding.

Background Engraftment failure (EF) is a formidable complication after autologous hematopoietic stem cell transplantation (auto-HSCT). Mesenchymal stem cells (MSCs) and cord blood (CB) have been found to support hematopoiesis. Thus, we designed a multicenter randomized clinical trial to investigate the effects and safety of MSCs alone or combined with CB infusion for patients with EF. Methods Twenty-two patients were randomly assigned to receive the treatment with MSCs alone (MSCs group, n=11) or MSCs combined with CB (CB group, n=11). MSCs were administered once every 2 weeks (2 doses were a cycle) in both groups, and single-unit CB was administered at the same day with the first application of MSCs in CB group; After one cycle of treatments (within 28 days), the patients who did not response to MSCs would receive the therapeutic schedule in CB group, and those patients with partial response (PR) in MSCs group and those without complete response (CR) in CB group would continue another cycle of MSCs treatment. If patients did not obtain CR after two cycles of treatments (within 56 days), they would receive other treatments including allogeneic HSCT. Results After the first treatment cycle, the effect rates were not significant difference in MSCs and CB groups (7/11 vs. 9/11, P=0.635), and the median time of hematopoietic reconstruction was 22 (18-28) and 17 (13-22) days, respectively (P=0.036) in MSCs and CB group. There was statistically significant difference regarding neutrophil engraftment, with 17 (range 9-28) and 8 (range 6-14) days respectively (P=0.030), but no difference regarding platelet engraftment, with 21 (range 18-28) and 18 (range 11-21) days respectively (P=0.092) between MSCs and CB groups. After two cycles of treatments, 17 patients obtained CR, 2 PR and 3 NR. CB chimerisms were not detected by short tandem repeat (STR) at +15 and +30 days after CB infusion. None of the patients experienced any adverse events of grade 3/4 with the Common Terminology Criteria for Adverse Events v3.0 (CTCAE v3.0) and acute GVHD or chronic GVHD during the period of study treatment and follow-up. One patient with PR in MSCs group and 1 NR in CB group received allogeneic HSCT at +249 and +273 days after auto-HSCT because of EF and primary disease relapse, respectively. At a median follow-up time of 345 (range 129–784) days post-transplantation, 16 patients remained alive, 3 died of relapse of primary diseases and 1 died of CMV pneumonia following allo-HSCT. None of patients developed EBV-DNA viremia and EBV-associated diseases in two groups. The 2-year overall survival, disease-free survival and tumor relapse post-transplantation were 75.2% (95% CI, 63.2-87.2%), 79.5% (95% CI, 70.1-88.9%) and 20.5% (95% CI, 11.1-29.9%) respectively. Conclusions Our data suggest that ex-vivo-expanded MSCs derived from HLA-mismatched BM alone or combined with unrelated CB are effective to EF after auto-HSCT. CB can facilitate the effect of MSCs to EF. Both two strategies do not result in GVHD or increase the risk of primary diseases relapse in patients with EF. This trial was registered at www.clinicaltrials.govas#NCT01763099. Disclosures: Liu: It was supported by 863 Program (No. 2011AA020105) and National Public Health Grand Research Foundation (Grant No. 201202017).: Research Funding; It was supported by National Natural Science Foundation of China (Grant No.81000231, No.81270647) and Science and Technology Program of Guangzhou of China (11A72121174). : Research Funding.

Imatinib can induce complete molecular remission (CMR) in relapse chronic myelogenous leukemia (CML) after allogeneic hematopoietic stem cell transplantation, but it is indefinite whether imatinib is required to maintain CMR. We retrospectively reviewed 37 relapse CML post-transplants treated with imatinib (n = 20) or donor lymphocyte infusion (DLI) (n = 17). The rate of CMR was 85% and 76.47% (P = 0.509) and treatment-related mortality was 0% and 29.4% (P = 0.019), respectively, in imatinib and DLI groups. Fifteen patients obtaining CMR voluntarily ceased imatinib, and did not experience relapse. The 8-year overall survival (OS) after relapse was 85%±8% and 40.3±12.1% (P = 0.017), and disease-free survival (DFS) after relapse was 85%±8% and 40.3±12.1% (P = 0.011), respectively, in imatinib and DLI groups. Imatinib resulted in higher OS and DFS than that of DLI in relapse CML. Imatinib maintenance might not be required for patients with relapse CML post-transplants after they achieved full donor chimerism and CMR.