Incidence, Biologic Features and Treatment Outcome of Myeloid-Antigen-Positive Acute Lymphoblastic Leukemia (My + ALL). In: Büchner T, Hiddemann W, Wörmann B, Schellong G, Ritter J, editors. Acute Leukemias IV. Berlin: Springer Berlin Heidelberg; 1994. pp. 24-32. [DOI: 10.1007/978-3-642-78350-0_4]

Aberrant immunophenotypes detected by flow cytometry in acute lymphoblastic leukemia

The present study was designed to analyse the proportion of ALL patients in which the phenotypic detection of minimal residual disease (MRD) is feasible, based on the presence of aberrant phenotypes: lineage infidelity, asynchronous expression, overexpression and ectopic phenotype. For this purpose we have prospectively investigated the phenotype of blast cells from 25 patients at diagnosis using a large panel of monoclonal antibodies by multiparametric flow cytometry. The mean age was 23.3 +/- 17.3 with 10 children and 15 adults. 14 patients were classified as L1, 9 L2 and 2 L3 according to the FAB classification. 17 cases were B-lineage ALL and 8 T-ALL. 23 out of 25 cases (92%) included in this study displayed phenotypic aberrations at diagnosis (15 out of 17 cases of B-lineage ALL and all T-ALL patients). 76% of patients displayed two or more than two aberrancies. The phenotypic aberrations were lineage infidelity, found in 12 patients, asynchronous antigen expression detected in 17 patients, antigen overexpression in 4 patients and ectopic phenotype in 7 patients. In summary our results show that when a large panel of MoAbs is used for the immunophenotypical characterization of ALL, most patients display aberrant phenotypes, the coexistence of more than two aberrant antigen expressions being frequently detected. These results suggest that the use of immunological methods for the detection of MRD in ALL based on the existence of aberrant phenotypes could be of great help for the follow-up of patients in complete remission.

Twenty-three cases of acute lymphoblastic leukemia with translocation t(4;11)(q21;q23): the implication of additional chromosomal aberrations

The translocation t(4;11)(q21;q23) is one of the most common specific chromosomal aberrations in acute lymphoblastic leukemia (ALL), occurring in 2% of childhood and in 5-6% of adult cases. Especially in adults, the t(4;11) is associated with a poor prognosis. In order to determine the significance of clonal chromosome aberrations that occur in addition to t(4;11), we studied the karyotypes and clinical courses of 23 patients with acute lymphoblastic leukemia and a translocation t(4;11)(q21;q23). Additional clonal chromosome aberrations were found in ten patients. An isochromosome i(7)(q10) and a trisomy 6 were observed most frequently as secondary anomalies. Clonal evolution was detected in four of six patients analyzed at diagnosis as well as at relapse. With treatment carried out according to modern risk-adapted therapy protocols, no difference in outcome was observed between patients with clonal chromosome aberrations in addition to t(4;11) at diagnosis and those without.