[Role of Telomere in Clonal Evolution of Acquired Aplastic Anemia--Review].

Studies have found that 1/3 patients with acquired aplastic anemia have shortened telomere length, and the shorter the telomere, the longer the disease course, the more prone to relapse, the lower the overall survival rate, and the higher the probability of clonal evolution. The regulation of telomere length is affected by many factors, including telomerase activity, telomerase-related genes, telomere regulatory proteins and other related factors. Telomere shortening can lead to genetic instability and increases the probability of clonal evolution in patients with acquired aplastic anemia. This article reviews the role of telomere in the clonal evolution of acquired aplastic anemia and factors affecting telomere length.

[The Efficacy and Influencing Factors of Cyclosporine Alone in the Treatment of Children with Acquired Aplastic Anemia].

OBJECTIVE: To analyze the efficacy and influencing factors of cyclosporine (CsA) alone in the treatment of children with acquired aplastic anemia (AA). METHODS: The clinical data of children diagnosed with AA and treated with CsA alone from January 1, 2016 to December 31, 2020 in the Children's Hospital of Chongqing Medical University were collected, and the efficacy and influencing factors of CsA treatment were evaluated. RESULTS: Among the 119 patients, there were 62 male and 57 female, with a median age of 7 years and 1 month. There were 45 cases of very severe AA (VSAA), 47 cases of severe AA (SAA), and 27 cases of non-severe AA (NSAA). At 6 months after treatment, the efficacy of VSAA was lower than that of SAA and NSAA, and there was a statistical difference (P < 0.01). 6 cases died early, 16 cases relapsed, 2 cases progressed to AML and ALL. The results of univariate analysis showed that the high proportion of lymphocyte in the bone marrow at 6 months was an adverse factor for the efficacy of CsA, while high PLT count was a protective factor (P =0.008, P =0.002). The ROC curve showed that the cut-off values of PLT count and the proportion of bone marrow lymphocyte at 6 months were 16.5×109 /L, 68.5%, respectively. Multivariate analysis showed that the high proportion of lymphocyte in bone marrow at 6 months was an independent adverse factor for IST (P =0.020, OR =0.062), and high PLT count was a protective factor (P =0.044, OR =1.038). At 3 months of treatment, CsA response and NSAA were the risk factor for recurrence (P =0.001, 0.031). CONCLUSION: The efficacy of NSAA was higher than that of SAA and VSAA after 6 months of treatment with CsA alone. A high PLT count at the initial diagnosis was a good factor for the effectiveness of CsA, and a high proportion of bone marrow lymphocyte was an unfavorable factor. CsA response at 3 months and NSAA were risk factors for recurrence.

Prognostic significance of measurable residual disease based on multiparameter flow cytometry in childhood acute myeloid leukemia. / åŸºäºŽæµå¼ç»†èƒžæœ¯çš„å¯æµ‹é‡æ®‹ç•™ç— å¯¹å„¿ç«¥æ€¥æ€§é«“ç³»ç™½è¡€ç— é¢„åŽæ„ä¹‰çš„å‰çž»æ€§ç ”ç©¶.

OBJECTIVES: To study the prognostic value of measurable residual disease (MRD) for childhood acute myeloid leukemia (AML) by analyzing MRD-guided risk stratification therapy. METHODS: A total of 93 children with AML were prospectively enrolled in this study. Chemotherapy with the 2015-AML-03 regimen was completed according to the risk stratification determined by genetic abnormality at initial diagnosis and MRD and bone marrow cytology after induction therapy I. Multiparameter flow cytometry was used to dynamically monitor MRD and analyze the prognostic effect of MRD on 3-year cumulative incidence of recurrence (CIR) rate, event-free survival (EFS) rate, and overall survival (OS) rate. RESULTS: The 93 children with AML had a 3-year CIR rate of 48%±6%, a median time to recurrence of 11 months (range 2-32 months), a 3-year OS rate of 65%±6%, and a 3-year EFS rate of 50%±5%. After induction therapy I and intensive therapy I, the MRD-positive children had a significantly higher 3-year CIR rate and significantly lower 3-year EFS and OS rates than the MRD-negative children (P<0.05). There were no significant differences in 3-year CIR, EFS, and OS rates between the MRD-positive children with a low risk at initial diagnosis and the MRD-negative children after adjustment of chemotherapy intensity (P>0.05). The multivariate analysis showed that positive MRD after intensive treatment I was a risk factor for 3-year OS rate in children with AML (P<0.05). CONCLUSIONS: MRD has predictive value for the prognosis of children with AML. Based on the MRD-guided risk stratification therapy, reasonable application of chemotherapy may improve the overall prognosis of children with AML.

Clinical features and prognosis of children with acute leukemias of ambiguous lineage under different diagnostic criteria. / ä¸åŒè¯Šæ–­æ ‡å‡†ä¸‹å„¿ç«¥æ€¥æ€§ä¸æ˜Žè°±ç³»ç™½è¡€ç— çš„ä¸´åºŠç‰¹ç‚¹å’Œé¢„åŽåˆ†æž.

OBJECTIVES: To study the clinical features and prognosis of children with acute leukemias of ambiguous lineage (ALAL) under different diagnostic criteria. METHODS: A retrospective analysis was performed on the medical data of 39 children with ALAL who were diagnosed and treated from December 2015 to December 2019. Among the 39 children, 34 received treatment. According to the diagnostic criteria for ALAL by World Health Organization and European Group for the Immunological Characterization of Leukemias, the 39 children were divided into two groups: ALAL group (n=28) and myeloid expression group (n=11). The clinical features, treatment, and prognosis were compared between the two groups. RESULTS: The 34 children receiving treatment had a 3-year event-free survival (EFS) rate of 75%±9% and an overall survival rate of 88%±6%. The children treated with acute myeloid leukemia (AML) protocol had a 3-year EFS rate of 33%±27%, those treated with acute lymphoblastic leukemia (ALL) protocol had a 3-year EFS rate of 78%±10%, and those who had no remission after induction with AML protocol and then received ALL protocol had a 3-year EFS rate of 100%±0% (P<0.05). The children with negative minimal residual disease (MRD) after induction therapy had a significantly higher 3-year EFS rate than those with positive MRD (96%±4% vs 38%±28%, P<0.05). Positive ETV6-RUNX1 was observed in the myeloid expression group, and positive BCR-ABL1, positive MLL-r, and hyperleukocytosis (white blood cell count ≥50×109/L) were observed in the ALAL group. There was no significant difference in the 3-year EFS rate between the myeloid expression and ALAL groups (100%±0% vs 66%±11%, P>0.05). CONCLUSIONS: ALL protocol has a better clinical effect than AML protocol in children with ALAL, and positive MRD after induction therapy suggests poor prognosis. Hyperleukocytosis and adverse genetic changes are not observed in children with myeloid expression, and such children tend to have a good prognosis, suggesting that we should be cautious to take it as ALAL in diagnosis and treatment.

[Serious adverse events associated with chemotherapy in children with acute lymphoblastic leukemia].

OBJECTIVE: To study the occurrence of serious adverse events (SAEs) related to chemotherapy with CCCG-ALL-2015 regimen in children with acute lymphoblastic leukemia (ALL) and the risk factors for death after the SAEs. METHODS: A retrospective analysis was performed on the medical data of 734 children with ALL. They were treated with CCCG-ALL-2015 regimen from January 2015 to June 2019. The occurrence of SAEs during the treatment was investigated. The children with SAEs were divided into a death group with 25 children and a survival group with 31 children. A multivariate logistic regression analysis was used to analyze the risk factors for death after the SAEs. RESULTS: Among the 734 children with ALL, 56 (7.6%) experienced SAEs (66 cases) after chemotherapy, among which 41 cases occurred in the stage of remission induction therapy. Of all 66 cases of SAEs, 46 (70%) were infection-related SAEs, including 25 cases of septic shock (38%), 20 cases of severe pneumonia (30%), and 1 case of severe chickenpox (2%), and 87% of the children with infection-related SAEs had neutrophil deficiency. The most common infection sites were blood and the lungs. The most common pathogens were Gram-negative bacteria, viruses, fungi, and Gram-positive bacteria. There were 16 cases (24%) of hemorrhage-related SAEs, with 11 cases of gastrointestinal bleeding (17%), 4 cases of pulmonary bleeding (6%), and 1 case of intracranial bleeding (2%). Of all 734 children with ALL, 66 (9.0%) died, among whom 25 died due to SAEs. The treatment-related mortality rate was 3.4%, and infection (72%) and bleeding (24%) were the main causes of death. Severe pneumonia was an independent risk factor for treatment-related death in ALL children (OR=4.087, 95%CI: 1.161-14.384, P=0.028). CONCLUSIONS: SAEs often occur in the stage of remission induction therapy, and infection-related SAEs are more common in ALL children accepting chemotherapy with CCCG-ALL-2015 regimen. The development of severe pneumonia suggests an increased risk for death in these children.

[Acute leukemia associated with Down syndrome: clinical analysis of 21 cases].

OBJECTIVE: To summarize the clinical characteristics, laboratory findings and prognosis of patients with Down syndrome-related acute leukemia (DS-AL). METHODS: The clinical data, laboratory findings, chemotherapy and prognosis of 21 children with DS-AL were analyzed. RESULTS: Most of the children had disease onset of leukemia at 1 to 5 years of age (85.7%), and acute myeloid leukemia accounted for 57.1% of these cases; 61.9% of the patients had increased lactate dehydrogenase level by 2 folds or more. Of the 13 cases undergoing echocardiaography, 10 (67.9%) showed abnormal findings, and complex congenital heart disease was common (38.5%). Six of the children received chemotherapy and complete remission was achieved in 4 cases; 2 patients died of infection, and the treatment-related mortality was 33.3%. The 2 patients receiving reduced intensive chemotherapy have so far had event-free survival for 21 and 43 months. CONCLUSION: Acute myeloid leukemia is the most common subtype of DS-AL. Patients with DS-AL are sensitive to chemotherapy and the prognosis was favorable with reduced intensive chemotherapy.

[A clinical study of drug-related toxicities of CCLG-ALL 08 protocol for childhood acute lymphoblastic leukemia].

OBJECTIVE: The Chinese Children's Leukemia Group (CCLG)-acute lymphoblastic leukemia (ALL) 08 protocol for childhood ALL was established in 2008. This study aims to evaluate the drug-related toxicities of CCLG-ALL 08 protocol in the treatment of childhood ALL. METHODS: A total of 114 children with newly diagnosed ALL were treated with the CCLG-ALL 08 protocol. The protocol was divided into five phases: remission induction (VDLD), early reinforcement (CAM), consolidation therapy, delayed reinforcement (DIa & DIb) and maintenance treatment. Drug-related toxicities in each phase were evaluated according to the Common Terminology Criteria for Adverse Events version 4.0. RESULTS: Toxicities were more frequent in phase VDLD than other treatment phases, including hepatotoxicity (87.7%), dental ulcer (20.2%), hyperglycemia (20.2%), prolonged activated partial thromboplastin time (21.1%) and decreased fibrinogen (34.2%), with the incidence rates of severe adverse events at 7%, 0, 1.3%, 0.8% and 2.7% respectively. The incidence of allergic reaction to L-ASP was significantly higher in phase DIa than in phase VDLD (28.0% vs 7.9%; P<0.01), and there were no longer any allergic reactions in 15 patients who received continuing treatment with pegaspargase instead. There was no severe arrhythmia, myocardial ischemia, decreased left ventricular function, osteonecrosis, myopathy, organ failure or treatment-related mortality. CONCLUSIONS: The drug-related toxicities of CCLG-ALL 08 protocol are common in phase VDLD, but they are mild and reversible. There is no treatment-related mortality. The CCLG-ALL 08 protocol for childhood ALL is safe.

[Analysis of thirteen cases with secondary coagulation disorder caused by raticide exposure].

OBJECTIVE: To summarize the clinical characteristics of secondary coagulation disorders caused by exposure to poison (raticide) in children and to investigate the diagnosis and corresponding treatment. METHOD: The process of diagnosis, clinical characteristics, response to treatment and the prognosis were analyzed. RESULTS: The main clinical manifestation was mucosal bleeding (66.6%), including epistaxis, gingival bleeding, hematomas and so on. All these children were previously well and had no history of bleeding. Activated partial thromboplastin time (APTT) and prothrombin time (PT) were prolonged, factor II was undetectable and the levels of factors VII, IX, and X were lower. The fibrinogen was normal. A raticide was detected in blood and urine of 13 children although 12 of the patients had no definite history of raticide ingestion. Prothrombin complex, fresh frozen plasma and vitamin K(1) were effective in these cases. However, 2 - 3 weeks later, 6 patients presented with recurrent bleeding. CONCLUSION: For children with secondary coagulation disorders of unknown cause, intoxication of raticide should be considered. The administration of blood coagulation factors and vitamin K(1) are effective in early treatment, and the treatment period should be more than 2 months. The PT and APTT should be followed up. Vitamin K(1) should be stopped when PT and APTT are normal.

[Effects of survivin antisense oligodeoxynucleotide on drug resistance in K562 cells].

OBJECTIVE: To study the effect of Survivin antisense oligodeoxgnucleotide (ASODN) on drug resistance and its mechanism in K562 cells. METHODS: Cells were divided into four groups: ASODN group, SODN group, Lip group and blank group. Survivin ASODN was transfered into K562 cells by liposomal reagent. The expression of Survivin mRNA was detected by RT-PCR. The sensitivity of K562 cells to adriamycin (ADM) and daunorubicin (DAM) was detected by MTT assay, while the intracellular concentration of ADM and DAM was measured by flowcytometry. RESULTS: Compared to control group Survivin mRNA expression in ASODN group decreased obviously. IC50(s) of ADM and ASODN+ADM were 0.5457 mg/L and 0.1933 mg/L respectively, IC50 (s) of DAM and ASODN+DAM were 0.5408 mg/L and 0.2027 mg/L respectively. Expression of Survivin mRNA decreased by 25.8% after the transfection of ASODN. Fluorescence intensity of ADM and ASODN+ADM in K562 cells were 51.64 and 89.92, Fluorescence intensity of DAM and ASODN+DAM in K562 cells were 63.71 and 88.47. CONCLUSION: Expression of Survivin mRNA in k562 cells was down-regulated by ASODN. Survivin ASODN is able to reverse the drug resistance via inhibition of Survivin expression and inducement of apoptosis.

[Differentiation of K562 cells induced by antisense oligonucleotide targeting survivin].

OBJECTIVE: Gene therapy of leukemia is a new and effective method. It is known to all that the pathogenesis and development of leukemia are related to a variety of genes. Survivin is a member of inhibitors of apoptotic proteins (IAP). Its cDNA was cloned from target cell protease receptor-1 (EPR-1). It is expressed in common tumors, but there is no expression in normal and mature tissues. High expression of survivin was detected in leukemic cells. The present study was conducted to examine the role of survivin in the differentiation of leukemic cells by using antisense-oligonucleotides. METHODS: Human leukemic cell K562 was used as the model for the study. K562 cells were divided into 4 groups randomly: antisense oligonucleuotide (ASON) group, nonsense oligonucleotide (NSON) group, lipofectin group and control group. There were 5 samples in each group, and the experiment was repeated for three times. ASON was designed with the reference to targeting survivin mRNA. K562 cells were cultured in RPMI1640 contained fetal cattle serum at a concentration of about 10 percent. Cell transfection was induced by lipofectin. Forty-eight hours after thansfection, the morphology and ultrastructure were observed. Twenty-four hours and 48 hours after thansfection, the function of K562 cells was detected by benzidine staining, POX staining and NBT staining, respectively. The mean fluorescence intensity of CD33 was determined by flow cytometry. The method of immunohistochemistry was used to examine the protein level of survivin. RESULTS: After thansfection with ASON, the size of K562 cells was reduced, but the cytoplasm was increased. The metarubricyte, segment granulocyte, apoptotic cells could be found. Morphologically and ultrastructurally, erythroid and myelocytic differentiation was observed. The positive level of benzidine staining in ASON group (11.90 +/- 2.30 at 24 h and 18.20 +/- 2.93 at 48 h) was higher than that of NSON group, lipofectin group and control group, respectively. The positive level of POX staining in ASON group (17.40 +/- 3.54 at 24 h and 29.40 +/- 3.70 at 48 h) was also higher than that of any other groups. The positive level of NBT staining in ASON group (7.50 +/- 2.26 at 24 h and 12.10 +/- 2.63 at 48 h) was significantly higher than that of NSON group, lipofectin group and control group, respectively (P < 0.01). In ASON group, the mean fluorescence intensity of CD33 (21.43 +/- 1.61 at 24 h and 14.86 +/- 1.20 at 48 h) was significantly lower than that of any other groups (P < 0.01). After thansfection for 24 h, the protein level of survivin in ASON group was decreased significantly compared to that of control group. There was no difference in survivin protein level amongst ASON group, NSON group and lipofectin group at 24 h (P > 0.05). Forty-eight hours after thansfection, the protein level of survivin was decreased significantly. CONCLUSIONS: ASON targeting survivin can induce K562 to erythroid and myelocytic differentiation. Survivin is related to differentiation of K562 cells, and it can be a target of gene therapy for leukemia.