Callea V, Morabito F, Francia di Celle P, Ronco F, Carbone A, Nobile F, Foa R
Divisione di Ematologia, Ospedali Riuniti, USL n. 31, Reggio Calabria, Italy.
Eur J Haematol. 1992 Apr;48(4):187-91. doi: 10.1111/j.1600-0609.1992.tb01583.x.
We report a case of Ph1-positive, bcr-positive chronic myeloid leukemia blast crisis (CML-BC) which at presentation showed a mixed myeloid/B-lymphoid immunophenotype along with TdT positivity and, at the molecular level, an oligoclonal rearrangement of the immunoglobulin heavy chain (IgH) gene region. After obtaining a successful remission, at the time of relapse the patient underwent a phenotypic and genotypic switch from mixed to myeloid phenotype, characterized by the loss of the lymphoid markers and TdT expression and by a germline configuration of the IgH gene region. The same bcr rearrangement was, however, found in both phases of the disease, supporting the suggestion of a true phenotypic and genotypic conversion. This report confirms that the neoplastic event in CML may take place at an early multipotent stem-cell level, prior to a well-defined phenotypic and genotypic lineage expression. Moreover, it is suggested that different factors (chemotherapy? growth factors?) may have either eradicated the bcr+/IgH+ clone and promoted the growth of bcr+/IgH- leukemic cells or, alternatively, supported the lymphoid differentiation program and induced a myeloid lineage shift.
我们报告1例Ph1阳性、bcr阳性的慢性髓性白血病急变期（CML-BC），初诊时表现为混合性髓系/B淋巴细胞免疫表型伴末端脱氧核苷酸转移酶（TdT）阳性，分子水平上免疫球蛋白重链（IgH）基因区域呈寡克隆重排。成功缓解后，复发时患者经历了从混合表型到髓系表型的表型和基因型转换，其特征为淋巴系标志物和TdT表达缺失以及IgH基因区域呈种系构型。然而，在疾病的两个阶段均发现相同的bcr重排，支持真正的表型和基因型转换这一观点。本报告证实，CML中的肿瘤形成事件可能发生在早期多能干细胞水平，早于明确的表型和基因型谱系表达。此外，提示不同因素（化疗？生长因子？）可能已根除bcr+/IgH+克隆并促进bcr+/IgH-白血病细胞生长，或者支持淋巴系分化程序并诱导髓系谱系转变。
