目的：不同类型急性淋巴细胞性白血病(ALL)对左旋门冬酰胺酶(LAsp)敏感度不完全相同,由于LAsp活性水平与细胞内门冬酰胺合成酶活性负相关,因此研究不同类型ALL患儿白血病细胞内门冬酰胺合成酶活性水平分布情况,有助于临床治疗中合理使用LAsp。方法：通过HPLCFLD及蛋白定量等技术,检测28例ALL患儿(免疫酶型TALL7例,B细胞系列ALL21例)白血病细胞内门冬酰胺合成酶活性水平。结果：TALL患儿肿瘤细胞内AS活性水平较B细胞系列ALL患儿的显著增高(P<0.05),其中TALL患儿肿瘤细胞内AS活性中位水平为每小时9.3nMAsn/mgprotein,B细胞系列ALL患儿为每小时5.2nMAsn/mgprotein。但无论是在B细胞系列ALL患儿还是在TALL患儿中,肿瘤细胞内AS活性存在多态性分布。结论：ALL患儿白血病细胞中门冬酰胺合成酶活性存在多态性分布,总体上TALL比B系ALL白血病细胞中门冬酰胺合成酶活性高。

OBJECTIVE: To study the cellular activity of asparagine synthetase in different types of childhood acute lymphoblastic leukemia (ALL). METHODS: The cellular activity of asparagine synthetase was detected by HPLC-FLD and Protein measurement in 28 ALL children (7 cases of T-ALL and 21 cases of B-lymphoid lineage ALL) before chemotherapy. RESULTS: The asparagines synthetase activity levels in T-ALL children were significantly higher than those of the B-lymphoid lineage ALL patients, with the median activity level of 9.3 nM Asn/mg protein/hr vs 5.2 nM Asn/mg protein/hr (P<0.05). The distribution of the asparagine synthetase activity demonstrated a polymorphism in either T-ALL or B-lymphoid lineage ALL patients. CONCLUSIONS: The cellular activity of asparagines synthetase in ALL patients is presented with a polymorphism distribution. The asparagines synthetase activity levels in T-ALL are significantly higher than in B-lymphoid lineage ALL.