目的：调查白血病和骨髓增生异常综合征（ＭＤＳ）患者红细胞酶和同工酶谱改变的患病率，并研究其临床意义。方法：采用ＩＣＳＨ介绍的方法及ＰＡＧＥ电泳测定红细胞酶活性及ＰＫ和ＡＤＡ同工酶，采用ＦＰＬＣ系统纯化ＡＤＡ同工酶，分析酶蛋白的生化性质。结果：患病率：在２２９例白血病和ＭＤＳ患者中，Ｇ６ＰＤ缺乏为４３．１％，ＰＫ缺乏为２７．８％。ＭＤＳ患者中的酶缺乏患病率：ＰＫ缺乏为５０．０％，Ｇ６ＰＤ缺乏为４８．０％，ＰＮＰ缺乏为３９．１％；酶过多患病率：ＡＤＡ过多为６９．６％，ＥＮＯＬ过多为４０．０％，ＡＬＤ过多为３０．４％。慢性粒细胞白血病（ＣＭＬ）的ＰＫ活性增高，而ＰＫ同工酶型均正常。急性白血病患者采用抗肿瘤抗生素后Ｇ６ＰＤ和６ＰＧＤ活性减低（Ｐ＜０．０５）。ＭＤＳ红细胞酶缺陷显著多于ＡＤＡ２同工酶表达见于ＡＭＬ（Ｍ４和Ｍ５）的单个核细胞及慢性粒－单核细胞白血病（ＣＭＭＬ）的红细胞，但ＡＬＬ不表达（Ｐ＜０．００１）。ＡＤＡ同工酶纯化分析示正常结构。结论：红细胞酶的检测可作为ＣＭＬ的预后参数，作为急性白血病抗肿瘤药物耐药预示指标，有助于ＭＤＳ－ＲＡ和再障、ＣＭＬ与ＣＭＭＬ的鉴别诊断。 Objective: To investigate the prevalence of erythrocyte enzyme and isoenzyme changes in patients with leukemia and myelodysplastic syndromes (MDS) and to study their clinical significance. Methods: The enzyme activity and PK and ADA isoenzymes of red blood cells were determined by the method of ICSH and PAGE electrophoresis. The ADA isozymes were purified by FPLC system and the biochemical properties of the enzyme proteins were analyzed. Results: Prevalence: Among 229 patients with leukemia and MDS, the G6PD deficiency was 43.1% and the PK deficiency was 27.8%. The prevalence of enzyme deficiency in patients with MDS: PK deficiency was 50.0%, G6PD deficiency was 48.0%, PNP deficiency was 39.1%; Enzyme overage rate: ADA excess was 69.6%, Excessive ENOL was 40.0%, and excess ALD was 30.4%. The PK activity of chronic myelogenous leukemia (CML) increased, while the PK isoforms were normal. The activity of G6PD and 6PGD was reduced in patients with acute leukemia after antitumor antibiotics (P<0.05). MDS erythrocyte enzyme deficiency was significantly greater than that of ADA2 isoforms expressed in mononuclear cells of AML (M4 and M5) and erythrocytes of chronic myelomonocytic leukemia (CMML) but not in ALL (P<0.001). ADA isozyme purification analysis showed normal structure. Conclusion: Erythrocyte enzyme assay can be used as a prognostic parameter of CML. As a predictor of anti-tumor drug resistance in acute leukemia, it is helpful for the differential diagnosis of MDS-RA and aplastic anemia, CML and CMML.