Telomerase Activity of the Blood Cells in Patients with Myeloproliferative Disorders in Childhood

目前尚不清楚儿童期骨髓增生性疾病（少年慢性髓细胞性白血病; JCML，短暂性骨髓增生性疾病; TMD）是否为真正的白血病。为解决这一问题，我们检测了MD患者血细胞端粒酶的表达。10例急性淋巴细胞白血病（ALL）患者的白血病细胞均检测到端粒酶活性，ALL患者的白血病细胞端粒酶活性较正常血细胞短，但无显著性差异。在2例JCML和1例TMD患者血细胞中也检测到端粒酶活性，但TRF的长度在8 ~ 15 kb之间，与年龄匹配的正常人血细胞一致。由于正常淋巴细胞和造血祖细胞均表达端粒酶活性，因此造血干细胞和造血干细胞端粒酶活性之间的关系尚需进一步研究。Southern杂交分析表明，MD患者外周血和骨髓线粒体DNA缺失的比例与血液学表现的严重程度有相关性，MD患者血细胞线粒体DNA异常与端粒酶活性的关系有待进一步研究。

It is not known exactly whether myeloproliferative disorders ; MD in childhood (juvenile chronic myelogenous leukemia ; JCML,transient myeloproliferative disorder ; TMD) are ture malignacy or not. To address this question, we examined telomerase expression of the blood cells in patients with MD.Telomerase activity was found in all leukemic cells of 10 patients with acute lymphoblastic leukemia ; ALL.Terminal restriction fragment ; TRF lengths in the leukemic cells were shorter than that in normal blood cells, although it was not significant. In two patients with JCML and one with TMD,telomerase activity was also found, but TRF lengths in the blood cells were within 8kb to 15kb consist with those of blood cells from age-matched normal donors. Because normal lymphocytes and hematopoietic progenitor cell express telomerase activity, further investigation is needed to clarify the relationship between hematological malignacy and telomerase activiry.In the next experiment, we examined the proportion of delected mitochondrial DNA in blood cells from three patients with Peason syndrome. Southern blot analysis represented that the proportion of deleted mitochondorial DNA in peripheral blood and bone marrow has a tendency to correlate to the severity of hematological manifestation.We will study the relationship between mitochondorial abnormality and telomerase acticity in blood cells from patients with MD in future.