Gene Expression of MPO (Myeloperoxidase) in Acute Undifferentiated Leukemia

细胞化学（cy） MPO（髓过氧化物酶）阴性的急性白血病细胞被归类为急性淋巴母细胞白血病（ALL）。然而，一些ALL细胞表达髓样抗原（CD13/33）。本课题的目的是对这类ALL/淋巴瘤细胞的MPO基因表达进行估计，从而对cy-MPO阴性白血病/淋巴瘤细胞的分类和正常造血分化方案有更深入的了解。收集的17例共表达CD13/33抗原的Pre-B ALL细胞中，电镜下MPO和MPO RNA均为阴性的15例。em-MPO和MPO RNA阳性2例。前一组HLA-DQ抗原阳性，后一组为阴性。对于肿瘤T细胞，12例成熟型细胞（CD1、3、4、8阳性）甚至不表达CD13/33抗原。9例未成熟型细胞（CD7、7+5、7+2、7+5+2）均表达CD13/33抗原。9例中有2例em-MPO和MPO RNA阳性。这一结果与未成熟肿瘤T细胞的AML转化特别有趣。未发现引入或增强MPO表达的细胞因子或化合物。然而，我们发现gammaIFN抑制MPO的基因表达。这一观察结果非常新颖，因为文献中没有类似的报道。

Acute leukemia cells negative for Cytochemical (cy) MPO (Myeloperoxidase) are classified as Acute Lymphoblastic Leukemia (ALL). Some ALL cells, however, express myeloid antigen (CD13/33). The estimation of MPO gene expression by such ALL/lymphoma cells is the purpose of this project, thereby having a deeper insight into the classification of cy-MPO-negative leukemia/lymphoma cells and the normal hematopoietic differentiation scheme.Among the collected 17 cases of Pre-B ALL cells co-expressing CD13/33 antigen 15 cases were negative for electronmicroscopical (em) MPO and MPO RNA. Only 2 cases were positive for em-MPO and MPO RNA. The former group was positive for HLA-DQ antigen, but the latter negative.As to neoplastic T cells, 12 cases of mature type cells (positive for CD1, 3, 4, 8) did not even express CD13/33 antigen. Nine cases of immature type of cells (CD7, 7+5, 7+2, 7+5+2) always expressed CD13/33 antigen. In 2 out of the 9 cases, em-MPO and MPO RNA were positive. This result was particularly intriguing in relation to AML conversion of immature neoplastic T cells.Cytokine or chemical compound introducing or enhancing MPO expression was not found. It was found, however, that gammaIFN suppresses the gene expression of MPO. This observation is very original, since no similar report has appeared in literatures.