ABSTRACT
Twenty-two B-cell chronic lymphocytic leukemia (CLL) patients were investigated to evaluate residual disease in clinico-hematological remission. Residual disease was determined by monotypy of surface light-chain expression and by dual-color staining with CD5 and CD19 markers. Samples were analyzed on flow cytometer. Total CD19+ cells above 25%, the CD5+CD19+/total CD19+ cells ratio above 0.25, clonal excess above 0.4 were considered positive for residual disease. According to these immunological criteria, only four cases achieved phenotypic remission. Our data confirm that dual marker analysis is more sensitive than clonal excess and may predict an early relapse. Ig gene rearrangements were studied by Southern blot analysis using IGHJ and IGKC probes in fifteen cases. All 12 cases that retained a detectable rearrangement displayed a phenotypic residual disease. Conversely, in two cases, DNA analysis failed to detect the residual disease characterized by flow cytometry. In conclusion, this study suggests that in B-CLL, dual marker analysis is sensitive in predicting an early relapse in sequential evaluations of residual disease, whereas rearranged bands are undetectable when the proportion of malignant cells is low.
Subject(s)
Leukemia, Lymphocytic, Chronic, B-Cell/diagnosis , Adult , Aged , Blotting, Southern , DNA, Neoplasm/analysis , Evaluation Studies as Topic , Female , Flow Cytometry , Follow-Up Studies , Gene Rearrangement , Genes, Immunoglobulin , Humans , Immunophenotyping , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Male , Middle Aged , Predictive Value of Tests , PrognosisABSTRACT
The less differentiated stage (CD10-) of B-lineage acute lymphoblastic leukaemia (ALL) described as preB1-ALL in the GEIL nomenclature, accounts for less than 10% of ALL. It is classically considered to be associated with translocation (4;11)(q21;q23), and to have a poor prognosis. We report an extensive immunophenotypic, genomic and clinical study of a series of 64 preB-1 ALL patients, representing 6.3% of a cohort of consecutive ALLs. The engagement of preB1-ALL cells in the B-lineage was confirmed by their B-lineage score, equal to or higher than 2. In addition, more than 90% of the cases tested showed rearranged IGH genes. Translocation (4;11) was the most frequent karyotypic anomaly seen, but only accounted for 24% of the preB1-ALL cases tested. Expression of the myeloid associated antigen CD15 was also found with high incidence in this subset. Clinical and biological features at presentation showed more significant differences between preB1- and T-ALL than between preB1- and preB2-ALL (CD10+). However, outcome characteristics of the 22 children with preB1-ALL confirmed the worse prognosis of this entity.