| Section I Dynamic monitoring of minimal residual disease in children with acute Iymphoblastic leukemia and its significanceObjective:To study the prognostic significance of dynamic monitoring of minimal residual disease (MRD) in children with acute Iymphoblastic leukemia(ALL).Methods:For seventy five ALL patients, we detected MRD by flow cytometry on the19th and33th days after induction chemotherapy and in maintenance chemotherapy. They were analyzed by Kaplan-Meier analysis and COX proportional hazards regression model. According to the level of MRD, they were divided into three groups:A group (MRD<10-4), B group (MRD between A and C group), C group (MRD>10-2).Results:1. On the19th days after induction chemotherapy, the survival rate of A group was obviously higher than B,C groups (x2=6.435,19.795,P<0.05).On the33th days, the survival rate of C group was lower than the other two groups (x2=5.057,8.346, P<0.05)2. In maintenance chemotherapy period, MRD at the third month, sixth month, twelfth month and twenty-fourth month were analyzed, Which showed that there was a significant difference(x2=6.133-22.558,P<0.05).The level of MRD at the thirty-sixth month had no effect on survival(P>0.05).3. The patients with MRD>10-2were divided into three groups:the survival rate of the third group was higher than the other two groups (x2=6.226,7.018,P<0.05). The patients with MRD≥10-2appearing in the first year after induction chemotherapy, the survival rate was lower in High-risk, T cell line, gene-positive patients(x2=5.661-10.682,P<0.05). 4. Multivariate analysis suggested that the level of MRD on the19th days was proved to be an independent predictor(RR4.01;95%CI0.968-8.995, P<0.05).The patients with MRD≥10-2in the first year after induction chemotherapy: High-risk(RR4.73;95%CI1.316-14.624, P<0.05),T cell line (RR1.779;95%CI0.101-6.014,P<0.05) and gene-positive(RR0.08;95%CI0.008-0.801, P<0.05) were the prognostic factors.Conclusions:Dynamic monitoring of MRD has prognostic value in ALL and is useful for individual treatment. Section Ⅱ Studys of L-asparaginase inhibition of cell proliferation of leukemia in vivo and vitroObjective:To explore the effects of L-ASP on Jurkat cells proliferation inhibition in vitro,and on leukemia cell cycle in vivo.Methods:Jurket cells were cultured in vitro, L-ASP interefered with Jurket cells in logarithmic growth phase.Jurket cells were treated with different concentrations of L-ASP(0.2U/ml,1.0U/ml,5.0U/ml) for24h,48h and72h.The proliferation inhibitions of Jurket cells were detected by CCK-8assays. The mononuclear cells extracted from the fresh bone marrows were processed in according to cell cycle kit. The effects of L-ASP on the leukemia cell cycles were detected by flow cytometry.Results:1. Jurkat cells were treated with different concentrations of L-ASP(0.2U/ml,1.0U/ml,5.0U/ml) for24h,48h and72h. The proliferation inhibitions of Jurkat cells were significantly diffrernt (P<0.05). In One-way ANOVE analysis:under the same concentrations of L-ASP,the proliferation inhibitions of Jurkat cells treated for24h,48h and72h were gradually increased(P<0.05).In the case of time-invariant, the higher of concentration of L-ASP, the higher of the inhibition rate (P<0.05).2. Jurkat cells were treated with different concentrations of L-ASP(0.2U/ml,1.0U/ml,5.0U/ml) for24h,the G1phase rates of Jurkat cells were significantly different (P<0.05).When Jurkat cells were treated with0.2U/ml L-ASP for24h,there was not a significant difference between this group and the control group(P<0.05).But the Jurkat cells were treated with0.2U/ml L-ASP for48h,72h, the Gl phase rates of Jurkat cells were significantly different between these groups and the control group(P <0.05). The proportion of cells in Gl phase of Jurkat cells treated for48h,72h with different concentrations (0.2U/ml,1.0U/ml,5.0U/ml)of L-ASP were significantly different(P<0.05). Jurkat cells treated with L-ASP(0.2U/ml) for24h,48h and72h, the G1phase rates were significantly different(P<0.05). Jurkat cells treated with L-ASP (1.0U/ml and5.0U/ml) for24h,48h,72h. The Gl phase rates of Jurkat cells were significantly different (P<0.05).The results suggested the longer of the ASP treated duration,the higher of the proportion of cells in G1phase in the same ASP concentration,3. The proportion of cells in Gl phase with newly diagnosed ALL children was (75.223±2.085)%.On the33th day after induction chemotherapy, the proportion of cells in Gl phase was (89.106±3.250)%, it was different between the two groups (P <0.01).On the33th day after induction chemotherapy, the proportion of cells in G1phase and the level of MRD was negatively correlated (r=-0.867,P<0.01).Conclusions:In vitro and in vivo,the proliferation of leukemia cells can be inhibited in the phase of Gl by L-ASP, On the33th day after induction chemotherapy,there is a negative correlation between the proportion of cells in G1phase and the level of MRD. |
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