Impact of posttransplant cyclophosphamide on the outcome of patients undergoing unrelated single-unit umbilical cord blood transplantation for pediatric acute leukemia.

BACKGROUND: Umbilical cord blood transplantation (UCBT) from unrelated donors is one of the successful treatments for acute leukemia in childhood. The most frequent side effect of UCBT is peri-engraftment syndrome (PES), which is directly associated with the greater prevalence of acute and chronic graft-versus-host-disease (aGvHD and cGvHD). In haploidentical stem cell transplantation, posttransplant cyclophosphamide (PTCY) has been demonstrated to be an effective method against GvHD. However, the effects of PTCY as a GvHD prophylactic in UCBT had not been investigated. This study aimed to evaluate the effects of PTCY on the outcomes of UCBT for pediatric acute leukemia. METHODS: This retrospective study included 52 children with acute leukemia who underwent unrelated single-unit UCBT after myeloablative conditioning regimens. The results from the PTCY and non-PTCY groups were compared. RESULTS: The incidence of transplantation-related mortality in non-PTCY and PTCY were 5% and 10% (p = 0.525), respectively. The incidence of relapse in non-PTCY and PTCY were 5% and 23% (p = 0.095), respectively. Second complete remission status (CR2) was an independent risk factor for relapse-free survival (hazard ratio = 9.782, p = 0.001). The odds ratio for sepsis or bacteremia incidence was significantly greater in the PTCY group (9.524, p = 0.017). PTCY group had increased rates of cytomegalovirus activity and fungal infection. The incidence of PES, aGvHD, cGvHD, and hemorrhagic cystitis in the PTCY group was lower than that in the non-PTCY group, although it was not significantly different. Additionally, higher doses of PTCY (29 mg/kg and 40 mg/kg) were associated with lower incidences of aGvHD and severe GvHD (65% and 29%, respectively) than lower doses (93% and 57%, respectively). Engraftment time and graft failure incidence were similar across groups. CONCLUSION: The results support the safety and efficiency of PTCY as part of PES controlling and GvHD prophylaxis in single-unit UCBT for children with acute leukemia. A PTCY dosage of 29 mg/kg to 40 mg/kg appears to be more effective in GvHD prophylaxis for UCBT patients.

A pyruvate kinase deficiency child with novel PK-LR gene mutations was successfully cured by matched unrelated donor peripheral blood stem cell transplantation.

BACKGROUND: Pyruvate kinase deficiency (PKD) is an autosomal recessive disorder caused by a PK-LR gene mutation. Allogeneic hematopoietic cell transplantation (HCT) is an effective cure for PKD. However, the experience of applying HCT in PKD is limited. METHODS: We present a child with novel PK-LR gene mutations who was successfully cured by matched unrelated donor peripheral blood stem cell transplantation (MUD-PBSCT). RESULTS: A 4-year-old, male patient suffered severe hemolytic anemia and jaundice 5 h after birth. Gene sequencing showed that the pyruvate kinase-liver and RBC (PK-LR) gene had a nonsense mutation in exon 5: c.602G>A (p.W201X), and large deletions in exons 3-9. Both of them were novel pathogenic mutations of the PK-LR gene. After transplantation, the hemoglobin level became normal and the nonsense mutation was undetectable. Grade Ⅳ acute graft-versus-host disease (aGVHD) and extensive chronic graft-versus-host disease (cGVHD) occurred in the patient. However, the GVHD was controlled effectively. The patient is alive and has good quality of life 22 months post-transplant, but has mild oral lichen planus-like lesion. CONCLUSION: Gene sequencing contributes to the diagnosis of PKD. HCT is an effective method for curing PKD, but we should explore how to reduce severe GVHD.

New cytotoxic alkylated anthraquinone analogues from a soil actinomycete Streptomyces sp. WS-13394.

Four new alkylated anthraquinone analogues (1-4) were isolated from a soil actimomycete Streptomyces sp. WS-13394. The structures of compounds 1-4 were elucidated to be 1,4,6-trihydroxy-8-alkylanthraquinones by means of spectroscopic methods, including UV, one dimensional (1D), 2D-NMR and MS spectrometry. All compounds showed activities against BGC-823 and MCF-7 with IC50 from 0.99 to 3.54 µg/mL, while 2 exhibited cytotoxicity against HepG2, A875, BGC-823 and MCF-7 with IC50 2.29, 4.90, 0.99, and 1.66 µg/mL, respectively.

[Relationship between MTHFR Gene Polymorphism(C677T) and Adverse Reactions of High-Dose Methotrexate in Pediatric Patients with Acute Lymphoblastic Leukemia].

OBJECTIVE: To explore the effects of methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphism on the adverse reactions of high-dose methotrexate (MTX) in pediatric patients with acute lymphoblastic leukemia (ALL). METHODS: A total of 69 children with ALL admitted to the department of Pediatrics of Sun Yat-sen Memorial Hospital of Sun Yat-sen University from November 2018 to October 2020 were included in this study. The clinical data of the children were collected, leukocytes were isolated from their peripheral blood, and MTHFR genotyping was performed by digital fluorescence molecular hybridization techniques. The adverse reactions and plasma drug concentration of MTX were monitored during the chemotherapy. Moreover, the effect of MTHFR gene polymorphism on MTX adverse reactions and plasma drug concentration were analyzed. RESULTS: Among the middle and high risk children, compared with the wildtype group (CC genotype), patients with MTHFR C677T mutations (CT+TT genotypes) had a higher risk of leukopenia (OR=2.38), neutropenia (OR=2.2), anemia (OR=1.83) and hepatoxicity (OR=1.98). However, no significant difference was found in the MTX plasma concentration between the MTHFR C677T mutantion group and the wildtype group at different timepoints (24 h, 48 h and 72 h). Multivariate analysis revealed that the plasma concentration of MTX (48 h), clinical risk level of ALL and MTHFR C677T gene polymorphism were independent factors for the adverse reactions of high-dose MTX. CONCLUSION: The MTHFR C677T mutations may be associated with myelosuppression and hepatotoxicity in children with ALL after high-dose MTX treatment.

[Comparison of the anti-leukemia effect and mechanism of L-asparaginase between two different strains].

This study was purposed to compare the anti-leukemic effects of E.coli-L-Asp and Erwinia-L-Asp in vitro, and to investigate their mechanism. The cell apoptosis and proliferation inhibition rate were measured by CCK-8 kit, and IC50 of two drugs was calculated by using SPSS software. Pro-apoptosis effect of E.coli-L-Asp and Erwinia-L-Asp on REH and Jurkat cell lines was also determined by flow cytometry with Annexin V/PI double staining. Concentration changes of 4 amino acids (Asn, Aspa, Gln, and Glu) before and after medication were detected by using high pressure liquid chromatography (HPLC) assay. The results showed that both REH and Jurkat cell lines were sensitive to L-Asp drugs from two different strains, and E.coli-L-Asp and Erwinia-L-Asp displayed the inhibition effect on the proliferation of Jurkat and REH cell lines in dose-dependent and time-dependent manners. The inhibition cell of proliferation and cell apoptosis in Erwinia-L-Asp group were higher than those in E.coli-L-Asp group after 24 hours (P < 0.05) . However, after treatment of REN and Jurkat cells with 2 kind of L-Asp for 48 hours, the inhibition of cell proliferation and apoptosis rates were not significantly different between the 2 L-Asp drugs (P > 0.05). The Asn in medium could be depleted by two different L-Asp drugs with low concentration. Both the two L-Asp drugs had the same capability to deplete the Asn surrounding leukemia cells (P > 0.05). The Gln in medium could be depleted by two L-Asp drugs with high concentration. The hydrolysis effect of Erwinia-L-Asp on Gln was stronger than that of E.coli-L-Asp (P < 0.05). It is concluded that in a certain range of concentrations, E.coli-L-Asp and Erwinia-L-Asp exert anti-leukemia effect in dose-dependent manner. Depletion of Gln and Asn in surrounding environment and induction of cell apoptosis are two potential mechanisms, by which leukemia cells can be killed. Erwinia-L-Asp may be chosen as the first-line drug to treat childhood ALL for its fast action and stronger hydrolysis effect on Gln.

Draft genome sequence of Bacillus amyloliquefaciens HB-26.

Bacillus amyloliquefaciens HB-26, a Gram-positive bacterium was isolated from soil in China. SDS-PAGE analysis showed this strain secreted six major protein bands of 65, 60, 55, 34, 25 and 20 kDa. A bioassay of this strain reveals that it shows specific activity against P. brassicae and nematode. Here we describe the features of this organism, together with the draft genome sequence and annotation. The 3,989,358 bp long genome (39 contigs) contains 4,001 protein-coding genes and 80 RNA genes.