三种血小板减少症患儿骨髓巨核细胞比较

Comparative study on bone marrow megakaryocytes in children with thrombocytopenic purpura, aplastic anemia and myelodysplastic syndrome

目的 观察特发性血小板减少性紫癜(ITP)、再生障碍性贫血(AA)及骨髓增生异常综合征(MDS)患儿骨髓巨核细胞(MK)形态与造血功能,分析不同血小板减少症发生的原因,以期对其进行早期鉴别诊断。方法 对 16例ITP、17例AA、16例MDS患儿,进行骨髓涂片CD41α免疫酶标染色检测;并采用血浆凝块法体外培养骨髓单个核细胞及免疫酶标法进行巨核细胞集落检测;分组进行统计学分析和比较。结果 ITP患儿小巨核细胞及I型淋巴样小巨核细胞检出率分别为 87%和 7%,与对照组比较差异无统计学意义;小巨核细胞总数及巨核细胞集落形成单位 (CFU MK)、爆式巨核细胞集落形成单位(BFU MK)分别为 602 /mm2、93个 /2×105 MNC和 6 5个 /2×105 MNC,高于对照组,前两者与对照组比较差异有统计学意义。AA患儿小巨核细胞检出率、计数及CFU MK与BFU MK的形成率分别为 43%、0 5 /mm2、0个 /2×105 MNC和 0个 /2×105 MNC,低于对照组,与对照组比较差异有统计学意义。MDS患儿小巨核细胞检出率 87%,与正常对照组比较差异无统计学意义,但总数及I型淋巴样小巨核细胞检出率分别为 37 /mm2、73%,高于对照组,差异有统计学意义;CFU MK形成率 3个 /2×105 MNC与对照组比较差异无统计学意义,与对照组 90%可信区间比较,有 63%的患儿CFU MK降低,

Objective Thrombocytopenic hemorrhage is one of the major appearance in pediatric hemorrhagic diseases, in which, idiopathic thrombocytopenic purpura ( ITP ) is the most common disease. Thrombocytopenia is the earliest phenomenon or the only one in certain phases of hemorrhagic diseases, such as ITP, aplastic anemia ( AA ) and myelodysplastic syndrome ( MDS ). By now, the pathogenesis of thrombocytopenia in different diseases has not been clearly determined. At present, it is very difficult to diagnose these diseases and estimate their prognosis with current clinical data. In this study, morphological characteristics and hematopoiesis function of bone marrow megakaryocyte in pediatric patients with ITP, AA and MDS were observed and the cause and mechanism of different thrombocytopenias were analyzed. Methods There were 16 children with ITP, 17 with AA and 16 with MDS in this study. CD41 McAb immunohistochemical technique was used to detect micromegakaryocyte on bone marrow smears. Plasma clot culture and CD41 McAb immunohistochemical technique were used for the MK-colony forming assay. The colony formation rate of colony formation unit-megakaryocyte ( CFU-MK ) and burst formation unit-megakaryocyte ( BFU-MK ) were counted. Results There was no statistical difference on the positive rates of micromegakaryocyte and type I lymphoid small micromegakaryocyte between groups of ITP and control. The number of micromegakaryocyte and the formation rates of CFU-MK in ITP group were significantly higher than those in control group. Among AA patients, the numbers of MK, micromegakaryocyte and the formation rates of CFU-MK, BFU-MK in vitro significantly decreased. There was no significant difference in the positive rate of micromegakaryocyte between groups of MDS and control, but the number of micromegakaryocyte and the positive rate of type I lymphoid micromegakaryocyte were significantly higher than those of control group. There was no statistical difference of the formation rate of CFU-MK between groups of MDS and control. But in 63% childhood patients, the formation rate of CFU-MK decreased, 25% increased,and 13% was normal;BFU-MK formation rate decreased significantly in MDS group. Conclusion(Overproliferation) of bone MKs may exist in most ITP patients. For obviating the nosogenetic factors, the normal MK releasing platelet could be easily found in the culture system. But the colony formation rate of MK decreased in a few patients with CITP. The abnormality of MK might be one of the reasons for thrombocytopenia in partial patients with ITP. Underproliferation of MKs may exist in AA, but no pathosishemogenesis was found. The dysfunction of early phase MK progenitor and stem cell might be the major reason for AA, but not the abnormality of hematopoietic microenvironment. There may be two kinds of megakaryocyte clones in bone marrow of children with MDS. One may be pathologic and potentially malignant micromegakaryocytes, the other may be the normal megakaryocytic precursors. The increase of pathologic MK resulted in abnormal development and maturation of MK in bone marrow. The change of megakaryopoiesis showed different in ITP, AA or MDS. Using bone marrow smear megakaryocyte counting, small micromegakaryocyte immunohistochemical detecting and the formation rate of bone marrow MK colony assay, the different thrombocytopenia can be diagnosed during the early stage of ITP, AA or MDS.